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DMU380SA Series USER MANUAL

1. Table 21 Message Table ASCII lt 2 byte lt payload Description Type Products Mnemonic packet byte length Available type U2 gt U1 gt PK 0x504B Ping Command Input Reply ALL and Response Message CH 0x4348 N Echo Command Input Reply ALL and Response Message Interactive Commands GP 0x4750 2 Get Packet Input ALL Request Message Doc 7430 0026 Rev 01 Page 48 DMU380SA Series User s Manual MEMSIC Algorithm Reset Input Reply VG AHRS INS Message 2 Error Response Reply ALL Message 2 Calibrate Input Reply AHRS INS V AR 0x4152 NAK 0x1515 Output Messages 0x5743 Command and Message Response Calibration Reply AHRS INS Completed Message 10 0x4944 5 N Identification Data Output Message CD 0x4344 Status amp Other Polled Only 0x5652 5 Version Data Output Message 28 Test 0 Detailed Output BIT and Status Message Scaled Sensor 0 Output AHRS INS Data Message Scaled Sensor 1 Output A Data Message Angle 1 Data Output AHRS INS Message Angle 2 Data Output VG AHRS Message INS Nav 0 Data Output VG AHRS Message INS Nav 1 Data Output VG AHRS Message INS numFields 4 Write Fields Input Request Message numFields 2 Write Fields Reply Response Message numFields 4 Set Fields Input 1 Request Message numFields 2 Set Fields Reply 1 Response Message numFields 2 Read Fields Input 1 Request Message numFields 4 Read Fields Reply 1 Response Message 0x4
2. e Straight and level flight is the phase of flight in which an aircraft reaches its nominal flight altitude and maintains its speed and altitude The aircraft is under equilibrium See Figure 17 e Maneuver is the phase of flight in which an aircraft accelerates decelerates and turns The aircraft is under non gravitational acceleration and or deceleration See Figure 17 e Descent is the phase of flight in which an aircraft decreases altitude for an approach to landing The aircraft 1s under vertical deceleration until it captures a glide slope See Figure 17 e Landing is the last part of a flight where the aircraft returns to the ground See Figure 17 Figure 17 Typical flight profiles of fixed wing aircraft and the corresponding advanced settings Pre launch or known straight and level un accelerated flight Straight and level Normal Dynamics Pre launch or Climb known Straight and Normal Dynamics Maneuver Descent High Dynamics level un accelerated Prelaunch Takeoff Landing __ Recommended Advanced Settings Doc 7430 0026 Rev 01 Page 45 DMU380SA Series User s Manual MEMSIC gt 6 Programming Guide The DMU380SA Series contains a number of different products which have different measurement capabilities Depending on the model you purchased various commands and output modes are supported However all models support a common packet structure that includes both command or inpu
3. ee m Ig 1 5 asas 2 pi 2 16 Pitch angle 360 2 16 yawAngleTrue 2 pi 2 16 im Yaw angle true north 360 2 16 xRateCorrected 12 7 pi 2 16 rad s X angular rate corrected 1260 2 16 sec yRateCorrected 12 7 pi 2 16 rad s Y angular rate corrected 1260 2 16 sec 10 zRateCorrected 12 T pi 2M6 rad s Z angular rate corrected Uu aa e 26 g Xaxomkr u wee e 26 g Yaxseomer wo uem e 26 g Zaxeomee 24 longitudeGPS l4 2 pi 2 32 Radians GPS Longitude 360 2 32 28 latitudeGPS l4 2 pi 2 32 Radians GPS Latitude 360 2 32 32 altitudeGPS 2M4 2M6 im GPS altitude 100 16284 34 xRateTemp TE UE X rate sensor temperature 36 timel TOW U4 ms DMU ITOW sync to GPS Not Implemented Bitstatus U2 MasterBIT and Status Doc 7430 0026 Rev 01 Page 61 DMU380SA Series User s Manual MEMSIC gt 8 Advanced Commands The advanced commands allow users to programmatically change the DMU380SA Series settings This section of the manual documents all of the settings and options contained under the Unit Configuration tab within NAV VIEW Using these advanced commands a user s system can change or modify the settings without the need for NAV VIEW 8 1 Configuration Fields Configuration fields determine various behaviors of the unit that can be modified by the user These include settings like baud rate packet output rate and type algorithm type
4. HK KK KK k ck k kCk kk ck ck kk k ck k kc k ck k ck ck kk ck ck k kc k ck k ck ck kk ck ck k kc k kk ck ck k kc k ck k ck ck kk ck ck k kc k ck k ck ck k kckck ck kck kk kk int Pop QUEUE TYPE queue ptr int numToPop int 1 0 char tempchar for i 0 i numToPop i if DeleteQueue amp tempchar queue ptr break return i f amp KKK KKK KK KKK KKK KK KK KK KKK KK KK KK KK OK KK KK KK ck ck ck KK KK KK ck ck KK kK KK kK k FUNCTION Size ARGUMENTS queue ptr is pointer to the queue RETURNS return the number of items in the queue KK I KK KK k ck kk ck ck k OK IKK KK KK KK k ck k kc k ck k KK KK OK KK ck ck k kc k ck k KK KK KK KK KK KKK KK int o126 QURUE TYPE queue ptr return queue ptr gt count KKK KK KK KK KK KK RK KK KK KKK KKK KK KKK KKK KK KK KK KKK KK KK ck ck ck k ck kck ck KK KK KK KKK FUNCTION Empty ARGUMENTS queue ptr is pointer to the queue RETURNS return 1 if empty O if not HK KK KK RK k kk kk k ck k kk ck k kc k ck kc k ck kk k ck k kc k ck kk ck kk ck ck k kc k ck Ck ck ck k kk ck kc k ck kk ck ck k kc k ck k ck ck kk kck ck kck kk kk int Empty QUEUE TYPE queue ptr return queue ptr count lt 0 x KKK KKK KK KK KK KK KK KK KK KKK KK KK KK KKK KK KK KK ck ck ck k ck ck k kc kck kc k ck KK kK KK KK FUNCTION Full ARGUMENTS queue ptr is pointer to the queue RETURNS return 1 if full O if not full KK KK KK KK ck ck kk ck KK KK ck ck k ck KK KK KK KK k ck k
5. 100 Hz X X Y Z Y Orientation Ux E jeux MET v uz x Ux Ys yy RM GPS Baud Rate 98400 baud Auto baud GPS Protocol Novatel bina ry fauto detect v Get All Values Set Values Temporary reset after reboot C Permanant saved after reboot 3 10 Advanced Configuration Users who wish to access some of the more advanced features of NAV VIEW and the DMU380SA Series products can do so by selecting the Advanced tab at the top of the Unit Configuration window N WARNING Users are strongly encouraged to read and thoroughly understand the consequences of altering the settings in the Advanced tab before making changes to the unit configuration These settings are discussed in detail in Chapter 4 below Behavior switches are identified at the top of the page with marked boxes A blue box will appear if a switch has been enabled similar to Figure 8 below The values can be set in the same manner as noted in the previous section To set a value users select the appropriate Modify checkbox on the left side of the menu and select or enable the appropriate value they wish to set At the bottom of the page users have the option of temporarily or permanently setting values When all selections have been finalized simply press the Set Values button to change the selected settings Doc 7430 0026 Rev 01 Page 14 DMU380SA Series User s Manual MEMSIC Figure 8 Advanced Setting
6. HE peame e eee vrate emperane _ a ae ae a 2 T DMU ITOW sync to GPS Not Implemented 28 BlTstatus PEE Master BIT and Status 7 4 5 Nav Data Packet 0 Nav Data N0 0x4E30 Packet Type Length Payload 0x5555 Ox4E30 lt NO payload lt CRC U2 gt This packet contains navigation data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of pi pi or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C Velocities are scaled to a range of 256 256 m s Altitude is scaled to a range of 100 16284 m using a shifted 2 s complement representation Longitude and latitude are scaled to a range of pi pi or 180 deg to 180 deg Doc 7430 0026 Rev 01 Page 59 DMU380SA Series User s Manual MEMSIC gt NO Payload Contents Byte Offset rollAngle 2 2 pi 2 16 Radians Roll angle 3607 2 16 2 pitchAngle 2 2 pi 2 16 Radians Pitch angle 360 2 16 4 yawAngleTrue 2 2 pi 2 16 Radians Yaw angle true north xRateCorrected 12 7 pi 2 16 rad s X angular rate corrected yRateCorrected 12 T pi 2 16 rad s Y angular rate corrected 10 zRateCorrected 12 7 pi 2 16 rad
7. Section 5 Application Guide Section 6 9 Programming Communicating Advanced Commands and BIT Table 1 Manual Content Who Should Read All customers should read sections 1 1 and 1 2 Customers who are connecting the DMU380SA Series products into a system with their own power supply and cable Customers who are installing the DMU380SA Series products into a system and need details on using NAV VIEW All customers should read Section 4 As the DMU380SA Series products are inter related use the chart at the beginning of Section 4 to ensure that you get an overview of all of the functions and features of your DMU380SA Series system For example if you have purchased a INS380SA you should read not only the section on the INS380SA but also familiarize yourself with the theory of operation for the IMU380SA VG380SA and AHRS380SA The INS380SA builds on the capabilities of the IMU380SA VG380SA and AHRS380SA Customers who want product configuration tips for operating the DMU380SA Series Inertial Systems in a wide range of applications fixed wing rotary wing unmanned vehicles land vehicles marine vessels and more should review the part of Section 5 that is relevant to your application Note INS and AHRS DMU380SA Series units are preconfigured for airborne applications with normal dynamics VG380SA Series units are preconfigured for land applications with automotive testing dynamics All DMU380SA Series
8. 26 timel TOW DMU ITOW sync to GPS Not Implemented 30 BlTstatus HE e e Master BIT and Status 7 44 Angle Data Packet 2 Default VG Data Angle Data A2 0x4132 Packet Type Length Payload 0x5555 0x4132 lt A2 payload gt lt CRC U2 gt This packet contains angle data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of pi p1i or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C Doc 7430 0026 Rev 01 Page 58 DMU380SA Series User s Manual MEMSIC gt A2 Payload Contents Byte Offset rollAngle 2 2 pi 2 16 Radians Roll angle 3607 2 16 2 pitchAngle l2 2 pi 2 16 Radians Pitch angle 360 2 16 4 yawAngleTrue 2 2 pi 2 16 Radians Yaw angle free xRateCorrected 2 7 pi 2 16 rad s X angular rate corrected yRateCorrected l2 T pi 2 16 rad s Y angular rate corrected 10 zRateCorrected 2 7 pi 2416 rad s Z angular rate corrected 1260 2 16 sec 12 xe 0 20246 tg X accelerometer 14 yAcoel 202M6 g accelerometer 16 Accel 02 202M6 g Zaccelerometer
9. Bitstatus U2 t Master BIT and Status 7 4 3 Angle Data Packet 1 Default AHRS Data Angle Data A1 0x4131 Packet Type Length Payload 0x5555 0x4131 A1 payload lt CRC U2 gt This packet contains angle data and selected sensor data scaled in most cases to a signed 216 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of pi pi or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Magnetometers scaled to a range of 10 10 Gauss Temperature scaled to a range of 100 100 C Doc 7430 0026 Rev 01 Page 57 DMU380SA Series User s Manual MEMSIC gt A1 Payload Contents Byte Offset rollAngle 2 2 pi 2 16 Radians Roll angle 3607 2 16 2 pitchAngle l2 2 pi 2 16 Radians Pitch angle 360 2 16 4 yawAngleMag 2 2 pi 2 16 Radians Yaw angle magnetic 360 2 16 north xRateCorrected 12 7 pi 2 16 rad s X angular rate Corrected yRateCorrected T pi 2 16 rad s Y angular rate Corrected zRateCorrected 7 pi 2 16 rad s Z angular rate Corrected 12607 2M46 sec 12 xace 0 2026 g X accelerometer 4 Accel 02 0216 g Yacelrmeer 16 zacel 2 200M6 g Z accelerometer m I anm
10. DMU380SA Series User s Manual MEMSIC gt 29 GPS Antenna Connection INS380SA The GPS receiver needs to receive signals from as many satellites as possible A GPS receiver doesn t work properly in narrow streets and underground parking lots or if objects or human beings cover the antenna Poor visibility may result in position drift or a prolonged Time To First Fix TTFF A good sky visibility is therefore a prerequisite Even the best receiver can t make up for signal loss due to a poor antenna in band jamming or a poor RF cable The DMU380SA Series unit ships with an external active antenna that must be connected properly to SMA jack located next to the DB 15 connector Placing the antenna on a 4 inch or larger ground plane is highly recommended gt IMPORTANT Place the antenna with optimal sky visibility and use a ground plane Route the GPS Antenna RF cable away from sources of radiated energy 1 e switching power supplies 2 10 No Connection During normal operation of the DMU380SA Series no connection is made to the factory test pins These pins have internal pull up mechanisms and must have no connections for the DMU380SA Series to operate properly 2 11 Quick Digital interface connection On a standard DB 9 COM port connector make the connections as described in Table 6 Doc 7430 0026 Rev 01 Page 7 DMU380SA Series User s Manual MEMSIC gt Table 6 DB 9 COM Port Connections COM Port Connector E DMU380SA Series
11. Hex Value Data g FFFE 0 001 Hex Value Data deg s Field Value masterFail hardwareError comError softwareError oms fo omansa fo enosis fo C Doc 7430 0026 Rev 01 Page 90 DMU380SA Series User s Manual Figure 23 5555 4631 2a OU0lbffdf3a5bfrfeO000rfte MEMSIC Example payload from Nav Data Packet 1 N1 fff8fff700000028d1900288a360300 a3ad invalid preamble type length 0O01bffdf3a5b fffe0000ffea fff8fff7f337 O015fda9fd4f 00000000000000000000 2d19 00288a3e 0300 Hex Value Data 9 FFF8 0 0024 FFF7 0 0027 F337 0 9988 Hex Value Data m s 0015 0 164 FDA9 4 680 FD4F 5 383 Hex Value Data deg 001b 0 148 FFFD 0 181 3A5B 82 062 Hex Value Data deg s GPS Doc 7430 0026 Rev 01 00000000 0 000000000 Rad 00000000 0 000000000 Rad Hex Value Data deg C 2D19 35 233 timeITOW Hex Data Value s 00288a3e 2656830 BIT status Field Field Value masterFail hardwareError comError softwareError 0000 reserved masterStatus 1 Dems o Deme o Dee o reeves o Page 91 DMU380SA Series User s Manual MEMSIC gt 14 Warranty and Support Information 14 1 Customer Service As a MEMSIC customer you have access to product support services which include e Single point return service e Web based support service e Same day troubleshooting assistance e Worldwide MEM
12. IMU VG AHRS Yo 5 3 25 THRU 16 50 22 25 Doc 7430 0026 Rev 01 Page 78 DMU380SA Series User s Manual MEMSIC gt Figure 20 DMU380SA Series Outline Drawing INS 16 50 22 25 Doc 7430 0026 Rev 01 Page 79 DMU380SA Series User s Manual MEMSIC gt 11 Appendix B NMEA Message Format The GPS receiver outputs data in NMEA 0183 format at 9600 Baud 8 bits no parity bit and 1 stop bit The GGA and RMC message packet formats are explained in this section 11 1 GGA GPS fix data Time and position together with GPS fixing related data number of satellites in use and the resulting HDOP age of differential data if in use etc SGPGGA hhmmss ss Latitude N Longitude E FS NoSV HDOP msl m Altref m DiffAge DiffStation cs lt CR gt lt LF gt me T GPGGA string Latitude dddmm mmmm a character borgu dddmm mmmm E character zu m character m Description Message ID GGA protocol header UTC Time Current time Latitude Degrees minutes N S Indicator N north or S south Longitude Degrees minutes E W indicator E east or W west Position Fix Indicator See Table below Satellites Used Range 0 to 12 rN oO A rm z AlS S Co s N NX Co a NO Q co e Se oO gt C1 co oO c oO HDOP Horizontal Dilution of Precision MSL Altitude m Units Meters fixed field Geoid Separation m Units Meters fixed field
13. O algorithm Enabled MEMSIC Selec O Internal GPS External Aiding i Unit Default Settings Packet Type Packet Rate Baud Rate External GPS GPS Baud GPS Protocol MUser Behavior Switch O Freely Integrate O Use Mags Use GPS O Stationary Yaw Lock Restart Over Range O Dynamic Motion Filter Clock Rate FilterClocks FilterClock 1 FilterClock2 FilterClock3 LP Cutoff H2 Doc 7430 0026 Rev 01 Magnetometers Parameters X hard iron offset Y hard iron offset Soft iron ratio Value L Axes Orientation Customer Axes Unit Reference Axes Heading Track Offset Turn Switch Threshold Hardware Status Enable Fields O Unlocked 1PPS O Unlocked Internal GPS O No DGPS O Unlocked Eeprom Software Status Enable Fields L Aleorithm Initializing O High Gain O Altitude Only Alg L Turn Switch Sensor Status Enable Fields O Sensor Over Range Comm Status Enable Fields L No External GPS Page 20 DMU380SA Series User s Manual MEMSIC gt 4 Theory of Operation This section of the manual covers detailed theory of operation for each member of the DMU380SA Series starting with the basic IMU380SA and then reviewing each major variant VG AHRS and INS with their associated additional features outputs and performance Table 7 shows the basic features of ea
14. Packet esc ssoesnose soe eo osiin pono SUE SEHE Sae ga Vo Sep ase sous RI No ae 54 7 3 3 Test 0 Detailed BIT and Status Packet eee 55 7 4 Output Packets Polled or ContinuousS ccccccccccecccccceeseeesesesseeeceeeeeeeeeeeeaaas 55 141 Scaled Sensor Data Packet D ooseastesescoissseertebssee cmi tusquetu basque nita ues abate autas 55 7 4 2 Scaled Sensor Data Packet 1 Default IMU Doata eene 56 7 4 3 Angle Data Packet 1 Default AHRS Data eeeeeeese 57 7 4 4 Angle Data Packet 2 Default VG Data eeeeeeeee 58 TAS Lr Dati udi m 59 7 4 06 Nav Data Packet 1 Default INS Data eee 60 MEE rue O ERU MTM 62 Sd MMT ALOT Fields asc cess cesi onna indo ei dace E adios tea ree 62 5 2 Contmuous Packet Type Field acc ccccsdssscsanccasacenasesascstaacacqadasvengnacteacenaghincertaacaseuieas 62 63 Digital Filt r SCM Suasucsescesbuasccduss oe cueien a toit xe aeu bnc usce deep o erus asc a PRERUR KM eL Dau Emu Ed UNUE 63 S4 Orientation Field 22 6 5255 cc sssseasestsacepnstone E leve sesdapui eti anE co bead ug DUE 63 89 User Behavior S IU DISSE eessen aetb EIER ec NEP HAE EE EE 64 8 6 Hard and Soft Iron Values esseri 65 S Pede ore ERE a E 65 8 8 Commands to Program Configuration eeeeesssssseseseseeeeeeeee nnne 66 5 5 1 Write Fields Command s a o02059052595062
15. Ui _ The numberof fields owie Ho fem fu o The fisted Dtowite 5 eoa U The first eld IDs data to write 5 est fu o The second field to write T iea uz The second fld Dsdata pe wu pe nmass fei Up TehsfediDbwie mumFis i fed Dda U2 ThelsfediDsddatowie Write Fields Hesponse Write Fields WF 0x5746 Packet Type Length Payload 0x5555 0x5746 1 numFields 2 WF payload CRC U2 gt The unit will send this packet in response to a write fields command if the command has completed without errors WF Payload Contents Bye Of mmes Ui The number of las writen ed U2 The itl ID writen field1 uu fe The second field ID written Doc 7430 0026 Rev 01 Page 66 DMU380SA Series User s Manual MEMSIC gt uU fe le More field IDs written numFields 1 Field U2 Thelastfield ID written 8 8 2 Set Fields Command Set Fields SF 0x5346 Packet Type Length Payload 0x5555 0x5346 1 numFields 4 lt SF payload gt lt CRC U2 gt This command allows the user to set the unit s current configuration SF fields immediately which will then be lost on power down NumFields is the number of words to be set The fieldO fieldl etc are the field IDs that will be written with the fieldOData field Data etc respectively This command can be used to set configuration fields The unit will not set cali
16. etc These fields are stored in EEPROM and loaded on power up These fields can be read from the EEPROM using the RF command These fields can be written to the EEPROM affecting the default power up behavior using the WF command The current value of these fields which may be different from the value stored in the EEPROM can also be accessed using the GF command All of these fields can also be modified immediately for the duration of the current power cycle using the SF command The unit will always power up in the configuration stored in the EEPROM Configuration fields can only be set or written with valid data from Table 22 below Table 22 Configuration Fields configuration fields field ID Valid Values Packet rate divider 0x0001 0 1 2 5 10 20 25 50 quiet 100Hz 50Hz 25Hz 20Hz 10Hz 5Hz 2Hz Unit BAUD rate 0x0002 0 1 2 3 9600 19200 38400 57600 Any output packet Not all output packets available for all products Continuous packet type 0x0003 type See detailed product descriptions woos 0 0 7142 65535 5Hz 3571 7141 10Hz 1530 3570 20Hz Sets low pass cutoff for rate sensors Cutoff 0 1529 50 Hz Frequency choices are 5 10 20 and 50Hz 7142 65535 5Hz 3571 7141 10Hz 1530 3570 20Hz Sets low pass cutoff for accelerometers Cutoff Accelerometer Filter Setting 0x0006 0 1529 50 Hz Frequency choices are 5 10 20 and 50Hz Determine forward rightward and downward Orientation 0x0007 Se
17. is the masterFail flag The softwareError bit also provides useful information regarding the status and quality of the AHRS380SA magnetic alignment If the AHRS380SA has not been properly magnetically calibrated the AHRS380SA shall indicate a softwareError The masterStatus flag is a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which has been enabled See Section 9 Advanced BIT for details on configuring the masterStatus flags Table 13 shows the BIT definition and default settings for BIT programmable alerts in the AHRS380SA Doc 7430 0026 Rev 01 Page 36 DMU380SA Series User s Manual MEMSIC Table 13 AHRS380SA Default BIT Status Definitions IT IT IT IT comError 2 0 normal 1 communication error softwareError 0 normal 1 internal software error or B magAlignOutofBounds 10 inal 1 masterStatus softwareStatus 0 nominal 1 Algorithm Initialization or High Gain Reserved 13 15 N A LL The AHRS380SA also allows a user to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm Like the VG380SA and IMU380SA MEMSIC recommends for the vast majority of users that the default Status byte for the AHRS380SA is sufficient For users who wish to have addition
18. s fourth generation of MEMS based Inertial Systems building on over a decade of field experience and encompassing thousands of deployed units and millions of operational hours in a wide range of land marine airborne and instrumentation applications At the core of the DMU380SA Series is a rugged 6 DOF Degrees of Freedom MEMS inertial sensor cluster that is common across all members of the DMU380SA Series The 6 DOF MEMS inertial sensor cluster includes three axes of MEMS angular rate sensing and three axes of MEMS linear acceleration sensing These sensors are based on rugged field proven silicon bulk micromachining technology Each sensor within the cluster is individually factory calibrated for temperature and non linearity effects during MEMSIC s manufacturing and test process using automated thermal chambers and rate tables Coupled to the 6 DOF MEMS inertial sensor cluster is a high performance microprocessor that utilizes the inertial sensor measurements to accurately compute navigation information including attitude heading and linear velocity thru dynamic maneuvers actual measurements are a function of the DMU380SA Series product as shown in Table 2 In addition the ARM processor makes use of internal and external magnetic sensor and or GPS data to aid the performance of the inertial algorithms and help correct long term drift and estimate errors from the inertial sensors and computations The navigation algorithm utilizes a mul
