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3DM-GX4 -25™ User Manual

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1. 0000000000000000 cece eee ec sees sese se esses re rers reis 61 13 1 1 Sensor Dimensions and Origin 0 2 20 2020 00c0ceccececcececcececcececcececcecececeececes 61 13 1 2 Power Supply Specifications RS232 kits only 62 13 1 3 Communication and Power Cables ccc cece cece eee cece cece ee eee 63 13 2 Reference Documents 2 cece cece eee cence eee cece ce cece ee eens lese e ense eei 64 Wee AROS SEI oe on te shee ret tS Se lee RENE 65 W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual System Overview 1 System Overview The LORD MicroStrain family of industrial and tactical grade inertial sensors provide a wide range of triaxial orientation measurements and computed navigation solutions In all models the Inertial Measurement Unit IMU includes direct measurement of acceleration and angular rate and some also offer atmospheric pressure readings Sensor measurements are processed through an Extended or Adaptive Kalman Filter EKF AKF to produce highly accurate computed outputs The computed outputs vary between models and include pitch and roll in the 3BDM GX4 15 IMU VRU model the full attitude solution pitch roll and yaw in the 3DM GX4 25 AHRS model and the full PVA position velocity and attitude solution in the 3DM GX4 45 and 3DM RQ1 45 GPS INS and 3DM GQ4 45 GNSS INS models The Kalman fil
2. 84 21 3 SENSOR ORIGIN 44 11 1 13 3 2 m 4 5 ALL DIMENSIONS ARE IN INCHES mm Figure 34 3DM GX4 Sensor Origin W4 LORD MicroStrain 9 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum 13 1 2 Power Supply Specifications RS232 kits only The power supply is only required for the RS232 devices These specifications describe the power supply included in the 3DM GX4 starter kit 31 0mm 1 22 in 7 1 77 in 1914 7mm 75 38in Operating Parameters AC input voltage rating 100 to 240V ac AC input voltage range 90 to 264 V ac AC input frequency range 47 to 63 Hz 0 25 A RMS maximum 120 V ac 0 125 A RMS maximum 240 V ac Leakage current 0 25 mA maximum Q 254 V ac Inrush current 30 A for 120V ac maximum load cold start e 25 C 60 A for 240 V ac maximum load AC input current Input power savin a DC voltage rating DC load capacity Ripple Holdup time Circuit protection gt 120 auto restart Over voltage protection gt 120 zener clamp Safely approvals Operating temperature Storage temperature 10 to 90 Emissions FCC Class B EN55022 Class B Dielectric withstanding hi pot test Physical Specifications primary to secondary 3000 V ac Wim 200 DC output connector 2 1 mm x 5 5 mm center positive stan
3. Write Spherical Fit write calibration to sensor PLOT CONTROL Clear Plots Re Plot Data Plot Local Field DATA FILE C Save Data fs save calibration Figure 24 Collect Calibration Data 5 When all possible rotations are completed select Stop Streaming next to Collect Data and then select Save Data to save the calibration data points on the host computer Figure 24 Collect Calibration Data W4 LORD MicroStrain ka SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual 33 6 Clickthe Spherical Fit or Ellipsoid Fit button depending on the application Spherical Fitis often best for applications with calibration rotations restricted to a 2D plane for example a ground vehicle or a boat because it will not likely not be rotated on all three axis Ellipsoid Fit is generally a better correction when soft iron effects are present but only if enough data points can be collected in all quadrants If the range of motion is restricted in one dimension the Spherical Fit may be the best choice If there are enough points in all dimensions the Ellipsoid Fit may be better Generally if the Spherical and Ellipsoid Fits are close in the mean diameter then the Ellipsoid Fit will be the best choice Click Write Spherical Fit or Write Ellipsoid Fit accordingly This will write the values to the sensor memory Cycle power to the sensor when prompted and then use the Refr
4. LORD USER MANUAL 3DM GX4 25 Attitute Heading Reference System AHRS W4 LORD MicroStrain SENSING SYSTEMS W4 LORD MicroStrain SENSING SYSTEMS MicroStrain Sensing Systems 459 Hurricane Lane Suite 102 Williston VT 05495 United States of America Phone 802 862 6629 Fax 802 863 4093 http www microstrain com sensing_support LORD com sensing sales LORD com Copyright O 2015 LORD Corporation 3DM 3DM DH 3DM DH3 3DM GX19 3DM GX2 3DM GX3 3DM GX4 15 3DM GX4 25 3DM GX4 45 3DM GX4 3DM RQ1 3DM GQ4 AIFP Ask Us How Bolt Link DEMOD DC DVRT DVRT Link EH Link EmbedSense ENV Link FAS A G Link G Link2 HS Link IEPE Link Inertia Link Little Sensors Big Ideas Live Connect LXRS MathEngine MicroStrain MVEH MXRS Node Commander PVEH RHT Link RTD Link SensorCloud SG Link Shock Link Strain Wizard TC Link Torque Link V Link Watt Link Wireless Simplicity Hardwired Reliability and WSDA are trademarks of LORD Corporation Document 8500 0047 Revision D Subject to change without notice 3DM GX4 25 Attitute Heading Reference System User Manual 1 Table of Contents System Overview l 0 0 c ccc ce cece ccc ecccceceececeecececceceeeececseceecseveceetecsveceeveceeeeeeeees 6 2 Sensor Overview uu 7 2 1 Components oee eg AA 8 2 2 Interface and Indicators ecce ala GG
5. and come with the sensor starter kits These cables will have the micro DB9 connector on one end to connect to the sensor and either a standard DB9 on the other end for RS232 communication or a USB connector for USB communications Alternately the micro DB9 can be purchased from LORD MicroStrain with flying leads or the connector by itself can be purchased from the manufacturer Ulti Mate Connector Inc See Parts and Configurations on page 54 for a list of available options a standard DB9 on the other end For the cable diagram see Reference Diagrams on page 61 The connector interface includes connections for USB and RS232 communications only connect one two options for sensor input power range only connect one and a precision hardware timing input PPS input for synchronizing with external timestamps The sensor selects the appropriate serial communication USB or RS232 on power up based on which connection is used sensor pin number 3 2V to 5 5 VDC RS232 RxD 5 2V to 36 VDC s Ramo sensor connector use either pin 3 OR pin 6 for sensor power Figure 31 Connector Wiring W4 LORD MicroStrain Mi SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual OEM System Integration 7 3 Sampling on Start up The Save Current Settings command can be used to instruct the sensor to start streaming data as soon as it powered on This can be useful in sensor integration applications in
6. 2 Sensor Overview The 3DM GX4 25 is a high performance miniature Attitude Heading Reference System AHRS that combines micro inertial sensors for use in a wide range of industrial grade applications such as unmanned vehicle navigation robotic control platform stabilization motion tracking and analysis vehicle health monitoring and device aiming The 3DM GX4 25 utilizes the strengths of integrated multi axis gyroscopes accelerometers and magnetometers in combination with temperature and pressure readings to provide highly accurate attitude including heading and inertial measurements Each of the integrated sensors is especially good at certain tasks and it is the weighted combination of their outputs that provides the best estimations for attitude All sensor measurements are temperature compensated and are mathematically aligned to an orthogonal coordinate system The combination of sensors environmental compensation and dual on board processing with an Adaptive Kalman Filter AKF allows the 3DM GX4 25 to perform well in a wide variety of applications that require low noise drift gain and offset errors Uncertainty monitoring and bias estimation outputs are available and settings for sensor filtering sensor noise sensor bias and more offer many adjustments for specific application needs The 3DM GX4 25 communicates through a serial connection and is monitored by a host computer Sensor measurements and computed o
7. A third source of error occurs when attempting to navigate between geographic way points expressed in latitude and longitude This error is due to the difference between detecting magnetic north which is output by the AHRS sensor and true north which is used to define lines of longitude If the AHRS is always used in one geographical location the user can correct for this difference using a constant offset If the AHRS is used over a wide range of longitude the magnetic declination must be calculated from a magnetic model The 3DM GX4 25 runs a Adaptive Kalman Filter with a full state dynamics model The state propagation utilizes Newton s and Euler s equations of motion with the acceleration and angular rate treated as control inputs The IMU magnetometer is available to correct heading mis alignments which occur during periods of low dynamics The magnetometer corrections can be disabled for applications where large non constant magnetic interference sources exist which would impair their use such as when mounting the 3DM GX4 25 on a gimbal close to the frame of a ground vehicle The Kalman filter attitude for a total of 16 states 4 attitude quaternion 3 accel bias 3 gyro bias 3 accel scale factor and 3 gyro scale factor The bias states are estimated in order to compensate for the time varying biases inherent in MEMS inertial sensors which are the largest error sources for these devices The bias states are subtracted from the
8. AG kan a Ga 9 Basic Setup and Operations o oon eee eee nee c ee arrani 10 3 1 Software Installation ERRORES NCI 11 3 2 System Connections La 12 3 3 Software Interab ank ot e bees see Eo Ue o deu ope Dou vay eucs oe Ede va OM CE SERERE E 13 3 3 1 Interactive Help Menu 020 cece ccc ec cece ec ccccecceceeceeceeeceeeeeceeceeceeeeseeeees 13 3 4 Sensor Communication oce ceteri de beh ade Rabe dae else ce A EDAD E KAN Gorg eroe dad Ege 14 3 5 Sensor Settings RENTRER CR 15 3 5 1 Saving Configurations 2 0 2 0 0ccc cece cece cece ccc ccceceececeececcececcececsececseceseese 16 3 6 Data Monitoring and Recording 0 200 c cece ccc ec eee eee ec cece ess e ee se ne se selle 17 3 7 Viewing Data c cece cece cece Ie se ee se ceeeeecueceeceeeeecereseeeeeeesees 20 Sensor Measurements aaa 21 4 1 Direct Sensor Measurements IMU Outputs eee cece eee cece cece eee es 22 4 2 Computed Outputs Estimation Filter AHRS 00 0 000 c cee eee cece eee eee ee eee eene 24 4 3 Sensor Reference Frames 0e cece cece ce cence eee cece cece ee ee ees sese nene e niei 26 4 3 1 Geodetic Frame mE 26 4 3 2 North East Down NED Frame 0 27 LAG Sensor Frama MEME 28 4 34 Platform Rrame sssr ER TOE a MR O REN 29 Performance Optimization 0 00 ccc cece cece cecccceccececeececececeececeec
9. Manual Troubleshooting Problem Possible cause and recommended solution 3 4 sensor data not recorded Verify data recording has been activated In MIP Monitor the device status information field will indicate Recording Data If the sensor isn t recording activate in the software Verify specific measurements have been enabled for sampling and recording NOTE Data is recorded in time sequence If measurements are set to different sample rates not all time intervals will include a reading from each output that is being recorded 3 5 sensor data recorded in binary format When data recording is started the user can choose between CSV and Binary output formats If the data is recorded in Binary format it will require a translation program that utilizes the LORD MicroStrain MIP Data Communications Protocol to make it readable 3 6 sensor has been magnetized Contact or close proximity with magnets may disrupt the sensor operation and cause magnetization of internal components which can affect magnetometer performance If magnetization is suspected use a degaussing tool to demagnetize 3 7 sensor is damaged With the sensor in a static neutral position data look for baseline offset or drift on the IMU sensor outputs Sensor damage can occur as a result of excessive g force other conditions outside of its operating specifications W4 LORD MicroStrain gt SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System Use
