Home
OEM User Manual
Contents
1. Figure 6 Sign conventions for heading pitch and roll outputs N 0 S 081 S Heading Pitch Roll The heading output increases clockwise from north The pitch output increases as the front of the host lifts and the roll output increases as the left side of the host lifts OEM models Each model in the OEM range shares similar core technology but differs subtly in specification to suit different applications The main differences are highlighted below Output frequency The inertial measurement unit is the same in all products but a 100 Hz or a 250 Hz version is fitted depending on the product Systems in the OEM3000 range have 100 Hz output while those in the OEM4000 range output at 250 Hz The OEMi 2 simply has 250 appended to the model name to identify the high speed version Sensors Extended measurement ranges of 30 g acceleration and 300 s angular rate may optionally be requested The specification using the extended measurement range sensors can be marginally worse than those listed for the standard model An X appended to the product name denotes extended measurement range sensors are fitted GNSS Receiver cards capable of receiving GLONASS data are available as an option for OEM3000 and OEM4000 devices A G appended to the product name denotes GLONASS capable receivers are fitted Single vs dual antenna Both single antenna and dual antenna configurations are available in the OEM3000 and
2. Colour Single antenna OEM3000 O0EM4000 Off Either the program is not running or the GNSS receiver has a fault valid only after start up Red flash No position lock Red The GNSS receiver has a standard position solution SPS or differential solution DGPS The GNSS receiver has an RTK float position solution 20 cm accuracy The GNSS receiver has an RTK integer position solution 2 cm accuracy Orange Green Dual antenna system OEM3000 OEM4000 Either the program is not running or a GNSS receiver has a fault valid only after start up GNSS receivers are active but no heading has yet been determined The GNSS receivers have a differential uncalibrated heading lock The GNSS receivers have a differential calibrated heading lock poor The GNSS receivers have an RTK integer calibrated heading lock good OEMit 2 Either the program is not running or a GNSS receiver has a fault valid only after start up GNSS receivers are active but no heading has yet been determined The GNSS receivers have a differential calibrated heading lock poor The GNSS receivers have an RTK integer calibrated heading lock good GNSS The GNSS LED gives information about the internal GNSS receiver Table 6 defines its states Table 6 GNSS LED states Colour Description Green flash Normal operation Red yellow flash Internal error Contact support oxts com Power The Power
3. ee RT Post Process Wizard bzs Select Data Source Choose where the initial settings should be read from RT3000 Inertial auki Read data file Measurement System Hint Choose where to get files from Step 1 of 9 Select Raw Data File from RT System gt C Select Raw Data File from Folder Select Raw Data File Working Directory Base Station Process Page Select Fields Output Config Output File v Finish Page Confidentty Accurately E aaa A Dev ID 121212 14a0 Cancel C Select NCOM File from Folder IP Address of RT System There are three options to the Wizard The Wizard can load an RD file from the OEM and save it on the PC before processing the file If the file has already been loaded on to the PC then the Wizard can process the file directly If the file has already been processed and is now in NCOM format then it can change the file to text A full explanation of RT Post process is given in the RT Post process Manual which can be downloaded from the OxTS website Revision 150709 Ea Field testing There are several field tests that can be performed to ensure the OEM is working correctly The most fragile items in the system are the accelerometers the other items are not subject to shock and do not need to be tested as thoroughly Accelerometer test procedure To check the accelerometers are working correctly follow this procedure 1 Connect power and a la
4. 0 0 1 sin 0 0 cos 0 sin d cos o where y is the heading angle O is the pitch angle and is the roll angle Revision 150709 ES Remember heading pitch and roll are usually output in degrees but the functions sin and cos require these values in radians Operating principles This short section gives some background information on the components in the OEM and how they work together to give the outputs A short overview of the algorithm is given and some explanation of how the software works The section is provided as interesting information and is not required for normal operation Internal components Figure 33 below gives a schematic view of the components in the OEM system Figure 33 Schematic showing the internal components of the OEM Accelerations z y Angular Rates x ay Ay az Wy Wy W IMU i Gii 40 MHz DSP 20 bit resolution Differential Corrections Radio Modem e g SATEL 3ds Serial or cellphone 64 MB Storage Ethernet Syne 1 PPS 100 Hz out or event in Power I I l I I I I I I I I j I I 300 MHz CPU I I I I I I I I I I 10 25 V dc I I The schematic shows the layout for a dual antenna system the second GNSS GNSS2 and the second antenna are not fitted on single antenna systems The accelerations and angular rates are measured in the inertial measurement unit The accelerometers are all mounted at 9
5. OEM4000 family the OEMi 2 is dual antenna only Single antenna products can achieve heading accuracies that are equivalent to dual antenna products in some conditions In normal conditions most land based applications can use a single antenna system as the heading lock and wheel configuration features use a land vehicle model to maintain accurate heading when stationary or driving with low vehicle dynamics 18 Oxford Technical Solutions OEM User Manual Qoxrs However dual antenna products offer almost constant heading performance under all conditions especially on aircraft boats or in low speed land vehicles Dual antenna systems are recommended for road vehicle testing on low friction surfaces e g ice aerial survey and marine use ships survey vessels While GNSS only dual antenna systems require open sky environments to operate and take several minutes to acquire heading lock advanced processing in OEM products allows relock to occur after just 5s of sky obstruction In this time the heading accuracy will not have degraded significantly The fast relock time is possible because the OEM s own heading is used to resolve ambiguities in the GNSS measurements Resolution of these ambiguities is what normally takes several minutes The OEM s heading software enables significantly better performance and coverage compared to GNSS only solutions Differential correction To improve the positioning accuracy of standard GNSS tw
6. configuration page To stop this return to the product selection page and make sure Always use this product is not selected EJ Oxford Technical Solutions OEM User Manual Qoxrs Figure 15 NAVconfig Product Selection page G 2 NAVconfig OEM r Product Selection Select the product for configuration WwIXIS Inertial GPS Product family Product model RT2000 All OEM3000 models RT3000 All OEM4000 models RT4000 OEMI 2 Inertial OEMI 2 250 Survey xNAV Read Configuration GNSS Selection Orientation Primary Antenna Secondary Antenna Wheel Configuration Options Commit Save Finish E Always use this product Dev ID 150610 14am EB English Read Configuration The Read Configuration page Figure 16 tells NAVconfig where it should get its initial settings from When configuring a new installation Use default settings should be selected This forces NAVconfig to load a clean set of base settings removing any advance features that may have been used previously committed It is possible to overwrite the standard OxTS default settings with a custom set see Overwriting NAVconfig s default settings on page 89 The Read settings from a folder and Read settings from an RD file options both perform similar tasks they load a configuration that was previously saved If the OEM is permanently installed in a host meaning the OEM and antennas cannot move then it saves time to Rea
7. i e after the IMU to vehicle attitude matrix has been applied It is a signed word in units of 10 m s Acceleration Z is the vehicle body frame acceleration in the z axis i e after the IMU to vehicle attitude matrix has been applied It is a signed word in units of 10 m s Angular Rate X is the vehicle body frame angular rate in the x axis i e after the IMU to Vehicle Attitude matrix has been applied It is a signed word in units of 10 radians s Angular Rate Y is the vehicle body frame angular rate in the y axis i e after the IMU to Vehicle Attitude matrix has been applied It is a signed word in units of 10 radians s Angular rate Z is the vehicle body frame angular rate in the z axis i e after the IMU to Vehicle Attitude matrix has been applied It is a signed word in units of 10 radians s See Table 18 This checksum allows the software to verify the integrity of the packet so far For a low latency output the accelerations and angular rates can be used to quickly update the previous solution The Latitude of the IMU It is a double in units of radians Ey Oxford Technical Solutions OEM User Manual 31 Longitude byte 0 Longitude of the IMU It is a double in units of radians 32 Longitude byte 1 33 Longitude byte 2 34 Longitude byte 3 35 Longitude byte 4 36 Longitude byte 5 37 Longitude byte 6 38 Longitude byte 7 39 Altitude byte 0 Altitude of the IMU It
8. 1 0 01 100 0 15 10 25 234 120 80 2 2 3202 4202 L1 1 8 0 6 0 4 0 1 10 0 01 100 0 05 0 05 0 01 100 0 15 10 25 20 234 120 80 2 4 3004 4004 L1 L2 100 0 03 0 1 0 01 100 0 1 10 25 15 234 120 80 2 2 3005 4005 L1 L2 100 0 03 0 05 0 01 100 0 1 10 25 20 234 120 80 2 4 I 2 I 2 250 L1 L2 0 02 0 05 10 0 01 100 0 03 0 05 0 01 0 1 100 0 07 10 18 20 234 120 76 2 4 EJ Oxford Technical Solutions OEM User Manual Qoxrs Common specifications Table 43 OEM common specifications Parameter Specification Calculation latency ms 3 5 Operating temperature CO 10 to 50 Vibration g Hz 5 500 Hz 0 1 Shock survival g ms 100 11 Internal storage GB 2 Notes on specifications For OmniSTAR XP and OmniSTAR HP at least 30 minutes of open sky condition may be required before full accuracy is achieved Both services easily achieve this accuracy in airborne applications The lo specification has been used for parameters where offset cannot be measured by the OEM device for example position the offset of the base station cannot be found by an OEM alone The RMS specification was used where the offset is known for example velocity For angles and measurements derived from the angles the lo specification is used because the mounting of the OEM compared to the vehicle gives an offset the OEM
9. 28 Status information channel 8 GyroSf Bytes Format Definition Valid when 0 1 Short Gyro scale factor x Age lt 150 2 3 Short Gyro scale factor y Age lt 150 4 5 Short Gyro scale factor z Age lt 150 6 UChar Age 7 Reserved Note The units of the gyro scale factors are 1 ppm 0 0001 Revision 150709 73 Table 29 Status information channel 12 GpsAntOffset Bytes Format Definition Valid when 0 1 Short Distance to primary GNSS antenna in x axis Age lt 150 2 3 Short Distance to primary GNSS antenna in y axis Age lt 150 4 5 Short Distance to primary GNSS antenna in z axis Age lt 150 6 UChar Age 7 Reserved Note The units of the distances are 1 mm Table 30 Status information channel 13 GpsAntAngles Bytes Format Definition Valid when 0 1 Short Heading orientation of the GNSS antennas Age lt 150 2 3 Short Pitch orientation of the GNSS antennas Age lt 150 4 5 Short Distance between the GNSS antennas Age lt 150 6 UChar Age 7 Reserved Note The units of the distances are 1 mm The units of the orientation angles are 1e 4 radians Table 31 Status information channel 14 GpsAntStdev Bytes Format Definition Valid when 0 1 Short Accuracy of distance to primary GNSS antenna in x axis Age lt 150 2 3 Short Accuracy of distance to primary GNSS antenna in y axis Age lt 150 4 5 Short Accuracy of distance to primary GNSS antenna in z axis Age lt 150 6 UChar Age 7 Reserved Note The uni
10. At this stage it does not matter where 2 Open NAVconfig and create a configuration using the settings that will be used as defaults 3 From the Save Finish page of Navconfig select Save settings in the following folder and using the Browse button point to the usersettings folder created in step 1 Click Finish to save the files to the folder 4 Check that the usersettings folder created in step 1 now contains a number of mobile files 5 Move the entire usersettings folder to the folder where NAVconfig is installed The default location is C Program Files x86 OxTS NAVconfig See Figure 35 A warning might pop up asking for administrator permission Click Continue if you see this message Revision 150709 EI 6 NAVconfig will now use the saved settings each time it runs Figure 35 Adding a usersettings folder to NAVconfig s application directory teta go gt Computer Local Disk C Program Files x86 OxTS NAVConfig gt v gt Search NAVC p Organize v Include in library v Share with v Burn Compatibility files New folder y Fil J Language Files J Resources J usersettings InertialOrientationDecode dil Nationallnstruments Common dil 8 Nationallnstruments ULdll Nationallnstruments ULStyles3D dll Nationallnstruments ULWindowsFor J NAVconfig exe t NAVconfig exe config OxTSConfigDataModel dil OxtsConfigUtils dil OxtsControls dll PCIPConfig dil RTGraphic
11. NAVconfig OEM g Performance Options Advanced options to improve the performance of the device f COX 7S N Inertial GPS Product Selection Read Configuration GNSS Selection Orientation Primary Antenna Secondary Antenna Wheel Configuration Option GNSS weighting Differential SBAS DGNSS service initialisation speed Heading lock Serial 1 output Serial 2 output Ethemet output Coordinate system Advanced Setting Medium RTCMV3 None Disabled 5m s Normal Disabled Disabled Enabled 100 Hz WGS84 Bllipsoidal Disabled Commit Save Finish Dev ID 150610 14am EEE English Commit Changes to the OEM s settings must be sent via Ethernet It is necessary to configure the computer s Ethernet settings so it is on the same network as the OEM If necessary ask the system administrator to help Figure 24 below shows the Commit screen where settings are finally sent Enter the IP address of the OEM you want to configure The drop down box will list all OEMs connected to the computer s network this function won t work if Enginuity or other software is using the OEM UDP port 46 Oxford Technical Solutions OEM User Manual Qoxrs Press Commit to save the configuration in the OEM This will automatically reset the OEM so the changes take effect It will be necessary to initialise and warm up the OEM again after the changes have been applied Figure 24 NAVconfig Commit
12. NMEA 0183 Description manual gives details about the different fields that are output in NMEA messages It can be downloaded from www oxts com support manuals Selecting Output approximate values before initialisation forces output of the raw GPS measurements before the RT is initialised Javad I RTK output can be used with Javad receivers With this output the OEM outputs a special set of messages in Javad s GREIS format which a Javad receiver can use to relock the RTK Integer position faster after bridges or other obstructions This is a tight coupling of the OEM and Javad receiver The tight coupling with Javad GNSS receivers was introduced in January 2010 and firmware after this date is required in the Javad receiver In order to use the Javad I RTK output it is essential to configure the output displacement option so the output of the OEM is at the GNSS antenna position It is also important that the position of the external antenna is known accurately and its position is configured with high accuracy better than 1 cm so the OEM will not move the antenna position If the OEM does not compute the correct position of the antenna the Javad receiver will not be able to use the output correctly MCOM is an extended version of OxTS NCOM format used in the marine market TSS1 gives heave pitch and roll output in TSS1 format TSSHHRP gives heading heave roll and pitch in TSSHHRP format text Simrad EM3000 outputs roll
13. OEM needs to measure this itself as part of the warm up process The OEM will lock on to satellites but it cannot estimate heading so it cannot start unless static initialisation is enabled The host vehicle moves forward at about 5 m s or the initialization speed and the OEM assumes the heading and track are similar and initializes heading to track angle If the OEM is mounted in the vehicle with a large heading offset then the initial heading value will be incorrect This can also happen if the OEM is initialised while turning This can lead to problems later Once the heading and secondary antenna orientation accuracy is sufficient the OEM will solve the RTK integer problem using the inertial heading There is no need for the OEM to solve the RTK integer problem by searching If the antennas have a large rotational offset from the OEM the RTK integer solution will be solved incorrectly It is essential to get the OEM orientation and the secondary antenna orientation to within 5 or lower if a separation of more 2 m is used Once the RTK integer solution is available the OEM can start to use the dual antenna solution to improve its heading The level of correction that can be applied depends on how accurately the angle of the secondary GNSS antenna is known compared to the inertial sensors The Kalman filter tries to estimate the angle between the inertial sensors and the secondary GNSS antenna The default value used in the co