19. 0 3 8 Packet Statistics View Packet statistics can be obtained from the View menu by selecting the Packet Statistics option See Figure 6 This view simply provides the user with a short list of Doc 7430 0026 Rev 01 Page 12 DMU380SA Series User s Manual MEMSIC gt vital statistics including Packet Rate CRC Failures and overall Elapsed Time that are calculated over a one second window This tool should be used to gather information regarding the overall health of the user configuration Incorrectly configured communication settings can result in a large number of CRC Failures and poor data transfer Figure 6 Packet Statistics Packet Statistics Packets Received 46442 CRC Failures Awe Packet Rate Hz 102 90 Elapsed Time 00 24 23 Reset Done 3 9 Unit Configuration The Unit Configuration window See Figure 7 gives the user the ability to view and alter the system settings This window 1s accessed through the Unit Configuration menu item under the configuration menu Under the General tab users have the ability to verify the current configuration by selecting the Get All Values button This button simply provides users with the currently set configuration of the unit and displays the values in the left column of boxes There are three tabs within the Unit Configuration menu General Advanced and BIT Configuration The General tab displays some of the most commonly use
20. 3 NAV VIEW Computer Requirements sess 9 NECI Sdn 9 32 SOS SILET Tm m T 9 39 oi up NAV VIEW m 10 S DACA NRCC ON MN ARTT 10 SS MEME Da P Da NORUNT UU tro 1 DO Wea ACA OMS E e S 11 2 7 Horizon and Compass View vccssdeccessiesasevidarcersucnccswustandevareraceasdanceesuengasesatandeoraert 12 O45 Packet Statistics VIC W esrereenreni rronin n E eai 12 XU UC On o O a E A URS PM D iE 13 3 10 Advanced Configuration s e ssssseeoeoeeeeeeesssssssssssseeeetereeessosssssssssseeecerereesssssss 14 3 11 X18 GO TUE OO E EE TT 15 3 12 Mag Alignment Procedure ecserin aieeao ieira a eni 16 3 12 1 Hard Iron Soft Iron Overview esee eene 16 Doc 7430 0026 Rev 01 Page i DMU380SA Series User s Manual MEMSIC gt 3 12 2 Mag Alignment Procedure Using NAV VIEW seeeeeeeme 17 3 13 eae init Coni UE AUION sessen aE SE eH te Ene EE ESR 19 A WIE ORY OF Operation oes cscs ER RS m mm 21 4 1 DMU380SA Series Default Coordinate System sees 24 Aled Advanced Seming Seeiso ee ee a TE aE Eea eua se RES 25 4 2 IMU380SA Theory of Operation cccccccccccccceceececeeeeseeeesseseeeeeeceeeeeeeeeeeaaas 25 4 2 1 IMU380SA Advanced Settings cccccccccccccceecssseesssesseseeeeecceeseeeeeeaaas 26 4 2 2 IMU380SA Built In TOSE irte Goin eabo sop Eta peu eu ee Ionia Cn ER sa stas eno Eeba penses 27 43 WVGoOSOUSA Theory OF Operatoren eed apos
21. AHRS380SA to a high gain state where the AHRS380SA rapidly estimates the gyro bias and uses the accelerometer feedback heavily This setting is recommended when the source of over range is likely to be sustained and potentially much greater than the rate sensor operating limit Large and sustained angular rate over ranges result in unrecoverable errors in roll and pitch outputs An unrecoverable error is one where the EKF can not stabilize the resulting roll and pitch reading If the over ranges are expected to be of short duration 1 sec and a modest percentage over the maximum operating range it is recommended that the Page 35 DMU380SA Series User s Manual MEMSIC restart on over range setting be turned off Handling of an inertial rate sensor over range is controlled using the restartOnOverRange switch If this switch is off the system will flag the overRange status flag and continue to operate through it If this switch is on the system will flag a masterFail error during an over range condition and continue to operate with this flag until a quasi static condition is met to allow for an algorithm restart The quasi static condition required is that the absolute value of each low passed rate sensor fall below 3 deg sec to begin initialization The system will then attempt a normal algorithm start Dynamic The default setting is ON for the AHRS380SA Turning off the dynamic motion setting Motion results in a higher gain state that uses
22. If you are using the cable supplied with the DMU380SA Series the power supply wires are broken out of the cable at the DB 9 connector The red wire is connected to the positive power input the black wire is connected to the power supply ground A WARNING Doc 7430 0026 Rev 01 Page 4 DMU380SA Series User s Manual MEMSIC gt Do not reverse the power leads or damage may occur 24 Serial Data Interface The main serial interface is standard RS 232 9600 19200 38400 or 57600 baud 8 data bits 1 start bit 1 stop bit no parity and no flow control and will output at a user configurable output rate Pins 3 and 5 are designated as the main RS 232 interface pins The secondary serial interface is also standard RS 232 9600 19200 38400 or 57600 baud 8 data bits 1 start bit 1 stop bit no parity and no flow control and is used by INS380SA models to output internal GPS data Pins 4 and 6 are designated as the secondary RS 232 interface pins used by the INU380SA models The user may opt to set the output to RS 422 using pin 7 When Pin7 is shorted to ground the standard RS 232 ports will be available When Pin 7 is left open then only the main serial interface will be available and it will be standard RS 422 9600 19200 38400 or 57600 baud 8 data bits 1 start bit 1 stop bit no parity and no flow control and will output at a user configurable output rate Pins 3 and 4 are used for the RS 422 Rx and Rx and pins 5 and 6 are u
23. advanced settings are accessible thru NAV VIEW under the Configuration Menu Unit Configuration settings Table 8 IMU380SA Advanced Settings Sum Dm Comments S Baud Rate 38 400 baud 9600 19200 57600 also available Packet Type S1 also available Packet Rate 100Hz This setting sets the rate at which selected Packet Type packets are output If polled mode is desired then select Quiet If Quiet is selected the IMU380SA will only send measurement packets in response to GP commands Orientation See Fig 12 To configure the axis orientation select the desired measurement for each axis NAV VIEW will show the corresponding image of the IMU380SA so it easy to visualize the mode of operation Refer to Section 8 4 Orientation Field settings for the twenty four possible orientation settings The default setting points the connector AFT Filter Settings 5 The low pass filters are set to a default of 20 Hz for the accelerometers and 20 10 20 50 Hz Hz for the angular rate sensors There is one filter setting for all three angular rate sensors There is one filter setting for all three accelerometers NOTE on Filter Settings Why change the filter settings Generally there is no reason to change the low pass filter settings on the IMU380SA or other DMU380SA Series Inertial Systems However when a DMU380SA Series product is installed in an environment with a lot of vibration it can be helpful to reduce the vibration based signal energy an
24. any asserted alert signals which the user has enabled The hierarchy of BIT and Status fields and signals is depicted here BliTstatus Field masterFail hardwareError e hardwareBIT Field powerError gt hardwarePowerBIT Field inpPower inpCurrent inpVoltage fiveVolt threeVolt twoVolt twoFiveRef sixVolt grdRef environmentalError gt hardwareEnvironmentalBIT Field pcbTemp combrror e combIT Field serialAError comSerialABIT Field transmitBufferOverflow receiveBufferOverflow ramingError breakDetect Docf7430 0026 Rev 01 se Page70 DMU380SA Series User s Manual MEMSIC gt parityError serialBError comSerialBBIT Field transmitBufferOverflow receiveBufferOverflow ramingError breakDetect parityError softwareError e softwareBIT Field algorithmError gt softwareAlgorithmBIT Field initialization overRange missedIntegrationStep dataError gt softwareDataBIT Field calibra onCRCError magAlignOutOfBounds masterStatus hardwareStatus e hardwareStatus Field unlockedl PPS enabled by default on INS unlockedInternalGPS enabled by default on INS noDGPS unlockedEEPROM comstatus e comStatus Field noExternalGPS enabled by default on VG and AHRS softwareStatus e softwareStatus Field algorithmInitialization enabled by default highGain enabled by default attitudeOnlyAlgorithm turnSwi
25. be used by the navigation mode filter when no magnetometer heading measurements are available See Table 28 Table 28 DMU380 Heading Track Offset Heading Track Offset 2 pi 2 16 Radians heading track 0x000C l2 360 2 6 Doc 7430 0026 Rev 01 Page 65 DMU380SA Series User s Manual MEMSIC gt 8 8 Commands to Program Configuration 8 8 1 Write Fields Command Write Fields WF 0x5746 Terminatio Preamble Packet Type Length Payload n 0x5555 0x5746 1 numFields 4 WF payload U2 gt This command allows the user to write default power up configuration fields to the EEPROM Writing the default configuration will not take affect until the unit is power cycled NumFields is the number of words to be written The fieldO fieldl etc are the field IDs that will be written with the fieldOData field Data etc respectively The unit will not write to calibration or algorithm fields If at least one field is successfully written the unit will respond with a write fields response containing the field IDs of the successfully written fields If any field 1s unable to be written the unit will respond with an error response Note that both a write fields and an error response may be received as a result of a write fields command Attempts to write a field with an invalid value is one way to generate an error response A table of field IDs and valid field values is available in Section 8 1 Scaling Unis co meds
26. el 2 ele 2al 2 2 D D o 3 3 3 3 sy D D AE D D D Sell DA Oo Oo Oo Oo Oo Age of Differential Corrections sec Blank Null fields when DGPS is not used Diff Reference Station ID Checksum DiffAge DiffStation NN NNNM Doc 7430 0026 Rev 01 Page 80 p C1 UJ DMU380SA Series User s Manual MEMSIC gt Po emmm NL on Doc 7430 0026 Rev 01 Page 81 DMU380SA Series User s Manual MEMSIC gt 12 Appendix C Sample Packet Parser Code 12 1 Overview This appendix includes sample code written in ANSI C for parsing packets from data sent by the DMU380SA Series Inertial Systems This code can be used by a user application reading data directly from the DMU380SA Series product or perhaps from a log file The sample code contains the actual parser but also several support functions for CRC calculation and circular queue access e process xbow packet for parsing out packets from a queue Returns these fields in structure XBOW PACKET see below Checks for CRC errors e calcCRC for calculating CRC on packets e Initialize initialize the queue e AddQueue add item in front of queue e DeleteQueue return an item from the queue e peekWord for retrieving 2 bytes from the queue without popping e peekByte for retrieving a byte from the queue without popping e Pop discard item s from queue e Size returns number of items in queue e Empty return 1 if queue i
27. in the system i e a vehicle and the vehicle is magnetic you will still see errors arising from the magnetism of the vehicle 3 12 2 Mag Alignment Procedure Using NAV VIEW The Mag Alignment Procedure using NAV VIEW can be performed using the following steps below 1 Select Mag Alignment from the Configuration drop down menu at the top 2 If you can complete your 360 degree turn within 120 seconds select the Auto Terminate box 3 Select the Start button to begin the MagAlign Procedure and follow the instructions at the bottom of the screen as shown in Figure 10 below Figure 10 Mag Alignment Doc 7430 0026 Rev 01 Page 17 DMU380SA Series User s Manual MEMSIC Lo Magnetometer Alignment Current Settin X Hard Iron Offset Y Hard Iron Offset Soft Iron Ratio Soft Iron Angle Instructions Slowly rotate the unit on a level surface about the Z axis until NAV VIEW reports that the calibration is done The operation will timeout in 120 seconds If you want to stop make sure switch is OFF before clicking STOP External Mag Leveling Alignment Rotational Alignment om Roll Offset Pitch Offset Cancel Roll 0 4 Pitch 0 1 Yaw 139 1 Magnetometer Output Y Field Gauss X Field Gauss 4 Rotate the AHRS or INS380SA product through 380 degrees of rotation or until you receive a message to stop 5 Once you have completed your rotation you will be given data concerning the ca
28. in the respective GPS protocol documents The user must configure the VG AHRS380SA to accept external GPS information using NAV VIEW as described in Chapter 3 If the VG AHRS380SA is parsing valid external GPS data and the GPS receiver has 3D lock then the comStatus gt noExternalGPS flag will be zero otherwise it will be one See section 9 for a complete description of system status indications Since NMEA protocol does not provide vertical velocity the vertical velocity that the DMU380SA Series estimates based upon GPS altitude changes may not be sufficient for airborne applications See Table 5 Therefore the NMEA protocol is not recommended for airborne applications Doc 7430 0026 Rev 01 Page 5 DMU380SA Series User s Manual MEMSIC gt Table 5 Configuration of An External GPS Receiver for VG380SA AHRS380SA Required Messages Required Message Rate Ublox binary NAV LLH NAV VELNED 4 Hz 9600 19200 38400 NAV STATUS 97600 NovAtel OEM4 and BestPosB BestVelB 4Hz 9600 19200 38400 OEMV Binary 57600 NovAtel OEM4 PosVelNavDopA 4Hz 19200 38400 57600 ASCII NMEA GPGGA GPVTG 4Hz 9600 19200 38400 57600 Not recommended for airborne applications 557600 is the preferred baud rate for optimum performance The GPS serial communication port should be configured to 8 data bits 1 start bit 1 stop bit no parity bit and no flow control 2 4 1 PPS Output Interface INS380SA The IPPS output signal on pin 8 is
29. integrates body frame sensed angular rate to orientation at a fixed 100 times per second within all of the DMU380SA Series products except IMU380S A For improved accuracy and to avoid singularities when dealing with the cosine rotation matrix a quaternion formulation is used in the algorithm to provide attitude propagation Doc 7430 0026 Rev 01 Page 37 DMU380SA Series User s Manual MEMSIC gt Following the integration to orientation block the body frame accelerometer signals are rotated into the NED level frame and are integrated to velocity At this point the data is blended with GPS position data and output as a complete navigation solution As shown in Figure 10 the Integration to Orientation and the Integration to Velocity signal processing blocks receive drift corrections from the Extended Kalman Filter EKF drift correction module The drift correction module uses data from the aiding sensors when they are available to correct the errors in the velocity attitude and heading outputs Additionally when aiding sensors are available corrections to the rate gyro and accelerometers are performed The INS380SA blends GPS derived heading and accelerometer measurements into the EKF update depending on the health and status of the associated sensors If the GPS link is lost or poor the Kalman Filter solution stops tracking accelerometer bias but the algorithm continues to apply gyro bias correction and provides stabilized angle outp
30. is the bit wise OR of this comSerialBBIT field Table 35 DMU380 Serial Port B BIT Field _comSerialBBIT Field Bits Meaning Category WansmiBufferOveriow 0 O normal t overflow Sot Reewd de NA 9 9 softwareBlT Field The softwareBIT field contains flags that indicate various types of software errors See Table 36 Each type has an associated message with low level error signals The softwareError flag in the BITstatus field is the bit wise OR of this softwareBIT field Table 36 DMU380 Softrware BIT Field softwareBIT Field Bis Menng Catgoy algorithmEror o o onoma teo fe Reewd s a Doc 7430 0026 Rev 01 Page 74 DMU380SA Series User s Manual MEMSIC gt 9 10 softwareAlgorithmBIT Field The softwareAlgorithmBIT field contains flags that indicate low level software algorithm errors See Table 37 The algorithmError flag in the softwareBIT field is the bit wise OR of this softwareAlgorithmBIT field Table 37 DMU380 Software Algorithm BIT Field SoftwareAlgorithmBIT Field emi aa overRange 1 0 normal 1 fatal sensor over range Hard missedNavigationStep 2 0 normal 1 fatal hard deadline missed for Hard navigation N A LE 9 11 softwareDataBIT Field The softwareDataBIT field contains flags that indicate low level software data errors See Table 38 The dataError flag in the softwareBIT field is the bit wise OR of this
31. kc KK KK ck ck k KK KK KK KK KK kK KK KK f int Ful OURGE TYPE gueue ptr return queue ptr gt count gt MAXQUEUE Doc 7430 0026 Rev 01 Page 88 DMU380SA Series User s Manual MEMSIC 13 Appendix D Sample Packet Decoding Figure 21 Example payload from Angle Data Packet 2 A2 5555 4132 le 0006ffe4ed9l1fffOfffdffedfff7fff9f3312c642ce12d8500010b1c0300 6945 preamble type length CRC invalid 0006ffe4ed91 fffO9fffdffed fff7fff9f331 2c642cel2d85 00010b1c 0300 timeITOW Hex Data Value s 00010b1c 68380 Hex Value Data deg 0006 0 033 roll FFE4 0 154 pitch ED91 25 922 yaw Hex Value Data deg s FFF9 0 13 roll FFFD pitch FFED 0 37 yaw Hex Value Data 9 FFF7 0 0027 x FFF9 0 0021 y F331 1 0007 z Hex Value Data deg C 2C64 34 680 2CE1 35 062 2D85 35 562 BIT status Field Field masterFail hardwareError comeError softwareError reserved masterStatus hardwareStatus comStatus softwareStatus sensorStatus Dm Doc 7430 0026 Rev 01 Page 89 DMU380SA Series User s Manual MEMSIC Figure 22 Example payload from Scaled Data Packet 1 1 5555 5331 18 0000fffef332 fff30001fff8 23b9242624ca2aff 9681 0300 248a Iu INI preamble type length counter CRC invalid BIT status Field Hex Value Data deg C 23B9 28 241 2426 28 741 24CA 33 591 2AFF 38 968
32. outputs An unrecoverable error is one where the EKF can not stabilize the resulting roll and pitch reading If the over ranges are expected to be of short duration 1 sec and a modest percentage over the maximum operating range it is recommended that the restart on over range setting be turned off Handling of an inertial rate sensor over range is controlled using the restartOnOverRange switch If this switch is off the system will flag the overRange status flag and continue to operate through it If this switch is on the system will flag a Doc 7430 0026 Rev 01 Page 29 DMU380SA Series User s Manual MEMSIC masterFail error during an over range condition and continue to operate with this flag until a quasi static condition is met to allow for an algorithm restart The quasi static condition required is that the absolute value of each low passed rate sensor fall below 3 deg sec to begin initialization The system will then attempt a normal algorithm start Dynamic The default setting is ON for the VG380SA Turning off the dynamic motion setting results Motion in a higher gain state that uses the accelerometer feedback heavily During periods of time when there is known low dynamic acceleration this switch can be turned off to allow the attitude estimate to quickly stabilize Turn Switch 10 0 With respect to centripetal or false gravity forces from turning dynamics or coordinated threshold deg sec turn the VG380SA monitors the yaw
33. positive direction your fingers curl around in the positive rotation direction For example if the DMU380SA Series product is sitting on a level surface and you rotate it clockwise on that surface this will be a positive rotation around the z axis The x and y axis rate sensors would measure zero angular rates and the z axis sensor would measure a positive angular rate The magnetic sensors are aligned with the same axes definitions and sign as the linear accelerometers For example when oriented towards magnetic North you will read approximately 0 25 Gauss along X 0 0 Gauss along Y and 40 35 Gauss along Z direction North America Magnetic values at other geographic locations can be found at http www ngdc noaa gov seg WMM DoDWMM shtml Pitch is defined positive for a positive rotation around the y axis pitch up Roll is defined as positive for a positive rotation around the x axis roll right Yaw is defined as positive for a positive rotation around the z axis turn right The angles are defined as standard Euler angles using a 3 2 1 system To rotate from the body frame to an earth level frame roll first then pitch and then yaw The position output from GPS is represented in Latitude Longitude and Altitude LLA convention on the WGS84 Ellipsoid This is the most commonly used spherical coordinate system The GPS velocity is defined in North East and Down reference frame The users can convert this into Cartesian coordina
34. ratio between the x and y axis softlronAngle l2 2 pi 2 16 Rad The soft iron phase angle 360 2M6 Deg between x and y axis Doc 7430 0026 Rev 01 Page 53 DMU380SA Series User s Manual MEMSIC gt 7 2 9 Error Response Error Response ASCII NAK NAK 0x1515 Packet Type Length Payload 0x5555 Ox1515 NAK payload lt CRC U2 gt The unit will send this packet in place of a normal response to a failledInputPacket Type request if it could not be completed successfully NAK Payload Contents Byte Offset 0 4 falledinputPacketType Hx a the failed request 7 3 Output Packets Polled The following packet formats are special informational packets which can be requested using the GP command 7 3 1 Identification Data Packet Identification Data ID 0x4944 Packet Type Length Payload 0x5555 Ox4944 ID payload lt CRC U2 gt This packet contains the unit serialNumber and modelString The model string is terminated with 0x00 The model string contains the programmed versionString 8 bit Ascii values followed by the firmware part number string delimited by a whitespace ID Payload Contents o swaNume Ui Untsremume 4 mese SN UhVesonSH 4N jm U ZesDemer 7 3 2 Version Data Packet Version Data VR 0x5652 Packet Type Length Payload 0x5555 0x5652 lt VR payload gt lt CRC U2 gt This packet contains firmware version inform
35. s Z angular rate corrected 12607 2 16 sec 5121216 North veloci 5121216 East velocity 5121216 Down velocity 18 longitudeGPS l4 2 pi 2 32 Radians GPS Longitude 360 2 32 22 latitudeGPS l4 2 pi 2 32 Radians GPS Latitude 360 2 32 altitudeGPS 244 216 GPS altitude 100 16284 28 GPSITOW U2 truncated ms GPS ITOW lower 2 bytes Not Implemented Bitstatus U2 MasterBIT and Status 7 4 6 Nav Data Packet 1 Default INS Data Nav Data N1 0x4E31 Packet Type Length Payload 0x5555 Ox4E31 lt N1 payload lt CRC U2 gt This packet contains navigation data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of pi p1 or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C Velocities are scaled to a range of 256 256 m s Altitude is scaled to a range of 100 16284 m using a shifted 2 s complement representation Longitude and latitude are scaled to a range of pi pi or 180 deg to 180 deg N1 Payload Contents Byte Offset 0 rolAngle 2 pi 2M6 Roll angle Doc 7430 0026 Rev 01 Page 60 DMU380SA Series User s Manual MEMSIC gt