10. and the sensor will be non responsive Contact LORD MicroStrain 9 Technical Support See Technical Support on page 52 1 5 sensor is damaged If all power settings and connections have been verified and the sensor is still unresponsive contact LORD MicroStrain 9 Technical Support See Technical Support on page 52 2 1 sensor not found in MIP Monitor 2 COMMUNICATION In MIP Monitor use the Refresh button to look for the sensor again If the sensor is still not found try cycling power to the no communication to i sensor and refreshing sensor or GPS receiver 2 2 communication cable not connected or miswired Check remove and reconnect communications and power cables as applicable Replace or rewire as needed 2 3 device drivers not installed Verify the drivers included with MIP Monitor Software Suite are installed on the computer and that the software has had W4 LORD MicroStrain a SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Troubleshooting Problem Possible cause and recommended solution sufficient time to detect it See Software Installation on page 11 2 4 serial baud rate setting not applicable to USB devices The host computer serial port baud rate and the sensor baud settings must match in order for communication be established In MIP Monitor this occurs automatically and the baud rate can only be changed once initial communication is established To change the
11. based statellites used to triangulate position co ordinates and provide time information for navigational purposes Gyroscope a device used to sense angular movements such as rotation H Heading an object s direction of travel with reference to a co ordinate frame such as lattitude and lon gitude Host computer The host computer is the computer that orchestrates command and control of attached devices or networks IMU Inertial Measurement System Inclinometer device used to measure tilt or tilt and roll Inertial pertaining to systems that have inertia or are used to measure changes in inertia as in angular or linear accelerations INS Inertial Navigation System systems that use inertial measurements exclusively to determine position velocity and attitude given an initial reference K Kalman Filter alinear quadratic estimation algorithm that processes sensor data or other input data over time factoring in underlying noise profiles by linearizing the current mean and covariance to pro duces an estimate of a system s current state that is statistically more precise than what a single measurement could produce W4 LORD MicroStrain o SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum L LOS Line of Sight Describes the ideal condition between transmitting and receiving devices in a wireless network As stated it means they are in view of each other with no obstructions Ma
12. below refer to the LORD MicroStrain website or contact the LORD MicroStrain Sales Department Table 6 Model Numbers describes the standard models available at the time this manual was published Once a model is selected the part number is further defined by desired configuration and interface options The model determines the first four digits of the product part number the options are indicated in the last four digits Figure 33 Standard Part Numbers model number 3DM GX4 xx model options model number part number triaxial accelerometers triaxial gyroscope triaxial magnetometer internal GPS receiver altitude measurements Adaptive Kalman Filter Extended Kalman Filter x lt Xx Xx 6233 xxxx x lt E e e x lt 6236 XXXX see EE Table 6 Model Numbers W4 LORD MicroStrain sa SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Parts and Configurations The same options are available in each model and are indicated in the last four digits of the product part number For a list of the starter kit contents see Components on page 8 part number 623X XXXX model number 3 3DM GX4 15 4 3DM GX4 25 6 3DM GX4 45 accelerometer range 4 4 5g 7 16g gyroscope range 0 150 second 1 75 second 2 300 second 7 900 second communication 2 RS232 4 USB kit type 0 sensor only 1 starter kit 9 custom Communication option is only for the selection of the
13. device normal functionality is not available The protocol commands used to interface with the IMU are a subset of the standard LORD MicroStrain MIP Data Communications Protocol and are further described in the LORD MicroStrain MIP Data Communications Protocol manual For additional information contact LORD MicroStrain Technical Support see Technical Support on page 52 To enter this mode select Advanced Communications Sensor Direct from the MIP Monitor main window Once in this mode the device status message will indicate Sensor Direct Mode Figure 30 Sensor Direct Mode To exit Sensor Direct Mode select the Refresh button in the MIP Monitor at any time or use Advanced Communication menu to select the Standard operating mode B4 MIP Monitor File t View Window Advanced Help ee e e a Model Name Serial Number FW ver Model Number Options COM Figure 30 Sensor Direct Mode W4 LORD MicroStrain SENSING SYSTEMS OEM System Integration 3DM GX4 25 Attitute Heading Reference System User Manual OEM System Integration 7 2 Sensor Wiring Only use power supplies within the operating range of the sensor or permanent sensor damage or personal injury could result There are two input power pins available each with different voltage ranges Connect only one at a time Observe connection polarity Sensor power and serial communications cables are available from LORD MicroStrain
14. gyroscope and accelerometer inputs thus providing more accurate inertial data to the propagation stage of the filter This enhances overall accuracy The Kalman filter also provides statistical information about the quality of the estimated states described in a covariance matrix The diagonal terms of the matrix are the variance of each state thus the square root of these values are 1 sigma standard deviations These values give the filters estimation of how well it knows the individual states given what it knows about the W4 LORD MicroStrain Be SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Performance Optimization statistical properties of the noise sources of the various sensors and also provide feedback to the user as uncertainty values 5 8 Estimation Filter Convergence 5 8 4 Initial Convergence After a successful initialization a period of convergence for the Kalman filter states occurs Roll angle and pitch angle typically converge very quickly Heading accelerometer bias and gyro bias take more time to converge If the initial attitude estimate provided to the filter is well outside of the true attitude the filter may diverge and never recover This is most likely to occur for the heading estimate when a poor value is used for initialization and when the vibration environment is strong Should this occur it is recommended that the filter be reset and new attitude estimate provided Refer to th
15. indicates data points the x axis is the measurement units and there is a tab for each measurement 1 Right click on the device in the main window and select Sensor Data Monitoring 2 Press the Start Streaming icon to start sampling Figure 12 Data Streaming W4 LORD MicroStrain 1B SENSING SYSTEMS Basic Setup and Operations 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 Torecord data select the Arm Recording icon at any time 4 Select the type of data file to generate Binary or CSV The CSV file is the most common and can be viewed and processed by data editors such as Microsoft Excel 9 If the data is recorded in Binary format it will require a translation program that utilizes the LORD MicroStrain MIP Data Communications Protocol to make it user readable arm data recording Ha 2g 8 uo ma code vice Status c Recording Data 3 e m m O Radians Degrees gt Run Time 00 00 22 700 hia sag ATRL Acceleration Angular Rate Pressure Moose x HM Eus v HN Esas 2 HN Choose a log file type Binary MIP Packet bin ng Log File Format Choose a log file type y Binary MIP Packet bin Spreadsheet File csv log file format 11750 11800 11850 11900 11950 12000 12050 12100 12150 12200 12250 12286 Figure 13 Data Recording 5 To end recording press the Arm Recording button agai
16. is oriented such that the x axis vector is parallel with the long side of the sensor and points toward the sensor connector the y axis is 90 to the right of the x axis and the z axis goes through the bottom of the sensor outward These axes were selected so that when the connector on the device is pointed north and the device is upright and level the sensor frame will match the NED frame exactly giving zero rotation The 3DM GX4 25 reports acceleration angular rate delta Theta delta velocity inertial sensor biases and corrections in this frame when no sensor to plattorm frame transformation has been provided see Platform Frame on page 29 The orientation of the sensor frame with respect to the local NED frame can be viewed in the MIP Monitor software at View gt 3D Attitude menu This window displays the orientation of the sensor in relationship to north and shows measurement origination for acceleration and angular rate The view can be rotated for clicking holding and dragging the image Options for true north and magnetic north georeferences are available through the magnetic declination correction setting at Device Settings EF settings Geographic Refer to the 3DM GX4 25 dimensional diagram for the location of the measurement origin see Reference Diagrams on page 61 sensor frame LORD MicroStrain 3DM 6X4 25 A CC 0 rotation Euler angles North with device level and in orientation sh
17. is sending data at a specified data rate continuously without requiring a prompt from the host U USB Universal Serial Bus A serial data communications protocol UTC Coordinated Universal Time The primary time standard for world clocks and time It is similar to Greenwich Mean Time GMT V Vector a measurement with direction and magnitude with refernce from one point in space to another Velocity The rate of change of position with respect to time Also called speed W WAAS Wide Area Augmentation System An air navigation aid developed to allow aircraft to rely on GPS for all phases of flight including precision approaches to any airport W4 LORD MicroStrain ea SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum WGS World Geodetic System a protocol for geo referencing such as WGS 84 Y Yaw In navigation yaw is what occurs when rotational force is applied at a distance forward or aft from the center of gravity of the platform causing it to move around the center axis of a sensor or platform frame origin W4 LORD MicroStrain fe SENSING SYSTEMS
18. operation Sensors will not be recognized without these drivers l l l The MIP Monitor Software Suite includes hardware drivers required for 3DM installed l To install the MIP Monitor Software Suite on the host computer complete the following steps 1 Launch the software installation menu by inserting the software CD or thumb drive into the host computer or by running the Autorun exe file from the software directory in Windows Explorer 2 In the software installation Figure 4 Software Installation Menu menu select Install MIP Monitor Software and follow the on screen prompts to completion 3 If the sensor has internal magnetometers select Install MIP Hard and Soft Iron Calibration Software and follow the on screen prompts to completion This is used for magnetometer field calibration 4 Select Install Inertial Drivers to install the hardware drivers required for operating the sensors and follow the on screen prompts to completion 5 Select Install Inertial Manuals if desired and reboot the host computer 6 Plug the communications adapter into the host computer and the drivers will install automatically Reboot the computer when complete LORD MicroStrain i SENSING SYSTEMS Inertial Software Install MIP Monitor Software Install MIP Hard and Soft Iron Calibration Software Install Inertial Drivers Install Inertial Manuals Copyright 2015 LORD MicroStrain F
19. settings see Interactive Help Menu on page 13 Ka Device Setup A TA Estimation Filter IMU AHRS_ Log Mentor T b ES EF Options EF Advanced Geographic Mounting 4 LI 1 Attitude Euler RPY b1 b2 Acceleration Linear wi 50 wf Hz Angular Rate v i a Device Setup PA Estimation Filter IMU AHRS IR Filter Y ci Auto BW Manual BW No Filter x Auto BW ok cancel Help Figure 9 Device Settings Menu W4 LORD MicroStrain us SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations When selecting sensor and estimation outputs to be recorded communications bandwidth considerations should be taken into account especially when using RS232 communications Lower baud rates equate to lower communications bandwidth which can be consumed quickly by selecting a large number of measurements at high sample rates Overrunning the communications bandwidth will result in dropped communications packets and lost data 3 5 4 Saving Configurations Sensor settings are saved temporarily by selecting the OK button in the Device Setup window after configuration but they are lost when the device is powered off To save current settings in the device memory for the future use the Save Current Settings feature First adjust the sensor settings to the desired values Next s