14. OEMi 2 are designed to seamlessly integrate with existing GNSS receivers giving system integrators the ability to increase the accuracy and reliability of existing GNSS only systems without the need to completely re engineer and at a much reduced cost As well as outputting real time inertial navigation measurements with a latency of just 3 5 ms each model in the OEM series can also record data internally for later download and analysis The post processing of this data is not covered in this manual but a separate manual covering it called RT Post process manual is available on the OxTS website The remainder of this section covers the basic information required to understand and set up OEM products Ei Oxford Technical Solutions OEM User Manual Qoxrs Front panel layout Figure 2 Front panel layout of OEMs Ga mary EAEI 0001 Si Ls ge Power ar Ethernet O Ie Digital VO fe Q Quam Q The function of each connector on an OEM is clearly marked with the exception of the main connector on the OEM3000 OEM4000 1 The front panel layout is the same for both single and dual antenna models of the OEM3000 OEM4000 The secondary antenna connector of single antenna models is not connected internally LED definitions The LEDs on an OEM s front panel give an indication of the internal state of the system They can also be used for some simple operational checks Table 3 LED descriptions LED Name Description
15. Oxfordshire OX25 5HD www oxts com Copyright Oxford Technical Solutions 2013 Confidential Information The information in this document is confidential and must not be published or disclosed either wholly or in part to other parties or used to build the described components without the prior written consent of Oxford Technical Solutions 0 10 20 30 Print Size A4 YEE YB YY YY NA NA NANA NI NA SY Scale 1 2 Half Tolerances X X 0 1 Projection 3rd Angle Material HE30 Alu Finish Anodised Notes A M4 x 10 Tapped Hole B 2mm dia x 3 hole WwW o CAC ACACACACACACAG LS NA NANA NA NA NA NA NZ MN DNOAADDADD gt O Date 14 10 13 Part 14A0007A Document OEM3000 0EM4000 out dimensions Oxford Technical Solutions 77 Heyford Park Upper Heyford Oxfordshire OX25 5HD www oxts com Copyright Oxford Technical Solutions 2013 oi CO The information in this document is confide
16. advance 3 When using a base station for DGPS corrections it is useful but not critical for it to be working before the dynamic movement starts so the device can use the best information to self calibrate Warm up example Figure 26 shows the route driven and Figure 27 shows the accuracy estimated by the Kalman filter for various output parameters during the first 25 minutes of a test The device in this example was turned on as soon as possible and there was a small amount of motion to get the device initialised The time on the graphs is the time from initialisation EJ Oxford Technical Solutions OEM User Manual Qoxrs Figure 26 Example warm up driving route 20 80 i ATE 120 3 ug Af 100 80 60 40 20 0 20 4 East It then took another 15 minutes to get all the other equipment in the test sorted out The device was stationary for most of this period which is not a problem During this time the Kalman filter cannot improve the position accuracy because the position of the GNSS antenna is not known accurately and cannot be estimated without motion The accuracy of the velocity roll and pitch steadily improves as the Kalman filter places more and more weight on the inertial sensors At this point the heading accuracy is worse than the scale of the graph the heading is not accurate and the dual antenna system cannot measure the angle of the GNSS antennas compared to the inertial sensors so the dual antenna c
17. after the first 22 characters have been received reducing additional latency to 1 9 ms More convenient processing of the data can be achieved after 62 characters have been received reducing additional latency to 5 3 ms Full functionality requires multiple packets to be received since low data rate information is divided up and sent in 8 bytes tagged on to the end of each packet To save space many of the data packets are sent as 24 bit signed integer words 16 bit precision does not provide the range precision required for many of the quantities whereas 32 bit precision makes the packet much longer than required All words are sent in little endian format meaning little end first or LSB first which is compatible with Intel microprocessors The packet is also transmitted over Ethernet as a 72 byte UDP broadcast The port number is 3000 Ethernet provides the lowest latency output from the system since the transmission speed is nearly 1000 times faster than the serial communications A Oxford Technical Solutions OEM User Manual Qoxrs Table 16 Word length definitions Terminology Data length Byte UByte 8 bit integer unsigned Short UShort 16 bit integer unsigned Word UWord 24 bit integer unsigned Long ULong 32 bit integer unsigned Float 32 bit IEEE float Double 64 bit IEEE float Note A U prefix indicates an unsigned value otherwise it is signed using 2 s complement The definition of the N
18. an accuracy of 10 cm Selecting an accuracy better than 10 cm does not improve results Using an accuracy figure worse than 20 cm will increase the drift of the device Use the accuracy fields to select or specify the accuracy of the measurements Figure 22 NAVconfig Wheel Configuration page FJ NAVconfig OEM lm Wheel Configuration Q Specify the position of the non steered axle AOXTS Ata GPS Lateral settings Vertical settings V The vehicle has a non steered ade Measured from the device Where is the centre point of the non steered ade Ahead 0 000m 0 100m Product Selection Read Configuration Right 0 000m Cio GNSS Selection Orientation How far below is the ground Primary Antenna Below 1 000 m Secondary Antenna Specify each accuracy separately Options Overall accuracy 0 100m v Commit Save Finish Select surface Normal Dev ID 150610 14am EE English The wheel configuration feature also requires some knowledge of the road surface Select one of the predefined options from the drop down list Normal or Low friction ice For the Vertical settings the system needs to know the position of the front axle A position at road height mid way between the wheels should be used like for the rear axle Measure the distances again from the device and enter them into the cells selecting the appropriate directions from the drop down lists When using Wheel Configur
19. be re committed to the OEM Figure 29 Get improved settings pages T P Get settings from device EE 03 cet settings from device Read improved configuration lo Select Configuration Choose where to read the configuration from j D Choose which settings should be used W IXTS Enac ki eae tems Description Orientation in vehicle Read configuration from File Zi Primary GNSS antenna Step 1of2 Step 2of2 Secondary GNSS antenna Wheel speed input Source Settings _Selectal Ceara Ba Frish J Conca _ Confidently Ey Oxford Technical Solutions OEM User Manual Qoxrs Setting up the base station For correct operation of the higher accuracy systems it is necessary to use a base station GNSS receiver All OEMs can be successfully used without a base station however the specification will only be met if a base station is used The base station is a separate GNSS receiver that monitors signals from the GNSS satellites Using its knowledge of position it works out the errors in each satellite s signal It also measures the carrier phase of the signal for kinematic corrections The carrier phase observations and the satellite signal errors are sent from the base station GNSS to the OEM via a radio modem not provided The position of the base station GNSS antenna can be determined by the base station GNSS receiver or by some other accurate method such as a chart
20. can be found using the Enginuity software Open Enginuity and connect to the OEM Click Calibration then scroll down the Status tab The OmniSTAR serial number is shown in parameter number 139 3 After the license has been sent the device will operate in VBS mode If an HP license has been sent it may take 45 minutes before HP will start to work an almanac transmission is required and this is only sent slowly Any break in the OmniSTAR transmission will mean that the almanac will take longer to receive completely After OmniSTAR is configured and a valid license is obtained the OEM3000 OEM4000 will automatically use OmniSTAR whenever it is available The availability of the OmniSTAR signal can be monitored using the status information EI Oxford Technical Solutions OEM User Manual Qoxrs RT Post process Wizard Data stored on the OEM is in a raw unprocessed format these files have an rd extension The advantage of logged data is it can be reprocessed with different configuration settings For example if the configuration was configured incorrectly while running in real time then the configuration can be changed and the data can be reprocessed post mission The RT Post process Wizard can be used to reprocess the data The RT Post process Wizard also gives the user the ability to change the NCOM binary output format to text Figure 30 below shows the first page of the Wizard Figure 30 RT Post process Wizard Step 1
21. cannot measure Environmental protection OEM products are rated to IP65 To achieve IP65 it is necessary to have connectors fitted to both TNC antenna connectors and to use self amalgamating tape over the TNC connectors Export control classification number Export control regulations change and so the classification number of an OEM device may also change The information here was correct when the manual was published OEM products fall under two different export control categories depending on the type of accelerometer fitted internally The type of accelerometer does not affect the specification of the product only the export control classification number ECCN This will be 7A103al or 7A003d see invoice or delivery note or contact support at OxTS Revision 150709 El Conformance notices OEMs comply with the radiated emission limits for 47CFR15 109 2010 class A of Part 15 subpart B of the FCC rules and with the emission and immunity limits for class A of EN 55022 These limits are designed to provide reasonable protection against harmful interference in business commercial and industrial uses This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to
22. error roll error gyro bias x y z gyro scale factor x y z accelerometer bias x y z GNSS antenna position x y z GNSS antennas orientation heading pitch and vehicle mounting angle The errors are applied smoothly to the states For example if the Kalman filter wants to correct a position error of 5 cm in the north direction then this is applied slowly rather than jumping directly to the new position This helps applications that use the OEM for control since any differential terms in the control algorithm do not have large step changes in them Overwriting NAVconfig s default settings OxTS devices can be returned to a default setting by selecting Use default settings on the Read configuration page of NAVconfig then committing the files to the device However there may be occasions when system integrators wish to define custom default settings that are different to the OxTS defaults This section explains how do accomplish that Each time NAVconfig is launched it checks the application directory for a folder called usersettings The usersettings folder does not exist by default and NAVconfig will not create one it must be created manually by the user If NAVconfig does not find a usersettings folder containing valid files it uses OxTS defaults that are stored within the application itself To force the application to use a different set of default values 1 Create a folder called usersettings somewhere on your PC
23. internal log file Table 36 22 ImuTimingStatus Internal information on timing of real time processing 23 BnsStatus System up time number of consecutive GNSS rejections 24 TrigInDown Trigger event timing falling edge triggers Table 37 25 Reserved1 Reserved 26 Reserved2 Reserved 21 GpsAttStatus1 Internal information about dual antenna ambiguity searches 28 GpsAttStatus2 Internal information about dual antenna ambiguity searches 29 UserOptions Details on the initial settings 30 OsInfo Operating system and script version information 31 ReservedHW Hardware configuration information 32 MotionInn Zero velocity and wheel configuration innovations 33 ZeroVelOffset Zero velocity lever arm 34 ZeroVelStdev Zero velocity lever arm accuracy 35 AdvSlipOffset Advanced slip lever arm 36 AdvSlipOffsetStdev Advanced slip lever arm accuracy 37 AngleOffsetHeading Advanced slip alignment angle 38 Reserved3 Zero velocity option settings 39 Reserved4 Zero velocity option settings 40 Reserved5 Reserved 41 Reserved6 Output baud rates 7 42 Reserved7 Heading lock options 43 TrigInUp Trigger2 event timing rising edge triggers Table 37 44 WheelSpeedSf Wheel speed configuration Table 38 45 WheelSpeedStatus Wheel speed counts Table 39 46 WheelSpeedOffset Wheel speed lever arm 47 WheelSpeedStdev Wheel speed lever arm accuracy 48 UndulationDOP Undulation DO
24. is a float in units of metres By default the 40 Altitude byte 1 altitude is output relative to mean sea level not WGS 84 The datum 41 Altitude byte 2 can be changed using RT Config 42 Altitude byte 3 43 North velocity LSB North velocity in units of 10 m s 44 North velocity 45 North velocity MSB 46 East velocity LSB East velocity in units of 10 m s 47 East velocity 48 East velocity MSB 49 Down velocity LSB Down velocity in units of 10 m s 50 Down velocity 51 Down velocity MSB 52 Heading LSB Heading in units of 10 radians Range n 53 Heading 54 Heading MSB 55 Pitch LSB Pitch in units of 10 radians Range 7 2 56 Pitch 57 Pitch MSB 58 Roll LSB Roll in units of 10 radians Range n 59 Roll 60 Roll MSB 61 Checksum 2 This checksum allows the software to verify the integrity of the packet so far For a medium latency output the full navigation solution is available Only low rate information is transmitted next 62 Channel The channel number determines what information is sent in bytes 0 to 7 below 63 Byte 0 64 Byte 1 65 Byte 2 66 Byte 3 67 Byte 4 68 Byte 5 Revision 150709 65 69 Byte 6 70 Byte 7 71 Checksum 3 This is the final checksum that verifies the packet See the section on status information p 67 for information on bytes 62 to 71 Table 18 NCOM navigation status byte 21 definition Value Description 0 All quantities in the packet a
25. pitch heave and heading in EM3000 format binary Simrad EM1000 outputs roll pitch heave and heading in EM1000 format binary The NCOM or MCOM output of an OEM via Ethernet can be configured for different data rates and delays or disabled completely When NCOM or MCOM is selected the data rate can be set using the Data Rate dropdown list box a Oxford Technical Solutions OEM User Manual Qoxrs The OEM can output additional Ethernet messages when an event rising or falling edge is detected on the Event input pin See Event input on page 14 for more details The output delay in Advanced should only be used with OxTS RT Range products It will delay the Ethernet broadcast from the OEM by a number of milliseconds so the wireless LAN in the RT Range can transmit each message at different time slots The timing is not guaranteed when using this option and it should not be used in other applications Coordinate system Devices can output position relative to different coordinate frames By clicking in the setting column you can access the Coordinate system properties window where you can choose which reference datum to output latitude and longitude relative to The default system and the standard for GPS is the WGS 84 datum Note Currently outputs will only reference datums other than WGS 84 in post processing Real time outputs will still be referenced to WGS 84 even if another option is selected The Altitude refe
26. profits or business interruption however caused and on any theory of liability whether in contract strict liability or tort including negligence or otherwise arising in any way out of the use of this software even if advised of the possibility of such damage Copyright Notice Copyright 2015 Oxford Technical Solutions Revision Document Revision 150709 See Revision History for detailed information Contact Details Oxford Technical Solutions Limited Tel 44 0 1869 238 015 77 Heyford Park Fax 44 0 1869 238 016 Upper Heyford Oxfordshire Web http www oxts com OX25 5HD Email support oxts com United Kingdom ea Oxford Technical Solutions OEM User Manual Qoxrs Warranty Oxford Technical Solutions Limited warrants OEM products to be free of defects in materials and workmanship subject to the conditions set forth below for a period of one year from the Date of Sale Date of Sale shall mean the date of the Oxford Technical Solutions Limited invoice issued on delivery of the product The responsibility of Oxford Technical Solutions Limited in respect of this warranty is limited solely to product replacement or product repair at an authorised location only Determination of replacement or repair will be made by Oxford Technical Solutions Limited personnel or by personnel expressly authorised by Oxford Technical Solutions Limited for this purpose In no event will Oxford Technical Solutions Limited be lia
27. radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following Re orient or relocate the receiving antenna Increase the separation between the equipment and the receiver OEMs incorporate a GNSS receiver No GNSS receiver will be able to track satellites in the presence of strong RF radiations within 70 MHz of the relevant GNSS frequencies OEMs conform to the requirements for CE Regulator testing standards 47CFR15 109 2010 class A radiated emissions EN 300 440 1 2008 test methods 8 3 2 conducted emissions and 8 3 3 radiated emissions EN55022 class A according to standard EN 301 489 1 2008 conducted emissions EN6100 4 3 criterion A according to standard EN 301 489 1 2008 radiated immunity 1SO7637 2 criterion B 12 V according to standard EN 301 489 1 2008 vehicular transients and surges immunity A Oxford Technical Solutions OEM User Manual Qoxrs Background information How the OEM uses the dual antenna measurements It is often useful to have an understanding of how the OEM uses the measurements from the dual antenna system This can lead to improvements in the results obtained 1 To use the measurements properly the OEM needs to know the angle of the GNSS antennas compared to the angle of the OEM This cannot be measured accurately by users without specialised equipment the
28. the OEM the Kalman filter is used to improve the position measurement made from two sources inertial sensors and GNSS Using a model of how one measurement affects another the Kalman filter is able to estimate states where it has no direct measurement Consider a lift or elevator in a building We might make measurements of acceleration and we might know what our position is when we pass a floor these are the two measurements our system makes A Kalman filter could be used to measure velocity in this situation even though no sensor measures velocity directly The Kalman filter could also be used to measure the bias or offset of the accelerometer thereby improving the system by providing on line calibration The bias of the accelerometer might mean the system always believes the lift arrives early at each floor by changing the bias on the accelerometer the measurement of lift position can be made to correlate with the floor sensor more accurately The same principles are used in the OEM Position and velocity are compensated directly but other measurements like accelerometer bias have no direct measurements 88 Oxford Technical Solutions OEM User Manual Qoxrs The Kalman filter tunes these so the GNSS measurements and the inertial measurements match each other as closely as possible The Kalman filter in the OEM has 24 states These are position error north east down velocity error north east down heading error pitch
29. used to identify if the trigger was generated by a falling edge or rising edge In the triggered output packets the OEM will automatically interpolate the measurement outputs so they relate to the exact trigger time Since the Time field only has a resolution of 1 ms the time in the status information must be used to find the time of the trigger with a higher resolution Triggers are logged to the internal RD file and will be output by RT Post process ES Oxford Technical Solutions OEM User Manual Qoxrs Specifications Specifications for OEM products can be found in Table 42 The specification of the OEMi 2 depends on the GNSS receiver it is connected to These specifications are correct under the following conditions e After a warm up period of 15 minutes continuous operation e Open sky environment free from cover by trees bridges buildings or other obstructions The host vehicle must have remained in open sky for at least five minutes for full accuracy e The host vehicle must exhibit some motion behaviour Acceleration of the unit in different directions is required so the Kalman filter can estimate any errors in the sensors Without this estimation some of the specifications degrade e The system must be told the distance between the OEM sensor and primary GNSS antenna with a precision of 5 mm or less The vibration of the system relative to the vehicle cannot allow this to change by more than 5mm The system will esti
30. velocity or slip angle is small If the definition of the host s x axis forward direction is incorrect then the OEM may not initialise correctly when the host drives forwards In permanent installations the Get improved settings button can be used to import improved settings from a previously post processed raw data file see Get improved settings on page 53 or from a live OEM that has been warmed up and has improved its settings EI Oxford Technical Solutions OEM User Manual Qoxrs Figure 18 NAVconfig Orientation page TENES 2 NAVconfig OEM b j Orientation ra D Specify how you have mounted the device in the vehicle Y axis points Right X Z axis points Down X T Edit advanced settings Product Selection LLU Read Configuration 0 000 deg GNSS Selection 0 000 deg Primary Antenna Secondary Antenna Wheel Configuration E g Run Get improved settings after Options warning the system up to remove any Commit emors that were made when orienting a the INS and ts antennas These will be Save Finish commited to the system and used next time it powers up WARNING This feature should not be used if the INS is not permanently installed there is a risk your INS will rotate in the vehicle or that the GNSS antennas can move Dev ID 150610 14am EES English Primary External Antenna Accurately defining the position of the primary antenna in NAVconfig helps achieve better results so
31. whether Ethernet or RS232 serial are configured independently of one another even though they use the same source signal For example it is possible to output additional Ethernet messages on both the rising and falling edges of the event signal by checking both options At the same time the serial 1 output can be configured to output a selection of NMEA strings on the rising edge of the event signal while serial 2 outputs a different selection of messages only on the falling edge The event pin has a pull up resistor so it can be used with a switch or as a CMOS input The input sees less than 0 8 volts as low and more than 2 4 volts as high There is input protection on this input that clips the voltage at 0 V and 5 V On 100 Hz OEM models the default maximum switching frequency on the event pin is 1 Hz On 250 Hz OEM models the default is 3 Hz This frequency increases when either the Output on falling edge of trigger or Output on rising edge of trigger check boxes on the Ethernet Output window are selected see Figure 23 on page 46 The increased switching frequency of the event pin is 50 Hz on 100 Hz OEM devices and 125 Hz on 250 Hz devices This fast trigger information can only be output over NCOM and used to generate NMEA messages Trigger information can be found in status message 24 and 43 output over NCOM MCOM and XCOM for the low rate triggers Digital outputs IMU sync pulse The inertial measurement unit sync pulse is a 100
32. 0 to each other so they can measure each direction independently The three angular rate sensors are mounted in the same three directions as the accelerometers A powerful 40 MHz floating point DSP controls the ADC and through advanced signal processing gives a resolution of 20 bits Digital anti aliasing filters and coning sculling motion compensation algorithms are run on the DSP Calibration of the accelerometers and angular rate sensors also takes place in the DSP EI Oxford Technical Solutions OEM User Manual Qoxrs this includes very high precision alignment matrices that ensure that the direction of the acceleration and angular rate measurements is accurate to better than 0 01 The sampling process in the inertial measurement unit is synchronised to GPS time so the 100 Hz or 250 Hz measurements from the OEM are synchronised to GPS The navigation computer is a Pentium class processor that runs the navigation algorithms more on this below Information from the DSP and the two GNSS receivers is fed into the navigation computer The navigation computer runs a real time operating system QNX so outputs are made in a deterministic amount of time The outputs from the navigation computer are available over Serial RS232 and UDP broadcast on Ethernet Differential corrections can be supplied directly to the GNSS receiver to improve the positioning accuracy The differential corrections can be supplied via radio modem from a base stat
33. 000004 Bytes Format Definition Valid when 0 1 UShort Wheel speed scaling in units of 0 1 pulses per metre Value not OxFFFF 2 3 UShort Wheel speed scaling accuracy in units of 0 002 Value not OxFFFF 4 7 Reserved Value not OxFF Table 39 Status information channel 45 WheelSpeedStatus Bytes Format Definition Valid when 0 3 ULong Cyclic wheel speed input counts the value increases each time a pulse is detected on the wheel speed input 4 5 UShort Timestamp of wheel speed input count measurement Value lt 60 000 above This time stamp is transmitted as milliseconds into the minute in GNSS time 6 UChar Time since the wheel speed count last changed in units of Value not OxFF 0 1 s 7 Reserved 76 Oxford Technical Solutions OEM User Manual Qoxrs Table 40 Status information channel 48 UndulationDOP Bytes Format Definition Valid when 0 1 Short Undulation value difference between OEM altitude and Value not WGS 84 ellipsoidal altitude OxFFFF 2 UChar HDOP of GNSS Value not OxFF 3 UChar PDOP of GNSS Value not OxFF 4 7 Reserved Units of undulation are 5 mm Units of HDOP PDOP are 0 1 In the default configuration the OEM outputs the geoidal altitude computed using the EGM96 lookup table To compute the WGS 84 or elliptical altitude use the following equation Ellipsoidal Altitude OEM Altitude Undulation Table 41 Status information channel 49 OmnistarTracking Bytes Format Definition Va
34. 5 Reserved for unlocked navigation output Do not use any values from this message 6 Expired firmware this is output if the firmware is time limited and the expiry time has passed 10 Status only only the status part of the message should be decoded This is used at the start of some logged NCOM files in order to save a complete set of status messages before the real data begins RT View relies on this so that the status fields are valid right at the start of the data 20 Trigger output while initialising navigation status 2 The status channel will always be 24 falling trigger 43 rising trigger or 65 output trigger 21 Trigger output while locking navigation status 3 The status channel will always be 24 falling trigger 43 rising trigger or 65 output trigger 22 Trigger output while locked navigation status 4 The status channel will always be 24 falling trigger 43 rising trigger or 65 output trigger Others Reserved ignore any outputs that have reserved navigation status values 66 Oxford Technical Solutions OEM User Manual Qoxrs NCOM status information Bytes 62 to 71 of the NCOM packet transmit the status information on the OEM There is a lot of internally used information in the status information but some of this is useful customers The status information is transmitted at a low rate Each cycle a different set of 8 bytes are transmitted The channel field defines which se
35. COM packet is given in Table 17 Note that to reduce the latency the SYNC character listed as the first character of the packet is transmitted at the end of the previous cycle On the communication link there will be a pause between the transmission of the SYNC and the next character It is not advised to use this pause to synchronise the packet even though the operating system should guarantee the transmission timing of the packet Revision 150709 63 Table 17 NCOM packet definition Byte 0 23 24 25 26 27 28 29 30 Quantity Sync Time Time Acceleration X LSB Acceleration X Acceleration X MSB Acceleration Y LSB Acceleration Y Acceleration Y MSB Acceleration Z LSB Acceleration Z Acceleration Z MSB Angular rate X LSB Angular rate X Angular rate X MSB Angular rate Y LSB Angular rate Y Angular rate Y MSB Angular rate Z LSB Angular rate Z Angular rate Z MSB Nav status Checksum 1 Latitude byte 0 Latitude byte 1 Latitude byte 2 Latitude byte 3 Latitude byte 4 Latitude byte 5 Latitude byte 6 Latitude byte 7 Notes Always E7h Time is transmitted as milliseconds into the minute in GPS time Range is 0 to 59999 ms Acceleration X is the vehicle body frame acceleration in the x axis i e after the IMU to vehicle attitude matrix has been applied It is a signed word in units of 10 m s Acceleration Y is the vehicle body frame acceleration in the y axis
36. Figure 12 They should also be at the same height where possible although if the antennas are mounted at significantly different heights this can be specified in the configuration software In the case of dual antennas it does not matter if they are positioned inline or perpendicular to the host s forward axis as this can also be configured in NA Vconfig Figure 12 Duel antenna orientation W N a GA PP Eee ee ba v gt A B Cc A The bases of the antennas are parallel but the cables exit in different directions B The cables exit in the same direction but the bases of the antennas are not parallel C The bases of the antennas are parallel and the cables exit in the same direction This configuration will achieve the best results EI Oxford Technical Solutions OEM User Manual Qoxrs When installing antennas the gap between antennas should ideally be no less than 1 m and not more than 5m If the antennas are positioned less than 2 m apart the full specification of the OEM may not be reached With separations above 5 m it becomes much more difficult to operate the OEM and static initialisation will take considerably longer and be less reliable If a separation greater than 2 m must be used improved settings from the OEM can be read using the button on the orientation page of NAVeconfig after performing a calibration run The distance between antennas must be measured to within 3 mm and entered into NAVconfig For b
37. Hz or 250 Hz output pulse synchronised to the inertial measurement unit sample time The output has a duty cycle of approximately 50 and the falling edge is synchronised to the sample file of the data from the inertial measurement unit The inertial measurement unit is already synchronised to GPS time so one pulse each second will line up with the one pulse per second output This signal output allows other systems to synchronise with the OEM s timing Revision 150709 15 One pulse per second output 1PPS The one pulse per second output is a pulse from the GNSS receiver The falling edge of the pulse coincides with the exact transition from one GPS second to the next The pulse is low for 1 ms then high for 999 ms repeating each second Figure 4 One pulse per second waveform Falling edge denotes GPS time 1000 ms crossing second boundary gt 1ms The output is a low voltage CMOS output with 0 8 V or less representing a low and 2 4 V or more representing a high No more than 10 mA should be sourced from this output There is no protection on this output protection circuitry would disturb the accuracy of the timing Co ordinate frame conventions OEM devices use a local co ordinate frame that is popular with most navigation systems as shown in Figure 5 By default the x axis expects to point towards the front of the host and the z axis expects to point down however it is not always possible to install the d
38. LED shows the state of the internal 5 V power supply and the state of the RS232 TX line Table 7 gives the states of this LED Table 7 Power LED states Colour Description Off There is no power to the system or the system power supply has failed internally Green The 5 V power supply for the system is active Orange The system is outputting RS232 data Revision 150709 E Connectors The main connector on the OEM3000 OEM4000 is a Deutsch Autosport AS series connector AS212 35PA It is keyed so only the correct connector will connect to it and only when it is correctly aligned The part number of the mating connector is AS612 35SA and one is supplied with each OEM The pins and sockets in the connector are clearly numbered on both the front and back of each connector The OEMi 2 utilises a number of different connectors However the main input and output of the unit is through D sub connectors DE 9P and DE 9S which are widely available The power connector fitted to the OEMi 2 is a Binder 763 male Connecting power requires the female version of this connector which is also widely available Connection to the Ethernet socket requires an RJ45 plug Table 8 to Table 11 describe the pinning of the various connectors Figure 3 Connectors used on the OEM series From left to right a Deutsch Autosport AS212 35PA as fitted to the O0EM3000 and OEM4000 A D Sub DE 9P and DE 9S used for input and output on the OEMi 2 and a Binde