36. section 8 4 Orientation Field settings for the twenty four possible orientation settings The default setting points the connector AFT The low pass filters are set to a default of 20Hz for the accelerometers and 20Hz for the angular rate sensors There is one filter setting for all three angular rate sensors There is one filter setting for all three accelerometer sensors The reason for filtering the accelerometers is that in many installations the vibration level can be high and it can prove helpful to filter accelerometers The Freely Integrate setting allows a user to turn the AHRS380SA into a free gyro In free gyro mode the roll pitch and yaw are computed exclusively from angular rate with no kalman filter based corrections of roll pitch or yaw When turned on there is no coupling of acceleration based signals into the roll and pitch or magnetometer based signals to the yaw As a result the roll pitch and yaw outputs will drift roughly linearly with time due to sensor bias For best performance the Freely Integrate mode should be used after the algorithm has initialized This allows the Kalman Filter to estimate the roll and pitch rate sensor bias prior to entering the free gyro mode Upon exiting the free gyro mode OFF one of two behaviors will occur 1 If the AHRS380SA has been in freely integrate mode for less than sixty seconds the algorithm will resume operation at normal gain settings 2 If the AHRS380SA has
37. softwareDataBIT field initialization O0 0 normal 1 error during algorithm initialization Table 38 DMU380 Software Data BIT Field SoftwareDataBIT Field e Cason calibrationCRCError 0 normal 1 incorrect CRC on Hard calibration EEPROM data or data has been compromised by a WE command magAlignOutOfBounds N A Parameter not implemented in this software version N A Reewd deas NA o 9 12 hardwareStatus Field The hardwareStatus field contains flags that indicate various internal hardware conditions and alerts that are not errors or problems See Table 39 The hardwareStatus flag in the BITstatus field is the bit wise OR of the logical AND of the hardwareStatus field and the hardwareStatusEnable field The hardwareStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Table 39 DMU380 Hardware Status BIT Field hardwareStatus Field Bis Menn uxkediPPS o O notassered 1 assered 2 3 noDGPS 2 0 DGPS lock 1 no DGPS unlockedEEPROM O locked WE disabled 1 unlocked WE enabled 9 13 comStatus Field The comStatus field contains flags that indicate various external communication conditions and alerts that are not errors or problems See Table 40 The comStatus flag in the BITstatus field is the bit wise OR of the logical AND of the comStatus field and the comStatusEnable field The c
38. the DMU380SA Series product 2 Connect the 9 pin sub DB end of the cable marked to the serial port of your computer 3 The additional black and red wires on the cable connect power to the DMU380SA Series product Match red to power and black to ground The input voltage can range from 9 32 VDC with a maximum current draw of 350 mA 4 Allow at least 60 seconds after power up for the DMU380SA Series product to initialize The DMU380SA Series needs to be held motionless during this period N WARNING Do not reverse the power leads Reversing the power leads to the DMU380SA Series can damage the unit although there is reverse power protection MEMSIC is not responsible for resulting damage to the unit should the reverse voltage protection electronics fail Doc 7430 0026 Rev 01 Page 9 DMU380SA Series User s Manual MEMSIC gt 3 3 Setting up NAV VIEW With the DMU380SA Series product powered up and connected to your PC serial port open the NAV VIEW software application 1 NAV VIEW should automatically detect the DMU380SA Series product and display the serial number and firmware version if it is connected 2 If NAV VIEW does not connect check that you have the correct COM port selected You will find this under the Setup menu Select the appropriate COM port and allow the unit to automatically match the baud rate by leaving the Auto match baud rate selection marked 3 If the status indicator at the bottom
39. the local magnetic field on input direction is called the soft iron effect Doc 7430 0026 Rev 01 Page 16 DMU380SA Series User s Manual MEMSIC gt The AHRS and INS380SA products can actually measure the constant magnetic field that is associated with your system and correct for it The AHRS and INS380SA products can also make a correction for some soft iron effects The process of measuring these non ideal effects and correcting for them is called the Mag Alignment Procedure Performing a Mag Alignment Procedure will help correct for magnetic fields that are fixed with respect to the DMU380SA Series product It cannot correct for time varying fields or fields created by ferrous material that moves with respect to the DMU380SA Series product The AHRS and INS380SA products account for the extra magnetic field by making a series of measurements and using these measurements to model the hard iron and soft iron environment in your system using a two dimensional algorithm The AHRS and INS380SA products will calculate the hard iron magnetic fields and soft iron corrections and store these as calibration constants in the EEPROM The Mag Alignment Procedure should always be performed with the AHRS or INS380SA product installed in the user system If you perform the calibration process with the DMU380SA Series product by itself you will not be correcting for the magnetism in the user system If you then install the DMU380SA Series product
40. to the masterStatus flag Table 42 DMU380 Sensor Status Field sensorStatus Fel Bis Men overrange fo 0 not asserted 1 assert 9 16 Configuring the Master Status The masterStatus byte and its associated programmable alerts are configured using the Read Field and Write Field command as described in Section 8 Advanced Commands Table 43 shows the definition of the bit mask for configuring the status signals Table 43 DMU380 Master Status Byte Configuration Fields configuration fields field ID Valid Values hardwareStatusEnable 0x0010 Bit mask of enabled hardware status signals comStatusEnable Bit mask of enabled communication status 0x0011 Any signals softwareStatusEnable 0x0012 Bit mask of enabled software status signals sensorStatusEnable 0x0013 Bit mask of enabled sensor status signals 9 16 1 hardwareStatusEnable Field This field is a bit mask of the hardwareStatus field see BIT and status definitions This field allows the user to determine which low level hardwareStatus field signals will flag the hardwareStatus and masterStatus flags in the BITstatus field Any asserted bits in this Doc 7430 0026 Rev 01 Page 76 DMU380SA Series User s Manual MEMSIC gt field imply that the corresponding hardwareStatus field signal if asserted will cause the hardwareStatus and masterStatus flags to be asserted in the BITstatus field 9 16 2 comStatusEnable Field This field is a bit mask of the comStatus field see BI
41. uova na uaa er saisi EERE 24 4 3 1 VG380SA Advanced Settings cccccccccccceecceceeeeeeeeessseeseeeceeseeeeeeeeeaaas 20 4 3 2 MVOSSUSA But M Ko enneereeererere tteeer rr rere errrrr reer erereer terrier raver tretrrs Tee a INE 30 4 4 AHRS380SA Theory of Operation cccccccccccecccceeeceeseeesseeseeeeeeeeeeeeseeeeeaaas 3l 4 4 1 AHRS380SA Magnetometer Calibration and Alignment 32 4 4 2 AHRS380SA Advanced Settings ccccccccccccccccccceesssseseesseeeceeceeeeeeeeeaaas 33 4 4 5 AHRS380SA Built In Test seen nennen 36 45 INSS805A Theory of Operation sessies rera oboe Ps oap Rb aae uaa er vo Eie AEE psa sets 37 4 5 1 INS380SA Magnetometer Calibration and Alignment 39 4 5 2 INS380SA Advanced SettingS cccccccccccccccccsececeeeessssseseeeeecceeeeeeeeeeaas 39 4 5 9 TNSISOSA Built In Test cccsscesecasassossavagsonscutsccasavaeesacansseassewsveewedceancaveutnenacands 40 POMC AIO Ml E SIC NR em 42 SUME DOCERE 42 PAM CREE rer IET Tm 42 S5 PROON NER 43 ZEN BT nuc 43 MER Cia mm T Tm 44 6 Programme OUKIG uini muet e E aA d RP E DIU Va ER V Xa d 46 DI Ciencral ctt S oosmaentitgcecie coded aa anaes icets 46 02 Nombr TOMAS ER EO OO TEE 46 0 9 CCE TOTA casos cte sss E E 47 Orel PACE TC AC Sea arse oec ee acca E 47 o Lord M Rus TTE n 47 Coo Pay TO ad
42. 0200000 90 009 0 9 28 98 009000 0 9 0898 00094 I 1 2 Overview of the DMU380SA Series Inertial Systems eseeeeessse 2 1 3 Summary of Major Changes from the 440 Series and the 350 Series 3 1 3 Mechanical Size and Footprint iiis errat torte Iob Eo dues ee e 3 1 3 2 Connector Pin Out amp Operating Voltage Current sss 3 BEN MEME iP CH CO ABI ENTRE 3 1 3 4 Operating Performance and Accuracy eeeeseeeeeeeerrmne 3 2 WCOBPICOTOIIS ois 555057059 ee eee eee eee 00 295 20 E 059 0 9405 1900 008 eee 4 24 COMM DI c E 4 Dr VOEE a ees E E AT E E E 4 2 3 Power Input and Power Input Ground ccccceeeeccccceceeeeceeceaaeseeeesseeeeeeeeeees 4 24 Seral Data TME bs oa eee ee ne eee ee ne eee 5 25 Seral GPS Interface IINS390SA sccevevcoivecscsecto save arrir N e EANAN NEE 5 2 6 External GPS Aiding VG380SA and AHRS380SA cc ccccccccccccceeeeeeeeseeeeeeeens 5 2 PPS Output Interface INS380SA esses nnne 6 2 8 Sync Pulse Input Interface IMU VG and AHRS3808SA ssssss 6 2 9 GPS Antenna Connection INS380SA seesssseeeseeeeee ne eene e enne nnns 7 2 10 INO 0 010 276 8 0 o ceo veu E ED OPE NOMINE EMEN eee 7 2 11 Quick Digital interface connection sess 7 3 Installation and Operation of NAV VIEW sssessssseeeeeccceeeeceeeeeaesaesensessseeeeeeess 9
43. 0Zffffffzlff5c laeg000000000000000000000000000 tfdoffba 0020000000lffffffZlff5cOlaeO000000000000000000000000000 tfd8ffba00020000000lffffffZlff5cOlaegQ000000000000000000000000000 tfd8ffba 00z 0000000lffffffzlff5cOlaegQ000000000000000000000000000 tfdaffba 00020000000lffffffZzlff5cOlaeO000000000000000000000000000 tfd8ffba0002z0000000lffffffzZff5cOlaeOQ000000000000000000000000000 tfd8ffba 0002z00000000ffffffz2Zff5cOlaeOQ000000000000000000000000000 tfd8ffba 0002z00000000ffffffz2Zff5cOlaeg000000000000000000000000000 tfd8ffbb 0020000000 0fffeffzzZf f5cOlaeg000000000000000000000000000 tfd8ffbbo00100000000fffeffzZff5cOlaeg000000000000000000000000000 tfd8ffbbo00100000000fffeffzZ2Zff5cOlaegQ000000000000000000000000000 tfd8ffba 001l00000000ffffffz2Zff5c laeg 000000000000000000000000000 tfd7ffba000100000000fffeffzZ2ff5cOlaeO0000000000000000000000000000 tfd7ffba000100000000ffffffzZZff5cOlaeO0000000000000000000000000000 3 Horizon and Compass View MEMSIC 9fde 00fa afe afte afte afte dde bS8ec bS8ec 9dfc a256 a256 8746 f 9c 2c36 If the DMU380SA Series product you have connected is capable of providing heading and angle information see Table 2 NAV VIEW can provide a compass and a simulated artificial horizon view To activate these views simply select Horizon View and or Compass View from the View drop down menu at the top of the page See Figure 5 Figure 5 Horizon and Compass View HOG 30
44. 0x5555 0x4746 1 numFields 4 GF Data lt CRC U2 gt The unit will send this packet in response to a get fields request if the command has completed without errors GF Payload Contents Byte Offset o mmH ds Ut f The numberof fields retieved 1 field0 U2 Thefistfield ID retrieved HU field Data lU e e The first field ID s data retrieved sooo n U 7 Teme ue o C u wi u Thelastfeld Dretieved mumFesi fed Dda U2 The last feld IDs data retrieved The second field ID retrieved The second field ID s data Doc 7430 0026 Rev 01 Page 69 DMU380SA Series User s Manual MEMSIC gt 9 Advanced BIT 9 1 Built In Test BIT and Status Fields Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is a hardware BIT signal on the user connector which is mirrored in the software BIT field as the masterFail flag This flag 1s thrown as a result of a number of instantly fatal conditions known as a hard failure or a persistent serious problem known as a soft failure Soft errors are those which must be triggered multiple times within a specified time window to be considered fatal Soft errors are managed using a digital high pass error counter with a trigger threshold The masterStatus flag is a configurable indication as determined by the user This flag is asserted as a result of
45. 2 _ The second feld ID s data read Lp o e e wi u Thelastfeld Dread mmFes4 fed Dda U2 e Thelastfeld D s data read 8 11 Get Fields Command Get Fields GF 0x4746 Packet Type Length Payload 0x5555 0x4746 1 numFields 2 lt GF Data gt lt CRC U2 gt Doc 7430 0026 Rev 01 Page 68 DMU380SA Series User s Manual MEMSIC gt This command allows the user to get the unit s current configuration fields NumFields is the number of fields to get The field0 fieldl etc are the field IDs to get GF may be used to get configuration calibration and algorithm fields from RAM Multiple algorithm fields will not necessarily be from the same algorithm iteration If at least one field is successfully collected the unit will respond with a get fields response with data containing the field IDs of the successfully received fields If any field 1s unable to be received the unit will respond with an error response Note that both a get fields and an error response may be received as the result of a get fields command GF Payload Contents Byte Offset 0 numFields Ui The number of fields to get A fed U2 f The firstfield IDtoget 3 field U2 f jThesecndfeldiDtoge pe e u fe JMoeefediDstoget mumFiele2 1 Field U2 jThelstfedlDtoget 0 12 Get Fields Response Get Fields GF 0x4746 Packet Type Length Payload
46. 4 cro peekByte queue ptr startlIndexti lt lt B for j 0 j 8 j 1 it ere amp 0x8000 cre cro lt lt 1 Oxl021 else cre cre lt lt 1 return crc KKK KR KKK KKK KK KK RK KK KK KK KK KK KK KK KK KKK KK KK KK KKK KK KKK k ck k ck ck KK KK KK KK FUNCTION Initialize initialize the queue ARGUMENTS queue ptr is pointer to the queue HK KK KK KK KK KK KK KK KK KKK KK ck KK KK KKK k ck kc KK KKK KK KK KK KKK KK KK KK KK void Initiasllze QUEUE TYPE queue ptr queue ptr gt count 0 queue ptr gt front 0 Doc 7430 0026 Rev 01 Page 85 DMU380SA Series User s Manual MEMSIC queue ptr gt rear 1 KKK KR KKK KKK KK KK RK KK KK KK KK KK KK KK KK KK KK KK KK KK KK KK ck ck ck k ck kck ck KK k ck KK KK KK k FUNCTION AddQueue add item in front of queue ARGUMENTS item holds item to be added to queue queue ptr is pointer to the queue RETURNS returns 0 if queue is full 1 if successful ECKCkCkCk kCkck ck k kk kk k ck kk k ck kk Ck k kc k ck kk k ck k ck ck ck k ck ck k kc k ck k kc k ck kc k ck k kc k ck kk ck kk ck ck k kc k ck k ck ck kk kck ck kck kk kk int AddOueue char Item QUEUE TYPE queue ptr int retval 0 if queue ptr count gt MAXQUEUE retval 0 queue is full else queue ptr gt counttt queue ptr rear queue ptr rear 1 MAXQUEUE queue prtr centry queue ptr crear item retval 1 return retval f RKCK
47. 5509859 0632 5 050965009 820 5 9 6502559 0626 9 550002858 66 5 5 2 Set Pields Cormmatid iu vede u oo EE E 67 5 9 Redd Prclds Command s0cc sceseeccsssteceseesevedeassnniessestsecepsotecmaeessbedepnencderbesebeceanenee 68 8 10 Read Fields Response as sracasaccnessaeecnesennespsceaucneesasneenesaheeenaseaesaoseueseidaneesnaee eee 68 Doc 7430 0026 Rev 01 Page iil DMU380SA Series User s Manual MEMSIC gt 8 11 re Ce Ws C OPDHEDOHO axe cccentictateenceticoendetaceenesteceentetaverauansceancenacerecetscersteheternence 68 8 12 OGCEEIEIdS RES O steht aces na sot a SEEE ESE 69 Oe PRI a e U c E A E T P E E E E E A E E T 70 9 1 Built In Test BIT and Status Fields 2 0 eee 70 9 2 Master BIT and Status BITstatus Field een 72 NS hardware el MOYENS eee eee re ee ee ene ree eer eee 73 94 hardwarePower Bly Piel isssssccsccsesscsccsssssencsdaceatecasesdsdesnedeseaeseeeassdacderecsesdeiemadeies 73 9 5 hardwareEnvironmentalBIT Field eese eene 73 VEM colli TES 73 97 comsenalABIT Heldeccsescereercorenior ia EEEE 74 205 eines M SL EE ree eet ererertenrrer ete torres teeter 0 TET 74 ZUM viii E mcm 74 9 10 softwareAlgorithmBIT Field eeeeeeessssssssssssseeeeeeeeeen nnn 75 9 11 software DataB IT Field NR RR T E 75 9 12 bardwarestatus Field oean A 75 9 13 Como ES TU Pe a EE E E 75 9 14 s ftwareStatas Field NN H 76 9 15 sao aa e a a A AAE 76 9 16 Confi
48. 746 numFields 2 Get Fields Input A 1 Request Message Doc 7430 0026 Rev 01 Page 49 A A A 4 AJ 0x5430 Output Messages Measurement Data Continuous or Polled S0 0x5330 LL LL LL LL 0x5331 0x4131 J gt Ro 0x4132 c 0x4E30 30 24 32 30 32 0x4E31 42 1 1 Advanced Commands 0x5746 Ti 0x5746 TH 0x5346 TH 0x5346 h 0x5246 A A A A A A a 0x5246 LL LL LL LL LL LL LL TH DMU380SA Series User s Manual MEMSIC gt GF 0x4746 numFields 4 Get Fields Reply ALL 1 Response Message Doc 7430 0026 Rev 01 Page 50 DMU380SA Series User s Manual MEMSIC gt 7 Communicating with the DMU380SA Series T Link Test 7 1 1 Ping Command Ping PK 0x504B Packet Type Length Termination 0x5555 0x504B The ping command has no payload Sending the ping command will cause the unit to send a ping response To facilitate human input from a terminal the length and CRC fields are not required Example 0x5555504B009ef4 or 0x5555504B 7 1 2 Ping Response Ping PK 0x504B Packet Type Length 0x5555 0x504B lt CRC U2 gt The unit will send this packet in response to a ping command 7 1 3 Echo Command Echo CH 0x4348 Packet Type Length Payload 0x5555 0x4348 lt echo payload gt lt CRC U2 gt The echo command allows testing and verification of the communication link
49. CKCK kCKkCk kCkCkCk kk Ck kk kk kk KC kk KK kk KK kk Kk Ck Ck Ck ck ck kck ck k ck ck ck k ck ck k ck ck ck kc k ck kk ck ck k kk kk FUNCTION DeleteQeue return an item from the queue ARGUMENTS item will hold item popped from queue queue ptr is pointer to the queue BETURNS returns 0 if queue is empty 1 if successful CkCkCkCkck kk k kk k ck kk k ck k kc k kk k ck k kk ck k kc k kk k ck k kc k ck kc k ck kk ck ck k ck ck ck kc k ck kk ck ck k ck ck k kc k ck k ck ck k ck kck k kck kk kk int DeleteQueue char item QUEUE TYPE queue ptr int retval 0 i queue ptr coounmt lt U retval 0 queue is empty else queue prr gt count item queue ptr entry queue ptr rronr queue ptr gt front queue ptr fronttl MAXQUEUE retval 1 Doc 7430 0026 Rev 01 Page 86 DMU380SA Series User s Manual MEMSIC return retval Jf RKCKCKCK kCKkCkCKCkCkCk kk KK Kk KKK KKK KK KK KK KK kk KK kk Ck Ck kk ck ck k ck ck k ck ck ck k ck ck k ck ck ck k ck ck kk kk FUNCTION peekByte returns 1 byte from buffer without popping ARGUMENTS queue ptr is pointer to the queue to return byte from index is offset into buffer to which byte to return RETURNS 1 byte REMARKS does not do boundary checking please do this first KK KK KK KK k ck k kc k kk KK k ck kc k ck k kc k ck k kc IKK KK ck ck k kc KK KK KK ck ck k KK KK KK KK KK KK char peekByte QUEUE TYPE queue ptr unsigned int index cha
50. Cluster a ae rade sh E E SE BEB BBB BEHNHNEHNEHNEHEHEN BEEBE EES EBENEN X Y Z Body a m m Rates n Soon H E z isi M Sensor x Int ti to 100 H B Signal h Integration to ntegration to z a is Du Ea Calibration Attitude Velocity GPS X Y Z Body H Axes Rotation Position Output E Chain Accelerometers B El E a ummmumumuuuuumu5 P db bbb Sb BEEHEHNHNEHNEHNEHNEHNEHNHEHEEEN gEBEHBNEHENEEHNEHHEHEHEHEHNEENEHENEHEEHEEEEHENEEHEENEN ee EEENE H P P L a Unit Settings amp Profile g Extended Kalman Filter EKF a m m g Drift Correction Module a g Builtin Test m m amp Status E E u Data E E Available to E E User E u m Kalman Filter and Dynamic State Model m m H L L E L H L L H L H L L L m Hard Soft Iron Free Integrate UseGPS E a Calibration TurnSwitch Stationary Yaw S z UseMags Threshold Lock E H L il H u a Huummuuummumuumuuu bk dbi iibi Tnt m m eZ RRR BPR RR RRP RR RR RRR RRP u m T L Aiding Sensors E a R Gravity Reference a a E X Y Z T R E Ei Magnetometers urn dies GPS Data B m INS AHBS oni Internal Internal External B m only Computation o ii E m BENHNHNEHNHEHNHEHNHEHNEHHEHNEHNHHEHHNHEHHHEHHNHEHHHENHHEENHEHEEHENF m Beeeeeee Simplified functional block diagrams for INS AHRS and VG series products derived from Figure 14 are shown in Figure 15 to highlight key f
51. Connector Lom sm mt sm 50 Hs m L s me l1 s jme Doc 7430 0026 Rev 01 Page 8 DMU380SA Series User s Manual MEMSIC gt 3 Installation and Operation of NAV VIEW NAV VIEW has been completely redesigned to allow users to control all aspects of the DMU380SA Series operation including data recording configuration and data transfer For the first time you will be able to control the orientation of the unit sampling rate packet type hard iron calibration and filter settings through NAV VIEW 3 1 NAV VIEW Computer Requirements The following are minimum requirements for the installation of the NAV VIEW Software e CPU Pentium class 1 5GHz minimum e RAM Memory 500MB minimum 1GB recommended e Hard Drive Free Memory 20MB e Operating System Windows 2000 or XP e Properly installed Microsoft NET 2 0 or higher 3 1 1 Install NAV VIEW To install NAV VIEW onto your computer 1 Insert the CD Inertial Systems Product Support Part No 8160 0063 in the CD ROM drive 2 Locate the NAV VIEW folder Double click on the setup exe file 3 Follow the setup wizard instructions You will install NAV VIEW and NET 2 0 framework 3 2 Connections The DMU380SA Series Inertial Systems products are shipped with a cable to connect the DMU380SA Series to a PC Serial port 1 Connect the 9 pin micro DB connector end of the digital signal cable to the port on
52. MEMSIC DMUS3SOSA Series USER MANUAL Document Part Number 7430 0026 01 MEMSIC Inc 1759 McCarthy Blvd Milpitas CA 95035 Tel 408 964 9700 Fax 408 854 7702 email infoca memsic com website www memsic com A WARNING This product has been developed by MEMSIC exclusively for commercial applications It has not been tested for and MEMSIC makes no representation or warranty as to conformance with any military specifications or that the product is appropriate for any military application or end use Additionally any use of this product for nuclear chemical biological weapons or weapons research or for any use in missiles rockets and or UAV s of 300km or greater range or any other activity prohibited by the Export Administration Regulations is expressly prohibited without the written consent of MEMSIC and without obtaining appropriate US export license s when required by US law Diversion contrary to U S law is prohibited 2014 MEMSIC Inc All rights reserved Information in this document is subject to change without notice MEMSIC SoftSensor INS380SA AHRS380SA VG380SA and IMU380SA are registered trademarks of MEMSIC Inc Other product and trade names are trademarks or registered trademarks of their respective holders DMU380SA Series User s Manual MEMSIC gt Table of Contents e rodo 01 t I I LL Mannal VET 1CW 05 20 920995059090 909908986259 020089802 950 5930 8 995