20. where a non immediate or potential hazard presents a lesser threat of injury that could result in minor or moderate injury to workers and or the general public Situations where a non immediate or potential hazard N O TI C E presents a risk to damage of property and equipment May be used to indicate important operational conditions 12 1 Disposal and Recycling ACAUTION MA The 3DM GX4 contains internal printed circuit boards and electronic components These items are known to contain toxic chemicals and heavy metals that are harmful to humans health and the environment Disposal is subject to federal and local laws Do not discard the device in the trash Follow proper electronic waste disposal protocol as dictated by federal and local authorities Some states also have programs for extracting reusable parts for recycling f i W4 LORD MicroStrain 9e SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum 13 Addendum 13 1 Reference Diagrams The diagrams in this section are to intended to aid in product installation and troubleshooting For more information contact LORD MicroStrain Technical Support see Technical Support on page 52 13 1 1 Sensor Dimensions and Origin This diagram describes the sensor physical specification including the measurement point of origin 1 42 36 0 1 30 32 9 SENSOR ORIGIN 96 24 4 1 44 36 6 48 12 2
21. 3 The sensor should automatically appear in the sensor list Figure 23 Sensor Menu If not use the Refresh button to query it and then select the sensor 4 Selectthe Arm Recording button next to Collect Data Figure 24 Collect Calibration Data The software will begin taking readings as indicated by the points counter in the graphing window The maximum number of points is 1000 however 100 is usually adequate As the readings are taken rotate the sensor or sensor platform in all possible directions to get a complete profile of the baseline magnetic influences throughout the sensor frame Data points will appear on the graph in red For mobile sensor platforms such as ground vehicles move the platform as much as possible to simulate actual use without exposing it to excessive magnetic sources such as driving over railroad tracks or near steel pilings The intention is to get a baseline of the platform in a neutral environment that still accounts for the platform itself in all orientations For stationary platforms the baseline may include significant magnetic influences that will be present during operation select sensor collect data LOCAL MAGNETIC FIELD PARAMETERS WMM on Web J rotate sensor throughout range Local Magnitude F 53630 nT Local Inclination k 694 qr ent E RR ag choose best fit a 7 Soft Iron Matrix Offset iac oo ooo 0 004 0 000 1 401 0 000 0 011 0 000 0 000 1401 0 012
22. 7 1 1 NA 42 7 1 2 Sensor Direct MOUB io a ad oic aa katao KA aa SAL atng ln nG aba DPI DELIS 43 7 2 AA 44 7 3 Sampling on Start up AA EE 45 7 4 Connecting to a Datalogger 000000000000000 000001 ese esses le esse elles eil 46 7 5 Using Wireless Adapters ess e sese es ss sse se ara 46 8 Troubleshooting 2 20 0010 0 00 ccc cece cece cece eee ee eee se se se se se rere e esse se aa 47 W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual 8 1 Troubleshooting Guide waaa paka aNG LAG GNG esee Laag bh e pao re var amsl cle Do G 47 8 2 Repair and Calibration 20 00 0c e IR I me e mes aiara 51 8 3 Technical SUDDOIT o oe Lo Lac eese sebo o eden ces otc bee asad eee RD OON 52 9 Maintenance ot ete en ieu lat Ei c LL eas cuu A UL UE D e E 53 10 Parts and Configurations ese e sess sess lesse lel 54 10 1 Standard Configurations se ees mes me seme lessen 54 10 2 Accessories a oos EUR gc DEUM I LLL AL PIRA LUN Leen ce ALAS A Dr dde E da SE EET 56 pak AA 57 11 Specifications eu nuu sce IMIDRIPip eI RI Ee BANAAG AERANN LAAD Daa o dip Purpose 58 12 Safety Information ese ese se esse sse sse reli 60 12 1 Disposal and Recycling ee e m me m e re le ens 60 13 Addendum cas Ie apeD LII suis annaa aD Aaa oaa D AA naano anaron dO Redde 61 13 1 Reference Diagrams
23. G SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual OEM System Integration 7 1 1 Packet Builder To expedite program development a packet builder tool is included in the MIP Monitor software The packet builder allows users to send multiple packets to the 3DM GX4 25 and view the resulting reply data Applicable protocol structure and design is described 3DM GX4 25 MIP DCP Manual The manual can be found with software installation thumb drive on the LORD MicroStrain website Support page or by contacting Technical Support see Technical Support on page 52 To use the packet builder select Advanced gt Packet Builder from the MIP Monitor main window Figure 29 Packet Builder The sensor must be in the Standard communications mode to use this feature Not Connected di enter field descriptor and data sendto sensor Timeout 2 00 Sent Packet sensor reply Ra Dees Timed Out umm Figure 29 Packet Builder W4 LORD MicroStrain a SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual 43 7 1 2 Sensor Direct Mode The MIP Monitor software can be used to put the sensor in a mode that allows direct programmatic access to the internal Inertial Measurement Unit IMU The IMU has its own processor and protocol commands and native data outputs from the individual IMU sensors that may not be available in MIP Monitor When in Sensor Direct mode the
24. N O TICE magnetization of internal components which can affect magnetometer performance If magnetization is suspected use a degaussing tool to demagnetize To acquire sensor measurements and computed outputs the 3DM GX4 25 uses a host computer a serial communications port and applicable software The LORD MicroStrain9 MIP Monitor software is provided with the system and includes all functions needed for sensor configuration and data acquisition Users may also utilize the LORD MicroStrain MIP Data Communications Protocol to write custom software applications with expanded or specific feature sets needed for the application MIP Monitor includes a message building tool that can be used to streamline this process For more information see OEM System Integration on page 41 In this section hardware and software setup is described including an overview of the MIP Monitor software menus required to configure a sensor and begin data acquisition This is intended as a quick start guide and is not a complete demonstration of all system or software features and capabilities amouesso O Co Baka OTTE cevice Status Streaming Data e Clear RUSSES Radians Degrees a Run Time 00 00 56 450 Figure 3 Acquiring Sensor Data with MIP Monitor W4 LORD MicroStrain n SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 1 Software Installation GX4 sensor
25. al installation is highly recommended This can be accomplished using LORD MicroStrain MIP Hard and Soft Iron Calibration software This software is included with the MIP Monitor Software Suite see Software Installation on page 1 1 The following are instructions for field calibrating the magnetometers 1 Connect and power on the sensor as normal and open the MIP Hard and Soft Iron Calibration software 2 Enter the Local Magnetic Field information Figure 23 Sensor Menu for the sensor to account for magnetic influences inherent to the sensor s geographic location on the Earth As needed use the WMM on Web button to access a World Magnetic Model calculator on the British Geographic Survey website This site and similar sites generate Local Magnitude F and Local Inclination values based on latitude and longitude entries In the calculator solution these values will be found in row MF column F and row MF column respectively oct ol in Model Name Serial Number FW Ver Model Number z gt refresh button 5 6223 3366 2006 6223 422 sensor list Performance Optimization COLLECT DATA ejO VERIFY CALIBRATION OIO LIT 31 Soft Iron Matrix SH Offset Figure 23 Sensor Menu local field co ordinates W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Performance Optimization
26. andard standard 16 g option 75 150 900 sec options DGS asus meon img owe Basissiiy omm om Adjussbiebendwid 225Hz mad asonaimay Offset error over 06 t 05 t ese a all 0 06 typ 0 05 typ Gems osxom Scale factor non linearity 0 02 typ 0 02 typ 25 C 0 06 max 0 06 max 0 0015 Gauss 0 072 s RMS g Data outputs Measurement range 0 001 s g RMS 4 stage filtering analog bandwidth filter to digital sigma delta wide band anti aliasing filter to user adjustable digital averaging filter sampled at 4 kHz and scaled into physical units coning and sculling integrals computed at 1 kHz Sampling rate IMU data output rate Range Noise density Sampling rate Vibration rectification error VRE W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Specifications Computed Outputs AKF outputs 30 25 RMS roll amp pitch 0 8 RMS heading typ Attitude accuracy CF outputs 0 5 roll pitch and heading static typ 2 0 roll pitch and heading dynamic typ Attitude heading range 360 about all axes Attitude repeatability rate CF outputs 1 Hz to 1000 Hz Communication USB 2 0 full speed RS232 9 600 bps to 921 600 bps default 115 200 Power source 3 2 to 36 V dc 100 mA typ 120 mA max with Vpri 3 2 V dc to 5 5 V dc 550 mW
27. art data streaming Table 3 Sampling and Recording Controls There are several data monitoring views available depending on what measurements are desired for monitoring and recording Each view corresponds to one of the main categories in W4 LORD MicroStrain Hn SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual the Device Settings window For example the 3DM GX4 25 includes Sensor Data Monitoring for the IMU AHRS measurements GPS Monitoring for the metrics and EF Monitoring for the Estimation Filter outputs Figure 12 Data Streaming During viewing and recording only the outputs that are selected in the Message Format tab of the Device Settings menu are displayed and recorded see Sensor Settings on page 15 Data streaming must be started before data can be recorded however it is not necessary to view it in a data monitoring window Data monitoring is used primarily to confirm the system is operating correctly or to view the outputs in near real time If sensor setup has already been confirmed streaming and recording can be initiated from the main window Figure 12 Data Streaming is an example of Sensor Data Monitoring which displays the selected IMU AHRS measurements In data monitoring windows no data will be displayed until data streaming is started and no data will be recorded even if it is being viewed until data recording is initiated armed In the example below the y axis of the graph
28. baud rate in MIP Monitor select Settings gt System and select the desired rate NOTE if the baud rate is set higher than the computer serial port is capable of reading communication will be permanently lost with the device To recover it will need to be connected to a higher speed port connected via USB cable or sent to LORD MicroStrain for reconfiguration 2 5 sensor or cables are damaged Verify all connections power and settings If available try installing an alternate cable or sensor one at a time to see if the faulty device can be identified If no conclusion can be determined or to send a device in for repair contact LORD MicroStrain Technical Support See Technical Support on page 52 3 1 sampling settings are incorrect 3 DATA ACQUISITION If unexpected measurements or sampling rates are displayed or recorded enter the Device Settings menu and verify the sampling settings sensor data is missing or incorrect 3 2 streaming has not started If data streaming is occurring the sensor device status indicator will also be flashing to indicate sampling In MIP Monitor the device status information field will indicate Streaming If the sensor is not streaming data activate it in the software 3 3 heading data incorrect If the magnetometers have not been field calibrated erroneous heading data could result W4 LORD MicroStrain to SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User