39. Manual Qoxrs Configuration using NAVconfig Each OEM is configured using NAVconfig Note that it is only possible to change an OEM s configuration using Ethernet It is necessary to have the Ethernet on your computer configured correctly in order to communicate with the device and change the settings The configuration files define where the OEM is and how it is orientated in relation to the host being measured They also specify any options to use while processing the data Creating a configuration using NAVconfig is a nine or ten step process depending on the model being configured that takes about five minutes Once a configuration has been committed to the OEM there is no need to update it unless the OEM device or an antenna is moved or different options are required The configuration files are used to generate real time data and are included in the raw data file that can be downloaded to a PC see Figure 13 In this way it is possible to see how the device was configured for any collected data set It is also possible to change the settings prior to post processing the file Figure 13 OEM internal files and how they are used during post process p eee m M 4 l Download from OEM l RT Post process Primary GNSS data Primary GNSS data i D Secondary GNSS data Secondary GNSS data IMU data I IMU data I SES00000000000 oo I I Sangaran tes f NGOM file DGPS corre
40. OEM Inertial and GNSS Measurement Systems User Manual Confidently Accurately Legal Notices Information furnished is believed to be accurate and reliable However Oxford Technical Solutions Limited assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use No license is granted by implication or otherwise under any patent or patent rights of Oxford Technical Solutions Limited Specifications mentioned in this publication are subject to change without notice and do not represent a commitment on the part of Oxford Technical Solutions Limited This publication supersedes and replaces all information previously supplied Oxford Technical Solutions Limited products are not authorised for use as critical components in life support devices or systems without express written approval of Oxford Technical Solutions Limited All brand names are trademarks of their respective holders The software is provided by the contributors as is and any express or implied warranties including but not limited to the implied warranties of merchantability and fitness for a particular purpose are disclaimed In no event shall the contributors be liable for any direct indirect incidental special exemplary or consequential damages including but not limited to procurement of substitute goods or services loss of use data or
41. P of GNSS Table 40 49 OmnistarTracking OmniSTAR tracking information Table 41 50 DebugStatus 51 SlipPoint1 Offset 52 SlipPoint2Offset 53 SlipPoint3Offset 54 SlipPoint4Offset 55 Gps1Status EI Oxford Technical Solutions OEM User Manual Qoxrs 56 Gps2Status 57 Gps1Offset 58 Reserved 59 ImuStatus 60 Ned2SurfAngles 61 GpsExtComms 62 GpsExtStatus 63 GpsAntOffset2 z 64 HwCfg 65 TrigOut Table 37 66 LocalRefl 67 LocalRef2 68 SlipPoint5Offset 69 SlipPoint6Offset 70 SlipPoint7Offset 71 SlipPoint8Offset 12 Reserved8 73 Reserved9 74 Reserved10 75 Reserved11 76 Reserved12 77 Reserved13 78 Reserved14 79 Reserved15 a 80 Reserved16 81 255 Reserved for future use Revision 150709 ES Note Channels with no corresponding table are not described in this manual Contact Oxford Technical Solutions if you require specific information on these channels Table 20 Status information channel 0 GNSSStatus Bytes Format Definition Invalid when 0 3 Long Time in minutes since GNSS began Value lt 1000 midnight 06 01 1980 4 UChar Number of satellites tracked by the primary GNSS Value 255 receiver 5 UChar Position mode of primary GNSS see Table 21 Value 255 6 UChar Velocity mode of primary GNSS see Table 21 Value 255 7 UChar Orientation mode of dual antenna systems see Table 21 Value 255 Note For the de
42. SDNav Strapdown navigator state See Table 4 Pos Head Single antenna position solution dual antenna heading solution GNSS GNSS state self test Power Pwr Power comms SDNav The SDNav LED shows the state of the strapdown navigator in the system Table 4 gives the states of this LED Revision 150709 Ee Table 4 SDNav LED states Colour Off Red green flash Red flash Orange flash Red Orange Green OEM3000 O0EM4000 The operating system has not yet booted and the program is not yet running This occurs at start up In this state the OEM is asleep Contact OxTS for further information The operating system has booted and the program is running The GNSS receiver has not yet output valid time position and velocity Not applicable The GNSS receiver has locked on to satellites and has adjusted its clock to valid time the one pulse per second output will now be valid The strapdown navigator is ready to initialise If the vehicle is travelling faster than the specified initialisation speed then the strapdown navigator will initialise and the system will become active On dual antenna models the system will initialise once the GNSS receivers have determined heading if the static initialisation option is selected even if the vehicle is stationary or moving slowly The strapdown navigator has initialised and data is being output but the system is not real time yet It takes 10 s for the system t
43. TAR corrections 56 RT Post process Wizard 57 Field testing 58 Accelerometer test procedure 58 Gyro test procedure 59 Testing the internal GNSS and other circuitry 60 System outputs 62 NCOM output 62 NCOM status information 67 Triggered outputs 71 Specifications 79 Common specifications 81 Notes on specifications 81 Environmental protection 81 Export control classification number 81 Conformance notices 82 Regulator testing standards 82 Background information 83 How the OEM uses the dual antenna measurements 83 Multipath effect on dual antenna systems 84 Revision 150709 a Using the orientation measurements 85 Operating principles 86 Internal components 86 Strapdown navigator 87 Kalman filter 88 Overwriting NAVconfig s default settings 89 Revision history 91 Drawing list 92 6l Oxford Technical Solutions OEM User Manual QOoxrs Scope of delivery OEM products are supplied in a bare bones configuration Details of where to obtain documentation and software is supplied with each delivery Note GNSS antennas must be sourced by the system integrator Table 1 Summary of OEM3000 4000 components per box Description Qty OEM base unit 2 Deutsch AS612 35SA connector with sockets 2 Instructions on where to download manual and software 1 Table 2 Summary of OEMi 2 components per box Description Qty OEM base unit 2 Instructions on where to download manual and software 1 Figure 1 OEM3000 base units in the de
44. al Qoxrs Making measurements with an OEM Before an OEM can be successfully operated three things must happen in order First a GNSS solution must be achieved on the primary or external receiver Second the OEM must be initialised by exceeding the initialisation speed defined in NAVconfig and finally the OEM must be warmed up in order to achieve the full specified accuracy The state of the GNSS receivers can be gauged by the Pos Head LED on the front panel LED definitions are given on page 9 The initialisation and warm up process are described below If the OEM is turned off or a new configuration file is sent using NAVconfig both processes will need to be repeated It is quite normal to perform this at the beginning of a test day and leave the OEM powered up all day This will not affect the accuracy of the device Initialisation Before an OEM can output navigation measurements it needs to initialise in order to know where it is and how it is orientated For this to happen the system needs six pieces of information as the initialisation threshold is reached 1 Time calculated from GNSS data 2 Position calculated from GNSS data 3 Velocity calculated from GNSS data 4 Heading On dual antenna systems this can be measured using GNSS measurements if the static initialisation option is checked If not and on single antenna systems heading is approximated to course over ground initially This is why it is necessary to ent
45. annot provide accurate information Just after 500 seconds the host vehicle is driven it is the small loop on the east side not the figures of eight This small amount of driving is sufficient for the Kalman filter to gain confidence in the antenna position and to improve the alignment of the two GNSS antennas compared to the inertial sensors After this period the position accuracy is better than 2 cm and the heading is better than 0 2 Revision 150709 EN Figure 27 Example warm up accuracy estimates 60 T T T T T T T E 40 4 3 3 gt 13 o i li Ni li 0 200 400 600 800 1000 1200 1400 1600 0 15 a 0 1 4 0 05 4 q A L L L i i i 0 200 400 600 800 1000 1200 1400 1600 Latitude BESSY Longitude Altitude 0 04 EN 2 0 03 3 0 02 3 001 gt 0 0 200 400 600 800 1000 1200 1400 1600 North Velocity Sere East Velocity Down Velocity Orientation Accuracy deg RMS 0 200 400 600 800 1000 1200 1400 1600 The main part of the motion occurs after 1100 s when the car was driven in a figure of eight for six minutes These are fairly large figures of eight driven at relatively low speeds Notice the brake stops in the velocity graph where the speed falls to zero These are important parts of the warm up so as many states in the Kalman filter as possible can be updated From the graphs you can see the device is accurate almost aft
46. arately and the rate at which each string is output to be independently configured in predefined steps from 1 Hz to the system speed of 100 or 250 Hz The serial baud rate can be set from 4800 to 115200 bps As well as configuring the periodic output of messages additional messages can be triggered in response to the rising falling or both edges of the event input Clicking in the Falling or Rising column for each message toggles the message output on that edge of the event input The number of characters that can be output over the serial port is limited The software computes the number of characters that will be output each second and displays this at the bottom of the window A serial port data overflow warning message will appear if the data rate is too high for the selected baud rate Note however that the software assumes the event triggered messages will occur at 50 Hz If you know the maximum rate of events it is possible to work out if it will overload the serial port To fix this overload warning it is necessary to lower the data rate of the selected NMEA sentences or increase the baud rate The NMEA messages from the OEMi 2 can conform to the NMEA specification but this limits the number of fields that can be output in the GGA and RMC messages To output full GGA and RMC messages which are longer than the NMEA specification allows select Allow extended length messages Revision 150709 43 Ethernet output The
47. at can be used In dual antenna configurations only one antenna splitter is required if the antenna splitter does not cause a significant phase change to the signal Both antennas need to be of the same design or the dual antenna system will not work Cable lengths should not be significantly different e g 1 m on one antenna and 15 m on the other is not recommended OxTS has tried and tested an antenna splitter from GPS Networking in a dual antenna configuration and we could not find a reduction in performance The details of the product tested are listed in Table 14 Revision 150709 EZ Table 14 GNSS antenna splitter Parameter Description Website http www gpsnetworking com Model HIALDCBS1X2 Description GPS Hi isolation amplified antenna splitter 2 outputs TNC Gain option 3 dB Note By default this antenna splitter comes with an 18 dB gain It must be ordered with a 3 dB gain for use with the Inertial otherwise the overall gain is likely to be too high This gain cannot be ordered through the web and GPS Networking must be contacted directly in order to have the 3 dB gain We have tested the hi isolation version by default which minimises the possibility of interference between the GNSS receivers This is the version that we would recommend We have also successfully used active antenna splitters from GPS Networking i e ones that do not get power from the GNSS receiver EJ Oxford Technical Solutions OEM User
48. ation the device can estimate the slip angle offset of the device compared to the vehicle After the device is initialised and warmed up use the Get improved settings utility to automatically read the device s slip angle offset Revision 150709 EI estimate This ensures a slip angle of zero is measured when driving straight on a level track Options GNSS weighting Differential OEM devices can place different amounts of emphasis on the GNSS receiver s measurements Selecting High causes the device to believe the GNSS receiver measurements more than the inertial sensors This might be used in open sky areas Selecting Low has the opposite effect and may be used in urban environments The default option of Medium is correct in most cases OEM3000 and OEM4000 models can be configured to use one of several differential correction messages listed below These are received via RS232 at configurable baud rates from 1200 to 115200 There is also an option to enable NTRIP using RTCM RTCMV3 or CMR When checked this option sends NMEA GGA messages from pin 6 of the main connector back to the NTRIP server RTCA is the standard adopted for aircraft The RT Base and GPS Base products from OxTS use RTCA by default although other formats can be used RTCM is the most common open standard used for differential corrections Old implementations of RTCM did not support 1 cm corrections which is why OxTS uses RTCA by default New versi
49. ble for any indirect incidental special or consequential damages whether through tort contract or otherwise This warranty is expressly in lieu of all other warranties expressed or implied including without limitation the implied warranties of merchantability or fitness for a particular purpose The foregoing states the entire liability of Oxford Technical Solutions Limited with respect to the products herein Revision 150709 3 Table of contents Scope of delivery a Introduction and basic information 8 Front panel layout LED definitions 9 Connectors 12 Inputs and outputs 14 Power supply 14 Digital inputs 14 Event input 14 Digital outputs 15 IMU sync pulse 15 One pulse per second output 1PPS 16 Co ordinate frame conventions 16 OEM models 18 Single vs dual antenna 18 Differential correction 19 Software installation 20 Ethernet communication 21 Installing an OEM 23 Environmental consideration 23 Orientation and alignment 23 Antenna placement and orientation 25 Configuration using NA Vconfig 29 Product Selection 30 Read Configuration 31 GNSS selection only applies to OEMi 2 32 Orientation 34 Primary External Antenna 35 Secondary Antenna 36 Wheel Configuration 38 a Oxford Technical Solutions OEM User Manual Qoxrs Options 40 Commit 46 Save Finish 47 Making measurements with an OEM 49 Initialisation 49 Warm up 50 Warm up example 50 Get improved settings 53 Setting up the base station 55 Using OmniS
50. cessed with GrafNav RTK Integer GNSS measurement post processed with GrafNav The GNSS measurement used OmniSTAR XP corrections The GNSS measurement used real time Canada wide DGPS service Not recognised Unknown Reserved or invalid Revision 150709 7 Table 22 Status information channel 1 GpsInn Bytes Format Definition Valid when 0 Char Bits 1 to 7 position x innovation Bit0 1 1 Char Bits 1 to 7 position y innovation Bit0 1 2 Char Bits 1 to 7 position z innovation Bit0 1 3 Char Bits 1 to 7 velocity x innovation Bit0 1 4 Char Bits 1 to 7 velocity y innovation Bit0 1 5 Char Bits 1 to 7 velocity z innovation Bit0 1 6 Char Bits 1 to 7 orientation pitch innovation Bit0 1 7 Char Bits 1 to 7 orientation heading innovation Bit0 1 Note The innovations are always expressed as a proportion of the current accuracy Units are 0 1 o As a general rule innovations below 1 0 o are good innovations above 1 0 o are poor Usually it is best to filter the square of the innovations and display the square root of the filtered value Note 2 If the orientation pitch innovation and or the orientation heading innovation are always much higher than 1 0 o then it is likely that the system or the antennas have changed orientation in the vehicle Or the environment is too poor to use the dual antenna system Table 23 Status information channel 3 PosNEDStdev Bytes Format Definition Valid when 0 1 Short North position accura
51. ch measurements are assumed to be zero with a large error and Revision 150709 EI Heading lock Serial 1 and 2 output the heading is approximated to the host s course over ground The default value of 5 m s is suitable for most applications The host should be travelling forwards and in a straight line as the initialisation speed is exceeded When stationary for extended periods of time the heading of single antenna systems can drift The heading lock option solves this by locking the OEM s heading to a fixed value while the system is stationary Heading lock cannot be used with host vehicles that can turn on the spot i e without longitudinal velocity Note that simply turning the steering wheel while stationary is often enough to change the heading on most road vehicles The normal setting assumes the host s heading will not change by more than 2 while stationary The accuracy then recovers quickly when the host moves The tight setting assumes the host s stationary heading will not change by more than 0 5 Recovery is fast if the stationary heading does not change but will be slow if it does The very tight setting assumes the stationary heading does not change by more than 0 3 Recovery is fast if the stationary heading does not change but will be slow if it does This setting can cause problems during warm up if the host remains stationary for a long period then suddenly moves The RS232 serial outpu