53. S380SA and INS380SA units must be mounted at least 24 away from large ferrous objects and fluctuating magnetic fields Failure to locate the unit in a clean magnetic environment will affect the attitude solution 44 2 AHRS380SA Advanced Settings In addition to the configurable baud rate packet rate axis orientation and sensor low pass filter settings the AHRS380SA provides additional advanced settings which are selectable for tailoring the AHRS380SA to a specific application requirements The AHRS380SA advanced settings are shown in Table 12 Doc 7430 0026 Rev 01 Page 33 DMU380SA Series User s Manual MEMSIC gt Doc 7430 0026 Rev 01 Page 34 DMU380SA Series User s Manual MEMSIC Table 12 AHRS380SA Series Advanced Settings Baud Rate 38 400 9600 19200 57600 also available baud Packet 0 S1 A2 NO N1 also available Type Packet 25 Hz Rate Orientation Fig 12 Filter 20 Hz Settings accels 20 Hz rates Freely Integrate Restart On OFF Over Range Doc 7430 0006 Rev 01 o Page85 This setting sets the rate at which selected Packet Type packets are output If polled mode is desired then select Quiet If Quiet is selected the VG380SA will only send measurement packets in response to GP commands To configure the axis orientation select the desired measurement for each axes NAV VIEW will show the corresponding image of the AHRS380SA so it easy to visualize the mode of operation See
54. SIC representation e Onsite and factory training available e Preventative maintenance and repair programs e Installation assistance available 14 2 Contact Directory United States Phone 1 408 964 9700 8 AM to 5 PM PST Fax 1 408 854 7702 24 hours Email techsupportca memsic com Non U S Refer to website www memsic com 14 3 Return Procedure 14 3 1 Authorization Before returning any equipment please contact MEMSIC to obtain a Returned Material Authorization number RMA Be ready to provide the following information when requesting a RMA e Name e Address e Telephone Fax Email e Equipment Model Number e Equipment Serial Number e Installation Date e Failure Date e Fault Description e Will it connect to NAV VIEW 14 3 2 Identification and Protection If the equipment is to be shipped to MEMSIC for service or repair please attach a tag TO THE EQUIPMENT as well as the shipping container s identifying the owner Also indicate the service or repair required the problems encountered and other information considered valuable to the service facility such as the list of information provided to request the RMA number Doc 7430 0026 Rev 01 Page 92 DMU380SA Series User s Manual MEMSIC gt Place the equipment in the original shipping container s making sure there is adequate packing around all sides of the equipment If the original shipping containers were discarded use heavy boxes with adequate padding and protect
55. T and status definitions This field allows the user to determine which low level comStatus field signals will flag the comStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding comStatus field signal if asserted will cause the comStatus and masterStatus flags to be asserted in the BITstatus field 9 16 3 softwareStatusEnable Field This field is a bit mask of the softwareStatus field see BIT and status definitions This field allows the user to determine which low level softwareStatus field signals will flag the softwareStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding softwareStatus field signal if asserted will cause the softwareStatus and masterStatus flags to be asserted in the BITstatus field 9 16 4 sensorStatusEnable Field This field is a bit mask of the sensorStatus field see BIT and status definitions This field allows the user to determine which low level sensorStatus field signals will flag the sensorStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding sensorStatus field signal if asserted will cause the sensorStatus and masterStatus flags to be asserted in the BITstatus field Doc 7430 0026 Rev 01 Page 77 DMU380SA Series User s Manual MEMSIC gt 10 Appendix A Mechanical Specifications Figure 19 DMU380SA Series Outline Drawing
56. Ten n estes nccobasanieveocasanziacuoltesnetn coteacaieosocanaens 48 US EMIL Ic NR 48 MEE iei 968 UM E 48 6 3 6 Messaging OVeEUTO QU acu sostener tUsbeimurdiese el Ea E Eae delatae ten ed 48 7 Communicating with the DMU380SA Series sseseseseeeeeeeneeeneeeeeeeennennnnns 51 FANE i 51 Page ii Doc 7430 0026 Rev 01 DMU380SA Series User s Manual MEMSIC gt TL Ping COMMA essei o EE EtA Oa 51 Wade Po Rem E TES 51 TES HC INO DOUDCHUN E E ER 51 TIE EIO REDONS censes nn tn nn ee even iium mp e PPM UE 51 TZ Juterdcttye Commands sses aiai 51 P NER OMIM EO SIN m TU TIT 51 7 2 2 Algorithm Reset Command ssssssssesseeeee enn nennen 52 7 2 9 Algorithm Reset Response isesoccicsaeissszesnscasssesesranseaceecsseetasiaesnsdassaesterarsaacencd 52 TL4 Calibrate Command a sii ocior auae i etae eee Rogue SUN Ea Era a ea Nee ineo ce naro aues tio san deua pna se 52 7 2 5 Calibrate Acknowledgement Response ccccccccceccecceceeeseesessssseeeeeeeeees 53 7 2 06 Calibration Completed Parameters Respomnse ccccccccsssssssssseeeeeeeseeeeeees 53 ede dor IR CS OSC sc cscacesc sons aqreoancatdetaccanscoeayete poocaazaeeansaidseaesaccnoansetateoatant oansaienst 54 Ta Output Packets CP OCG m c M 54 7 3 1 Identification Data Packet 2 0 0 ceeccceeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 54 7 9 4 Version Data
57. The unit will respond with an echo response containing the echo data The echo data is N bytes long 7 1 4 Echo Response Echo Payload Contents Scaling Unis 0 eps Ui Webyeofedodia i echoData Ui Semdbfeofedodia e WW hota N2 feco Ut Sewdtksbyeoedo da Na echoData 01 Lastbyte ofecho data 7 2 Interactive Commands Interactive commands are used to interactively request data from the DMU380SA Series and to calibrate or reset the DMU380SA Series 7 2 1 Get Packet Request Get Packet GP 0x4750 Packet Type Length Payload 0x5555 0x4750 lt GP payload gt lt CRC U2 gt Doc 7430 0026 Rev 01 Page 51 DMU380SA Series User s Manual MEMSIC gt This command allows the user to poll for both measurement packets and special purpose output packets including T0 VR and ID GP Payload Contents Byte Offset an requestedPacketType e popo The requested packet type Refer to the sections below for Packet Definitions sent in response to the GP command 7 2 2 Algorithm Reset Command Algorithm Reset AR 0x4152 Packet Type Length Payload 0x5555 0x4152 o ew This command resets the state estimation algorithm without reloading fields from EEPROM All current field values will remain in affect The unit will respond with an algorithm reset response 7 2 3 Algorithm Reset Response Alg
58. These 6 DOF signals pass through one or more of the processing blocks and these signals are converted into output measurement data as shown Measurement data packets are available at fixed continuous output rates or on a polled basis The type of measurement data packets available depends on the unit type according to the software block diagram and Table 6 Aiding sensor data is used by an Extended Kalman Filter EKF for drift correction in the INS AHRS and VG Series products Built In Test and Status data is available in the measurement packet or via the special Status Packet TO As shown in the software block diagram the DMU380SA Series has a unit setting and profile block which configures the algorithm to user and application specific needs This feature is one of the more powerful features in the DMU380SA Series architecture as it allows the DMU380SA Series to work in a wide range of commercial applications by settings different modes of operation for the DMU380SA Series Doc 7430 0026 Rev 01 Page 22 DMU380SA Series User s Manual MEMSIC Figure 14 DMU380SA Series Software Block Diagram P Es Measurement IMU Scaled Packets VG AHRS Angl m E gie Data Available to S0 S1 Packets ee HERES a u S1 NO N1 User Fixed Rate All Units A1 A2 Polled INS AHRS VG 8 g OFFolle INS AHRS VG IMU INS AHRS VG BEEBE EBB Bees a a m a BEHNHNEHNEHNEHNEHNHNEHNHEEN BEEBE EBs Toe ee eee ep BEEBE eB eee El 6 DOF Sensor
59. U380SA Series Inertial Systems is significantly smaller compared to the prior generation Inertial Systems including MEMSIC s 440 Series IMU440 VG440 AHRS440 and INS440 and 350 series products The mounting plate foot print is the smaller and the connector is miniature For detailed mechanical and installation drawings see appendix A of the manual 1 3 2 Connector Pin Out amp Operating Voltage Current The micro DB9 female socket connector on MEMSIC s DMU380SA Series Inertial Systems is new to MEMSIC s product lines and provides a significant size reduction and performance improvement The DMU380SA Series has a secondary optional use communications port for internal or external GPS 1 3 3 Software Compatibility MEMSIC s DMU380SA Series Inertial Systems are software compatible with the MEMSIC 440 series products and 350 series products The DMU380SA Series products utilize the same extensible communication protocol as the 440 series and 350 series products The protocol is documented in section 7 of this manual 1 3 4 Operating Performance and Accuracy The DMU380SA Series has been characterized in a wide range of land and airborne applications In the qualification testing the dynamic accuracy of the DMU380SA Series has shown improved performance when compared to the equivalent model of 440 and 350 series products reducing attitude estimation errors in half during certain critical dynamic maneuvers without the use of GPS aiding W
60. VG380SA Table 11 VG380SA Default BIT Status Definition e 00000 omm E BlTstatus Field masterFail HardwareError comError NN NN CENT 0 nominal 1 Algorithm Initialization or High Gain hardwareStatus comStatus softwareStatus sensorStatus 0 nominal 1 Sensor Over Range Doc 7430 0026 Rev 01 Page 30 DMU380SA Series User s Manual MEMSIC gt The VG380SA also allows a user to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm Like the IMU380SA MEMSIC recommends for the vast majority of users that the default Status byte for the VG380SA is sufficient For users who wish to have additional visibility to when the VG380SA EFK algorithm estimates that the VG380SA is turning about its Z or Yaw axis the softwareStatus bit can be configured to go high during a turn In other words the turnSwitch will turn on the softwareStatus bit In the VG380SA the turnSwitch is by default set at 10 0 deg sec about the z axis 4 4 AHRS380SA Theory of Operation The AHRS380SA supports all of the features and operating modes of the IMU380SA and VG380SA and it includes an additional internal 3 axis magnetometer and associated software running on the ARM processor for the computation of dynamic heading as well as dynamic roll and p
61. aa 93 14 3 5 Return Shipping Address cc ccccssssssssssseseeecccccececeeseeeaaaseesesesseeeeeeeess 94 14 4 A En EA A EE E E E TU TN 94 Doc 7430 0026 Rev 01 Page v DMU380SA Series User s Manual MEMSIC gt About this Manual The following annotations have been used to provide additional information 4 NOTE Note provides additional information about the topic M EXAMPLE Examples are given throughout the manual to help the reader understand the terminology IMPORTANT This symbol defines items that have significant meaning to the user N WARNING The user should pay particular attention to this symbol It means there 1s a chance that physical harm could happen to either the person or the equipment The following paragraph heading formatting is used in this manual 1 Heading 1 1 1 Heading 2 1 1 1 Heading 3 Normal Page vi Doc 7430 0026 Rev 01 DMU380SA Series User s Manual 1 1 Manual Overview MEMSIC 1 Introduction This manual provides a comprehensive introduction to MEMSIC s DMU380SA Series Inertial System products For users wishing to get started quickly please refer to the three page quick start guide included with each shipment Table table highlights the content in each section and suggests how to use this manual Manual Section Section 1 Manual Overview Section 2 Connections Section 3 Installation and Operation of NAV VIEW Section 4 Theory of Operation
62. al visibility to when the AHRS380SA EFK algorithm estimates that the AHRS380SA is turning about its Z or Yaw axis the softwareStatus bit can be configured to go high during a turn In other words the turnSwitch will turn on the softwareStatus bit In the AHRS380SA the turnSwitch is by default set at 0 5 deg sec about the Z axis hardwareStatus 4 5 INS380SA Theory of Operation The INS380SA supports all of the features and operating modes of the IMU V G AHRS380SA and it includes an additional internal WAAS capable GPS receiver and associated software running on the ARM processor for the computation of navigation information as well as orientation information The product name INS380SA stands for Inertial Navigation System 380 and it is indicative of the navigation reference functionality that the INS380SA provides by outputting GPS information Latitude Longitude and Altitude inertially aided 3 axis velocity information as well as heading roll and pitch measurements in addition to digital IMU data An AHRS380SA configured and properly connected to an external GPS also behaves as a INS380SA At a fixed 100Hz rate the INS380SA continuously maintains the digital IMU data the dynamic roll pitch and heading data as well as the navigation data As shown in the software block diagram in Figure 10 after the Sensor Calibration block the IMU data is passed into an Integration to Orientation block The Integration to Orientation block
63. also respond to a ping command using the full packet formation with payload 0 and correctly calculated CRC Example 0x5555504B009ef4 6 3 1 Packet Header The packet header is always the bit pattern 0x5555 6 3 2 Packet Type The packet type is always two bytes long in unsigned short integer format Most input and output packet types can be interpreted as a pair of ASCI characters As a semantic aid consider the following single character acronyms P packet F fields Refers to Fields which are settings or data contained in the unit E EEPROM Refers to factory data stored in EEPROM R read Reads default non volatile fields G get Gets current volatile fields or settings W write Writes default non volatile fields These fields are stored in non volatile memory and determine the unit s behavior on power up Modifying default fields take effect on the next power up and thereafter S set Doc 7430 0026 Rev 01 Page 47 DMU380SA Series User s Manual MEMSIC gt Sets current volatile fields or settings Modifying current fields will take effect immediately by modifying internal RAM and are lost on a power cycle 6 3 3 Payload Length The payload length is always a one byte unsigned character with a range of 0 255 The payload length byte is the length in bytes of the lt variable length payload gt portion of the packet ONLY and does not include the CRC 6 3 4 Payload The payload is of variable length based
64. as an RS 232 serial communications link Doc 7430 0026 Rev 01 Page 25 DMU380SA Series User s Manual MEMSIC After passing thru a digitally controlled programmable low pass filter the rate and acceleration sensor signals are obtained at 200Hz The sensor data is filtered by the ARM using FIR filters The factory calibration data stored in EEPROM is used by the ARM to remove temperature bias misalignment scale factor errors and non linearities from the sensor data Additionally any advanced user settings such as axes rotation are applied to the IMU data The 200Hz IMU data is continuously being maintained inside the IMU380SA Digital IMU data is output over the RS 232 serial link at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command The digital IMU data is available in one of several measurement packet formats including Scaled Sensor Data S1 Packet In the Scaled Sensor Data SI Packet data is output in scaled engineering units See Section 7 of the manual for full packet descriptions IMPORTANT The Delta Theta Delta V packet is only recommended for use in continuous output mode at SHz or greater Polled requests for this packet will produce values accumulated since the last poll request and thus are subject to overflow data type wrap around 4 2 1 IMU380SA Advanced Settings The IMU380SA advanced settings are described in Table 8 below All of the
65. ate with no kalman filter based corrections of roll pitch or yaw When turned on there is no coupling of acceleration based signals into the roll and pitch As a result the roll pitch and yaw outputs will drift roughly linearly with time due to sensor bias For best performance the Freely Integrate mode should be used after the algorithm has initialized This allows the Kalman Filter to estimate the roll and pitch rate sensor bias prior to entering the free gyro mode Upon exiting the free gyro mode OFF one of two behaviors will occur 1 If the VG380SA has been in freely integrate mode for less than sixty seconds the algorithm will resume operation at normal gain settings 2 If the VG380SA has been in freely integrate mode for greater than sixty seconds the algorithm will force a reset and reinitialize with high gains automatically Restart On This setting forces an algorithm reset when a sensor over range occurs i e a rotational Over Range rate on any of the three axes exceeds the maximum range The default setting is OFF for the VG380SA Algorithm reset returns the VG380SA to a high gain state where the VG380SA rapidly estimates the gyro bias and uses the accelerometer feedback heavily This setting is recommended when the source of over range is likely to be sustained and potentially much greater than the rate sensor operating limit Large and sustained angular rate over ranges result in unrecoverable errors in roll and pitch
66. ation majorVersion changes may introduce serious incompatibilities minorVersion changes may add or modify functionality but maintain backward compatibility with previous minor versions patch level changes reflect bug fixes and internal modifications with little effect on the user The build stage is one of the following O release candidate 1 development 2 alpha 3 beta The buildNumber is incremented with each engineering firmware build The buildNumber and stage for released firmware are both zero The final beta candidate is v w x 3 y which is then changed to v w x 0 1 to create the first release candidate The last release candidate is v w x 0 z which is then changed to v w x 0 0 for release VR Payload Contents Doc 7430 0026 Rev 01 Page 54 DMU380SA Series User s Manual MEMSIC gt 0 majorverson Ui Major fmware version rt minorVersion Ui Minor fmware version 2 ph fui Patel 3 stage Development Stage release candidate 1 development 2 alpha 3 beta buldNumber Ut f Build number 7 3 3 Test 0 Detailed BIT and Status Packet Test T0 0x5430 Packet Type Length Payload 03 3x5555 0x5430 TO payload lt CRC U2 gt This packet contains detailed BIT and status information The full BIT Status details are described in Section 9 of this manual T0 Payload Contents O Bisaus U2 f f Master BIT and Status Field 2 hardwareBIT U2 f f Hardware BIT F
67. avier than air craft where movement of the wings in relation to the aircraft is not used to generate lift The term is used to distinguish from rotary wing aircraft where the movement of the wing surfaces relative to the aircraft generates lift The fixed wing aircraft can range in size from the smallest experimental plane to the largest commercial jet The dynamic characteristics of the fixed wing aircraft depends upon types of aircraft 1 g glider propeller aircraft and jet aircraft and mission phases 1 e launch landing and maneuver In order to meet application requirements users must dial in proper advanced settings so that the DMU380SA Series can provide the best possible solution under given dynamic conditions For example Table 16 provides the recommended advanced settings for four different dynamic conditions Table 16 Recommended Advanced Settings for Fixed Wing Aircraft Recommended AHRS380SA or INS380SA Product Dynamic Condition o Dmm Condon ume n Pre launch or known Normal straight and level un Dynamics High Dynamics accelerated flight Default A cutoff frequency of filters may be varied depending on the fastest dynamic mode of the aircraft For example the conventional aircraft has five dynamic modes short period phugoid spiral dutch roll and roll and the fastest one is the roll mode The natural frequency of this mode is around 6 8 radian sec or about 2 Hz in most cases Therefore the recommended filte
68. been in freely integrate mode for greater than sixty seconds the algorithm will force a reset and reinitialize with high gains automatically The Use Mags setting allows users to turn on and off the magnetometer feedback for yaw heading stabilization The default setting is ON for the AHRS380SA When Use Mags is turned ON the AHRS380SA uses the magnetic field sensor readings to stabilize the drift in yaw and it slaves the yaw to the compass reading provided from the magnetic field sensor readings When Use Mags is turned OFF the heading yaw angle measurement of the AHRS380SA will drift and freely integrate In effect this setting converts an AHRS380SA into the functionality of the VG380SA However unlike a VG380SA this can be done on a selectable basis and changed in real time during a mission The reason for this setting is to give the user an ability to turn off the magnetometer stabilization when severe magnetic distortion may be occurring This setting is desirable when the user system temporarily moves in close proximity to a large ferrous object When the Use Mags switch is turned from OFF to ON the AHRS380SA will reinitialize the yaw heading angle with the compass reading provided from the magnetic field sensor readings This setting forces an algorithm reset when a sensor over range occurs i e a rotational rate on any of the three axes exceeds the maximum range The default setting is OFF for the AHRS380SA Algorithm reset returns the