29. cable provided in starter kits The sensoris capable of RS232 and USB communication Use 2 for sensor only kits Figure 33 Standard Part Numbers LORD MicroStrain Description Part Number 3DM GX4 15 Starter Kit RS232 5g 300 sec 3DM GX4 15 Starter Kit USB 5g 300 sec 62334241 USB 3DM GX4 25 Starter Kit RS232 5g 300 sec 3DM GX4 25 Starter Kit USB 5g 300 sec 6234 4241 3DM GX4 45 Starter Kit RS232 5g 300 sec 62364221 3DM GX4 45 Starter Kit USB 5g 300 sec 6236 4241 Table 7 Example Part Numbers W4 LORD MicroStrain m SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Parts and Configurations 10 2 Accessories The following parts are available for use with the 3DM GX4 and some are included in sensor starter kits see Components on page 8 For the most current product information refer to the LORD MicroStrain website or contact the Sales Department See Sales Support on page 57 LORD MicroStrain Part Number Sensor mating connector micro DB9 with flying leads Table 8 Sensor Accessories Description Manufacturer Description part number A Series or P Series 9 pin male Micro D connector Ulti Mate PRO9NO05 Table 9 Sensor Mating Connector W4 LORD MicroStrain id SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Parts and Configurations 10 3 Sales Support Produ
30. ctors The communication protocol used for configuring and acquiring sensor data and estimations outputs is available for these applications as well 7 1 Data Communications Protocol DCP The LORD MicroStrain 9 MIP Data Communications Protocol includes all commands available for controlling and acquiring data from the 3DM GX4 25 including many that are not available in the MIP Monitor software Programming is performed through a standard serial interface program The programming interface is comprised of setup and control commands and a very flexible user configurable data output format The commands and data are divided into four command sets and three data sets corresponding to the internal architecture of the device The protocol is packet based All commands replies and data are sent and received as fields in a message packet The packets have a descriptor type field based on their contents so it is easy to identify if a packet contains commands replies or data The MIP software developers kit SDK includes sample code and can be found on the LORD MicroStrain website Support page or by contacting Technical Support see Technical Support on page 52 The LORD MicroStrain MIP Data Communications Protocol describes each command description message syntax and message option It also provides examples and can also be found on the LORD MicroStrain website or through Technical Support W4 LORD MicroStrain i SENSIN
31. cts can be ordered directly from the LORD MicroStrain9 website by navigating to the product page and using the Buy feature http Awww microstrain com inertial For further assistance our sales team is available to help with product selection ordering options and questions Sales Support sensing sales LORD com Phone 802 862 6629 Fax 802 863 4093 9 00 AM to 5 00 PM Eastern Time US amp Canada W4 LORD MicroStrain Bf SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Specifications 11 Specifications t cruel rur O Triaxial accelerometer triaxial gyroscope triaxial magnetometer temperature sensors and pressure altimeter Inertial Measurement Unit IMU outputs acceleration angular rate magnetic field ambient pressure deltaTheta deltaVelocity Integrated sensors Computed outputs Adaptive Kalman Filter AKF filter status timestamp attitude estimates in Euler angles quaternion orientation matrix bias compensated angular rate pressure altitude gravity free linear acceleration attitude uncertainties gyroscope and accelerometer bias scale factors and uncertainties gravity and magnetic models and more Complementary Filter CF attitude estimates in Euler angles quaternion orientation matrix stabilized north and gravity vectors correlation timestamp Inertial Measurement Unit IMU Sensor Outputs PT Accelerometer Gyroscope Magnetometer 300 sec 5 g st
32. d vector delta Theta and delta velocity Transformed acceleration is expressed at the location of the sensor but within the platform frame For example if the sensor is offset from the center of gravity CG and the platform is undergoing a rotation an acceleration in addition to any linear acceleration of the CG will be sensed in accordance with the following formula tangent acceleration angular rate distance from CG W4 LORD MicroStrain m SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual 5 Performance Optimization 5 1 Magnetometer Calibration Although the 3DM GX4 25 magnetometers are calibrated at the factory to remove any internal magnetic influences in the device measurements are still subject to influence from external magnetic anomalies when the sensor is installed These anomalies are divided into two classes hard iron offsets and soft iron distortions Hard iron offsets are created by objects that produce a magnetic field Soft iron distortions are considered deflections or alterations in the existing magnetic field Ideally these influences are mitigated by installing the sensor away from magnetic sources such as coils magnets and ferrous metal structures and mounting hardware However often these sources are hard to avoid or hidden To mitigate this effect when using the 3DM GX4 25 magnetometer to aid in heading estimations a field calibration of the magnetometer after fin
33. dard Mating connector Kycon KLD 0202 A or equivalent W4 LORD MicroStrain BE SENSING SYSTEMS Addendum 3DM GX4 25 Attitute Heading Reference System User Manual 13 1 3 Communication and Power Cables These diagrams describe the cables included in the 3DM GX4 starter kits Only one is included in each kit depending on the type of kit ordered DETAIL B POWER JACK 2 1mm X 5 5mm VIEWED FROM CONNECTOR SIDE DETAIL C DB9 FEMALE VIEWED FROM CONNECTOR SIDE DETAIL A MICRO DB 9 FEMALE VIEWED FROM CONNECTOR SIDE CENTER CONTACT 5 4 3 1 243 is V ka 1 AU a L OUTER 9g NG CONTACT GND m 2 51m 8 22 ft es EN KV os Z 3 a t 3 DETAILA DETAIL C i l Ng ri 1 N 4 DETAIL A sace ka GREEN BEIM DETAIL B 4 3 R9 RED 2 td V CENTER 6 Nes TA 5 DETAIL B GND OUTER BLACK g BLACK 5 9 Figure 35 Communications and power cable RS232 Kits PN 4005 0037 DETAIL A DETAIL B MICRO DB 9 FEMALE VIEWED FROM CONNECTOR SIDE Mar o VIEWED FROM CONNECTOR SIDE DETAILA DETAIL B 5 TT Green 2 02 7 3 RED 3 D 3 1 V 244m 4 qi S 8 ft ees 5 21 a Ta by y N 6 F a BLACK a 8 4 GND EN x 7 9 is um hou d DETAIL A DETAIL B Figure 36 Communications cabl
34. ded W4 LORD MicroStrain at SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 Sensor Measurements The 3DM GX4 25 block diagram Figure 15 3DM GX4 25 Block Diagram describes its primary hardware components and internal configuration Integrated Micro Electro Mechanical System MEMS sensors within the 3DM GX4 25 are collectively known as the Inertial Measurement Unit IMU and include tri axial gyroscopes gyros tri axial accelerometers tri axial magnetometers and a pressure altimeter This technology provides direct measurements of acceleration angular rate magnetic field pressure delta Theta change in acceleration and delta v change in velocity Temperature and pressure sensors provide environmental information for measurement compensation and altitude estimations Computed estimations for attitude and heading reference systems AHRS are available outputs on the 3DM GX4 25 To achieve these estimations the MEMS sensors are processed by an AHRS Estimation Filter EF microprocessor with an Adaptive Kalman Filter AKF Additional user settings such as measurement filtering biasing and tolerance values offer adjustments for specific applications digital temperature triaxial gyroscope 32 Bit Cortex 32 Bit Cortex AHRS MCU IMU MCU 16 Bit 4 kHz IA ADC Extended Kalman sayy bae war output RS 232 user digital Filter Hz manage
35. e The icon in the left column indicates the status of the device Red indicates that recording to a log file has been enabled List of available devices Figure 7 Context Sensitive Help Menu W4 LORD MicroStrain 18 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 4 Sensor Communication Once power has been applied to the sensor it is on The sensor selects the appropriate serial communication USB or RS232 on power up based on which cable is connected If the hardware drivers have been installed communication can be established using the MIP Monitor software interface 1 Verify the sensor device status indicator is on 2 Openthe MIP Monitor software 3 The sensor should appear in the device list automatically when the software is running The list includes the device information and communication port assignment Figure 8 Sensor Communication If the sensor is not automatically discovered use the refresh button device list refresh device list File Control SettingsE View Window Advanced Help COole Not Connected Model Name Serial Number FW ver Model Number Options COM Figure 8 Sensor Communication l l l i If data is not actively being exchanged between the sensor and host computer the status message may display Not Connected This indicates the port status not the sensor availability When commands a
36. e USB Kits PN 9022 0019 W4 LORD MicroStrain 63 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum MAX 395 MAX 18 50 50 ALL DIMENSIONS IN INCHES WI RING q BLACK BROWN RED ORANGE YELLOW GREEN BLUE VIOLET GRAY PIN 785 MAX 000 Ol amp C N 26 AWG TYPE E WIRE PER NEMA HP 3 FORMERLY MIL W 16878 4 9 PLACES 2 56 LOW PROFILE RETAINING RING SLOTTED HEAD JACKSCREW 2 PLACES 2 PLACES Figure 37 Connecter interface cable sold separately PN 6224 0100 13 2 Reference Documents Many references are available on the LORD MicroStrain9 website including product user manuals technical notes and quick start guides These documents are continuously updated and may provide more accurate information than printed or file copies Document Where to find it 3DM GX4 25 Software Developers Kit http www microstrain com software development kits sdks 3DM GX4 25 MIP DCP Manual http www microstrain com support docs Product Technical Notes http www microstrain com support docs Product Application Notes http www microstrain com applications Product Datasheets http www microstrain com lord microstrain inertial sensors all products NIST Calibration Procedures http www nist gov calibrations ASTM Testing Procedures http www astm org Standard standards and publications html Tabl
37. e 10 Document Resources W4 LORD MicroStrain o SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum 13 3 Glossary A A D Value The digital representation of analog voltages in an analog to digital A D conversion The accuracy of the conversion is dependent on the resolution of the system electronics Higher res olution produces a more accurate conversion Acceleration In physics acceleration is the change in the rate of speed velocity of an object over time Accelerometer A sensor used to detect and measure magnitute and direction of an acceleration force g force in reference to its sensing frame For example at rest perpendicular to the Earth s surface an accelerometer will measure 9 8 meters second squared as a result of gravity If the device is tilted the acceleration force will change slightly indicating tilt of the device When the accel erometer is moving it will measure the dynamic force including gravity Adaptive Kalman Filter AKF A type of Extended Kalman Filter EKF that contains an optimization algorithm that adapts to dynamic conditions with a high dependency on adaptive technology Adaptive technology refers to the ability of a filter to selectively trust a given measurement more or less based on a trust threshold when compared to another measurement that is used as a reference Sensors that have estimation filters that rely on adaptive control elements to improve their e
38. e 3D M GX4 25 MIP DCP Manual for the various ways of providing an initial attitude estimate through a user designed interface 5 8 2 Bias Convergence Accurate estimation of the biases can take several minutes to converge therefore after the filter is initialized the free inertial performance will continue to improve until the bias estimations settles The MEMS sensor manufacturers quote bias drift stability numbers which correspond to the expected drift in bias while the sensor is operating The filter attempts to track the changing biases over time and a user can expect these bias estimates will be non constant during a navigation run 5 8 3 Output Uncertainty The 3DM GX4 25 estimation data set includes a filter status field that contains a set of status flags These flags pertain to high covariance values for attitude and inertial sensor parameters These flags should be monitored and cross checked against the corresponding uncertainty fields when they appear This can assist in determining how trustworthy the solution generated by the Kalman filter is When the filter is first initialized it is likely that some of these values will be beyond limits and the flags may be asserted This fact should be taken into account when developing automated monitoring systems W4 LORD MicroStrain ae SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual 5 9 Vibration Isolation The 3DM GX4 25 should be isolated