52. config GNSS Selection page TE 2 NAVconfig OEM ec lm i GNSS Selection fp D Choose the external GNSS receiver connected to the device Manufacturer Model Leica GPS1230 NavCom SF 3050 Novatel OEM3 Product Selection Novatel OEM4 Read Configuration MARR OEMV Orientation Novatel OEM638 External Antenna Omnistar 4305 HP Secondary Antenna Topcon GB 500 Wheel Configuration Options Commit Save Finish 50000000 Edit advanced settings Use intemal GNSS receiver Use heading from extemal receiver Dev ID 150610 14am English X Revision 150709 EJ Orientation The Orientation page is where the host vehicle co ordinate frame is defined relative to the OEM s co ordinate frame Settings entered on this page do not affect the accuracy of the OEM measurements but they do affect how those measurements are translated into the host s co ordinate frame To define how the OEM is mounted in the host it is necessary to tell NAVconfig which direction two of the OEM s axes point Select the correct option for Y axis points and Z axis points The diagram to the right of the settings window will change to reflect the defined configuration If it is not possible to mount the OEM squarely to the host s co ordinate frame select Edit advanced settings and define the OEM s orientation using these values It is important to note that during initialisation the OEM assumes the lateral
53. cted to avoid the 0 25 per minute rotation of the earth The transport rate is also corrected this is the rate that gravity rotates by due to the host vehicle moving across the earth s surface and it is proportional to horizontal speed Finally the angular rates are integrated to give heading pitch and roll angles These are represented internally using a quaternion so the OEM can work at any angle and does not have any singularities The accelerations have their bias corrections from the Kalman filter applied Then they are rotated to give accelerations in the earth s co ordinate frame north east down Gravity is subtracted and Coriolis acceleration effects removed The accelerations are integrated to give velocity This is integrated to give position The strapdown navigator uses a WGS 84 model of the earth the same as GPS uses This is an elliptical model of the earth rather than a spherical one The position outputs are in degrees latitude degrees longitude and altitude The altitude is the distance from the model s earth sea level The Kalman filter used in the OEM is able to apply corrections to several places in the strapdown navigator including position velocity heading pitch roll angular rate bias and scale factor and acceleration bias Kalman filter Kalman filters can be used to merge several measurements of a quantity and therefore give a better overall measurement This is the case with position and velocity in
54. ction data Download The internally logged data and configuration files are copied to the PC RT Post process blends the logged files DGPS corrections and configuration data to create an NCOM file If the configuration is changed in any way the simulated processed data will no longer replicate what was output in real time The NAVconfig program window is split into three areas see Figure 14 There is a navigation area on the left hand side a button area along the bottom while most space is taken up by the settings area Revision 150709 EI Figure 14 Layout of NAVconfig application window Navigation area Settings area Button area The application s language can be changed using a menu located in the button area The software version Dev ID is also shown here Product Selection NAVeonfig is a universal application used to configure several different OxTS products The first step in the configuration process see Figure 15 tells the application what type of sensor is being configured The program then shows the correct options specific to that device Select OEM from the Product family window and select the model to be configured from the Product model window If there are multiple generations of a product be sure to select the correct one If Always use this product is selected NAVconfig will default to the currently selected product model next time the software starts and immediately jump to the read
55. cy Age lt 150 2 3 Short East position accuracy Age lt 150 4 5 Short Down position accuracy Age lt 150 6 UChar Age 7 Reserved Note The units of the position accuracies are 1 mm Table 24 Status information channel 4 VeINEDStdev Bytes Format Definition Valid when 0 1 Short North velocity accuracy Age lt 150 2 3 Short East velocity accuracy Age lt 150 4 5 Short Down velocity accuracy Age lt 150 6 UChar Age 7 Reserved Note The units of the velocity accuracies are 1 mm s 72 Oxford Technical Solutions OEM User Manual Table 25 Status information channel 5 AngleStdev Bytes Format Definition Valid when 0 1 Short Heading accuracy Age lt 150 2 3 Short Pitch accuracy Age lt 150 4 5 Short Roll accuracy Age lt 150 6 UChar Age 7 Reserved Note The units of the orientation accuracies are le 5 radians Table 26 Status information channel 6 GyroBias Bytes Format Definition Valid when 0 1 Short Gyro bias x Age lt 150 2 3 Short Gyro bias y Age lt 150 4 5 Short Gyro bias z Age lt 150 6 UChar Age 7 Reserved Note The units of the gyro biases are 5e 6 radians Table 27 Status information channel 7 AccelBias Bytes Format Definition Valid when 0 1 Short Accelerometer bias x Age lt 150 2 3 Short Accelerometer bias y Age lt 150 4 5 Short Accelerometer bias z Age lt 150 6 UChar Age 7 Reserved Note The units of the accelerometer biases are 0 1 mm s Table
56. d settings from a folder If the settings were not saved in a separate folder last time the OEM was configured NAVeonfig can still retrieve them from the raw data files that were logged using that configuration Select Read settings from an RD file and a file navigation bar will appear Click Browse navigate to the RD file and click Open Revision 150709 EI The fourth option is to Read initial settings from device When this option is selected a menu will appear Select the IP address of an available OEM from the list 195 0 0 138 OEM for example then click Next A small window will open as NAVeonfig extracts the configuration from the OEM Note this option will not work if Enginuity is running Figure 16 NAVconfig Read Configuration page F NAV config wizard o gt 8 Read Configuration o E M 3000 Choose where the initial settings should be read from Inertial and GNSS Use default settings Navigation Read settings from a folder Step 2 of 10 Read settings from an RD file Product Selection GNSS Selection Read initial settings from OEM3000 Orientation Primary Antenna Secondary Antenna Wheel Configuration Options Commit Save Finish Dev ID 130916 14am EE Enolish lt Back f Net gt Cancel GNSS selection only applies to OEMi 2 It is essential to select the correct external GNSS receiver so the OEMi 2 can interpret the data it receives correctly An integration docu
57. e host moves forwards the OEM reports forward velocity regardless of which internal axis happens to be aligned to that motion The configuration sent with NAVconfig will be read each time the system is powered up so there is no need to configure it each time it is turned on Figure 10 shows an alternative mounting orientation of the OEM sensor In this case it will be necessary to use the orientation page of NAVconfig Figure 18 to indicate that the y axis points up and the z axis points backwards The system can then work out that the x axis must point right Once the configuration has been committed to the OEM the data output by the OEM would be identical to the output by the device shown in Figure 9 Ey Oxford Technical Solutions Figure 10 Non standard installation of OEM relative to host As long as NAVconfig is used to tell the OEM sensor how its axes are orientated relative to the host it can be installed in any orientation Antenna placement and orientation It is important to mount the GNSS antenna s so they have a clear and uninterrupted view of as much sky as possible GNSS antennas do not just receive signals from directly above signals can be received from near the horizon too So it is important parts of the host vehicle located around the perimeter of each antenna do not block its view For this reason it is normally best to mount the antenna on top of the host While the instructions supplied by the antenna manufactu
58. ed in a host it can be beneficial to import these improved values back into the original configuration file to be used next time as it can make the results more consistent This is done by clicking Get improved settings on NAVconfig s orientation page Figure 28 shows the steps required diagrammatically However this feature should not be used if there is a risk the OEM will rotate in the vehicle or that the GNSS antennas can move even by a few millimetres Improved settings can be read from two sources e From a forward processed or simulated NCOM file If an NCOM file has been saved to disk or processed using the Post process utility then improved settings extracted from this file Use this setting if you have an NCOM file Revision 150709 EJ e From an OEM connected to the Ethernet port This will get the information that the OEM is using at the moment and apply it next time the device starts Use this setting if the OEM is running has initialised and has warmed up Once the source has been selected the software will find which settings can be obtained from the source Settings that cannot be obtained will be shown in grey this may be because the OEM is not calculating these values at present You may update several parameters at once Select the settings you want to update and uncheck the ones that you do not want to update When you press Finish these settings will be transferred to NAVconfig The configuration will then need to
59. er the correct orientation in NAVconfig and to drive forwards and straight when first exceeding the initialisation speed 5 Roll angle This is estimated over the first 40 s of motion once the initialisation threshold is reached 6 Pitch angle This is estimated over the first 40 s of motion once the initialisation threshold is reached Note that during initialisation the system s outputs employ a 1s delay allowing GNSS information to be compared to information from the inertial sensors Once initialisation is complete the system has to reduce this delay in order to output real time data It takes 10 s to do this Therefore the first 10 s of output after initialisation is not real time but the delay decays to the specified latency linearly over this 10 s period The SDNav LED is orange while the outputs are not real time Once the system is running in real time the SDNav LED turns green Revision 150709 49 Warm up After initialisation the OEM requires a 15 minute warm up in order to reach its full specification In the past some customers upgrading to OxTS devices from more basic measurement devices have expressed concern about the duration of this warm up period and asked if it can be reduced The simple answer is no not if the aim is to gather highly accurate and comparable data The reason for this is that all measurements systems are prone to errors and small variations regardless of cost In the OEM s case those error
60. er the first figure of eight After that the improvement is very small However experience tells us the Kalman filter will continue to make some improvements not obvious during the first few figures of eight A Oxford Technical Solutions OEM User Manual Qoxrs Notice the device is close to specification even without the figure of eight manoeuvres Warm up is recommended in order to achieve the highest level of accuracy In aircraft applications flying figures of eight will remove a few hundredths of a degree of roll and pitch error which can be critical for geo referencing applications The same is true for marine applications However the effect is small and only significant when you need the full performance of the OEM device Get improved settings While the OEM is running it tries to improve some of its configured parameters In particular it will try to improve the GNSS antenna position the orientation of the dual antennas the yaw orientation of the OEM in the vehicle and the wheel speed calibration values Figure 28 Process of improving OEM settings 1 2 3 4 Install OEM As the host is Use the Get improved settings The new values help and configure driven the OEM button on the orientation page the next initialisation using accurate improves certain of NAVconfig and then commit unless the OEM or measurements measurements the new improved configuration antennas are moved In applications where the OEM is permanently install
61. ered surveyor If the base station GNSS receiver determines its own position through position averaging then any error in the base station receiver will also result in error at the OEM In order to relate the OEM signals to maps or other items on the world it is necessary for its position to be known accurately For many applications it is not necessary to survey in the base station antenna since an absolute world reference is not required Instead a local grid can be used Revision 150709 EI Using OmniSTAR corrections OEM3000 and OEM4000 products can get corrections from OmniSTAR satellites The devices support OmniSTAR VBS giving 50 cm CEP OmniSTAR XP giving 15 cm CEP in extended periods of open sky and OmniSTAR HP giving 10cm CEP in extended periods of open sky Before OmniSTAR corrections can be used it is essential to get a license from OmniSTAR To get a license the following must be done 1 Using NAVconfig the device must be told which satellite to use for corrections There are only a few satellites available so this is not something that needs to be changed often 2 Set up the device outside and turn it on Make sure it has a good view of the open sky Check the OEM is tracking the OmniSTAR satellite this can be found in the status information Call OmniSTAR and ask them to activate the OmniSTAR receiver They will need the serial number of the OmniSTAR card in the OEM This is given on the delivery note or
62. evice in this way To solve this the configuration software can be used to tell the OEM how it has actually been installed in the host It will then use the information to re orientate its measurements into the host s coordinate frame in real time This is covered in more detail on the installation section 16 Oxford Technical Solutions OEM User Manual Qoxrs Figure 5 Definition of co ordinate frames and measurement origins g TI TL TL TI TL IL I I TI e Measurement origin 30 mm 70 mm 30 mm Measurement origin HA Os 30 mm 70 mm When defining the OEM s position in relation to the host it is installed in measurements should be taken from to the measurement origin indicated on the right Table 12 lists the directions that the axes should point for zero heading pitch and roll outputs when the default mounting orientation is used Table 12 Direction of axes for zero heading pitch and roll in default configuration Axis Direction Host axis x North Forward y East Right Z Down Down Figure 6 shows the sign conventions for heading pitch and roll rotations These are the standard clockwise positive rotations about the z axis heading y axis pitch and x axis roll Revision 150709 17
63. finitions of position mode velocity mode and orientation mode see below ES Oxford Technical Solutions OEM User Manual Table 21 Definition of position velocity and orientation mode Value 0 1 10 11 12 13 14 15 16 17 18 19 20 21 255 Name None Search Doppler SPS Differential RTK float RTK integer WAAS OmniSTAR OmniSTAR HP No data Blanked Doppler PP SPS PP Differential PP RTK float PP RTK integer PP OmniSTAR XP CDGPS Not recognised Unknown N A Definition The GNSS is not able to make this measurement The GNSS system is solving ambiguities and searching for a valid solution The GNSS measurement is based on a Doppler measurement Standard positioning service the GNSS measurement has no additional external corrections The GNSS measurement used code phase differential corrections The GNSS measurement used L1 carrier phase differential corrections to give a floating ambiguity solution The GNSS measurement used L1 L2 carrier phase differential corrections to give an integer ambiguity solution The GNSS measurement used SBAS corrections The GNSS measurement used OmniSTAR VBS corrections The GNSS measurement used OmniSTAR HP corrections No data Blanked Doppler GNSS measurement post processed with GrafNav SPS GNSS measurement post processed with GrafNav Differential GNSS measurement post processed with GrafNav RTK Float GNSS measurement post pro