69. bration or algorithm fields If at least one field is successfully set the unit will respond with a set fields response containing the field IDs of the successfully set fields If any field is unable to be set the unit will respond with an error response Note that both a set fields and an error response may be received as a result of one set fields command Attempts to set a field with an invalid value is one way to generate an error response A table of field IDs and valid field values is available in Section 8 1 SF Payload Contents Byte Offset Units o oo U ooo fd QU 5 freo u uw uw uw E i eo fs s ae HN Thesecondfeeld ID s data to set e E C e 7 field1Data numFields 4 3 field U2 numFields 4 1 field Data U2 The last field ID to set The last field ID s data to set U1 U2 U2 U2 U2 U2 U2 U2 Set Fields Response Set Fields SF 0x5346 Packet Type Length Payload 0x5555 0x5346 1 numFields 2 lt SF payload gt lt CRC U2 gt The unit will send this packet in response to a set fields command if the command has completed without errors SF Payload Contents Byte Offset Units 0 mms Ui __ The number of las sa 1 feld u The second field ID sat eoo e Mr field IDs set 1 field0 U2 0 The first field ID set numFields 2 1 Field U2 f Thelastfield ID set Doc 7430 0026 Rev 01 Page 67 DMU380SA Series User s Manual MEMSIC g
70. c Motion ON ON When not in distorted magnetic environment 5 5 Water Vehicle Water vehicle is a craft or vessel designed to float on or submerge and provide transport over and under water Table 19 provides the recommended advanced settings for two different types of application Table 19 Recommended Advanced Settings for Water Vehicle Recommended Settings When not in distorted magnetic environment Doc 7430 0026 Rev 01 Page 44 DMU380SA Series User s Manual MEMSIC M EXAMPLE Figure 17 shows a typical flight profile of the fixed wing aircraft and the corresponding advanced settings that one can configure adaptively depending on a flight phase e Prelaunch is the phase of flight in which an aircraft goes through a series of checkups hardware and software on the ground before takeoff The aircraft is a static condition e Takeoff is the phase of flight in which an aircraft goes through a transition from moving along the ground taxiing to flying in the air usually along a runway The aircraft is under horizontal acceleration and may suffer from vibrations coming from an engine and ground contact forces transmitted from its landing gear e Climb is the phase of a flight after take off consisting of getting the aircraft to the desired flight level altitude More generally the term climb means increasing the altitude The aircraft is under vertical acceleration until it reaches the steady state climb rate
71. ch member of the DMU380SA Series with cross references to important sections for review Table 7 DMU380SA Series Overview mde rars O tmi IMU380SA 6 DOF Digital IMU Read 4 1 and 4 2 VG380SA 6 DOF IMU plus Dynamic Roll Pitch optional external Read 4 1 4 2 and 4 3 GPS AHRS380SA 6 DOF IMU with 3 Axis Internal Magnetometer Dynamic Read 4 1 4 2 4 3 and 4 4 Roll Pitch and Heading Optional External GPS INS380SA 6 DOF IMU with 3 Axis Internal Magnetometer and Read 4 1 4 2 4 3 4 4 and 4 5 Internal WAAS Capable GPS Receiver Position Dynamic Velocity and Dynamic Roll Pitch Heading Figure 13 shows the DMU380SA Series hardware block diagram At the core of the DMU380SA Series is a rugged 6 DOF Degrees of Freedom MEMS inertial sensor cluster that is common across all members of the DMU380SA Series The 6 DOF MEMS inertial sensor cluster includes three axes of MEMS angular rate sensing and three axes of MEMS linear acceleration sensing These sensors are based on rugged field proven silicon bulk micromachining technology Each sensor within the cluster is individually factory calibrated using MEMSIC s automated manufacturing process Sensor errors are compensated for temperature bias scale factor non linearity and misalignment effects using a proprietary algorithm from data collected during manufacturing Accelerometer rate gyro and magnetometer sensor bias shifts over temperature 40 C to 71 C are compensated and verif
72. d noise prior to further processing on the signal Installing the IMU380SA in the target environment and reviewing the data with NAV VIEW can be helpful to determine if changing the filter settings would be helpful Although the filter settings can be helpful in reducing vibration based noise in the signal low filter settings e g 5Hz also reduce the bandwidth of the signal 1 e can wash out the signals containing the dynamics of a target Treat the filter settings with caution Doc 7430 0026 Rev 01 Page 26 DMU380SA Series User s Manual MEMSIC gt 4 2 2 IMU380SA Built In Test The IMU380SA Built In Test capability allows users of the IMU380SA to monitor health diagnostic and system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there is a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each hardware and software subsystem in the IMU380SA See Sections 6 8 Programming Guide for details on the TO packet The BIT word which is contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal p
73. d settings The Advanced and BIT Configuration menus provide users with more detailed setting information that they can tailor to meet their specific needs To alter a setting simply select the check box on the left of the value that you wish to modify and then select the value using the drop down menu on the right side Once you have selected the appropriate value these settings can be set temporarily or permanently a software reset or power cycle is required for the changes to take affect by selecting from the choices at the bottom of the dialog box Once the settings have been altered a Success box will appear at the bottom of the page IMPORTANT Caution must be taken to ensure that the settings selected are compatible with the system that is being configured In most cases a FAIL message will appear if incompatible selections are made by the user however it 1s the users responsibility to ensure proper configuration of the unit IMPORTANT Doc 7430 0026 Rev 01 Page 13 DMU380SA Series User s Manual MEMSIC Unit orientation selections must conform to the right hand coordinate system as noted in Section 4 1 of this user manual Selecting orientations that do not conform to this criteria are not allowed Figure 7 Unit Configuration Unit Configuration General advanced BIT Configuration Field Modify Current Value Value to Set Baud Rate 1 57600 baud 57600 baud Y Packet Type Navo Packet Rate p
74. e below facing sides Free Integrate 60 seconds Use Mags Use GPS User Behavior Switches 0x0008 Any otationary Yaw Lock X Hard Iron Bias 0x0009 I2 scaled from 1 1 Y Hard Iron Bias 0x000A I2 scaled from 1 1 Soft Iron Scale Ratio 0x000B U2 scaled from 0 2 Heading Track Offset Heading Track Offset to use in NAV filter track 0x000C Any update mode Note BAUD rate SF has immediate effect Some output data may be lost Response will be received at new BAUD rate Gyro Filter Setting 0 2 Continuous Packet Type Field This is the packet type that is being continually output The supported packet depends on the model number Please refer to Section 6 4 for a complete list of the available packet types Doc 7430 0026 Rev 01 Page 62 DMU380SA Series User s Manual MEMSIC gt 0 3 Digital Filter Settings These two fields set the digital low pass filter cutoff frequencies See Table 23 Each sensor listed is defined in the default factory orientation Users must consider any additional rotation to their intended orientation Table 23 Digital Filter Settings Filter Setting FilterGyro Ux Uy Uz Rate FilterAccel Ux Uy Uz Accel 8 4 Orientation Field This field defines the rotation from the factory to user axis sets This rotation is relative to the default factory orientation connector aft baseplate down The default factory axis setting for the DMU380SA orientation field is Ux Uy Uz as shown in F
75. e hardwareBIT field 1s the bit wise OR of this hardwareEnvironmentalBIT field Table 32 DMU380 Hardware Environment BIT Field hardwareEnvironmentalBIT Field Bits _ Meaning ss Category pcbTemp 0 4 0 normal 1 out of bounds Rew 95 NA 96 comBIT Field The comBIT field contains flags that indicate communication errors with external devices See Table 33 Each external device has an associated message with low level error signals The comError flag in the BITstatus field is the bit wise OR of this comBIT field Table 33 DMU380 COM BIT Field comBiT Field Bis Menig Category seraiAEmr 0 Osmmaisem E seralbErr Reserved eis NA Doc 7430 0026 Rev 01 Page 73 DMU380SA Series User s Manual MEMSIC gt 9 7 comSerialABIT Field The comSerialABIT field See Table 34 contains flags that indicate low level errors with external serial port A the user serial port The serial AError flag in the comBIT field is the bit wise OR of this comSerialABIT field Table 34 DMU380 Serial Port A BIT Field comSerialABIT Field Bis Meaning Category transmitBufferOverflow LEN 0 normal 1 overflow receiveBufferOverflow 0 normal 1 overflow Reewd de NA 98 comSerialBBIT Field The comSerialBBIT field See Table 35 contains flags that indicate low level errors with external serial port B the aiding serial port The serialBError flag in the comBIT field
76. eatures of each product The DMU380SA Series products are mainly differentiated by types of aiding sensors used in the EKF for the drift correction of the 6 DOF inertial sensor cluster For the AHRS product a 3 axis magnetometer is used for correcting the drift on yaw heading angle For the INS product a 3 axis magnetometer and a GPS receiver are used for correcting the drift on yaw heading angle increasing the accuracy of the attitude estimation by incorporating these sensor signals into the EKF and providing a navigation solution The common aiding sensor for the drift correction for the attitude 1 e roll and pitch only is a 3 axis accelerometer This is the default configuration for the VG product Doc 7430 0026 Rev 01 Page 23 DMU380SA Series User s Manual MEMSIC gt Figure 15 Functional Block Diagram of INS AHRS and VG Default Operating Mode acces rates mags atttude voloaty GPS position nut fal NAV Mode NAY 440 or AHR SATO with Erina GPS hy AHRS Mode AHA S440 or NAVAAOG with loss of GPS accels rates rage attitude accels rates atstude heading yaw free drifting accels rates altitude velocity GPS position Cm fo WSS Made VG440 with External GPS al VG Mode vG440I 4 1 DMU380SA Series Default Coordinate System The DMU380SA Series Inertial System default coordinate system is shown in Figure 16 As with many elements of the DMU380SA Series the coordi
77. ects by selecting the Misalignment option on the Configuration Menu and viewing the magnetic circle during the calibration The AHRS380SA uses these measurements to model the hard iron and soft iron environment in your system and store these as calibration constants in the EEPROM The status of the AHRS380SA magnetometer calibration is indicated by the softwareError dataError gt magAlignOutOfBounds error flag available in the TO packet The current release of this software does not currently implement this feature however In future releases this functionality will be restored The user can access the hardIron and softIronScaleRatio calibration data as configuration fields in NAV VIEW or by using the communication protocol Also the softwareError bit of the masterFail byte within the BIT word is transmitted in every measurement packet When the AHRS380SA has not been properly calibrated this softwareError bit will be set to fail high The current release of this software does not currently implement this feature however In future releases this functionality will be restored In order for the AHRS380SA calibration to work properly the AHRS380SA must be installed in your system prior to calibration If you perform the calibration process with the AHRS380SA by itself you will only correct for the magnetism in the AHRS380SA itself If you then install the AHRS380SA in a vehicle for instance and the vehicle is magnetic you will still s
78. ee To configure the axis orientation select the desired measurement for each axes NAV Fig 12 VIEW will show the corresponding image of the INS380SA so it easy to visualize the l mode of operation See section 8 4 Orientation Field settings for the twenty four possible orientation settings The default setting points the connector AFT Filter Settings 20 Hz The low pass filters are set to a default of 20Hz for the accelerometers and 20Hz for the accels angular rate sensors There is one filter setting for all three angular rate sensors There is one filter setting for all three accelerometer sensors The reason for filtering the 20 Hz bM e accelerometers is that in many installations the vibration level can be high and it can prove helpful to filter accelerometers Freely Integrate The Freely Integrate setting allows a user to turn the INS380SA into a free gyro In free gyro mode the roll pitch and yaw are computed exclusively from angular rate with no kalman filter based corrections of roll pitch and yaw When turned on there is no coupling of acceleration based signals into the roll and pitch or magnetometer based signal to the yaw As a result the roll pitch and yaw outputs will drift roughly linearly with time due to sensor bias For best performance the Freely Integrate mode should be used after the algorithm has initialized This allows the Kalman Filter to estimate the roll and pitch rate sensor bias prior to entering the f
79. ee errors arising from the magnetism of the vehicle The AHRS380SA must be calibrated after installation and prior to use of the system The AHRS380SA also provides a command interface for initiating the hard iron soft iron calibration without the using NAV VIEW The user can send a WC command to initiate the calibration and then rotate the user system through 360 degrees The WC command has two options auto termination and manual termination With auto termination the AHRS380SA tracks the yaw movement and after 380 degrees of rotation returns the calibration complete response CD The auto termination sequence can falsely terminate if the 360 degree rotation is not completed within 2 minutes of the WC command initiation Manual termination requires the user to send a second WC command with the termination code in the payload Manual termination is a good option when the user system moves very slowly e g large marine vessel and completing the 360 degree rotation may require more than two minutes The calibration complete CD command response message contains the X and Y hard iron bias as well as the soft iron ratio and soft iron phase angle This information can be interpreted to give an indication of the quality of the calibration See Section 3 12 for more information on the hard iron bias and soft iron ratio Section 7 has programming details for the WC and CD commands N WARNING The AHR
80. ermeer 2 yAcoel 02 20216 g Yaccelerometer A Accel 0D 20246 g Zaccelerometer xRate 2 T pi 2 16 rad s X angular rate 1260 2 16 sec yRate 2 7 pi 2 16 rad s Y angular rate 10 zRate l2 7 pi 2416 rad s Z angular rate 26 GPSITOW U2 truncated ms GPS ITOW lower 2 bytes Not implemented BlTstatus ENG Master BIT and Status 7 4 2 Scaled Sensor Data Packet 1 Default IMU Data Scaled Sensor Data S1 0x5331 Packet Type Length Payload 0x5555 0x5331 S1 payload lt CRC U2 gt This packet contains scaled sensor data Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C 1 Payload Contents Name DAxd e XQ 6 sg Xaxeomde o ame g Y accelerometer 4 zes 2 2mw s Zaceeomer l2 T pi 2 16 rad s X angular rate 12607 2 16 Isec 2 T pi 2 16 rad s Y angular rate 12607 2 16 sec l a Z angular ri Doc 7430 0026 Rev 01 Page 56 DMU380SA Series User s Manual MEMSIC gt me p X DNE a In ra yRaeTem 12 20026 deg C Y rate temperature 18 boardTemp 2 200 2 16 deg C CPU board temperature 20 Contr U2 packets Output packet counter
81. figuration By enabling 4 given status BIT the signal will be included in the corresponding category BIT and in the master status BIT sent by the DMU Field Modify Current Value Enable Disable Hardware Status Enable O Unlocked 1PPS O Unlocked Internal GPS O No DGPS O Unlocked Eeprom EEN Software Staus Enable D O Algorithm Initializing O High Gain O Altitude Only alg O Turn Switch EE NI Sensor Status Enable P Bl Sensor Over Range Comm Status Enable O No External GPS Get All Values Set Values Temporary reset after reboot Permanant saved after reboot 3 12 Mag Alignment Procedure IMPORTANT The following section only applies to DMU380SA Series products with magnetometers AHRS and INS380SA If your particular model does not utilize magnetometers for heading or performance you can disregard Section 3 12 3 12 1 Hard lron Soft Iron Overview The AHRS and INS380SA products use magnetic sensors to compute heading Ideally the magnetic sensors would be measuring only earth s magnetic field to compute the heading angle In the real world however residual magnetism in your system adds to the total magnetic field measured This residual magnetism called hard iron and soft iron will create errors in the heading measurement if it is not accounted for In addition magnetic material can change the direction of the magnetic field as a function of the input magnetic field This dependence of
82. ftware block diagram the Integration to Orientation block receives drift corrections from the Extended Kalman Filter or Drift Correction Module In general rate sensors and accelerometers suffer from bias drift misalignment errors acceleration errors g sensitivity nonlinearity square terms and scale factor errors The largest error in the orientation propagation is associated with the rate sensor bias terms The Extended Kalman Filter EKF module provides an on the fly calibration for drift errors including the rate sensor bias by providing corrections to the Integration to Orientation block and a characterization of the gyro bias state In the AHRS380SA the internally computed gravity reference vector and the distortion corrected magnetic field vector provide an attitude and a heading reference measurement for the EKF when the AHRS380SA is in quasi static motion to correct roll pitch and heading angle drift and to estimate the X Y and Z gyro rate bias The AHRS380SA adaptively tunes the EKF feedback gains in order to best balance the bias estimation and attitude correction with distortion free performance during dynamics when the object is accelerating either linearly speed changes or centripetally false gravity forces from turns Because centripetal and other dynamic accelerations are often associated with yaw rate the AHRS380SA maintains a low passed filtered yaw rate signal and compares it to the turnSwitch threshold field user adju
83. guring the Master Status ccccccssssssssssssseeeeeceeeeeeeeeeeaeassesssesseseeeeeeees 76 9 16 1 hardwareStatusEnable Field 0 eee ceeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 76 9 162 comStatusEnable Field iseseisana oapenseesanacaras senses T1 9 16 3 softwareStatusEnable Field cesses eene eene 77 91604 SEMSORS AUIS Ale Fielden nanon ren nN NEENA NOREEN TI 10 Appendix A Mechanical Specifications esses 78 1 Appendix B NMEA Message Format cccccccccecccceeeeenseeeseeseeseeeceeceeeseeeenaaas 80 11 1 OGA GPS TIX Gate NETT m T TT 80 12 Appendix C Sample Packet Parser Code ccccccccecccceeeeeeeeeeaeaeesesseseseeeeeeeeees 82 12 1 S ag P 82 12 2 RS UE EDU 83 15 Appendix D Sample Packet Decoditig csccvascccsssdesssssssenssealeraaaceutaersoubessssssannesssen 89 14 Warranty and Support Information esses enne 92 14 1 reri Miel d e TETTE DOT 02 14 2 Sanrrvdbcead m T 92 14 3 BU PO CCI eaten os yeast ean cce sens ener seco se rentbe eecoanemnewt eee oesb een tna eekeean se 92 TDM PRAM OUT ZA CIO OTT 92 14 3 2 Identification and Protection ccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 92 Fes Oe ait die Contanos aE EE REEE 93 Page iv Doc 7430 0026 Rev 01 DMU380SA Series User s Manual MEMSIC gt INS MESE O ea
84. he manual before proceeding to use the INS380SA IMPORTANT For optimal performance the INS380SA utilizes GPS readings from its internal GPS receiver The GPS receiver requires proper antennae installation for operation See section 4 4 1 for information and tips regarding installation and calibration 4 5 1 INS380SA Magnetometer Calibration and Alignment The INS380SA requires the three axis magnetic field sensor to be calibrated while installed in its operating environment See section 4 4 1 for information and tips regarding installation and calibration and why magnetic calibration is necessary Please review this section of the manual before proceeding to use the INS380SA 4 5 2 INS380SA Advanced Settings In addition to the configurable baud rate packet rate axis orientation and sensor low pass filter settings the INS380SA provides additional advanced settings which are selectable for tailoring the INS380SA to a specific application requirements The INS380SA advanced settings are shown in Table 14 below Table 14 INS380SA Series Advanced Settings Default Comments Baud Rate 38 400 9600 19200 57600 also available baud Packet Type 90 1 A1 A2 NO also available Packet Rate 25 Hz This setting sets the rate at which selected Packet Type packets are output If polled mode is desired then select Quiet If Quiet is selected the INS380SA will only send measurement packets in response to GP commands Orientation S
85. here is a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for Turn Switch 0 5 With respect to centripetal or false gravity forces from turning dynamics or coordinated threshold deg sec turn the INS380SA monitors the yaw rate If the yaw rate exceeds a given Turnswitch Doc 7430 0026 Rev 01 Page 40 DMU380SA Series User s Manual MEMSIC each hardware and software subsystem in the INS380SA See Section 6 and 7 Programming Guide for details on the TO packet The BIT word contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is the masterFail flag The softwareError bit also provides useful information regarding the status and quality of the INS380SA magnetic alignment If the INS380SA has not been properly magnetically calibrated the INS380SA shall indicate a softwareError The masterStatus flag is a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which have been enabled See Advanced Settings for details for configuring the masterStatus flags Table 15 shows the BIT definition and default settings for BIT programmable alerts