39. e name and includes the most used items from the header row menus Figure 6 Main Window The header row menu includes selections for data sampling recording device settings opening windows selecting which open window to view and advanced features such as selecting the communications mode The icon toolbar includes buttons for Help Menu access device refresh and data sampling and recording see Data Monitoring and Recording on page 17 device status information 4 MIP Monitor File Control Settings View Window Advance icon toolbar Cooke TI Inet Connected TI Model Name Serial Number FW ver Model Number Options header row menus device list and menu nan ly Device Settings Sensor Data Monitor GPS Data Monitor EF Data Monitor Data Log Monitor Packet Monitor 3D Attitude Figure 6 Main Window 3 3 1 Interactive Help Menu MIP Monitor also includes a mouse over feature that provides explanations of the information and settings This feature is enabled by selecting the question mark icon or Help button in any window enable help menu mwv 5 7CNAMNS File Control Settings View Window Advanced Help Goole coe t ei Model Name Serial Number FW ver Model Number Options on Context Help a Devices List This displays a list of available devices To display newly connected devices press the refresh button on the right Devices may be selected one at atim
40. elect Settings Save Current Settings from the main window Figure 10 Save Sensor Settings The setting will now remain intact when the sensor is powered off and then on again To recall the last saved settings select Settings Load Startup Settings To revert the settings back to the factory defaults select Settings gt Load Default Settings Jl te File Control ES View Window Advanced Help Device GOO system Not Connected ex Model Nam Capture Gyro Bias FW ver Model Number Options Save Current Settings Load Startup Settings Load Default Settings Figure 10 Save Sensor Settings W4 LORD MicroStrain 1 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 6 Data Monitoring and Recording Format tabs in the Device Setup menu are displayed and recorded see Sensor l l l During viewing and recording only the outputs that are selected in the Message l l l Settings on page 15 l Throughout the MIP Monitor menus the same icons are used to control data streaming sampling and recording Table 3 Sampling and Recording Controls These icons can be found in the MIP Monitor main window icon toolbar and in each data monitoring window The same commands are also found in the main window Control menu sampling and recording controls main window Figure 11 Main Window Controls Icon Command Run st
41. er Manual OEM System Integration 7 4 Connecting to a Datalogger Many inertial applications incorporate dataloggers of all different types to collect and distribute sensor outputs For more information and examples refer to the Using Dataloggers with Inertial Sensors Technical Note on the LORD MicroStrain 9 website or contact LORD MicroStrain Technical Support see Technical Support on page 52 7 5 Using Wireless Adapters In some applications it can be very useful to set up wireless communications between the sensor to the host computer One way this can be accomplished is by connecting the serial output of the sensor to a serial to wireless converter and then connecting the wireless receiver to the host computer For more information and an example refer to the Using RS232 Bluetooth Adapters Technical Note on the LORD MicroStrain website or contact LORD MicroStrain Inertial Sensor ProductsTechnical Support see Technical Support on page 52 W4 LORD MicroStrain a SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Troubleshooting 8 Troubleshooting 8 1 Troubleshooting Guide 47 1 POWER sensor does not power on 11 no power is applied 12 power source is off or miswired 115 power supply is the wrong voltage 1 4 sensor is in firmware update mode TS sensor is damaged 2 COMMUNICATION no communication to sensor 23 sensor
42. erformance Optimization 5 2 Gyroscope Bias Gyroscope biases offsets can be zeroed out to set a baseline value for the static home position and conditions in the application This should be done after sensor installation To set the gyroscope baseline place the sensor or sensor platform in the desired home position Allow 2 3 minutes for the sensor to warm up and for the temperature to stabilize for the best bias capture Select Settings gt Capture Gyro Bias Figure 26 Gyro Bias Capture The sensor must remain stationary for about twenty seconds while the outputs are being measured A status message will appear when the capture has been completed Save Current Settings Load Startup Settings KZ MIP Monitor E SO File Control Settings View Window Goole ole Model Name IDI Gyro Bias capture complete Figure 26 Gyro Bias Capture W4 LORD MicroStrain kai SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Performance Optimization 5 3 Heading Drift and Compensation There are three options for the heading reference source the magnetometer an external reference or none If the setting is an external reference the user has to provide a heading reference If the setting is none the estimated heading will drift when little or no changes in velocity are sensed e g when stationary or traveling in the same direction at a constant velocity If the setting is the magnetome
43. esh button if needed to re establish communication with the sensor Start a calibration verification by clicking the Start Streaming Data button next to Verify Calibration Figure 25 Verify Calibration Rotate the device in all orientations in the same way as during calibration When completed click the Stop Streaming Data button next to Verify Calibration The resulting data points should be on or near the spherical grid Hold the left mouse button and drag to rotate the image The mouse wheel can be used to zoom in and out If the fit is not close the sensor may require re calibration If it is close as shown calibration and verification is complete KA MIP Hard amp Soft iron Cakbration PA CNN NB Gom CNN A rt RR eH RC Model Name Serial FW Ver Model Number 2 25 6223 2006 6223 4220 5 LUC ae Ue a i verify calibration couscr DATA SO A verir CALIBRATION Oj O Naam verify calibration CY LOCAL MAGNETIC FIELD PARAMETERS WMM on Web Local Magnitude F 53630 nT Local Inclination E 694 Current Cal Spherical Fit Ellipsoidal Fit Soft Iron Matrix Offset quu mee morcs mens Reset to Default PLOT CONTROL Clear Plots Re Plot Data Plot Local Field DATA FILE Save Data Load Data Figure 25 Verify Calibration W4 LORD MicroStrain SENSING SYSTEMS Performance Optimization 3DM GX4 25 Attitute Heading Reference System User Manual P
44. eueeceeeeceeeecees 31 W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual 5 1 Magnetometer Calibration 0 0 00 00 c cece cece cee e e Im em emen 31 5 2 Gyroscope Bias eese RE IEIUNII EI DH Ie Md JALA debct AG BALE NAAN a kisa 34 5 3 Heading Drift and Compensation LL 35 5 4 Angular Rate and Acceleration Limits liliis memes eene 36 SES Tei UI EMT PAN 36 5 6 Platform Frame Transformation se eese sese sei 36 5 7 Estimation Filter Operation 0c ccc cece cece eee cece cece esee eme esee sse sni 36 5 8 Estimation Filter Convergence 2 0 2 2 0 c ccc cece cece cece ec ce cee cececcececcececceceececseceees 38 5 8 1 Initial Convergence 2 2 0 cece eee cece eee cece eese ee e eese se e sete sese me eres eres ei 38 5 8 2 Bias Convergence naag eet escis esse teci cca ie ded icbc eese DALIG RADAR NAN kanta 38 5 8 3 Output Uncertainty esee eta fee nG a a bA Sep NG NG BIG OD NAPAKA KA Gaan DO uil cele a 38 5 9 Vi rati n Solato 4 6645 each e ee eile NAA aE ioe kkk ATA deo utet rie ANA se PSP Dee SUPE 39 5 10 IMU Sensor Calibration MERI K m 39 5 11 Temperature Compensation 2 22 2 0 020 c cece cece cece cece ccc ec cececceceececeececcececcecesees 39 6 Sensor Installation 40 61 AA AN 40 7 OEM System Integration a 41 7 1 Data Communications Protocol DCP Ha 41
45. fixed earth coordinate quaternion Quaternions convert the axis angle rep resentation of the object into four numbers and to apply the corresponding rotation to a position vector representing a point relative to the origin R Resolution In digital systems the resolution is the number of bits or values available to represent analog voltages or information For example a 12 bit system has 4096 bits of resolution and a 16 bit System has 65536 bits RMS acronym for Root Mean Squared Roll In navigation roll is what occurs when a horizontal force is applied at a distance right or left from the center of gravity of the platform causing itto move side to side with respect to the sensor or platform frame origin RPY acronym for Roll Pitch Yaw RS232 a serial data communications protocol RS422 a serial data communications protocol S Sampling the process of taking measurements from a sensor or device W4 LORD MicroStrain e SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum Sampling rate rate at which the sensors are sampled Sampling Rate the frequency of sampling Sensor a device that physically or chemically reacts to environmental forces and conditions and pro duces a predictable electrical signal as a result Sigma In statistics sigma is the standard deviation from the mean of a data set Space Vehicle Information refers to GPS satellites Streaming typically when a device
46. from strong vibrations a much as possible Strong continuous vibrations appear as unaccounted noise to the estimation filter degrading its performance 5 10 IMU Sensor Calibration All of the internal sensors in the 3DM GX4 25 are calibrated when the device is manufactured and the calibration values are saved in the device memory With the exception of the magnetometer field calibration see Magnetometer Calibration on page 31 recalibration is not required unless the device has been under conditions that exceed the operating specifications For example if the sensor has been exposed to excessive shock beyond the rated g force performance may be compromised Indications of internal sensor damage may be seen as measurement offsets or drift when the sensor is in a neutral motionless position 5 11 Temperature Compensation All sensor conversion and calibration formulas include temperature compensation All computed outputs and IMU sensor outputs are automatically adjusted for local temperature see Direct Sensor Measurements IMU Outputs on page 22 W4 LORD MicroStrain id SENSING SYSTEMS Performance Optimization 3DM GX4 25 Attitute Heading Reference System User Manual 6 Sensor Installation 40 6 1 Sensor Mounting The 3DM GX4 25 sensor housing is rated for indoor use only unless used inside a protective enclosure The sensor has two mounting tabs with holes for fastening There are two additional holes used for p
47. gnetometer A type of sensor that measures the strength and direction of the local magnetic field with refernce to the sensor frame The magnetic field measured will be a combination of the earth s magnetic field and any magnetic field created by nearby objects MEMS Micro Electro Mechanical System The technology of miniaturized devices typically made using micro fabrication techniques such as nanotechnology The devices range in size from one micron to several millimeters and may include very complex electromechanical parts N NED North East Down A geographic reference system 0 OEM acronym for Original Equipment Manufacturer Offset A non zero output signal of a sensor when no load is applied to it typically due to sensor imper fections Also called bias Orientation The orientaion of an object in space with reference to a defined frame Also called attitude P Pitch In navigation pitch is what occurs when vertical force is applied at a distance forward or aft from the center of gravity of the platform causing it to move up or down with respect to the sensor or platform frame origin W4 LORD MicroStrain go SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum Position The spatial location of an object PVA acronym for Position Velocity Attitude Q Quaternion Mathematical notation for representing orientation and rotation of objects in three dimensions with respect to the