64. ion via cell phone from a base station or from a separate differential source such as OmniSTAR or NTRIP Strapdown navigator The outputs of the system are derived directly from the strapdown navigator The role of the strapdown navigator is to convert the measurements from the accelerometers and angular rate sensors to position Velocity and orientation are also tracked and output by the strapdown navigator Figure 34 below shows a basic overview of the strapdown navigator Much of the detail has been left out and only the key elements are shown here Figure 34 Schematic of the strapdown navigator Angular Rates amp t1 K Bias Correction Scale Factor Correction Heading Pitch Roll Earth Rotation Rate Transport Rate Accelerations gt rP Velocity Bias Correction Gravity 7 Position Coriolis Acceleration People familiar with inertial navigation systems will note that angular rates and accelerations are labelled as the inputs In reality the DSP in the OEM converts these to change in angle and change in velocity to avoid problems of coning and sculling Revision 150709 Some other rotations are also missed in the diagram The OEM does not use a wander angle so it will not operate correctly on the North and South poles The angular rates have their bias and scale factor corrections from the Kalman filter applied Earth rotation rate is also subtra
65. iver output 2 Event input 3 No default function 4 No default function 5 IMU sync pulse digital output 6 Ground 7 Ground 8 9 Table 11 Power connector OEMi 2 Binder 763 male Pin Function 1 Power in 10 18 V dc 2 Power in 10 18 V dc 3 Ground 4 Ground Inputs and outputs Power supply OEM3000 and OEM4000 products require a power supply of 10 25 V dc OEMi 2 products require 10 18 V dc Both units have limited over voltage and reverse polarity protection However this is a precaution and should not be relied upon Reversing the polarity of the power supply for short periods of time is unlikely to damage the product Digital inputs Event input The event input is used to place reference marks in the data allowing synchronisation with external events like the release of a camera shutter or application of a switch Additional NCOM and MCOM Ethernet messages can be generated on the rising 14 Oxford Technical Solutions OEM User Manual Qoxrs falling or both edges of the event signal This is configured in the Ethernet output option Additional NMEA strings triggered by the same event input can also be output on serial 1 and or serial 2 Like the Ethernet options additional messages can be output on the rising falling or both edges of the event signal This is configured using the NMEA tab of the serial 1 and serial 2 options which appears when the NMEA packet type is selected All additional messages
66. kes a huge difference to the lateral drift performance of the RT when GNSS is not available This feature must be disabled for airborne and marine systems where the lateral velocity can be significant This feature is also not suitable for land vehicles that use all wheels to steer i e no fixed wheels The vertical settings should not be used if the vehicle can perform wheelies Figure 21 Measurement point for Wheel Configuration page The wheel configuration feature applies heading correction when the land vehicle is not slipping When the vehicle is slipping the lateral acceleration is usually large enough that the normal heading corrections provide excellent results Figure 22Wheel Configuration shows the Wheel Configuration page of NAVconfig For the Lateral settings the system needs to know the position of the non steered axle rear wheels on a front wheel steering vehicle and vice versa A position at road height mid way between the rear wheels should be used as shown in Figure 21 Vehicles with all wheels steering cannot use this feature reliably although minor steering of the rear wheels does not significantly affect the results Measuring from your device measure the distances to the non steered axle position in each axis in the vehicle co ordinate frame Select the direction from the drop down lists and enter the distances EJ Oxford Technical Solutions OEM User Manual Qoxrs Typically the measurements are made to
67. lar rate measurement check x axis y axis z axis i NCTE av AY Check for positive and Check for positive and Check for positive and i di A negative readings about negative readings about rede de di pe a this axis The other axes this axis The other axes Se ie value s should remain value s should remain VA acd al small small small Note that the OEM is capable of correcting the error in the angular rate sensors very accurately It is not necessary to have very small values for the angular rates when stationary since they will be estimated during the initialisation process and warm up period This estimation process allows the OEM to go for long periods without requiring recalibration It is hard to do a more exhaustive test using the angular rate sensors without specialised software and equipment For further calibration testing it is necessary to return the unit to Oxford Technical Solutions Testing the internal GNSS and other circuitry To check all the internal circuits in the OEM are working correctly and the navigation computer has booted correctly use the following procedure 60 Oxford Technical Solutions OEM User Manual Qoxrs 1 Connect power to the system connect the system to a laptop computer and run the visual display software Enginuity 2 Use Table 15 below to check the status fields are changing Table 15 Status field checks Field Increment rate IMU packets 100 per seco
68. lation to the device Measured from the device Where is the measurement point of the GNSS antenna Ahead 0 000m 0 100 m Right 0 000m 0 100m Above X 1 000m Product Selection Harai Cae C Soe GNSS Selection Orientation Overall accuracy 0 100m v Secondary Antenna Wheel Configuration Options Commit Save Finish Dev ID 150610 14am EES English Secondary Antenna The Secondary Antenna page is used to define the position of the antenna connected to the secondary receiver relative to the primary one The secondary antenna should be placed in accordance with the information given in the installation section on page 25 The distance between antennas and the direction must be entered in order to configure the OEM correctly It should be measured to within 3 mm If the option is not already selected select Enable secondary antenna to activate the controls It is important to measure between the same point on each antenna e g centre to centre or from cable to cable The OEM does not estimate the distance between antennas so measure accurately EI Oxford Technical Solutions OEM User Manual Qoxrs If there is a significant difference in height between the two antennas select Edit advanced settings and enter the Orientation and Height offset The Orientation angle is given in degrees and positive values indicate an anti clockwise rotation when viewed from above Static initialisation i
69. lid when 0 1 UShort Frequency of OmniSTAR tracking loop Value not OxFFFF 2 UChar SNR of OmniSTAR signal Value not OxFF 3 UChar Time of continuous tracking of OmniSTAR signal Value not OxFF 4 UChar OmniSTAR status Value not OxFF 5 7 Reserved The frequency of the OmniSTAR tracking loop is 1 52 Value 1e6 GHz Units of SNR is 0 2 dB Units of time for tracking of OmniSTAR signal is 1 0 s Triggered outputs Triggered outputs are generated when a transition occurs on the event input pin The transition can be a rising or falling edge transition Triggered outputs can also be configured to occur when the OEM generates a pulse on the distance output but only under some conditions The OEM uses two methods of outputting triggered values Status information channels 24 and 43 are output periodically over NCOM The status information gives the exact time of the trigger it is necessary to look back through the data find the values just before and just after the trigger time then interpolate to find the exact values Using NCOM over Ethernet it is possible to get higher data rate triggers up to 50 Hz These need to be configured using the Ethernet options in NAVconfig When the Ethernet is configured to output triggered packets additional asynchronous NCOM packets will be output when a trigger occurs The navigation status for these triggered Revision 150709 EA packets will be different see Table 18 and the status channel can be
70. livery packaging Revision 150709 Ea Introduction and basic information Thank you for choosing OEM products from Oxford Technical Solutions OxTS The OEM series is a selection of highly accurate inertial navigation systems designed to be directly incorporated by system integrators who require real time capture output of position orientation and movement measurements Building on an already proven platform OEM devices seamlessly blend inertial measurements and GNSS data to give users a robust solution capable of outperforming products that rely solely on either technology In the real world this translates to high accuracy data that continues to be output at 100 or 250 Hz during GNSS blackouts Although an OEM sensor is a complex and precise piece of equipment a lot of time and effort has been spent over many years to ensure the device is as easy to set up as possible This manual covers the installation configuration and operation of OEM products While it is not necessary to understand every feature of the device we strongly suggest reading the entire manual in order to become familiar with the product before use The different models of the OEM series have been designed to cover the broad range of accuracy performance and price that system integrators require While most models are self contained solutions incorporating one or two high quality GNSS receivers the series also includes the OEMi 2 Unlike stand alone OEM models
71. mate this value itself in dynamic conditions e For dual antenna systems the system must know the relative orientation of the two antennas to 0 05 or better The system will estimate this value itself under dynamic conditions e For single antenna systems the heading accuracy is only achieved under dynamic conditions Under benign conditions such as motorway driving the performance will degrade The performance is undefined when stationary for prolonged periods of time Optionally extended measurement ranges covering 30g acceleration and 300 s angular rate may be requested The specification using the extended measurement range sensors can be marginally worse than those listed here Revision 150709 79 Table 42 OEM performance specification 100 Hz Model 250 Hz Model GPS type Position accuracy CEP SPS m CEP SBAS m CEP DGPS m CEP VBS m CEP XP m CEP HP m lo L1 m 1o L1 L2 m Velocity accuracy km h RMS Acceleration Bias mm s lo Linearity lo Scale factor lo Range m s Roll pitch lo Heading lo Angular rate Bias s lo Scale factor lo Range s Track at 50 km h lo Input voltage V dc Power consumption W Dimensions body only Length mm Width mm Height mm Mass kg Dual antenna 3200 4200 Ll 1 8 0 6 0 4 0 1 10 0 01 100 0 05 0
72. ment giving details on how to connect and configure an external GNSS receiver is available from the Manuals folder that is installed with NAVconfig To find these documents click Start gt All programs gt OxTS gt Manuals gt Inertial integration manuals These PDFs give essential information on each GNSS receiver and should be followed carefully in order to obtain the best performance If the PC has software for viewing PDF files the integration manual can also be opened by clicking the red icon to the right of each manufacturer s name in NAVconfig A Oxford Technical Solutions OEM User Manual Qoxrs For some GNSS receivers it is necessary to change the External GNSS port settings to match the port settings of the external GNSS receiver Select Use Advanced Settings to change the port settings The advanced settings can also be used to change the format of the receiver being used For example if a Novatel OEMV receiver using NMEA is being used then select the OEMV from the top window but change Format to NMEA in the advanced settings The OEMi 2 s internal GNSS receivers can be used by selecting Use internal GNSS receiver However the internal receivers are low cost units designed for synchronising with GPS time and generating heading They are not capable of giving good position measurements When Use internal GNSS receiver is selected the wording of step 5 changes from External Antenna to Primary Antenna Figure 17 NAV
73. nd or 250 per second IMU chars skipped Not changing but not necessarily zero GPS packets Between 2 and 20 per second depending on system GPS chars skipped Not changing but not necessarily zero GPS2 packets Between 2 and 20 per second only for dual antenna systems GPS2 char skipped Not changing but not necessarily zero only for dual antenna systems These checks will ensure the signals from the GNSS receivers and from the inertial sensors are being correctly received at the navigation computer Revision 150709 EI System outputs OEMs can output data on two serial ports and over Ethernet The pinning of the various connectors is given in the connector section on page 12 The standard serial output of the OEM navigation data is a proprietary binary format referred to as NCOM Oxford Technical Solutions offers C and C code that will interpret the packet This can be used freely to interpret the output from the OEM It is also possible to output a standard NMEA string from the OEM to mimic the output of standard GNSS receivers Oxford Technical Solutions offers a service to tailor the serial output format to the customer s specification Contact Oxford Technical Solutions for details of this service NCOM output The NCOM packet format is a 72 byte packet transmitted over serial links at 115 200 baud rate with 8 data bits 1 stop bit and no parity It has an optional low latency format where the output can be derived
74. nfiguration software 5 is not accurate enough for the OEM to improve the heading using this value If you want the vehicle heading to 0 1 but you only know the angle of the two GNSS antennas to 5 then the measurements from the antenna are not going to be able to improve the heading of the host vehicle Revision 150709 EJ Driving a normal warm up with stops starts and turns helps the Kalman filter improve the accuracy of the secondary GNSS antenna angle The accuracy of this angle is available in Enginuity s calibration window status tab 7 In the unlikely event that the RTK integer solution is incorrect at the start the Kalman filter can update the secondary antenna orientation incorrectly If this happens then things start to go wrong The Kalman filter becomes more convinced that it is correct so it resolves faster but it always solves incorrectly Solving incorrectly makes the situation worse To avoid the Kalman filter from getting things wrong it is possible to drive a calibration run and then use the button on the orientation page of NAVconfig to read improved settings This tells the Kalman filter it has already estimated the angle of the secondary antenna in the past and it will be much less likely to get it wrong or change it This step should only be done if the OEM is permanently mounted in a host and the antennas are bolted on Any movement of either the OEM or the antennas will upset the algorithms Mul
75. ntial and must not be fat es published or disclosed either wholly or in part to other parties or used to Qa E M cp 10 g et Co build the described components 100 Hz Red i d _ without the prior written consent of pact a Oamg WWW OXTS COM i i WWW OXUS COM Exces Oxford Technical Solutions Print Size A4 Scale Not to Scale Units mm Material Alu Finish Anodised Notes A M4 x 10 Tapped Hole B 2mm dia x 3 hole Date 14 10 2013 Part 14A0040A Document OEMi 2 outer dimensions
76. o become real time after initialisation The strapdown navigator is running and the system is real time OEMi 2 Same as OEM3000 4000 Same as OEM3000 4000 Same as OEM3000 4000 The GNSS receiver has locked on to satellites and has adjusted its clock to valid time the one pulse per second output will now be valid but the external GNSS receiver does not have valid position or velocity The external GNSS receiver has locked on to satellites and has a valid position and velocity measurement The strapdown navigator is ready to initialise If the vehicle exceeds the defined initialisation speed the strapdown navigator will initialise and the system will become active The system will initialise once the internal GNSS receivers have determined heading if the static initialisation option is selected even if the vehicle is stationary or moving slowly Same as OEM3000 4000 Same as OEM3000 4000 In current versions of the software the strapdown navigator will not leave green and return to any other state This may change in future releases Pos Head On single antenna devices the Pos Head LED shows what type of position solution is currently being used by the Kalman filter to update the strapdown navigator On dual antenna versions this LED indicates the heading solution of the dual antenna receiver Table 5 gives the states of this LED 10 Oxford Technical Solutions OEM User Manual Table 5 Pos Head LED states