86. ied using calibrated thermal chambers and rate tables The 6 DOF sensor cluster data is fed into a high speed microprocessor The processor outputs attitude and navigation data via the RS 232 port As shown in the block diagram Figure 13 the INS380SA and AHRS380SA include an internal 3 axis magnetometer and the INS380SA includes an internal WAAS capable GPS receiver In addition the AHRS380SA and VG380SA can accept input from external GPS sources as noted in Chapter 2 of this manual Doc 7430 0026 Rev 01 Page 21 DMU380SA Series User s Manual MEMSIC Figure 13 DMU380SA Series Hardware Block Diagram BERR RRR BRR RRR RRR RRR RRR eee ee eee eee gZ BBB Bee System Digital Outputs and Inputs Pins 3 4 5 6 X Y Z High Speed MEMSIC Serial Protocol Gyros Sampling amp X Y Z Acceleration X Roll Pitch Yaw Rate Vie Sensor X Y Z Magnetic Fields INS AHRS only Accelerometers Compensation Filtering Roll Pitch Yaw Angle Position Velocity NAV only Temperature Navigation amp Attitude Sensor Optional use Pins 4 6 Kalman Filter when configured as RS 232 6 DOF Sensor Cluster External GPS Input VG AHRS BEEBE Be eee m Sync 1 KHz Pulse GPS Receiver 3 External GPS 1 PPS Input X Y Z m Pin8 WAAS m ia site INS only GPS Antenna INS only Figure 14 shows the software block diagram The 6 DOF inertial sensor cluster data 1s fed into a high speed 200Hz signal processing chain
87. ield 4 hardwarePowerBIT_ U2 f Hardware Power BIT Field hardwareEnvironmentalBIT U2 op Hardware Environmental BIT Field U2 fa communication BIT Field 2 comSerialABIT U Communication Serial A BIT Field comSerialBBIT epo po Communication Serial B BIT Field 10 softwareBIT Software BIT Field softwareAlgorithmBlT U2 software Algorithm BIT Field U2 CEN um Software Data BIT Fid Hardware Status Fid Communication Staus Field Software Status Field Sensor Status Field softwareStatus 7 4 Output Packets Polled or Continuous 7 4 1 Scaled Sensor Data Packet 0 Scaled Sensor Data S0 0x5330 Packet Type Length Payload 0x5555 0x5330 S0 payload lt CRC U2 gt This packet contains scaled sensor data The scaled sensor data is fixed point 2 bytes per sensor MSB first for 13 sensors in the following order accels x y z gyros x y z mags x y z temps x y z board Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Doc 7430 0026 Rev 01 Page 55 DMU380SA Series User s Manual MEMSIC gt Accelerometers scaled to a range of 10 10 g Magnetometers scaled to a range of 1 1 Gauss Temperature scaled to a range of 100 100 C S0 Payload Contents o wAccel f 2 20216 g Xace
88. ield sensor readings When UseMags is turned OFF the heading yaw angle measurement of the INS380SA will be slaved to the GPS heading if GPS is available otherwise the heading will drift feely The reason for this setting is to give the user an ability to turn off the magnetometer stabilization when severe magnetic distortion may be occurring This setting is desirable when the user vehicle temporarily moves in close proximity to a large ferrous object When the Use Mags switch is turned from OFF to ON the INS380SA will reinitialize the yaw heading angle with the compass reading provided from the magnetic field sensor readings Restart On Over This setting forces an algorithm reset when a sensor over range occurs i e a rotational Range rate on any of the three axes exceeds the maximum range The default setting is OFF for the INS380SA Algorithm reset returns the INS380SA to a high gain state where the INS380SA rapidly estimates the gyro bias and uses the accelerometer feedback heavily This setting is recommended when the source of over range is likely to be sustained and potentially much greater than the rate sensor operating limit Large and sustained angular rate over ranges result in unrecoverable errors in roll and pitch outputs An unrecoverable error is one where the EKF can not stabilize the resulting roll and pitch reading If the over ranges are expected to be of short duration 1 sec and a modest percentage over the maximum operating
89. igure 18 below With this default orientation X is defined as opposite where the connector 1s pointing Z is down through the base and Y is created by making the final orthogonal axis right hand rule The user axis set is X Y Z as defined by this default orientation field loaded at the factory but this can be changed as per Table 24 Figure 18 DMU380 Orientation Field 0x0009 X Ux Roll Pitch Yaw Y Uy Z Uz Table 24 DMU380 Orientation Definitions Bis Meaning X Ars Sig o Ospsiwcmgae X A Y As Sig Y A Description Z Axis Sign 0 positive 1 negative Z Axis 0 Uz 1 Ux 2 Uy 3 N A Reserved There are 24 possible orientation configurations See Table 25 Setting Writing the field to anything else generates a NAK and has no effect Doc 7430 0026 Rev 01 Page 63 DMU380SA Series User s Manual MEMSIC gt Table 25 DMU380 Orientation Fields ec Fen 2 E H Ux Uy Uy Uz 0x008C Uz 0x0085 i 0x0092 Uy 03 ty DA ty mun 4 O08 x 3 J mo 5A 020 uz J 00150 UK 0x0159 amp Ux ES H2 3 8 5 User Behavior Switches This field allows on the fly user interaction with behavioral aspects of the algorithm See Figure 26 Table 26 DMU380 Behavior Switches pem mmm Free Integrate 0 use feedback to stabilize the algorith
90. in the INS380SA Table 15 INS380SA Default BIT Status Definitions won oy 0 normal 1 internal software error or magAlignOutofBounds BlTstatus Field masterFail HardwareError comError softwareError masterStatus 0 nominal 1 one or more status alert 0 nominal 1 Internal GPS unlocked or 1PPS Status invalid 0 nominal 1 Algorithm Initialization or high gain The INS380SA also allows a user to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm Like the IMU VG and AHRS380SA MEMSIC recommends for the vast majority of users that the default Status byte for the INS380SA is sufficient For users who wish to have additional visibility or alerts relative to the GPS sensor status or algorithm status they can configure additional triggers for both the softwareStatus and hardwareStatus See Sections 9 of the user s manual for all the BIT fields hardwareStatus comStatus softwareStatus Doc 7430 0026 Rev 01 Page 41 DMU380SA Series User s Manual MEMSIC 5 Application Guide 5 1 Introduction This section provides recommended advanced settings for tailoring the DMU380SA Series of inertial systems to different types of application and platform requirements 5 2 Fixed Wing Aircraft A fixed wing aircraft is a he
91. ion 14 3 3 Sealing the Container Seal the shipping container s with heavy tape or metal bands strong enough to handle the weight of the equipment and the container 14 3 4 Marking Please write the words FRAGILE DELICATE INSTRUMENT in several places on the outside of the shipping container s In all correspondence please refer to the equipment by the model number the serial number and the RMA number Doc 7430 0026 Rev 01 Page 93 DMU380SA Series User s Manual 14 3 5 Return Shipping Address Use the following address for all returned products MEMSIC Inc 1759 McCarthy Blvd Milpitas CA 95035 Attn RMA Number XXXXXX 14 4 Warranty The MEMSIC product warranty is one year from date of shipment Doc 7430 0026 Rev 01 MEMSIC gt Page 94 DMU380SA Series User s Manual MEMSIC gt MEMSIC 1759 McCarthy Blvd Milpitas CA 95035 Phone 408 964 9700 Fax 408 854 7702 Website www memsic com Email infoca memsic com Doc 7430 0026 Rev 01 Page 95
92. ion command Begin magnetic calibration with automatic termination Rotate the unit through 380 degrees in yaw The unit will send a CC response containing the hard iron and soft iron values upon completion of the turn To accept the 0x000C parameters store them using the write magnetic calibration command Write magnetic calibration The unit will write the parameters to EEPROM Ox000E and then send a calibration response 7 2 5 Calibrate Acknowledgement Response Calibrate WC 0x5743 Packet Type Length Payload 0x5555 0x5743 WC payload lt CRC U2 gt The unit will send this packet in response to a calibrate request if the procedure can be performed or initiated WC Payload Contents Byte Offset calibrationRequest Moro pog The requested calibration task 7 2 6 Calibration Completed Parameters Response Calibrate Completed CD 0x4344 Packet Type Length Payload 0x5555 Ox4344 CD payload lt CRC U2 gt The unit will send this packet after a calibration has been completed Currently there is only one message of this type sent after a magnetic calibration has been completed with or without automatic termination and the parameters have been calculated Thus the calibrationRequest field will be 0x000B or OxOO0C CD Payload Contents Byte Offset calibrationRequest op opo The requested calibration task 20046 G The x hard iron bias softlronScaleRatio U2 2 2 16 The scaling
93. is green and states Unit Connected you re ready to go If the status indicator doesn t say connected and 1s red check the connections between the DMU380SA Series product and the computer check the power supply and verify that the COM port is not occupied by another device 4 Under the View menu you have several choices of data presentation Graph display is the default setting and will provide a real time graph of all the DMU380SA Series data The remaining choices will be discussed in the following pages 3 4 Data Recording NAV VIEW allows the user to log data to a text file txt using the simple interface at the top of the screen Customers can now tailor the type of data rate of logging and can even establish predetermined recording lengths To begin logging data follow the steps below See Figure 3 1 Locate the icon at the top of the page or select Log to File from the File drop down menu 2 Thefollowing menu will appear Figure 3 Log to File Dialog Screen P Log to File Log File PO Browse Log Type Logging Rate Enginerring Data Fractional Rate C HexData C Raw Packets Hex Full Sample Rate C 4 2 Sample Rate C 4 4 Sample Rate C 4 10 Sample Rate C 1 100 Sample Rate Test Duration Days bo 4 Hours o 4 Samples Second y Minutes bf 4 Seconds Sample y Seconds o Cancel OK 3 Select the Browse box to enter the file name and location that you w
94. ish to save your data to 4 Select the type of data you wish to record Engineering Data records the converted values provided from the system in engineering units Hex Data provides the raw hex values separated into columns displaying the value and the Doc 7430 0026 Rev 01 Page 10 DMU380SA Series User s Manual MEMSIC gt 3 9 Raw Packets will simply record the raw hex strings as they are sent from the unit Users can also select a predetermined Test Duration from the menu Using the arrows simply select the duration of your data recording Logging Rate can also be adjusted using the features on the right side of the menu Once you have completed the customization of your data recording you will be returned to the main screen where you can start the recording process using the button at the top of the page or select Start Logging from the File menu Stopping the data recording can be accomplished using the Bl button and the recording can also be paused using the ll button Data Playback In addition to data recording NAV VIEW allows the user to replay saved data that has been stored in a log file l 3 6 To playback data select Playback Mode from the Data Source drop down Data Source LIVE Mode From DMU LIVE Made From DMU Playback Mode from File Selecting Playback mode will open a text prompt which will allow users to specify the location of the file they wish
95. itch The product name AHRS380SA stands for Attitude Heading Reference System 380 and it is indicative of the attitude and heading reference functionality that the AHRS380SA replicates by providing dynamic heading roll and pitch measurements in addition to the VG and IMU data The dynamic heading measurement is stabilized using the 3 axis magnetometer as a magnetic north reference As in the VG380SA the dynamic roll and pitch measurements are stabilized using the accelerometers as a long term gravity reference Unlike the AHRS400 and earlier MEMSIC AHRS Series products the AHRS380SA can be configured to turn on and off the magnetic reference for user defined periods of time see Section 8 Advanced Commands In addition the AHRS380SA can accept external GPS data refer to the INS380SA section for details for improved performance At a fixed 200Hz rate the AHRS380SA continuously maintains the digital IMU data as well as the dynamic roll pitch and heading As showing in Figure 10 after the Sensor Calibration Block the IMU data is passed to the Integration to Orientation block The Integration to Orientation block integrates body frame sensed angular rate to orientation at a fixed 200 times per second within all of the DMU380SA Series products For improved accuracy and to avoid singularities when dealing with the cosine rotation matrix a quaternion formulation is used in the algorithm to provide attitude propagation As also shown in the so
96. ith GPS aiding in the INS380SA attitude estimation is improved over the 440 series products Recommended product configuration settings are discussed in Section 5 and theory of operation is discussed in Section 4 Doc 7430 0026 Rev 01 Page 3 DMU380SA Series User s Manual MEMSIC gt 2 Connections 2 1 Connections The DMU380SA Series has a micro DB9 female connector as shown in Figure 1 The signals are as shown in Table 3 Figure 1 9 Pin Micro DB Connector Female Pinout Nm ON UJ A Un ONI oo N I oo E Table 3 Connector Pin Assignments Sg 0000000000000 7 Mode Select RS 232 Short RS 422 Open GPS 1PPS Output INS380SA Sync Pulse Input IMU VG and AHRS380SA Signal Return 2 2 I O Cable The user must provide a shielded cable with the shield connected to the I O connector shell in order to provide improved EMI protection The cable sent with the unit 1s intended to provide the user with the ability to test the unit right out of the box and will not provide adequate shielding for all environments A WARNING The cable sent with the unit is intended to provide the user with the ability to test the unit right out of the box and will not provide adequate shielding for all environments 2 3 Power Input and Power Input Ground Power is applied to the DMU380SA Series on pins 1 and 2 Pin 2 is ground Pin 1 should have 9 to 32 VDC unregulated at 350 mW
97. k ck k kc kck k kk k FUNCTION process xbow packet looks for packets in a queue ARGUMENTS queue ptr 1 pointer Lo queue to process result will contain the parsed info when return value is 1 RETURNS 0 when failed m 1 when successful KKK ck k kk kk k ck kk ck ck kk Ck kk ck ck k kk ck k ck ck k kk ck k kc k ck k ck ck kk Ck ck k kc k kk ck ck k kc k ck k ck ck kk ck ck k ck ck k ck kck k kck kk kk int process xbow packet OUEURB TYPE queue ptr XBOW PACKET result unsigned short myCRC 0 packetCRC counter 0 0 packet type D numToPop 0 char packet 100 tempchar dataLength if Empty queue ptr return 0 empty buffer Doc 7430 0026 Rev 01 Page 83 DMU380SA Series User s Manual MEMSIC find header PorinumrToPop 0 numToPoptlsSize queue ptr f numDoPopt l if 0x5555 peekWord queue ptr numToPop break Pop queue ptr numToPop LE Oize queue ptr lt 0 header was not found return 0 make sure we can read through minimum length packet if Size queue ptr lt 7 return 0 get data length 5th byte of packet databLength peekByte queue ptr 4 make sure we can read through entire packet LE Size queue ptr lt 7 dataLength return 0 check CRC myCRC calcCRC queue ptr 2 dataLengtht3 packetCRC peekWord queue ptr databengtht5 if myCRC packetCRC bad CRC on packet
98. libration accuracy The X and Y offset values indicate how far the magnetic field has been offset due to hard iron affects from components surrounding the unit In addition you will see a soft iron ratio indicating the effect of soft iron on the AHRS or INS380SA product 6 Save this data to the AHRS or INS380SA product by selecting the Apply button See Figure 11 Figure 11 Magnetometer Alignment Doc 7430 0026 Rev 01 Page 18 DMU380SA Series User s Manual MEMSIC gt Magnetometer Alignment New Settings x Hard Iron Offset Y Hard Iron Offset Soft Iron Ratio 0 035380 D 0184 0 99997 ms 7 Upon completion of the Mag Alignment Procedure the heading accuracy should be verified with all third party systems active using a known reference such as a compass rose GPS track or a calibrated compass Heading inaccuracies greater than the values specified on the data sheet or fluctuating heading performance may be an indication of magnetic field disturbances near the unit IMPORTANT An acceptable calibration will provide X and Y Hard Iron Offset Values of lt 2 5 and a Soft Iron Ratio gt 0 95 If this procedure generates any values larger than stated above the system will assert the softwareError gt dataError gt magAlignOutOfBounds error flag See section 9 for details on error flag handling Note that the current release of the software does not have this functionality Future releases of software will
99. m 1 6DOF inertial integration without stabilized feedback for 60 seconds Use Mags 1 0 Do not use mags to stabilize heading heading will run open loop or be stabilized by GPS track 1 Use mags to stabilize heading Use GPS 0 Do not use GPS to stabilize the system 1 Use GPS when available Stationary Yaw Lock 3 0 Do not lock yaw when GPS speed is near zero 0 75 m s 1 Lock yaw when GPS speed is near zero Restart on Over range 0 Do not restart the system after a sensor over range 1 restart the system after a sensor over range Dynamic Motion O vehicle is static force high gain corrections 17 vehicle is dynamic use nominal corrections Doc 7430 0026 Rev 01 Page 64 DMU380SA Series User s Manual MEMSIC gt 8 6 Hard and Soft Iron Values These fields allow access to hard iron bias and soft iron scale ratio values for magnetometer alignment See Table 27 Table 27 DMU380 Magnetic Alignment Parameters X Hard Iron Bias 0x0009 20 2 16 Y Hard Iron Bias 0x000A 20 26 Soft Iron Scale Ratio 0x000B 22M6 J e The hard iron bias values are scaled from 1 1 Gauss These values are subtracted from the tangent plane magnetometer vector before heading is calculated The soft iron scale ratio is scaled from 0 2 and is multiplied by the tangent plane x magnetometer value before heading is calculated 8 7 Heading Track Offset This field is used to set the offset between vehicle heading and vehicle track to
100. ments Table 17 provides the recommended advanced settings for two different dynamic conditions Table 17 Recommended Advanced Settings for Rotorcraft Recommended Product AHRS380SA or INS380SA Dynamic Condition Recommended Settings High Dynamics Normal Dynamics with uncoordinated tail motion FreelyIntegrate 0F OFF 2g lt 29 F Z Z UseMags ON ON Stationary Yaw Lock 5H 5H XY Filter Accel The helicopter can change its heading angle rapidly unlike the aircraft which requires banking A turn switch threshold that is too low may cause turn switch activation with high duty cycle causing random walk in roll and pitch angles due to low feedback gains ON ON OFF OFF Restart Over Range OFF ON 5 Hz 5 Hz A cutoff frequency must be far away from major frequency components caused by the rotor vibration 54 Land Vehicle Some examples of land vehicles are Automobiles trucks heavy equipment trains snowmobiles and other tracked vehicles Table 18 provides the recommended advanced settings for two different types of application Doc 7430 0026 Rev 01 Page 43 DMU380SA Series User s Manual MEMSIC Table 18 Recommended Advanced Settings for Land Vehicle Recommended Product VG380SA or INS380SA Dynamic Condition Recommended Settings Heavy Equipment y Equip Automotive Testing IMU and VG default Application UseMags UseGPS Stationary Yaw Lock Restart Over Range Dynami
101. nate system is configurable with either NAV VIEW or by sending the appropriate serial commands These configurable elements are known as Advanced Settings This section of the manual describes the default coordinate system settings of the DMU380SA Series when it leaves the factory With the DMU380SA Series product connector facing you and the mounting plate down the axes are defined as follows Figure 16 DMU380SA Series Default Coordinate System Y Z X axis from face with connector through the 380 unit Y axis along the face with connector from left to right Z axis along the face with the connector from top to bottom Doc 7430 0026 Rev 01 Page 24 DMU380SA Series User s Manual MEMSIC gt The axes form an orthogonal SAE right handed coordinate system Acceleration is positive when it is oriented towards the positive side of the coordinate axis For example with a DMU380SA Series product sitting on a level table it will measure zero g along the x and y axes and 1 g along the z axis Normal Force acceleration is directed upward and thus will be defined as negative for the DMU380SA Series z axis The angular rate sensors are aligned with these same axes The rate sensors measure angular rotation rate around a given axis The rate measurements are labeled by the appropriate axis The direction of a positive rotation is defined by the right hand rule With the thumb of your right hand pointing along the axis in a
102. nd to avoid singularities when dealing with the cosine rotation matrix a quaternion formulation is used in the algorithm to provide attitude propagation As also shown in the software block diagram the Integration to Orientation block receives drift corrections from the Extended Kalman Filter or Drift Correction Module In general rate sensors and accelerometers suffer from bias drift misalignment errors acceleration errors g sensitivity nonlinearity square terms and scale factor errors The largest error in the orientation propagation is associated with the rate sensor bias terms The Extended Kalman Filter EKF module provides an on the fly calibration for drift errors including the rate sensor bias by providing corrections to the Integration to Orientation block and a characterization of the gyro bias state In the VG380SA the internally computed gravity reference vector provides a reference measurement for the EKF when the VG380SA is in quasi static motion to correct roll and pitch angle drift and to estimate the X and Y gyro rate bias Because the gravity vector has no horizontal component the EKF has no ability to estimate either the yaw angle error or the Z gyro rate bias The VG380SA adaptively tunes the EKF feedback in order to best balance the bias estimation and attitude correction with distortion free performance during dynamics when the object is accelerating either linearly speed changes or centripetally false gravity force
103. omStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Doc 7430 0026 Rev 01 Page 75 DMU380SA Series User s Manual MEMSIC gt Table 40 DMU380 COM Status BIT Field comStatus Field Bits Meaning noExternalGPS 0 external GPS data is being received 1 no external GPS data is available N A 9 14 softwareStatus Field The softwareStatus field contains flags that indicate various software conditions and alerts that are not errors or problems See Table 41 The softwareStatus flag in the BITstatus field is the bit wise OR of the logical AND of the softwareStatus field and the softwareStatusEnable field The softwareStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Table 41 DMU380 Software Status Field softwareStatusField Bits Meaning algrthmnit 0 0 normal 1 the algorithm is in initialization mode 9 15 sensorStatus Field The sensorStatus field contains flags that indicate various internal sensor conditions and alerts that are not errors or problems See Table 42 The sensorStatus flag in the BITstatus field is the bit wise OR of the logical AND of the sensorStatus field and the sensorStatusEnable field The sensorStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up