48. he time integral of velocity expressed with refernce to the device local coordinate system in units of g second where g is the standard gravitational constant E ECEF Earth Centered Earth Fixed a reference frame that is fixed to the earth at the center of the earth and turning about earth s axis in the same way as the earth Estimation Filter A mathematical algorithm that produces a statistically optimum solution using measurements and references from multiple sources Best known estimation filters are the Kalman Filter Adaptive Kalman Filter and Extended Kalman Filter Euler angles Euler angles are three angles use to describe the orientation of an object in space such as the x y and z or pitch roll and yaw Euler angles can also represent a sequence of three elemental rotations around the axes of a coordinate system Extended Kalman Filter EKF Used generically to describe any estimation filter based on the Kalman Filter model that can handle non linear elements Almost all inertial estimation filters are fundamentally EKFs G GNSS Global Navigation Statellite System a global network of space based statellites GPS GLONASS BeiDou Galileo and others W4 LORD MicroStrain oF SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum used to triangulate position co ordinates and provide time information for navigational purposes GPS Global Positioning System a U S based network of space
49. igure 4 Software Installation Menu W4 LORD MicroStrain n SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 2 System Connections Power is applied to the sensor either through a host computer USB port or an external power supply such as the one provided in the RS232 starter kit Use only power supplies within the operating range of the sensor or damage or injury could result Once power is applied the sensor is on and active see Specifications on page 58 To acquire sensor data the following components are needed 3DM GX4 25 sensor communication cable power cable as applicable for RS232 communications and a host computer with LORD MicroStrain MIP Monitor installed host computer communication cable power cable as needed not used with USB communication IN s ee wO sensor Figure 5 System Connections W4 LORD MicroStrain Je SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 3 Software Interface The MIP Monitor software includes a main window with system information and menus a device settings window see Sensor Settings on page 15 and several data monitoring windows see Data Monitoring and Recording on page 17 The main window provides an overview of connected devices Devices are selected by clicking on them A device menu is available by right clicking on the devic
50. n Linear Fa Device Setup Alb Angular Rate Context Help 5 c A Geographic Mounting Bias Model Sensor Noise Accel Adaptive 4 Lan Enable Accelerometer Adaptive Measurement SS ee Enabling this feature allows the filter to stabilize attitude readings when undergoing linear accelerations The bandwidth setting determines the cutoff frequency of the filter applied to linear acceleration changes The high and low limits determine the trigger points at which the stabilization is applied The limit values are in g s and the bandwith is in Hz T Enable Accelerometer Adaptive Measurement Lo Enable Accelerometer Adapative Measurement Low Limit High Limit Accel Signal Range 00 o Accel Uncertainty 9 RR Figure 17 Estimation Filter Settings All of the estimation filter outputs are available to view and record in MIP Monitor In addition to the standard attitude and heading AHRS solution additional filter outputs such as uncertainties inertial sensor bias and scale factors filter status and physical models WGS84 WMM and SAM are available Table 5 Estimation Filter Outputs To view and record Estimation outputs see Basic Setup and Operations on page 10 W4 LORD MicroStrain zi SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements Measurement Description indica
51. n and select OK in the confirmation prompt window 6 Selectthe Stop Streaming icon to end sampling 7 Usethe red X in the upper right of the sensor monitoring window to exit monitoring mode W4 LORD MicroStrain ic SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 7 Viewing Data Acquired data is stored in either Binary bin or Comma Separated Values CSV format depending on what was selected at the initiation of data recording The files can be found in the directory specified at that time or in the default directory on the host computer desktop CSV files can be viewed with Microsoft Excel Quattro Pro Open Office or other CSV editors and spreadsheet programs Data recorded in Binary format requires a translation program utilizing the LORD MicroStrain MIP Data Communications Protocol to make it user readable File Edit View Toots Help Organize v f Open Print E mail Burn New folder z e DT Favorites Name Size Item type Bi Desktop wl 3DM GX4 45 6236 39291 Data Log 2 9 2015 1 1646 PM bin UB Downloads Gi 3DM GX4 45 6236 39291 Data Log 2 9 2015 11 33 04 AM csv Recent Places sy Libraries 1M Computer amp Local Disk C Figure 14 Exploring Data Data in the data files is displayed in time sequence If measurements are set to different data rates not all time intervals will include a reading from each output that is being recor
52. not found in MIP Monitor 2 2 comm cable not connected or miswired 2 3 device drivers not installed 2 4 mismatched serial baud rate setting 25 sensor or cables are damaged 3 DATA ACQUISITION sensor data is missing or incorrect 3 1 sampling settings are incorrect 3 2 streaming has not started 33 heading data incorrect 3 4 sensor data not recorded 3 5 sensor data recorded in binary format 3 6 sensor has been magnetized 37 sensor is damaged W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Troubleshooting Problem Possible cause and recommended solution 1 1 no power is applied 1 POWER The status indicator on the device will be off Make sure the sensor is connected to a power source and the status indicator sensor does not power illuminates on 1 2 power source is off or miswired Verify the device power source is connected correctly 1 3 power supply is the wrong voltage Using a power supply other than the one provided with the device or a supply that is outside of the device operating range could result in permanent damage or cause it to not work properly 1 4 sensor is in firmware update mode Firmware update mode is used when updating firmware on the device If the firmware updater fails it is possible that the device can get stuck in the firmware update mode
53. nter of an object Bias A non zero output signal of a sensor when no load is applied to it typically due to sensor imper fections It is also called offset C Calibration to standardize a measurement by determining the deviation standard and applying a cor rection or calibration factor Complementary Filter CF A term commonly used for an algorithm that combines the readings from multiple sensors to produce a solution These filters typically contain simple filtering elements to smooth out the effects of sensor over ranging or anomalies in the magnetic field Configuration A general term applied to the sensor indicating how it is set up for data acquisition It includes settings such as sampling rate active measurements measurement settings offsets biases and calibration values Convergance when mathematical computations approach a limit or a solution that is stable and optimal W4 LORD MicroStrain m SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum D Data Acquisition the process of collecting data from sensors and other devices Data Logging the process of saving acquired data to the system memory either locally on the device or remotely on the host computer Data rate the rate at which sampled data is transmitted to the host Delta Theta the time integral of angular rate expressed with refernce to the device local coordinate system in units of radians Delta velocity t
54. own Figure 20 Sensor Frame W4 LORD MicroStrain et SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 3 4 Platform Frame The 3DM GX4 25 includes the option to define an orientation transformation from the sensor frame to a user definable platform frame This is useful when the sensor cannot be mounted in the same orientation as the desired reference point on the platform frame The transformation from sensor to platform frame is defined with Euler angles and is expressed as a rotation from the sensor frame to the platform frame In the following example Figure 21 Platform Frame Transformation the user has defined the desired reference point on the platform frame to be located under the center of the vehicle In accordance with aircraft co ordinate systems the platform frame is oriented with the x axis pointed in the forward direction of travel the z axis pointed down and the y axis pointed towards the passenger side The sensor has been mounted face down therefore the proper transformation in this example would be 180 degrees roll O degrees pitch and 0 degrees yaw KEY axis direction outward itch ap F axis direction inward x platform frame assigned by user roll El A sensor frame with reference to vehicle frame 180 roll 0 pitch 0 yaw sensor mounted face down under vehicle Figure 21 Platform Frame Transformation W4 LORD MicroS
55. r temperature 1000 digital lem 4 kHz temperature Complementary filters Input Output ADC g sensitivity iiis a triaxial accelerometer and orthogonality ES compensation digital sculling integral EP calculation triaxial digital magnetometer EEPROM user selectable parameters EEPROM digital factory calibration atmospheric coefficients pressure altimeter ayy Bae Ngt 3DM GX4 25 C Figure 15 3DM GX4 25 Block Diagram W4 LORD MicroStrain 3 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 1 Direct Sensor Measurements IMU Outputs The sensors in an Inertial Navigation System INS from which measurements for navigation and orientation are obtained are collectively known as the Inertial Measurement Unit IMU These sensors are arranged on the three primary axes x y and z to sense angular rate acceleration and the local magnetic field The gyroscopes are used to adjust the current attitude estimate when an angular rate is sensed The accelerometers sense gravity as well as linear acceleration The magnetometers sense the Earth s magnetic field along with local magnetic anomalies All measurements are temperature compensated and are mathematically aligned to an orthogonal coordinate system The IMU sensors can be read directly to report stand alone inertial measurements or computed measurements Because
56. r Manual Troubleshooting 8 2 Repair and Calibration General Instructions In order to return any LORD MicroStrain product you must contact LORD MicroStrain Sales or Technical Support to obtain a Return Merchandise Authorization RMA number All returned merchandise must be in the original packaging including manuals accessories cables etc with the RMA number clearly printed on the outside of the package Removable batteries should be removed and packaged in separate protective wrapping Please include the LORD MicroStrain model number and serial number as well as your name organization shipping address telephone number and email Normal turn around for RMA items is seven days from receipt of item by LORD MicroStrain Warranty Repairs LORD MicroStrain warrants its products to be free from defective material and workmanship for a period ofone 1 year from the original date of purchase LORD MicroStrain will repair or replace at its discretion a defective product if returned to LORD MicroStrain within the warranty period This warranty does not extend to any LORD MicroStrain products that have been subject to misuse alteration neglect accident incorrect wiring mis programming or use in violation of operating instructions furnished by LORD MicroStrain It also does not extend to any units altered or repaired for warranty defect by anyone other than LORD MicroStrain Non Warranty Repairs All non wa