77. o satellite based differential correction services are available to OEM3000 and OEM4000 models These are SBAS and OmniSTAR SBAS services such as WAAS and EGNOS are wide area differential corrections provided for free They can provide an accuracy of better than 0 6 m CEP WAAS is available in North America EGNOS is available in Europe MSAS is available in Japan Other parts of the world are not covered and cannot use this service OmniSTAR is a subscription service OEM systems that have OmniSTAR capability include the necessary hardware to receive the OmniSTAR corrections In addition to this it is necessary to pay OmniSTAR a license fee to activate the corrections OmniSTAR provide three levels of correction They are VBS Virtual Base Station XP and HP High Performance OmniSTAR is available on all continents Marine versions also exist In addition there is a GLONASS based high performance service XP and HP only if the GLONASS option has been installed on the receiver card For more information see OmniSTAR s website www omnistar com Revision 150709 19 Software installation Details on where to download the configuration software are supplied with each OEM The software can be installed on a PC running 32 64 bit versions of Microsoft Windows XP Vista 7 8 Double click NAVsetup exe then follow the onscreen instructions By default the installer creates a folder in the Programs part of the Start menu This can be found b
78. onary due to multipath Environment Typical error Complete open sky 30 0 6 lo 0 2 Near trees buildings 1 Next to trees buildings 2 Typical figures using a 1 m base line For accuracy specification of 0 1 RMS a 2m separation is required Using a 2 m base line can halve these figures Using the orientation measurements This section has been provided to clarify the definitions of heading pitch and roll that are output by the OEM The OEM uses quaternions internally to avoid the problems of singularities and to minimise numerical drift on the attitude integration Euler angles are used to output the heading pitch and roll and these have singularities at two orientations The OEM has rules to avoid problems when operating close to the singularities if you regenerate the rotation matrices given below then they will be correct The Euler angles output are three consecutive rotations first heading then pitch and finally roll that transform a vector measured in the navigation co ordinate frame to the body co ordinate frame The navigation co ordinate frame is the orientation on the earth at your current location with axes of north east and down If V 1s vector V measured in the navigation co ordinate frame and V is the same vector measured in the body co ordinate frame the two vectors are related by V n C bn Vpb cos y sin w 0 cos 0 o sin 0 0 0 V n siy cos y of 0 1 0 40 cos gt sin V
79. oner It is important to measure as accurately as possible but do not overstate the accuracy Doing so may cause the OEM to look in the wrong place increasing the time taken to find the correct solution Measure the antenna position with an accuracy of 10 cm or better When configuring an OEMi 2 that is connected to an external GNSS receiver the name of this page changes from Primary Antenna to External Antenna making it clear which antenna the measurements relate to If the OEMi 2 is not connected to an external receiver and the Use internal GNSS receiver option was selected on the GNSS selection page the name of this page reverts back to Primary Antenna Some external GNSS receivers can compensate for the height difference between the antenna s phase centre and its base This option should not be used with the OEMi 2 The GNSS receiver assumes that the roll and pitch of the antenna are zero in order to do the compensation The OEMi 2 can perform the compensation correctly even when the roll and pitch are not zero Revision 150709 ES With all models of OEM the terms Behind Right and Above are relative to the host s co ordinate frame not the OEM s For visual confirmation the position of the antenna in the image will change to reflect the specified configuration Figure 19 NAVconfig Primary Antenna page 6 SS SS a EO 2 NAVconfig OEM anm Primary Antenna Specify the primary GNSS antenna position on the vehicle in re
80. ons of the RT products support 1 cm corrections over RTCM RTCM V3 is the latest version of RTCM This option gives the best accuracy and should be used if your differential corrections are in Version 3 format CMR is a standard adopted by Trimble OEM products support both CMR and CMR formats Advanced This option is reserved for future use The Networked DGPS controls allow devices to be configured to broadcast or receive differential corrections over Wi Fi when connected to an RT XLAN When Network correction transmitter is selected a device will broadcast differential corrections it is receiving via a radio modem from an OxTS base station using its RT XLAN Other devices that are on the 40 Oxford Technical Solutions OEM User Manual Qoxrs same network as the broadcasting device will then be able to receive the DGPS messages and use them To do this the Network correction receiver option should be selected on those devices and the IP address of the system carrying the radio modem should be selected from the box Using this system reduces complexity in situations where multiple devices need DGPS corrections as only one pair of radio modems needs to be used Networked DGPS can also use corrections received via NTRIP rather than a local base station As before the device that is connected to the NTRIP server should be configured with Network correction transmitter selected Other RTs should be configured with Network co
81. oth single and dual antenna systems it is essential the GNSS antenna cables are not extended shortened or replaced and should be the same length within 1 m This is even more critical for dual antenna systems and the two antenna cables must be of the same specification Do not for example use a 5 m antenna cable for one antenna and a 15 m antenna cable for the other Do not extend antenna cables used with the OEM3000 and OEM4000 even using special GNSS signal repeaters that are designed to accurately repeat the GNSS signal It is possible to use an antenna splitter with the OEMi 2 so that only one antenna us needed two for dual antenna systems If an antenna splitter is used then there are a few important points to consider The OEMi 2 supplies a 5 V output to the antenna with up to 100 mA supply This is probably enough to power both the antenna and the antenna splitter If the OEMi 2 is supplying the power to the antenna splitter then both the antenna and the antenna splitter need to work correctly from a 5 V supply The OEMi 2 has an extremely sensitive GNSS receiver in it High gain antennas can sometimes have a signal that is too large for the OEMi 2 Antenna splitters often contain some additional gain to overcome cable and connector losses Having an antenna with a gain of more than 40 dB is not recommended This may be 35 dB for the antenna and 5 dB for the antenna splitter Cable loss may increase the amount of gain th
82. page 2 NAVconfig OEM Commit Commit configuration to the device IP Address of the device that you want to configure 192 0 0 76 0EM v Product Selection Read Configuration GNSS Selection Orientation Primary Antenna Secondary Antenna Wheel Configuration Options Save Finish Dev ID 150610 14am EE English Back Commt Cance Save Finish It is possible to save a copy of the configuration settings in a folder on the computer which can be reloaded later The Finish screen also confirms if the settings have been committed successfully or not Figure 25 below shows the Finish page To save a copy of the settings in a local folder select Save settings in the following folder then use Browse to define a path where the configuration files will be saved The files are written as the application exits Revision 150709 a7 Inertial GPS Figure 25 NAVconfig finish screen F NAVconfig OEM c ma Finish Save configuration to a folder liner GPS You have not yet committed your changes to the device Go back to the Commit screen to retry Save settings V Save settings in the following folder CAOxTS OEMcfg Product Selection Read Configuration GNSS Selection Orientation Primary Antenna Secondary Antenna Wheel Configuration Options Commit Dev ID 150610 14am EE English Back Finish Cancel 48 Oxford Technical Solutions OEM User Manu
83. ptop to the system 2 Commit an OxTS default setting to the OEM using NAVconfig then run Enginuity 3 Click the Calibration button then select the Navigation tab and ensure values 19 to 21 are within specification when the OEM is placed on a level surface as shown in Figure 31 EJ Oxford Technical Solutions OEM User Manual Qoxrs Figure 31 Accelerometer measurement specification check il Acceptable 9 8 m s 0 1 Fj l l x axis l values I y axis values z axis values Acceptable 9 8 m s 0 1 Acceptable 9 8 m s 0 1 To check the accelerometers place the OEM on a level surface in the position shown and use the calibration button in Enginuity to view the live values Parameters 19 21 in the Navigation tab This test is sufficient to ensure the accelerometers have not been damaged Gyro test procedure To check that the gyros angular rate sensors are working correctly follow this procedure Revision 150709 EJ 1 Connect power and a laptop to the OEM then commit a default configuration to the device using NAVconfig 2 Run the visual display software Enginuity 3 Rotate the OEM according to Figure 32 and check the angular rate measurements occur 4 With the unit stationary check all the angular rates are within 5 s In general they will be within 0 5 s but the algorithm in the OEM will work to specification with biases up to 5 s Figure 32 Angu
84. r 763 male which is used as the power connector The pinning of each connector is listed in the tables below 12 Oxford Technical Solutions OEM User Manual Table 8 Main connector pinning OEM3000 4000 Deutsch AS212 35PA No Function System power 10 25 V dc System ground Serial 1 RS232 TX Serial 1 RS232 RX IMU sync pulse digital output Radio data RS232 TX Radio data RS232 RX Event digital input Serial 2 RS232 TX Serial 2 RS232 RX Co oo u Dn A W N g 11 1PPS from GNSS digital output 22 Function RS232 ground Ethernet ETX Ethernet ERX No default function RS232 ground RS232 ground Digital signal ground No default function Ethernet ETX Ethernet ERX Ground not normally used OEM3000 and OEM4000 products are protected against over voltage and reverse polarity by a TRIAC and thermal fuse However this protection is precautionary and should not be relied upon Pins 12 16 17 and 18 are signal grounds and are protected by a 100 Q resistor There is input protection on all digital inputs that will clip the voltage at 0 V and 5 V Table 9 Serial 1 serial 2 and external GNSS pinning OEMi 2 D Sub DE 9P Pin Function 1 gt 2 Serial RS232 TX 3 Serial RS232 RX 4 5 RS232 ground 6 a i 8 9 Revision 150709 13 Table 10 Digital I O pinning OEMi 2 D Sub DE 9S Pin Function One pulse per second from internal GNSS rece
85. r to communicate via Ethernet each OEM is configured with a static IP address that is shown on the delivery note If the delivery note is unavailable the default IP address normally takes the form 195 0 0 si where sn is the last two digits of the OEM s serial number The serial number can be found on the front of the OEM or on the delivery note It can also be found by running Enginuity when the device is connected To change the IP address of the computer 1 From Start type Control Panel and open it for Windows 8 or select the Control Panel earlier versions of Windows 2 In category view select Network and Internet then Network and Sharing Center 3 Select Change adapter settings then right click the adapter to configure and select Properties 4 In the window that opens select Internet Protocol Version 4 TCP IPv4 and click Properties 5 The Internet Protocol Version 4 TCP IPv4 Properties window will open Select Use the following IP address and enter the IP address and subnet mask to use Revision 150709 EI 6 Click OK when finished General You can get IP settings assigned automatically if your network supports this capability Otherwise you need to ask your network administrator for the appropriate IP settings Obtain an IP address automatically Use the following IP address IP address 5 0 8s FZ Subnet mask 255 255 255 O Default gateway n DNS server address automatically U
86. re invalid 1 Raw IMU measurements These are output at roughly 10 Hz intervals before the system is initialised They are useful for checking the communication link and for verifying the operation of the accelerometers and angular rate sensors in the laboratory In this mode only the accelerations and angular rates are valid they are not calibrated or to any specification The information in the other fields is invalid 2 Initialising When GPS time becomes available the system starts the initialisation process The strapdown navigator and Kalman filter are allocated but do not yet run Angular rates and accelerations during this time are output 1 s in arrears There will be a 1 s pause at the start of initialisation where no output will be made while the system fills the buffers The system has to run 1 s in arrears at this time in order to synchronise the GPS data with the inertial data and perform the initialisation checks During the initialising mode the time acceleration and angular rate fields will be valid 3 Locking The system will move to the locking mode if a The velocity exceeds 5 m s or b The dual antenna GPS locks a suitable heading solution In locking mode the system runs in arrears but catches up by 0 1 s every second locking mode lasts 10 s During locking mode the outputs are not real time 4 Locked In locked mode the system is outputting real time data with the specified latency guaranteed All fields are valid
87. rence can be compared to either ellipsoidal or geoidal height If Ellipsoid is selected the altitude will be output with respect to the reference ellipsoid selected in the coordinate datum section If Geoid receiver default is selected the altitude will be relative to the geoid used in the GNSS receivers A Custom geoid file can be used for local variations To download supported geoid files go to http support oxts com local geoid files The UGF file must be saved in C Users username Documents OXTS Shared Custom geoid files Once the file is downloaded and saved in this location it can be selected from the dropdown box A constant offset to the specified altitude reference can be applied by checking the Set offset box typing in a value into the cell Advanced The Advanced settings window is used to send special commands to OxTS devices These commands have a wide range of functions and should only be entered when advised to do so When advance commands are active the setting will change to active Revision 150709 45 The list of active commands can viewed and modified from the Advanced settings window If a configuration from another device has been loaded advanced commands may be present that cause the OEM to behave in unexpected ways If advance commands are active it is best to remove any command you do not know the effect of To do this delete the command and click OK Figure 23 NAVconfig Options page 7
88. rer should be followed OxTS has found that it is good practice to mount antennas that do not feature a built in ground plane at least 300 mm from any edge where possible and on metal surfaces as this reduces multipath Multipath affects stationary vehicles more than moving vehicles and it can lead to heading errors of 0 5 RMS if the antennas are mounted poorly on the vehicle It is critical to have the OEM mounted securely in the vehicle If the angle of the OEM can change relative to the vehicle then the dual antenna system will not work correctly This is far more critical for dual antenna systems than for single antenna systems The user should aim to have no more than 0 05 of mounting angle change throughout the test If the OEM is shock mounted then the OEM mounting will change by more than 0 05 this is acceptable but the hysteresis of the mounting may not exceed 0 05 Revision 150709 Ea Figure 11 GNSS antenna placement The GNSS antennas should be installed with a clear view of the sky both above and around their perimeter Antennas without a built in ground plane should be mounted on a metal surface 300 mm from any edge for best performance Where possible mount antennas on top of host vehicles to avoid the signal being blocked or reflected When using dual antenna systems it is essential the same type of antenna is used for both the primary and secondary receiver Antennas should be identically orientated as show in
89. rrection receiver selected and the IP address of the system that is configured as the transmitter should be selected in the box Regardless of whether DGPS corrections are received via NTRIP or a local base station only RTCMv3 corrections are currently supported in networked DGPS mode SBAS In Europe North America and Japan SBAS can be used for differential corrections on the OEM3000 and OEM4000 models These services will improve the position accuracy of an OEM In North America the SBAS service is known as WAAS in Europe it is known as EGNOS and in Japan it is known as MSAS Select the option that is most suitable for the territory the device will be used in DGNSS service Where vl devices are being configured the DGNSS service will be OmniSTAR v2 devices use TERRASTAR D Select either Automatic or Manual from the corrections drop down list in the properties window to enable corrections When manual is used the correct satellite should be selected for the region where you are operating Several satellites have been pre programmed into the software In the future more satellites may exist or their properties may change In this case it is necessary to select Use advanced settings to set the satellite s Frequency and Baud rate Initialisation speed Before dynamic initialisation can occur the primary GNSS receiver needs valid time position and velocity measurements When the host exceeds the initialisation speed the roll and pit