104. on the packet type 6 3 5 16 bit CRC CCITT Packets end with a 16 bit CRC CCITT calculated on the entire packet excluding the 0x5555 header and the CRC field itself A discussion of the 16 bit CRC CCITT and sample code for implementing the computation of the CRC is included at the end of this document This 16 bit CRC standard is maintained by the International Telecommunication Union ITU The highlights are Width 16 bits Polynomial 0x1021 Initial value OXFFFF No XOR performed on the final value See Appendix C for sample code that implements the 16 bit CRC algorithm 6 3 6 Messaging Overview Table 21 summarizes the messages available by DMU380SA Series model Packet types are assigned mostly using the ASCH mnemonics defined above and are indicated in the summary table below and in the detailed sections for each command The payload byte length is often related to other data elements in the packet as defined in the table below The referenced variables are defined in the detailed sections following Output messages are sent from the DMU380SA Series inertial system to the user system as a result of a poll request or a continuous packet output setting Input messages are sent from the user system to the DMU380SA Series inertial system and will result in an associated Reply Message or NAK message Note that reply messages typically have the same lt 2 byte packet type U2 gt as the input message that evoked it but with a different payload
105. orithm Reset AR 0x4152 Packet Type Length 0x5555 0x4152 lt CRC U2 gt The unit will send this packet in response to an algorithm reset command 7 2 4 Calibrate Command Calibrate WC 0x5743 Packet Type Length Payload 0x5555 0x5743 lt WC payload gt lt CRC U2 gt This command allows the user to perform various calibration tasks with the DMU380SA Series See the calibration command table below for details The unit will respond immediately with a calibrate response containing the calibrationRequest received or an error response if the command cannot be performed WC Payload Contents Byte Offset Name Format Scaling Units calibrationRequest Moo pog The requested calibration task Currently magnetic alignment is the only function supported by the calibrate command There are two magnetic alignment procedures supported 1 magnetic alignment with automatic yaw tracking termination and magnetic alignment without automatic termination calibrationRequest Description 0x0009 Begin magnetic alignment without automatic termination Rotate vehicle Doc 7430 0026 Rev 01 Page 52 DMU380SA Series User s Manual MEMSIC gt through gt 360 degrees yaw and then send 0x000B calibration request to terminate Terminate magnetic alignment The unit will send a CC response containing the hard iron and soft iron values To accept the parameters store them 0x000B using the write magnetic calibrat
106. orrect CRC s will be ignored e Each complete communication packet must be transmitted to the DMU380SA Series inertial system within a 4 second period 6 2 Number Formats Number Format Conventions include e x as a prefix to hexadecimal values e single quotes to delimit ASCII characters e no prefix or delimiters to specify decimal values Table 20 defines number formats Table 20 Number Formats Size bytes Unsigned Char 1 Otos Unsigned Sto 2 oessa Unsignedint 4 002924 Doc 7430 0026 Rev 01 Page 46 DMU380SA Series User s Manual MEMSIC gt D signed Short HER 2 s Complement 2 15 to 2 15 1 Signed Short Shifted 2 s Complement Shifted to specified range Signed Int 4 2 s Complement 2 31 to 2 31 1 Floating Point EE Single 1 2 127 to 2 127 Precision SN Smp a a 6 3 Packet Format All of the Input and Output packets except the Ping command conform to the following structure 0x5555 2 byte packet type payload byte length variable length lt 2 byte CRC U2 gt U2 gt U1 gt payload gt The Ping Command does not require a CRC so a DMU380SA Series unit can be pinged from a terminal emulator To Ping a DMU380SA Series unit type the ASCH string UUPR If properly connected the DMU380SA Series unit will respond with PK All other communications with the DMU380SA Series unit require the 2 byte CRC Note A DMU380SA Series unit will
107. products allow for complete flexibility in configuration by the user Customers who wish to communicate with the DMU380SA Series system for sensor and navigation data should review Section 6 and 7 Section 8 is for users who wish to configure the DMU380SA Series operating parameters e g baud rate or power up output rate without NAV VIEW Doc 7430 0026 Rev 01 age Page 1 DMU380SA Series User s Manual MEMSIC gt 1 2 Overview of the DMU380SA Series Inertial Systems This manual provides a comprehensive introduction to the use of MEMSIC s DMU380SA Series Inertial System products listed in Table 2 This manual is intended to be used as a detailed technical reference and operating guide for the DMU380SA Series MEMSIC s DMU380SA Series products combine the latest in high performance commercial MEMS Micro electromechanical Systems sensors and digital signal processing techniques to provide a small cost effective alternative to existing IMU systems and mechanical gyros Table 2 DMU380SA Series Feature Description IMU380SA 6 DOF Digital IMU VG380SA 200 400 6 DOF IMU plus Roll and Pitch AHRS380SA 200 400 9 DOF IMU 3 Axis Internal Magnetometer plus Roll Pitch and Heading Standard Range High Range INS380SA 200 400 9 DOF IMU 3 Axis Internal Magnetometer and Internal WAAS Capable GPS Receiver plus Position Velocity Roll Pitch and Heading Standard Range High Range The DMU380SA Series is MEMSIC
108. provided by the internal GPS receiver when GPS timing is known on INS380SA products The I PPS output signal is open collector and should be interfaced to a rising edge trigger with pull up resistor between 1k and 10k ohms The INS380SA Series products synchronize sensor data collection to this 1PPS signal internally when available Therefore the 100Hz navigation algorithm will run exactly 100 times each second with no slip when locked to 1PPS Packet data is valid on the rising edge of IPPS and 10ms boundaries thereafter There is however up to 500us of additional latency in sensor data collection If 1PPS is provided by the internal GPS receiver in NAV products then the rising edge of IPPS will correspond to the UTC second boundary When the system is synchronized to 1PPS the hardwareStatus 2 unlocked1 PPS flag will be zero otherwise it will be one Figure 2 shows the sequential order of the signal present at 1 PPS OUT pin The 1 PPS signal is aligned to the sampling clock of 23 104 MHz This results in a timing resolution of 43 ns Figure 2 1PPS Output Signal GPS 8 30 00 GPS 8 30 01 TIMEPULSE 28 Sync Pulse Input Interface IMU VG and AHRS380SA The Sync Signal Input signal allows the user of IMU VG and AHRS 380 products to force synchronization of sensor data collection to an external synchronization signal 1 KHz The signal must maintain 0 0 0 2 V zero logic and 3 0 5 0 volts high logic Doc 7430 0026 Rev 01 Page 6
109. r byte int firstIndex firstindex queue ptr gt front index lt MAXQUEUE pyte e queus DLEI entry rirstrindex return byte KKK KKK KK KKK KK KK KK KK KK KKK KK KK KK KK Ck kCkCk KK KK ck ck ck k ck kck ck KK ck ck KK kK KK kK KK FUNCTION peekWord returns 2 byte word from buffer without popping ARGUMENTS queue ptr is pointer to the queue to return word from index is offset into buffer to which word to return RETURNS 2 byte word REMARKS does not do boundary checking please do this first HK KK KK kk kCk kk k ck kk ck ck k kc k ck k ck ck kk k ck k kc k ck kk ck kk ck ck k kc k ck kc k ck kk ck ck kk ck kk ck ck k kc k ck k ck ck kk kck k kck kk kk unsigned short peekWord QUEUE TYPE queue ptr unsigned int index 4 unsigned short word firstIndex secondIndex firstIndex queue ptr gt front index MAXQUEUE secondIndex queue ptr gt front index 1 MAXQUEUE word queue ptr entry firstliIndex lt lt 8 amp OxFEOO word 0x00FF amp queue ptr entry secondIndex return word f RKCKCKCK kCKkCkCkCkCkCk kk Ck KC KK RK KK KK KK Ck KK kk KK Kk KC kk Ck Ck kk kCk ck ck ck kck ck k kc k ck k ck ck k ck ck ck k kk kk FUNCTION Pop discard item s from queue ARGUMENTS queue ptr is pointer to the queue i numToPop is number of items to discard RETURNS return the number of items discarded Doc 7430 0026 Rev 01 Page 87 DMU380SA Series User s Manual MEMSIC
110. r setting would not reject desired frequency components or dynamic modes that one wants to capture However the larger the bandwidth or cutoff frequency is the noisier the corresponding signal is which may result in the performance degradation If the aircraft is operated under severe vibrations also the recommended filter setting may need to be further reduced in order to reject the frequency components caused by the vibration FreelyIntegrate should only be set to ON for severe launch conditions Normal takeoff dynamics that a standard aircraft would experience will see the best performance with this setting in the OFF position Doc 7430 0026 Rev 01 Page 42 DMU380SA Series User s Manual MEMSIC 5 3 Rotorcraft Rotorcraft is a category of heavier than air flying machines that use lift generated by rotors They may also include the use of static lifting surfaces but the primary distinguishing feature being lift provided by rotating lift structures Rotorcraft includes helicopters autogyros gyrodynes and tiltrotors The rotor blade dynamics itself is much faster than that of the fixed wing aircraft and contains high frequency components At the same time however it may cause severe vibrations on the airframe Also the overall dynamics translational and rotational motion of the rotor craft is much slower than the fixed wing aircraft due to a mechanical mechanism of rotors generating the aerodynamic forces and mo
111. range it is recommended that the restart on over range setting be turned off Handling of an inertial rate sensor over range is controlled using the restartOnOverRange switch If this switch is off the system will flag the overRange status flag and continue to operate through it If this switch is on the system will flag a masterFail error during an over range condition and continue to operate with this flag until a quasi static condition is met to allow for an algorithm restart The quasi static condition required is that the absolute value of each low passed rate sensor fall below 3 deg sec to begin initialization The system will then attempt a normal algorithm start Dynamic Motion The default setting is ON for the INS380SA Turning off the dynamic motion setting results in a higher gain state that uses the accelerometer feedback heavily During periods of time when there is known low dynamic acceleration this switch can be turned off to allow the attitude estimate to quickly stabilize threshold the feedback gains from the accelerometer signals for attitude correction are reduced because they are likely corrupted 4 5 3 INS380SA Built In Test As with the IMU VG and AHRS380SA the Built In Test capability allows users of the INS380SA to monitor health diagnostic and system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition t
112. rate If the yaw rate exceeds a given Turnswitch threshold the feedback gains from the accelerometer signals for attitude correction are reduced because they are likely corrupted EE See 4 3 2 4 3 2 VG380SA Built In Test As with the IMU380SA the VG380SA Built In Test capability allows users of the VG380SA to monitor health diagnostic and system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there is a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each hardware and software subsystem in the VG380SA See Sections 6 and 7 for details on the TO packet The BIT word contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is the masterFail flag The masterStatus flag is a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which have been enabled See Advanced BIT Section 9 for details on configuring the masterStatus flags Table 11 shows the BIT definition and default settings for BIT programmable alerts in the
113. ree gyro mode Upon exiting the free gyro mode OFF one of two behaviors will occur 1 Ifthe INS380SA has been in freely integrate mode for less than sixty seconds the algorithm will resume operation at normal gain settings 2 If the INS380SA has been in freely integrate mode for greater than sixty seconds the algorithm will force a reset and reinitialize with high gains automatically Doc 7430 0026 Rev 01 Page 39 DMU380SA Series User s Manual MEMSIC The Use GPS setting allows users to turn on and off the GPS feedback The default setting is ON for the INS380SA When Use GPS is turned OFF the INS380SA s behavior will revert to that of an AHRS380SA See the AHRS380SA Theory of Operation for detailed description Stationary Yaw This setting defaults to OFF on the INS380SA and it is recommended to be OFF for the INS380SA The stationary yaw lock setting is only recommended for consideration when the INS380SA is operating with GPS Use GPS ON and WITHOUT magnetometer feedback Use Mags OFF Stationary yaw lock may be appropriate if the user platform is a wheeled land vehicle Lock The Use Mags setting allows users to turn on and off the magnetometer feedback for yaw heading stabilization The default setting is ON for the INS380SA When Use Mags is turned ON the INS380SA uses the magnetic field sensor readings to stabilize the drift in yaw and it slaves the yaw to the compass reading provided from the magnetic f
114. rement packet After the initialization phase the AHRS380SA operates with lower levels of feedback also referred to as EKF gain from the accelerometers and magnetometers to continuously estimate and correct for roll pitch and heading yaw errors as well as to estimate X Y and Z rate sensor bias The AHRS380SA digital data is output over the RS 232 serial link at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command The AHRS400 supports the same scaled sensor and angle mode packet format of the VG380SA The AHRS380SA defaults to the A1 Angle Packet which outputs the roll angle pitch angle yaw angle and digital IMU data In the AHRS380SA the A1 packets contain accurate magnetometer readings See Sections 6 and 7 of the manual for full packet descriptions IMPORTANT For proper operation the AHRS380SA relies on magnetic field readings from its internal 3 axis magnetometer The AHRS380SA must be installed correctly and calibrated for hard iron and soft iron effects to avoid any system performance degradation See section 4 4 1 for information and tips regarding installation and calibration 44 1 AHRSS380SA Magnetometer Calibration and Alignment The AHRS380SA uses magnetic sensors to compute heading Ideally the magnetic sensors would measure only the earth s magnetic field to compute the heading angle In the real world however residual magnetism in yo
115. remove the bad packet from the queue and return Pop queue ptr dataLength t7 return 0 fill out result of parsing in structure result packet type peekWord queue ptr 2 result gt length peekByte queue ptr 4 Doc 7430 0026 Rev 01 Page 84 DMU380SA Series User s Manual MEMSIC result crc packetCRC for counter 0 counter lt result gt length counter t result e data counter peekByte queue ptr Stcounter Pop queue ptr databengthb t return 1 f RKCKCKCK kCKCkkCkCkCk kk Ck kk kk Ck KK Kk kk Ck KK kk KK kk KC kCkCk ck ck k ck ck k ck ck ck k ck ck k ck ck ck k ck ck kk k ko k kk k FUNCTION calcCRC calculates a 2 byte CRC on serial data using CRC CCITT 16 bit standard maintained by the ITU 5 International Telecommunications Union ARGUMENTS queue ptr is pointer to queue holding area to be CRCed il startIndex is offset into buffer where to begin CRC calculation num is offset into buffer where to stop CRC calculation RETURNS 2 byte CRC EOKCkCkCk kCkck ck k kk kk k ck kk k ck k kc k ck Ck k ck kk ck ck k ck ck ck k ck ck k kc k ck k kc k kk ck ck k kc k ck kc k ck kk ck ck k kc kckck ck ck kckckck ck kck kk kk unsigned short oaloCcRC QUEUE TYPE queue prr unsigned int startindex unsigned int num unsigned int i 0 j 20 unsigned short crc 0x1D0F non augmented inital value equivalent to augmented initial value OxFFFF for 105 3 nums i 1
116. restore this functionality The magnetometer ranges is 4 gauss thus 2 5 gauss is the recommended maximum hardiron that should be tolerated for the installation and still provide ample resolution and headroom to properly determine the earth s magnetic field strength lt 0 5 gauss If the hard iron estimates are larger than 2 5 gauss then a different installation location should be investigated 3 13 Read Unit Configuration NAV VIEW allows users to view the current settings and calibration data for a given DMU380SA Series unit by accessing the Read Configuration selection from the Configuration drop down menu See Figure 12 From this dialog users can print a copy of the unit s current configuration and calibration values with the click of a button Simply select the Read button at the top of the dialog box and upon completion select the Print or Print Preview buttons to print a copy to your local network printer This information can be helpful when storing hard copies of unit configuration replicating the original data sheet and for troubleshooting if you need to contact MEMSIC s Support Staff Figure 12 Read Configuration Doc 7430 0026 Rev 01 Page 19 DMU380SA Series User s Manual Read Unit Configuration Read Print Preview r Unit ID Model Version Serial Number Firmware Aoo O Contains Mags Architecture Product Configuration
117. rigger over range on accelerometer readings 4 3 VG380SA Theory of Operation The VG380SA supports all of the features and operating modes of the IMU380SA and it includes additional internal software running on the ARM processor for the computation of dynamic roll and pitch The product name VG380SA stands for Vertical Gyro 380 and it 1s indicative of the vertical gyro functionality that the VG380SA replicates by Doc 7430 0026 Rev 01 Page 27 DMU380SA Series User s Manual MEMSIC gt providing dynamic roll and pitch measurements in addition to the IMU data The dynamic roll and pitch measurements are stabilized by the using the accelerometers as a long term gravity reference Unlike the VG400 and earlier MEMSIC VG Series products the VG380SA can also output a free integrating yaw angle measurement that is not stabilized by a magnetometer or compass heading see AHRS380SA or INS380SA for stabilized heading At a fixed 200Hz rate the VG380SA continuously maintains both the digital IMU data as well as the dynamic roll and pitch data As shown in the software block diagram Figure 14 after the Sensor Calibration block the IMU data is passed into an Integration to Orientation block Please refer to the Figure 11 if external GPS aiding will be used The Integration to Orientation block integrates body frame sensed angular rate to orientation at a fixed 200 times per second within all of the DMU380SA Series products For improved accuracy a
118. roblem is the masterFail flag The masterStatus flag 1s a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which have been enabled See Advanced BIT Section 9 for details regarding the configuration of the masterStatus flags Table 9 shows the BIT definition and default settings for BIT programmable alerts in the IMU380SA Table 9 IMU380SA Default BIT Status Definition UBUseusFd o Meaning Caegy masterFail 0 0 normal 1 fatal error has occurred BT O Parmar 0cnemd hemderweeenr BT Rema a a mswSms le 0E roninai T Nen Sensor GverRange Seus termas o Om O Ses mew o NA The IMU380SA also allows a user to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm In the case of the IMU380SA which has fewer features and options than other DMU380SA Series products the only meaningful parameter is sensor over range It is recommended that users leave the default configuration which is sensorStatus enabled and flag on sensor over range The over range only applies to the rotational rate sensors Because instantaneous acceleration levels due to vibration can exceed the accelerometer sensor range in many applications none of the DMU380SA Series products t
119. s Unit Configuration General Advanced err Configuration Field Modify Current Value Value to Set User Behavior Switches E O Freely Integrate B Use Mags B Use GPS O Stationary Yaw Lock Restart Over Range Bl Dynamic Motion a1 itd 1 0 00000 EX 0 00000 H 0 00000 0 00 0 40 X Hard Iron Bias Y Hard Iron Bias 5 9 S E co e Soft Iron Scale Ratio Heading Track Offset T Turn Switch Threshold 10 00 ES 10 00 15 00 Filter XZ Accel r3 I in e Filter Y Accel Filter Rate Sensor i Set Values Temporary reset after reboot C Permanant saved after reboot 3 11 Bit Configuration The third and final tab of the unit configuration window is Bit Configuration See Figure 9 This tab allows the users to alter the logic of individual status flags that affect the masterStatus flag in the master BITstatus field available in most output packets By enabling individual status flags users can determine which flags are logically OR ed to generate the masterStatus flag This gives the user the flexibility to listen to certain indications that affect their specific application The masterFail and all error flags are not configurable These flags represent serious errors and should never be ignored Doc 7430 0026 Rev 01 Page 15 DMU380SA Series User s Manual MEMSIC Figure 9 BIT Configuration Unit Configuration General Advanced BIT Con
120. s empty O if not e Full return 1 if full O if not full The parser will parse the queue looking for packets Once a packet is found and the CRC checks out the packet s fields are placed in the XBOW PACKET structure The parser will then return to the caller When no packets are found the parser will simply return to the caller with return value 0 The XBOW PACKET stucture is defined as follows typedef struct xbow packet unsigned short packet type char length unsigned short crc char data 256 XBOW PACKET Typically the parser would be called within a loop in a separate process or in some time triggered environment reading the queue looking for packets A separate process might add data to this queue when it arrives It is up to the user to ensure circular queue integrity by using some sort of mutual exclusion mechanism withing the queue access funtions Doc 7430 0026 Rev 01 Page 82 DMU380SA Series User s Manual 12 2 Code listing include lt stdio h gt buffer size define MAXQUEUE 500 Jk circular queue TP typedef struct queue tag int count int front int rear char entry MAXQUEUE QUEUE TYPE MEMSIC packet ur typedef struct xbow packet unsigned short packet type char length unsigned short crc char data 256 XBOW PACKET QUEUE TYPE Cire Dur MEMSIC KKK KR KKK KKK KK KK Ck KK KK RK KK kk KK KKK kk KKK Ck KC kk Ck Ck kk ck k ck ck ck k ck ck k ck ck ck k c