57. rain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Overview 2 2 Interface and Indicators The 3DM GX4 25 sensor interface is a communications and power input connector The sensor is mounted using the mounting and alignment holes as needed see Sensor Mounting on page 40 The indicators on the 3DM GX4 25 include a device status indicator and the device information label Table 2 Indicator Behaviors describes the basic status indicator behavior The device information label includes the sensor frame diagram axis orientation which will be critical during device installation see Sensor Frame on page 26 i mounting hole davies statis alignment hole g indicator NA j e E W4 NN blink l Z device Tl 7 f information label A f b Erunt P4 NC N h f jjj gt s I 3 Pa LO 3 communication and power port alignment hole mounting hole Figure 2 Interface and Indicators Indicator Behavior Device Status i device status 9 no power applied indicat rapid flash streaming data Bie panes idle mode awaiting commands Table 2 Indicator Behaviors W4 LORD MicroStrain P SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 Basic Setup and Operations Do not put the 3DM GX4 in contact with or in close proximity to magnets Magnets may disrupt operation and cause
58. re sent to the sensor the software will automatically connect to it before sending the message l l W4 LORD MicroStrain is SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Basic Setup and Operations 3 5 Sensor Settings Device settings are stored in the sensor memory Only the configuration options that are available for the type of sensor being used will be available in the configuration menus 1 Toenter the settings menu right click on the sensor name and select Device Settings a Main menu tabs The main tabs break up the setting into broad functional groups for the types of measurement available For the 3DM GX4 25 these include calculated meas urements Estimation Filter and direct inertial sensor measurements IMU AHRS b Message Format first sub menu tab Under each main menu tab there are additional sub menu tabs including the Message Format tab The Message Format tab allows the user to select the measurement type to be displayed and recorded b1 and the data rate rate at which data is sent to the host computer in samples second b2 c Measurement parameters other sub menu tabs Available sub menu tabs besides the Message Format tab depend on the selected main menu tab These tabs include the configurable settings for each measurement d Scrolling used to navigate to additional sub menus e Help menu Enable the context sensitive help menu for explanations of specific
59. recise alignment with 2mm dowel pins One of the holes is slotted to allow for relaxed pin positioning accuracy The sensor can be mounted in any orientation as required for the application see Sensor Reference Frames on page 26 The axes are labeled on the face of the sensor for reference and the sensor measurement origin is shown in the sensor dimensional drawing see Reference Diagrams on page 61 0 07951 0005 G2 019 0 013 PRECISION ALIGNMENT HOLE 74 18 7 FOR OPTIONAL USE WITH 2mm i DOWEL PIN 59 14 9 2X 9 13 2X 23 2 E M e 1 260 005 1 44 37 32 00 0 13 1 20 30 5 ACTUAL DIMENSION SECONDARY ALIGNMENT SLOT FOR OPTIONAL USE WITH 2mm DOWEL PIN 03 6 1 30 32 9 ALL DIMENSIONS ARE IN INCHES mm Figure 28 Mounting the Sensor W4 LORD MicroStrain SENSING SYSTEMS Sensor Installation 3DM GX4 25 Attitute Heading Reference System User Manual OEM System Integration 7 OEM System Integration The 3DM GX4 25 starter kit comes with everything that is needed for sensor configuration operation and data collection However many applications will require custom solutions because of physical or environmental constraints required sensor output processing or for integration into control systems that react to the sensor outputs For these applications the 3DM GX4 25 is available as a stand alone component with optional interface conne
60. ressure meters altitude altitude as derived from the U S Standard pressure milli bars Atmospheric Model SAM using the temperature C sensed barometric pressure and air density kg m temperature Acceleration Linear Heading Update Table 5 Estimation Filter Outputs W4 LORD MicroStrain en SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 3 Sensor Reference Frames 4 3 1 Geodetic Frame The World Geodetic System is the standard for cartography and navigation The latest revision WGS84 is the reference coordinate system for GPS and the 3DM GX4 25 reports position using this coordinate frame It also calculates the magnitude of the local gravity vector using the WGS84 reference formulas The WGS coordinates are latitude longitude A and height h above the reference ellipsoid Latitude ranges from 90 degrees at the South Pole to 90 degrees at the North Pole Longitude ranges from 180 to 180 degrees with O degrees being the prime meridian The 180 180 degree switchover occurs in the middle of the Pacific Ocean and includes a section of the International Date Line The model takes into account the oblateness of the Earth s surface A point P on or above the Earth in the WGS84 coordinate system is notated as latitude longitude A and height above the reference ellipsoid h Prime Meridian KEY P point of measurement h height above
61. rranty repairs replacements include a minimum charge If the repair replacement charge exceeds the minimum LORD MicroStrain will contact the customer for approval to proceed beyond the minimum with the repair replacement W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Troubleshooting 8 3 Technical Support There are many resources for product support found on the LORD MicroStrain9 website including technical notes FAQs and product manuals http www microstrain com support overview aspx For further assistance our technical support engineers are available to help with technical and applications questions Technical Support sensing support LORD com Phone 802 862 6629 Fax 802 863 4093 SKYPE microstrain orientation support Live Chat is available from the website during business hours 9 00 AM to 5 00 PM Eastern Time US amp Canada W4 LORD MicroStrain ag SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Maintenance 9 Maintenance There are no user serviceable parts on the 3DM GX4 25 Removing the device cover or disassembling in any way voids the product warranty W4 LORD MicroStrain e SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Parts and Configurations 10 Parts and Configurations 10 1 Standard Configurations For the most current product information custom and OEM options not listed
62. stimations are refered to as an AKF AHRS Attitude and Heading Reference System A navigation device consisting of sensors on the three primary axes used to measure vehicle dir ection and orientation in space The sensor measurements are typically processed by an onboard algorthim such as an Estimation Filter to produce a standardized output of attitude and heading Algorithm In math and science an algorithm is a step by step process used for calculations Altitude the distance an object is above the sea level Angular rate The rate of speed of which an object is rotating Also know as angular frequency angular speed or radial frequency It is typically measured in radians second W4 LORD MicroStrain 22 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Addendum API Applications Programming Interface A library and or template for a computer program that specifies how components will work together to form a user application for example how hardware will be accessed and what data structures and variables will be used ASTM Association of Standards and Testing a nationally accepted organization for the testing and calibration of technological devices Attitude the orientaion of an object in space with reference to a defined frame such as the North East Down NED frame Azimuth A horizontal arc measured between a fixed point such as true north and the vertical circle passing through the ce
63. tch and roll angles This error is the direct result of the assumption that the accelerometers are only sensing Earth s gravity A second source of error occurs when the device attempts to measure the Earth s magnetic field This field is very weak compared to the numerous magnetic anomalies typically W4 LORD MicroStrain dd SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Performance Optimization found on platforms or naturally occurring close to the Earth s surface If the magnetic anomalies in the platform remain constant with respect to the sensor no translation or rotation between the two they can be compensated for by performing a hard iron and or soft iron calibration of the magnetometers internal to the 3DM GX4 25 see Magnetometer Calibration on page 31 The hard iron calibration compensates for magnetic effects that cause offsets in the magnetic field additive effects The soft iron calibration compensates for effects that cause a non uniformity of the magnetic field which results in an ellipsoidal distortion in the field Non constant and external sources such as those found when traveling through cities cannot be compensated and may cause large errors in the heading estimation Transient errors can be suppressed when the magnetometer readings are combined with information from the gyroscopes but only for periods on the order of a few seconds Longer duration anomalies will result in heading errors
64. ter there will be no drift but the accuracy will only be as good as the magnetometer To select between the heading sources in MIP Monitor select Settings gt Device gt Estimation Filter gt EF Options EF settings Estimation Filter IMU AHRS Message Format EF Options EF Advanced Geographic Mounting 4 gt Message Format EF Options Nr Advanced Geographic Mounting f 7 Vehicle Dynamics Mode Portable Internal GPS GPS Update Source Heading Update Input Source External Message xi Enable Auto EF Initialization Enable EF Velocity ZUPT Enable Fast Convergence 0 0000 Theshold Enable Angular Rate ZUPT 0 0000 Theshold Figure 27 Heading Source Setting W4 LORD MicroStrain id SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Performance Optimization 5 4 Angular Rate and Acceleration Limits The 3DM GX4 25 angular rate and acceleration range depend on the sensors installed in the device Exceeding the specified range for either sensor will result in estimated state errors and elevated uncertainties until the over range event is corrected and the filter can resolve the errors 5 5 Bandwidth When selecting sensor and estimation outputs to be recorded communication bandwidth considerations should be taken into account especially when using RS232 serial communications Lower baud rates equate to lower communica
65. ter provides EKF technologies to compensate for magnetic and linear acceleration anomalies as applicable to the model It also provides sensor bias tracking auto zero update options ZUPT and user adjustable sensor noise factors All sensors are fully temperature compensated and calibrated over the full operating temperature range The use of Micro Electro Mechanical System MEMS technology allows for small lightweight devices Sensors are integrated into customer systems using serial communication protocols such as RS422 RS232 and USB The LORD MicroStrain MIP Monitor software can be used for device configuration real time measurement monitoring and data recording The LORD MicroStrain MIP Data Communications Protocol that is used to communicate with LORD MicroStrain inertial sensors is also available for users who want to develop customized software solutions Because of the unified set of commands across the sensor family it is easy to migrate code from one inertial sensor to another Common applications of LORD MicroStrain inertial sensor products include vehicle health monitoring platform stabilization down hole and drilling operations and inertial navigation systems such as unmanned air and ground vehicles and personal navigation systems Position Velocity Attitude G Inclination N W4 LORD MicroStrain a SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Overview
66. tes the current state of the EF such as running or initializing soe an to the calculated filter Euler angles representation of Attitude t di tis orientation expressed as roll pitch and yaw Euler RPY RPY with one sigma uncertainly estim ation available transformation matrix that describes Attitude orientation with reference to the ECEF Matrix coordinate system Attitude unit quaternions representation of Quaternion orientation with one sigma uncertainly estimation available linear acceleration readings with reference to either the sensor or vehicle frame meter second depending on settings with bias and scale readings and one sigma uncertainty estimations also available measured angular rate corrected using the Compensated estimated gyroscope scale factor and bias radians second Angular Rate with reference to either the sensor or vehicle frame depending on settings estimated WGS84 gravity vector with Gravity Vector meter second reference to either the sensor or vehicle frame depending on settings WSG 84 Local 2 Gravity Magnitude local WGS84 gravity vector magnitude heading used to update EF calculated from the selected heading source magnetometer external etc with one sigma uncertainty reading available WMM World Mag Gauss WMM local magnitude inclination and netic Model declination based on coordinates Pressure Altitude meters altitude altitude estimate from barometric p