90. s are estimated recognised and allowed for by the Kalman filter resulting in more accurate and repeatable data which is generally what users want Time spent warming the system up correctly is time saved during analysis because you can be confident in the data Throughout the warm up period the Kalman filter runs a more relaxed model for the sensors This allows the system to make better estimates of errors in the long term because correction becomes more difficult as time goes on The relaxed model also allows the system to track errors in the inertial sensor which change more quickly than normal as their operating temperature stabilises To help the Kalman filter learn about the system during the warm up period it is necessary to operate the host vehicle in a way that excites each sensor about its axis In the case of land based vehicles this means completing several figures of eight combined with some acceleration and braking In airborne applications the addition of dives and climbs is also useful Once proficient with the equipment the entire installation configuration initialisation and warm up of a system can be completed in about 30 minutes The following steps help make the entire installation and warm procedure as time efficient as possible 1 Turn the device on as soon as possible 2 Configure the device accurately Tip GNSS antenna position wheel configuration measurements and dual antenna separation can all be measured in
91. s useful on slow moving hosts that can struggle with dynamic initialisation but static initialisation can be unreliable in environments with lots of multipath If the antennas are within 15 of horizontal during static initialisation entering the command gps_pitch 15 0 via the advanced option see page 45 can speed up the process and make it more reliable The command is a pitch constraint that tells the ambiguity resolution algorithm to only search within 15 of the horizontal Note that this is the angle between antennas and is independent of the height offset entered in the software Figure 20 NAVconfig Secondary Antenna page FJ NAVconfig OEM c ma os Secondary Antenna Q Specify the secondary GNSS antenna position on the vehicle in relation to the primary antenna WaxTs v Enable secondary antenna 7 Antennas are level Measured from the primary antenna Where is the measurement point of secondary antenna Behind v 1000m towthn 0 050m v Product Selection Read Configuration Enable static initialisation GNSS Selection Orientation Primary Antenna Edit advanced settings Wheel Configuration Options Commit Save Finish Dev ID 150610 14am ESE English Revision 150709 Ea Wheel Configuration The wheel configuration feature uses characteristics of land vehicle motion to improve heading and slip angle and to reduce drift Specifying the position of the non steered wheels ma
92. sUtilityLibrary dll RTIPConfig exe 2 RTPing dil UtilityLibrary Win32 WindowsAPL dll ZedGraph dil a 19 items Alternatively it is possible to tell the application to look elsewhere for the usersettings folder This can be done by editing the rtconfigsettings xml file located at C Users lt username gt Documents OXTS NAVeonfig Note that the file is only created after NAVconfig has been run for the first time Locate the lt UserDefinedDefaultSettings gt and lt UserDefinedDefaultSettings gt tags and then replace the path between them with the new path NAVconfig will use the new location next time it is run EJ Oxford Technical Solutions OEM User Manual Qoxrs Revision history Table 45 Revision history Revision Comments 131014 Initial draft 150709 Updated for Spring 2015 release of NAVsuite Revision 150709 EI Drawing list Table 46 lists the available drawings that describe components of the OEM system Many of these drawings are attached to the back of this manual Note that the x following a drawing number is the revision code for the part If you require a drawing or different revision of a drawing that is not here then contact Oxford Technical Solutions Table 46 List of available drawings Drawing Description 14A0007x OEM3000 OEM4000 outer dimensions 14A0040x OEMi 2 outer dimensions 92 Oxford Technical Solutions Oxford Technical Solutions 77 Heyford Park Upper Heyford
93. se the following DNS server addresses Preferred DNS server Alternate DNS server F Validate settings upon exit OxTS recommends an address in the range 195 0 0 2 to 195 0 0 9 as these are never used by OEM products Once the PC is configured you can find the IP address of an OEM by running Enginuity software this will display the IP address of any connected OEMs The operating system at the heart of the OEM product also allows connection to the unit via FTP The use of FTP allows the user to manage the data logged to the unit files can be uploaded for reprocessing and deleted to make space for future files Configuration files for alternative configurations require FTP to put the configuration files on to the OEM Anonymous FTP is supported or the username user and password user can be used A Oxford Technical Solutions OEM User Manual Qoxrs Installing an OEM Environmental consideration Installation of OEM sensors is not hard but care should be taken as they are precision instruments With this in mind select a mounting location that will not expose the unit to extreme temperature or excessive vibration check specifications The TNC GNSS antenna connectors are only IP65 rated when mated or the protective cap is fitted Orientation and alignment OEM products are extremely accurate measuring devices As such they do not expect users to install them with same degree of accuracy to which they can mea
94. sure as this would require expensive equipment Instead an OEM expects to be given relatively accurate information on how it is mounted within a host It then recognises and manages the approximation of that mounting error over time For this reason it is important to understand what information an OEM sensor needs and how to find it as this will help achieve the best and most consistent results The orientation of an OEM s default co ordinate frame is shown on page 17 In order to fully define the OEM s orientation relative to a host it is necessary to specify the direction of two of its axes In default configuration the device expects its x axis to point in the same direction as the host s forward movement and its y axis to point to the right In this scenario the third axis z must point down This is illustrated in Figure 9 Revision 150709 EJ Figure 9 Orientation of OEM relative to host in default configuration Using its default configuration the OEM sensor expects its x axis to match the host s forwards direction and the y axis to point right There are times however when installing an OEM using the default orientation is not possible For this reason the OEM can be installed in any orientation relative to the host as long as NAVconfig is used to describe the installation The OEM sensor will then handle the conversion from its co ordinate frame to the host s coordinate frame internally The result is that when th
95. t Definition Valid when 0 1 Short Age of the differential corrections from the base station 2 5 4 x Char Differential station ID 6 7 Reserved Note The unit of the differential corrections is 0 01 seconds Table 36 Status information channel 21 DiskStatus Bytes Format Definition Valid when 0 3 Long Disk space remaining on OEM Note that the OEM Value gt 0 always leaves about 20 KB spare on the disk 4 7 Long Size of current logged raw data file When there is Value gt 0 insufficient space on the disk no more data will be written Note The values are output in kilobytes Revision 150709 75 Table 37 Status information channel 24 TrigIinDown channel 43 TrigInUp and channel 65 TrigOut Bytes Format 0 3 ULong 4 5 UShort 6 UChar 7 UChar Definition Minutes of falling edge of Event Input since GNSS began 6 January 1980 TRIG_MINUTE variable below Milliseconds of falling edge of Event Input within the minute TRIG_MSEC variable below Microseconds of falling edge of Event Input within the millisecond units of 441s TRIG_USEC variable below Trigger Count increments each time there is a new trigger Note To find the time of the trigger in GNSS seconds compute TRIG_MINUTE 60 0 TRIG_MSEC 0 001 Table 38 Status information channel 44 WheelSpeedSf Valid when Value gt 0 Value gt 0 Value gt 0 Value gt 0 TRIG_USEC 0
96. t of an OEM can be configured to any one of the protocols listed below It can also be disabled completely to reduce the computational load on the system NCOM is an OxTS proprietary protocol and the normal output of OEM sensors The NCOM format is described in more detail on page 62 and has a dedicated manual that can be downloaded from the OxTS website Software drivers exist for decoding NCOM data IPAQ is simply NCOM output at a reduced rate The baud rate of the serial port is set to 19200 and the update rate is 25 Hz It is used because the IPAQ cannot manage to receive the data reliably above 25 Hz IPAQ is NCOM output at a reduced rate and polled Windows Mobile 5 on IPAQs crashes if the OEM is sending data when the IPAQ is turned on Using IPAQ the IPAQ will poll the A Oxford Technical Solutions OEM User Manual Qoxrs OEM the OEM will not send data while the IPAQ is off preventing the turn on crash of the IPAQ NMEA causes the OEM to output NMEA sentences from the primary receiver The NMEA outputs conform to the National Marine Electronics Association Standard NMEA 0183 version 3 01 The NMEA sentences available are GPGGA GPHDT GPVTG GPZDA GPGST PASHR GPRMC GPGSV GPGSA PTCF GPPPS PRDID GPROT GPGGK and GPUTC More than one message can be output on the same serial port The NMEA 0183 description manual gives details of the fields output in the NMEA sentences The NMEA tab allows strings to be enabled sep
97. t of information is included in the 8 bytes Some of the status fields have special bits or values that denote invalid The invalid values or the validity bits are noted in the tables Table 19 NCOM channel number byte 62 definition Channel Information See dual antenna mode 1 GpsInn Kalman filter innovations Table 22 2 Gps1Comms Internal information about GNSS1 3 PosNEDStdev Position accuracy Table 23 4 VelNEDStdev Velocity accuracy Table 24 5 AngleStdev Orientation accuracy Table 25 6 GyroBias Gyro bias Table 26 7 AccelBias Accelerometer bias Table 27 8 GyroSf Gyro scale factor Table 28 9 GyroBiasStdev Gyro bias accuracy 10 AccelBiasStdev Accelerometer bias accuracy 11 GyroSfStdev Gyro scale factor accuracy 12 GpsAntOffset Position estimate of the primary GNSS antenna Table 29 13 GpsAntAngles Orientation estimate of dual antenna systems Table 30 14 GpsAntStdev Accuracy of position of the primary GNSS antenna Table 31 15 GpsAntAngleStdev Accuracy of the orientation of dual antenna systems Table 32 16 Imu2VehAngles OEM to vehicle rotation from initial setting defined by Table 33 user 17 Gps2Comms Internal information about GNSS2 18 ImuComms Internal information about inertial measurement unit 19 Devld Software version running on OEM Table 34 Revision 150709 67 20 GpsDiffAge Age of differential corrections Table 35 21 DiskStatus Disk space size of current
98. that shown in Figure 7 may be triggered This is because the program is attempting to listen for and communicate with OxTS devices on the network The firewall must be configured to allow each program to talk on the network or programs will not work as intended Ey Oxford Technical Solutions OEM User Manual Qoxrs Figure 7 Windows Firewall warning message P Windows Security Alert Windows Firewall has blocked some features of RT Post Process on all public and private networks Q Name RT Post Process Publisher Oxford Technical Solutions Path C program files x86 oxts stpostprocess tpostprocess exe Allow RT Post Process to communicate on these networks 7 Private networks such as my home or work network Ea Public networks such as those in airports and coffee shops not recommended because these networks often have litte or no security _ he What are the risks of allowing a program a firewall A firewall warning message may be triggered the first time OxTS software is run Access must be allowed for each application that requires it or the program cannot work properly Sometimes a warning will not be triggered but the firewall may still block certain functions If a program fails to display the IP address of a connected OEM check the firewall settings for that connection Ethernet communication OEM products are programmed and communicate via Ethernet using a UDP broadcast In orde
99. tipath effect on dual antenna systems Dual antenna systems are very susceptible to errors caused by multipath This can be from buildings trees roof bars etc Multipath is where the signal from the satellite has a direct path and one or more reflected paths Because the reflected paths are not the same length as the direct path the GNSS receiver cannot track the satellite signal as accurately The dual antenna system in the OEM works by comparing the carrier phase measurements at the two antennas This tells the system the relative distance between the two antennas and which way they are pointing the heading For the heading to be accurate the GNSS receivers must measure the relative position to about 3 mm The level of accuracy can only be achieved if there is little or no multipath In an ideal environment with no surrounding building trees road signs or other reflective surfaces the only multipath received should be from the vehicle s roof High quality antennas are designed to minimise multipath from the vehicle s roof when the roof is made of metal For use on non metallic roofs a different type of antenna is required When stationary the heading from the OEM will show some error the size of the error depends on the multipath in the environment Table 44 lists the error you can expect when stationary with a 1 m base line EI Oxford Technical Solutions OEM User Manual Qoxrs Table 44 Typical heading error when stati
100. ts of the distance accuracies are 0 1 mm Table 32 Status information channel 15 GpsAntAngleStdev Bytes Format Definition Valid when 0 1 Short Accuracy of heading orientation of the GNSS antennas Age lt 150 2 3 Short Accuracy of pitch orientation of the GNSS antennas Age lt 150 4 5 Short Accuracy of distance between the GNSS antennas Age lt 150 6 UChar Age 7 Reserved Note The units of the distances are 1 mm The units of the orientation angle accuracies are le 4 radians 74 Oxford Technical Solutions OEM User Manual Qoxrs Table 33 Status information channel 16 Imu2VehAngles Bytes Format Definition Valid when 0 1 Short Heading of the vehicle in the IMU co ordinate frame Byte 6 0 2 3 Short Pitch of the vehicle in the IMU co ordinate frame Byte 6 0 4 5 Short Roll of the vehicle in the IMU co ordinate frame Byte 6 0 6 UChar Validity 7 Char Bits 1 7 UTC time offset BitO 1 Note The units of the orientation angles are le 4 radians To compute UTC time from GNSS time add the offset Currently the offset is 14 s The offset is always an integer number of seconds UTC time slips or gains a second occasionally whereas GNSS time does not Table 34 Status information channel 19 DevId Bytes Format Definition Valid when 0 7 8 x Char This is the software version or development id that is running in the OEM in ASCII format Table 35 Status information channel 20 GpsDiffAge Bytes Forma
101. y clicking on Start gt All Programs gt OxTS The contents of the folder are listed in Table 13 Table 13 Installed software components Software package O Enginuity f NAVeonfig CS RT Post process NAVegraph a Manuals i Description NAVdisplay has now superseded Enginuity and is significantly more powerful however Enginuity is still included with NAVsuite and the two can be used interchangeably NAVceonfig is used to create send and receive configurations from OxTS products including OEM As configurations vary between devices there is no manual for NAVconfig The options relevant to the OEM products are covered in this manual on page 46 This program downloads raw data files from the OEM It then post processes the data and can export NCOM MCOM XCOM and CSV file formats Differential corrections can also be applied using this software and the data can be reprocessed using a different configuration See Manuals below for more details NAVegraph is a graphing program for NCOM MCOM XCOM and RCOM files created in post process It can display graphs cursor tables and map plots and data can be exported in CSV or KML Google Earth format See Manuals below for more details This folder contains PDF versions of relevant OxTS manuals Other manuals can be downloaded from the website by navigating to www oxts com support manuals The first time some OxTS applications are run a firewall warning message similar to
Download Pdf Manuals
Related Search
Related Contents
DSTO-TR-1215 PR pdf形式 - 日立地区産業支援センター Hoja de características del generador de canales 2007/11発行 (PDF8MB) SmartMetals 063.0610 mounting kit Manual - USB Abocom WU5202 User's Manual SERVICE MANUAL SHIMANO NEXUS 7-SPEED HUB CLUB3D CGAX-3452I graphics card Copyright © All rights reserved.