Xsense MTI-G-710 GPS precision and configuration parameters

Autonomous Vehicles DRIVE AGX Xavier DRIVE AGX Xavier General
1

Software Version
DRIVE OS Linux 5.2.6
DRIVE OS Linux 5.2.6 and DriveWorks 4.0
DRIVE OS Linux 5.2.0
DRIVE OS Linux 5.2.0 and DriveWorks 3.5
NVIDIA DRIVE™ Software 10.0 (Linux)
NVIDIA DRIVE™ Software 9.0 (Linux)
other DRIVE OS version
other

Target Operating System
Linux
QNX
other

Hardware Platform
NVIDIA DRIVE™ AGX Xavier DevKit (E3550)
NVIDIA DRIVE™ AGX Pegasus DevKit (E3550)
other

SDK Manager Version
1.7.1.8928
other

Host Machine Version
native Ubuntu 18.04
other

I’m using an Xsens MTI-710 sensor, and I’m experiencing a very low accuracy (up to about 50 meters, horizontally), when the sensor is connected to the Xavier board. If the sensor is connected to a Windows laptop using the Xsens MT Manager software, the precision drop to less than 5 meters.
In the following image it is possible to see the track recorded using the Xavier with the recorder-tui application (the black line) and a set of 4 other records (green, red, yellow and cyan lines), made using a laptop and the Xsens MT Manager software.

GPS_track_comparison
GPS_track_comparison379×770 54.2 KB

The recording where made the same day, on the same vehicle (so the GPS antenna was not moved). The drawn black line is from the last of the loops we performed, so the sensor was working from many minutes and had enough time to align. Immediately after the end of the loop, we performed the recording on the same route using Xsens MT Manager software. Also, when recording with the laptop, and it find a very good position just in some seconds. The behavior is present both when we travel in a city zone or in open fields.

  1. What could be the cause of this position error?

  2. Also, there is some place where ALL the possible sensor parameters for the Xsens sensor are described?

Using the sample_sensors_info, the parameters showed are:

gps.xsens ? device=0[,frequency=100,xsens-raw-gps=true,time-smoothing=false,fifo-size=1024,baudrate=115200,stop-bits=2]

The frequency, baudrate and stop-bits parameters are for the serial connection, and the fifo-size is the dimension of the buffer to store the received data.

  1. What behavior do the xsens-raw-gps and time-smoothing parameters control?

In this forum thread (which is for the IMU section of the sensor):
https://forums.developer.nvidia.com/t/how-can-i-get-xsens-imu-data-which-set-own-setting/147330
is described that exists also the slave=1 or slave=true parameter, and in the section from the
/usr/local/driveworks/tools/capture/configs/rwd/hyperion7_1/release.json file, another parameter is added (index_table=off) that is not in the output from sample_sensors_info. Both the slave and index_table parameters can not be found in the documentation (I checked also on the online documentation for driveworks-4.0 release).

  1. Are the slave and index_table parameters applicable also for the GPS configuration? What do they mean?

  2. There are other un-documented parameters?

  3. Does setting slave=true means that also the GPS sensor retains the configuration set previously using the Xsens utility?

1 Like
3

Hi @m.giardino

Yes, “slave=true” will skip configuring the device. Please try with it to see if the issue will be gone.

Also, I would suggest you run sample_sensors_info on your setup, DRIVE Software 10, to know what’s available there instead of checking the document of DW4.0. Thanks.

4

Hi, VickNV, thanks for your reply.

We will try using a slave=false parameter and analyze the outputs.

But what do the different parameters from the output of the sample_sensors_info application configure? This output came from our AGX board, so from DRIVE Software 10:
gps.xsens ? device=0[,frequency=100,xsens-raw-gps=true,time-smoothing=false,fifo-size=1024,baudrate=115200,stop-bits=2]

  1. What does the xsens-raw-gps=true parameter do?

  2. What does the time-smoothing=false parameter do?

In the /usr/local/driveworks/tools/capture/configs/rwd/hyperion7_1/release.json file, in the GPS section (which has a "protocol": "gps.xsens" property), there is another parameter:

  1. What does the index_table=off parameter do, used in that rig file from Nvidia?

  2. There are other configuration parameters for the Xsens sensor that are not described in the documentation?

5

If they are the same, that’s fine. just wanted to double confirm.

xsens-raw-gps is for LLA GPS raw data and time-smoothing is for SampleTimeFine of Xsens.
For the details, you may need to check with Xsens.

“index_table” and “file” are to create index table for seeking. There is no other parameter.

6

@m.giardino
Have you figured out the inaccuracy problem? If yes, welcome to share your experience back here. Thanks.