67. the Earth A longitude Equator latitude Figure 18 World Geodetic System WGS84 Reference Ellipsoid W4 LORD MicroStrain En SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 3 2 North East Down NED Frame The North East Down NED frame is a local coordinate frame which is formed by a tangent plane located at a particular point current coordinates on the WGS84 reference ellipse The NED frame is constructed with the true North vector along the line of longitude the East vector along the line of latitude and the Down vector normal to and towards the tangent plane Figure 19 North East Down Frame The assumption when using the NED frame is that the local surface can be reasonably approximated by a flat plane For most applications this assumption is valid and provides a more intuitive reference frame for expressing velocity and attitude information than a global frame The 3DM GX4 25 reports velocity in this frame and attitude with respect to this frame KEY L fL tude A Ar ME GALE P point of measurement A longitude latitude Line of Latitude q P Local Tangent Plane at Reference point P p A 0 Figure 19 North East Down Frame W4 LORD MicroStrain ef SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 3 3 Sensor Frame The sensor frame is indicated on the top of the device and
68. the sensor system is digital the analog voltage readings from the sensors are converted into a digital equivalent value based on the volt to bit scale of the internal analog to digital voltage converter In the MIP Monitor software the conversion values are not configurable but there are user settable options for how the measurement is made These settings are available at Settings Device IMU tab With the Help window open accessed with the Help button mousing over context sensitive settings provides a detailed explanation of the setting Figure 16 IMU Settings N4 Device Setup Estimation Filter NIMU AHRS A Message Format EF Options EF Advanced Geographic Attitude Euler RPY 50 Hz Acceleration une 4 Device Setu Acceleration Linear i i e guiarte Estimation Filter IMU AHRS Angular Rate C 7 Message Format CF Options Low Pass Filter 1 Low Pass Filter 2 Cord gt ua M c 8 m8 mmc n8 H8 ttc nm cm Context Help u Gyro BW Mel Gyro Selecting Auto will pin the filter bandwidth NoFilter Y IR Filter Y to half the data rate selected for this data quantity If you select 100Hz for the data rate then the 3db bandwidth for the selected filter will be set to SOHz D Auto BW e Marf sl BW Filter bandwidth selection U 250 500 j Selecting Manual
69. tion bandwidth which can be consumed quickly by selecting a large number of measurements at high sample rates Severely overrunning the communication bandwidth can have adverse effects on the sensor performance due to excessive processor usage Most computer RS232 ports are limited to 115 200 baud even though the 3DM GX4 25 is capable of running at 921 600 baud 5 6 Platform Frame Transformation The transformation from the sensor frame to the platform frame see Platform Frame on page 29 should be defined to the highest angular accuracy possible The easiest way to accomplish this is to co align the frames If this is not possible using a simple transformation such as 90 or 180 degree rotations on a single axis is preferred For complex transformations between the frames a calibration should be performed or analysis from a model should be conducted 5 7 Estimation Filter Operation The 3DM GX4 25 combines the information from the IMU sensors to calculate an Attitude and Heading Reference System AHRS solution that incorporates the strengths of the individual sensors while minimizing their weaknesses In a conventional attitude estimations several sources of error exist First the algorithm assumes the acceleration vector is dominated by Earth s gravity with only transient linear accelerations When long duration linear accelerations are experienced such as when an aircraft performs a sustained 2G turn the AHRS will report incorrect pi
70. train x SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements In the MIP Monitor software the transformation setting is entered at Settings gt Device gt Estimation Filter Mounting in the Mounting Orientation field Figure 22 Platform Frame Settings Although the settings for Antenna Offset and Mounting Offset are shown these features are only available in the 3DM GX4 45 and 3DM RQ1 45 sensors EF settings Estimation Filter IMU AHRS Message Format EF Options EF Advanced Geographic Mounting 4 LI Attitude Euler RPY v s v wil Hz Acceleration Linear wi 50 wi Hz Mounting settings Angular Rate l sy Ka Device Setup zr Estimation Filter IMU AHRS 5 ge EF Options EF Advanced Geographie Mounting Bigs Model Sen BIL 5 Antenna Offset re X 0 000 v 0 000 z 0 000 Mounting Offset Ses x 0 000 v 0 000 z 0 000 Mounting Orientation Roll 0 0000 Pitch 0 0000 Yaw 0 0000 Lok cancel Help Figure 22 Platform Frame Settings The orientation transformation affects the following EF outputs see Computed Outputs Estimation Filter AHRS on page 24 attitude position linear and compensated acceleration compensated angular rate and gravity vector It also affects the following IMU outputs acceleration angular rate magnetic fiel
71. typ 800 mW max with Vaux 5 2 V dc to 36 V dc Operating temperature 40 C to 85 C 500 g calibration unaffected Mechanical shock limit 1000 g bias may change 5000 g survivability MTBF 1 2 million hours Telcordia method I GL 35C 0 45 million hours Telcordia method GM 35C Physical Specifications a 36 0 mm x 24 4 mm x 11 1 mm excluding mounting tabs 36 6 Dimensions i mm width across tabs wam essems OOOO MIP Monitor MIP Hard and Soft Iron Calibration Windows Software j XP Vista 7 8 compatible mmm p 7 ni E TM Compatibility Protocol compatibility with 3DM GX3 and 3DM RQ1 45 sensor families Software development kit MIP data communications protocol with sample code SDK available OS and computing platform independent Power consumption W4 LORD MicroStrain id SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Safety Information 12 Safety Information This section provides a summary of general safety precautions that must be understood and applied during operation and maintenance of components in the LORD MicroStrain Inertial Sensor Products Throughout the manual ANSI Z535 standard safety symbols are used to indicate a process or component that requires cautionary measures Situations in which potentially hazardous conditions exist that could result in death or serious injury of workers and or the general public if not avoided Situations
72. urable time period Timestamp status indicators ing IMU sensor data pressure sensor Complementary Filter CF Euler angles Euler RPY representation of orientation Matrix matrix representation of orientation Quaternion quaternions representation of orientation CF North Vector Complementary Filter CF north vector CFUpVector Complementary Filter CF up vector Table 4 IMU Measurements W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements 4 2 Computed Outputs Estimation Filter AHRS The computed outputs are measurements from the 3DM GX4 25 IMU sensors that are blended through an Adaptive Kalman Filter AKF algorithm The Kalman Filter produces a better estimation of attitude and heading AHRS outputs than can be achieved by the inertial sensors individually Refer to Table 5 Estimation Filter Outputs for a complete list of outputs In the MIP Monitor software there are user settable options for how the estimations are made These settings are available at Settings Device EF With the Help window open accessed with the Help button mousing over context sensitive settings provides a detailed explanation of the setting Figure 17 Estimation Filter Settings 1MU AHRS Estimation Filter Message Format EF Options EF Advanced Geographic Attitude Euler RPY wi so iuz Acceleratio
73. utputs can be viewed and recorded with the LORD MicroStrain MIP Monitor software that is provided with system starter kits and also available as a free download from the LORD MicroStrain website Alternatively users can write custom software with the LORD MicroStrain open source data communication protocol The data is time aligned and available by either polling or continuous stream Figure 1 3DM GX4 25 Sensor W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Overview 2 1 Components The 3DM GX4 25 can be purchased by itself or in a starter kit that includes everything needed to begin using it The starter kits include the 3DM GX4 25 inertial sensor a serial communication cable either RS232 or USB a power supply with international plug adapters RS232 kits only and all software drivers and documentation This manual covers all items included in the starter kits For a complete list of available configurations accessories additional system products and ordering information see Parts and Configurations on page 54see Parts and Configurations on page 54 Item Description Quantity 3DM GX4 25 Inertial Sensor Communications cable USB or RS232 EM mee uc Power supply and plug adapters for RS232 only BET aa MIP Monitor Software Suite User Documentation and Calibration Certificate Table 1 Starter Kit Components List W4 LORD MicroSt
74. which immediate data acquisition is desired and connection to MIP Monitor for data logging is not required This functionality can also be embedded in user designed applications by using the corresponding LORD MicroStrain MIP Data Communications Protocol command see Data Communications Protocol DCP on page 41 for more information When setting the sensor to begin sampling on start up verify that the sensor is sampling by reading the status indicator on the device see Interface and Indicators on page 9 or by viewing the serial data stream from the host computer If communication with MIP Monitor is established the sampling will stop to facilitate device configuration To save the current sensor configuration first adjust the sensor settings to the desired values and then start streaming Next select Settings Save Current Settings from the main window Figure 32 Save Sensor Settings The setting will remain intact when the sensor is powered off and then on again To recall the last saved settings select Settings Load Startup Settings n mem ts File Control Era View Window Advanced Help Device System Not Connected eu Model Nam Capture Gyro Bias FW ver Model Number Options COM Save Current Settings Load Startup Settings Load Default Settings Figure 32 Save Sensor Settings W4 LORD MicroStrain A5 SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System Us
75. will allow you to manually set the bandwidth of the selected filter B t Figure 16 IMU Settings W4 LORD MicroStrain SENSING SYSTEMS 3DM GX4 25 Attitute Heading Reference System User Manual Sensor Measurements Table 4 IMU Measurements lists the IMU measurements available for the 3DM GX4 25 Additional measurement units may be available in MIP Monitor for some outputs however they are converted values and do not represent the actual sensor outputs Only actual output units are listed The Complementary Filter CF attitude and up and north vector outputs are computed estimations from the LORD MicroStrain 3DM GX3 inertial sensor family and are available to maintain backwards compatibility For new applications it is recommended that these estimations be computed with the 3DM GX4 EF Outputs algorithms see Computed Outputs Estimation Filter AHRS on page 24 To view and record IMU outputs see Basic Setup and Operations on page 10 Measurement Units Description me three axis acceleration readings in Acceleration gravitational force g engineering units Magnetic Field Gauss G three axis magnetic field readings in engineering units ARUUISERISES three axis rotational velocity reading from gyroscope in engineering units Delta Angle Theta time integral of angular rate with configurable time period Delta Velocity g seconds time integral of acceleration with config

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