121. s from turns Because centripetal and other dynamic accelerations are often associated with yaw rate the VG380SA maintains a low passed filtered yaw rate signal and compares it to the turnSwitch threshold field user adjustable When the user platform to which the VG380SA is attached exceeds the turnSwitch threshold yaw rate the VG380SA lowers the feedback gains from the accelerometers to allow the attitude estimate to coast through the dynamic situation with primary reliance on angular rate sensors This situation is indicated by the softwareStatus gt turnSwitch status flag Using the turn switch maintains better attitude accuracy during short term dynamic situations but care must be taken to ensure that the duty cycle of the turn switch generally stays below 10 during the vehicle mission A high turn switch duty cycle does not allow the system to apply enough rate sensor bias correction and could allow the attitude estimate to become unstable The VG380SA algorithm has two major phases of operation The first phase of operation is the initialization phase During the initialization phase the VG380SA is expected to be stationary or quasi static so the EKF weights the accelerometer gravity reference heavily in order to rapidly estimate the roll and pitch angles and X Y rate sensor bias The initialization phase lasts approximately 60 seconds and the initialization phase can be monitored in the softwareStatus BIT transmitted by default in each meas
122. s in order to properly initialize the rate sensor bias The initialization phase lasts approximately 60 seconds and the initialization phase can be monitored in the softwareStatus BIT transmitted by default in each measurement packet After the initialization phase the INS380SA operates with lower levels of feedback also referred to as EKF gain from the GPS accelerometers and magnetometers Digital data is output over the RS 232 serial link at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command In addition to the angle mode packets of the AHRS380SA and scaled sensor packets of the IMU380SA the INS380SA has additional output measurement packets including the default N1 Navigation Packet which outputs the Latitude Longitude Altitude X Y Z velocities accelerations and roll angle pitch angle yaw angle and digital IMU data See Section 6 and 7 of the manual for full packet descriptions IMPORTANT For proper operation the INS380SA relies on magnetic field readings from its internal 3 axis magnetometer The INS380SA must be installed correctly and calibrated for hard iron and soft iron effects to avoid any system performance degradation See section 4 4 1 for information and tips regarding installation and calibration and why magnetic Doc 7430 0026 Rev 01 Page 38 DMU380SA Series User s Manual MEMSIC calibration is necessary Please review this section of t
123. sed for the RS 422 Tx and Tx These settings allow interaction via a standard PC serial port The serial data settings can be configured on a DMU380SA Series unit with NAV VIEW In order to set the serial data interface select Unit Configuration under the Menu Tab 25 Serial GPS Interface INS380SA The internal GPS receiver in INS380SA products outputs data in NMEA 0183 format as defined by the National Marine Electronics Association NMEA Standard For Interfacing Marine Electronic Devices Version 2 20 January 1 1997 The packets are sent at 9600 Baud 8 data bits 1 start bit 1 stop bit no parity bit and no flow control and are output over the secondary serial interface RS 232 on pins 4 and 6 The GPS receiver outputs the following messages as shown in Table 4 Refer to Appendix B for the detailed message format Table 4 GPS Output Packet Format NMEA Record Global positioning system fixed data RMC Recommended minimum specific GNSS data VTG Course over ground and ground speed data 2 6 External GPS Aiding VG380SA and AHRS380SA The VG380SA AHRS380SA allows the use of an external GPS receiver to be connected to the secondary serial interface RS 232 on pins 4 and 6 port The user is required to configure the GPS receiver to output the GPS messages that the DMU380SA Series expects The table below shows the supported GPS protocols and guidelines for configuration Note that the details of the GPS messages can be found
124. stable When the user platform with the AHRS380SA attached exceeds the turnSwitch threshold yaw rate the AHRS380SA Doc 7430 0026 Rev 01 Page 31 DMU380SA Series User s Manual MEMSIC gt lowers the feedback gains from the accelerometers to allow the attitude estimate to coast through the dynamic situation with primary reliance on angular rate sensors This situation is indicated by the softwareStatus gt turnSwitch status flag Using the turn switch maintains better attitude accuracy during short term dynamic situations but care must be taken to ensure that the duty cycle of the turn switch generally stays below 10 during the vehicle mission A high turn switch duty cycle does not allow the system to apply enough rate sensor bias correction and could allow the attitude estimate to become unstable As described in 4 3 VG380SA theory of operation the AHRS380SA algorithm also has two major phases of operation The first phase of operation is the high gain initialization phase During the initialization phase the AHRS380SA is expected to be stationary or quasi static so the EKF weights the accelerometer gravity reference and Earth s magnetic field reference heavily in order to rapidly estimate the X Y and Z rate sensor bias and the initial attitude and heading of the AHRS380SA The initialization phase lasts approximately 60 seconds and the initialization phase can be monitored in the softwareStatus BIT transmitted by default in each measu
125. t 8 9 Read Fields Command Read Fields RF 0x5246 Packet Type Length Payload 0x5555 0x5246 1 numFields 2 RF payload lt CRC U2 gt This command allows the user to read the default power up configuration fields from the EEPROM NumFields is the number of fields to read The fieldO fieldl etc are the field IDs to read RF may be used to read configuration and calibration fields from the EEPROM If at least one field is successfully read the unit will respond with a read fields response containing the field Ds and data from the successfully read fields If any field is unable to be read the unit will respond with an error response Note that both a read fields and an error response may be received as a result of a read fields command 0 i nmre ut O The numberof feds torea 1 fedo fuz f Thefirstfield ID toread 3 i fieldt U2 f The secondfield IDtoread D 000 de Morefield Dstoread numFiel s2 1 Field U2 Thelastfield IDtoread 8 10 Read Fields Response Read Fields RF 0x5246 Packet Type Length Payload 0x5555 0x5246 1 numFields 4 lt RF payload gt lt CRC U2 gt The unit will send this packet in response to a read fields request if the command has completed without errors RF Payload Contents Byte Offset 0 nms Ui fe The numberof fields read field fu S The fist fed ID read 5 Treo Ul s ed U T fedibwa v
126. t data packets data sent to the DMU380SA Series and measurement output or response packet formats data sent from the DMU380SA Series This section of the manual explains these packet formats as well as the supported commands NAV VIEW also features a number of tools that can help a user understand the packet types available and the information contained within the packets This section of the manual assumes that the user is familiar with ANSI C programming language and data type conventions For an example of the code required to parse input data packets please see refer to Appendix C For qualified commercial OEM users a source code license of NAV VIEW can be made available under certain conditions Please contact your MEMSIC representative for more information 6 1 General Settings The serial port settings are RS232 with start bit 8 data bits no parity bit 1 stop bit and no flow control Standard baud rates supported are 9600 19200 38400 and 57600 Common definitions include e A word is defined to be 2 bytes or 16 bits e All communications to and from the unit are packets that start with a single word alternating bit preamble 0x5555 This is the ASCII string UU e All multiple byte values are transmitted Big Endian Most Significant Byte First e All communication packets end with a single word CRC 2 bytes CRC s are calculated on all packet bytes excluding the preamble and CRC itself Input packets with inc
127. tch sensorstatus Doc 7430 0026 Rev 01 Page 71 DMU380SA Series User s Manual MEMSIC gt e sensorStatus Field overRange enabled by default 9 2 Master BIT and Status BlTstatus Field The BITstatus field is the global indication of health and status of the DMU380SA Series product See Table 29 The LSB contains BIT information and the MSB contains status information There are four intermediate signals that are used to determine when masterFail and the hardware BIT signal are asserted These signals are controlled by various systems checks in software that are classified into three categories hardware communication and software Instantaneous soft failures in each of these four categories will trigger these intermediate signals but will not trigger the masterFail until the persistency conditions are met There are four intermediate signals that are used to determine when the masterStatus flag is asserted hardwareStatus sensorStatus comStatus and softwareStatus masterStatus is the logical OR of these intermediate signals Each of these intermediate signals has a separate field with individual indication flags Each of these indication flags can be enabled or disabled by the user Any enabled indication flag will trigger the associated intermediate signal and masterStatus flag Table 29 DMU380 BIT Status Field BiTstatusField Bits Meaning Category maseral 0 J O normal 1 fatal error has occ
128. te system called Earth Centered Earth Fixed ECEF ECEF uses three dimensional XYZ coordinates in meters to describe the location of a GPS user or satellite Several online resources are available to help users with this transformation For example refer to the application note on MEMSIC website http www memsic com support documentation inertial systems category 3 application notes html 4 1 1 Advanced Settings The DMU380SA Series Inertial Systems have a number of advanced settings that can be changed The specific settings available vary from unit to unit and a detailed description of each unit IMU VG AHRS and INS is found in the subsequent sections of this manual All units support baud rate power up output packet type output rate sensor low pass filtering and custom axes configuration The units can be configured using NAV VIEW as described in Section 3 and also directly with serial commands as described in Sections 6 9 4 2 IMU380SA Theory of Operation The product name IMU380SA stands for Inertial Measurement Unit 380 and the name is indicative of the inertial measurement unit functionality that the IMU380SA provides by providing inertial rate and acceleration data in 6 DOF six degrees of freedom The IMU380SA signal processing chain consists of the 6 DOF sensor cluster programmable low pass filters and the ARM signal processor for sensor error compensation The IMU380SA as with other DMU380SA Series variants h
129. the accelerometer feedback heavily During periods of time when there is known low dynamic acceleration this switch can be turned off to allow the attitude estimate to quickly stabilize Turn 0 5 With respect to centripetal or false gravity forces from turning dynamics or coordinated Switch deg sec turn the AHRS380SA monitors the yaw rate If the yaw rate exceeds a given Turnswitch threshold threshold the feedback gains from the accelerometer signals for attitude correction are reduced because they are likely corrupted 44 3 AHRS380SA Built In Test As with the IMU380SA and VG380SA the Built In Test capability allows users of the AHRS380SA to monitor health diagnostic and system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there is a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each hardware and software subsystem in the AHRS380SA See Sections 6 and 7 of the Programming Guide for details on the TO packet The BIT word contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem
130. ti state configurable Extended Kalman Filter EKF to correct for drift errors and estimate sensor bias values Another unique feature of the DMU380SA Series is the extensive field configurability of the units This field configurability allows the DMU380SA Series of Inertial Systems to satisfy a wide range of applications and performance requirements with a single mass produced hardware platform The basic configurability includes parameters such as baud rate packet type and update rate and the advanced configurability includes the defining of custom axes and how the sensor feedback is utilized in the Kalman filter during the navigation process The DMU380SA Series is packaged in a fully sealed lightweight housing which provides EMI vibration and moisture resistance to levels consistent with most land marine and airborne environments The DMU380SA Series utilizes an RS 232 serial link for data communication and each data transmission includes a BIT Built In Test message Doc 7430 0026 Rev 01 Page 2 DMU380SA Series User s Manual MEMSIC gt providing system health status The DMU380SA Series is supported by MEMSIC s NAV VIEW a powerful PC based operating tool that provides complete field configuration diagnostics charting of sensor performance and data logging with playback 1 3 Summary of Major Changes from the 440 Series and the 350 Series 1 3 1 Mechanical Size and Footprint The mechanical footprint of MEMSIC s new DM
131. to play back All three file formats are supported Engineering Hex and Raw for playback In addition each time recording is stopped started a new section is created These sections can be individually played back by using the drop down menu and associated VCR controls menu at the top Once the file is selected users can utilize the VCR style controls at the top of the page to start stop and pause the playback of the data NAV VIEW also provides users with the ability to alter the start time for data c playback Using the slide bar at the top of the page users can adjust the starting time Raw Data Console NAV VIEW offers some unique debugging tools that may assist programmers in the development process One such tool is the Raw Data Console From the View drop down menu simply select the Raw Data Console This console provides users with a simple display of the packets that have been transmitted to the unit Tx and the messages received Rx An example is provided in Figure 4 Doc 7430 0026 Rev 01 Page 11 DMU380SA Series User s Manual Figure 4 Raw Data Console gt Raw Data Console Tx 5555 504b 5555 4750 5555 4746 5555 4750 5555 504b 5555 4750 5555 4746 5555 4750 00 02 07 02 00 0z 07 0z 9ef4 4944 233d 0300010003071c 49f9 5652 4287 Sef4 4944 233d O30001000307lc 49f9 5652 4287 tfd8ffba0002z0000000ZzO0000ffzZlff5cOlaeg000000000000000000000000000 tfd8ffba 002000000
132. ur system will add to the magnetic field measured by the AHRS380SA This extra magnetic field will create errors in the heading measurement if they are not accounted for These extra magnetic fields are called hard iron magnetic fields In addition magnetic material can change the direction of the magnetic field as a function of the input magnetic field This dependence of the local magnetic field on input direction is called the soft iron effect The AHRS380SA can actually measure any constant magnetic field that is associated with your system and correct for it The AHRS380SA can also make a correction for some soft iron effects The process of measuring these non ideal effects and correcting for them is called hard iron and soft iron calibration This calibration will help correct for magnetic fields that are fixed with respect to the AHRS380SA It cannot help for time varying fields or fields created by parts that move with respect to the AHRS380SA Because time varying fields cannot be compensated selection of a proper installation location is important Doc 7430 0026 Rev 01 Page 32 DMU380SA Series User s Manual MEMSIC gt During the calibration procedure the AHRS380SA makes a series of measurements while the user system is being turned through a complete 360 degree circle A 360 degree rotation gives the AHRS380SA visibility to hard and soft iron distortion in the horizontal plane Using NAV VIEW a user can see the hard and soft iron eff
133. urement packet After the initialization phase the VG380SA operates with lower levels of feedback also referred to as EKF gain from the accelerometers to continuously estimate and correct for roll and pitch errors as well as to estimate X and Y rate sensor bias If a user wants to reset the algorithm or re enter the initialization phase sending the algorithm reset command AR will force the algorithm into the reset phase Doc 7430 0026 Rev 01 Page 28 DMU380SA Series User s Manual MEMSIC The VG380SA outputs digital measurement data over the RS 232 serial link at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command In addition to the scaled sensor packets described in the IMU380SA section the VG380SA has additional measurement output packets including the default A2 Angle Packet which outputs the roll angle pitch angle and digital IMU data NO and N1 packets are also available for use with an external GPS receiver See Section 6 and 7 of the manual for full packet descriptions 4 3 1 VG380SA Advanced Settings In addition to the configurable baud rate packet rate axis orientation and sensor low pass filter settings the VG380SA provides additional advanced settings which are selectable for tailoring the VG380SA to a specific application requirements These VG380SA advanced settings are shown in Table 10 below Table 10 VG380SA Series Ad
134. urred BIT Reseved ar a o masterStatus 0 nominal 1 hardware sensor com or Status software alert harwarestats o 0 nominal t programmableaien Sets Reed oe m O Doc 7430 0026 Rev 01 Page 72 DMU380SA Series User s Manual MEMSIC gt 93 hardwareBIT Field The hardwareBIT field contains flags that indicate various types of internal hardware errors See Table 30 Each of these types has an associated message with low level error signals The hardwareError flag in the BITstatus field is the bit wise OR of this hardwareBIT field Table 30 DMU380 Hardware BIT Field hardwareBIT Field Bits Meaning Category powetmr O Oznomat eror Soft mew s NA l 94 hardwarePowerBIT Field The hardwarePowerBIT field contains flags that indicate low level power system errors See Table 31 The powerError flag in the hardwareBIT field is the bit wise OR of this hardwarePowerBIT field Table 31 DMU380 Hardware Power BIT Field hardwarePowerBIT Field Bits Meaning Category inpPower 0 jO nomalt outofbounds Soft woFveRef 6 normal 1 outofbounds Soft gem 8 jO nomalt outofbounds Soft Reseved es NA j 95 hardwareEnvironmentalBIT Field The hardwareEnvironmentalBIT field contains flags that indicate low level hardware environmental errors See Table 32 The environmentalError flag in th
135. uts The EKF tracking states are reduced to angles and gyro bias only The accelerometers will continue to integrate velocity however accelerometer noise bias and attitude error will cause the velocity estimates to start drifting within a few seconds The attitude tracking performance will degrade the heading will freely drift and the filter will revert to the VG only EKF formulation The UTC packet synchronization will drift due to internal clock drift The status of GPS signal acquisition can be monitored from the hardwareStatus BIT as discussed in Section 4 5 3 INS380SA Built in Test From a cold start it typically takes 40 seconds for GPS to lock The actual lock time depends on the antenna s view of the sky and the number of satellites in view The ARM performs time triggered trajectory propagation at 100Hz and will synchronize the sensor sampling with the GPS UTC Universal Coordinated Time second boundary when available As with the AHRS380SA and VG380SA the algorithm has two major phases of operation Immediately after power up the INS380SA uses the accelerometers and magnetometers to compute the initial roll pitch and yaw angles The roll and pitch attitude will be initialized using the accelerometer s reference of gravity and yaw will be initialized using the leveled magnetometers X and Y axis reference of the earth s magnetic field During the first 60 seconds of startup the INS380SA should remain approximately motionles
136. vanced Settings 38 400 9600 19200 57600 also available baud A2 S1 NO N1 also available Packet Rate 25Hz This setting sets the rate at which selected Packet Type packets are output If polled mode is desired then select Quiet If Quiet is selected the VG380SA will only send measurement packets in response to GP commands Setting Baud Rate Packet Type Orientation See To configure the axis orientation select the desired measurement for each axes NAV Fig 12 VIEW will show the corresponding image of the VG380SA so it easy to visualize the mode of operation See Section 8 4 Orientation Field settings for the twenty four possible orientation settings The default setting points the connector AFT Filter 20 Hz The low pass filters are set to a default of 5Hz for the accelerometers and 20 Hz for the Settings 5 angular rate sensors There is one filter setting for all three angular rate sensors There 10 20 50 Hz are two settings for the accelerometers one for the X and Y axes and a separate setting for the Z axis The reason for a separate setting in the Z axis is that in many installations the Z axis vibration level is much higher than in the X and Y axes and it can prove helpful to filter the Z axis at a lower cutoff than the X and Y axes Freely The Freely Integrate setting allows a user to turn the VG380SA into a free gyro In free Integrate gyro mode the roll pitch and yaw are computed exclusively from angular r

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