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moving base application (simpleRTK2B kit LR)

Q&A forumCategory: Questionsmoving base application (simpleRTK2B kit LR)
thehari asked 4 weeks ago
Hello together,
For a project I’m working on, I need to get the position and heading of a vehicle. I have the simpleRTK2B – starter kit LR and I managed to set up the “regular” base/rover configuration and get fixed mode.
Since I only have two boards, I have tried configuring them as follows, with help of the moving base application note from ublox:

  • Board #1 (Base): Base config with enabling RTCM type 4072.0, 1074, 1084, 1094, 1124, 1230 on UART2
  • Board #2 (Rover): Rover config with enabling UBX-NAV-RELPOSNED on UART1

With this configuration, the base managed to get into TIME mode and the rover into 3D/GNSS/FLOAT (sometimes fixed). On the rover, I got the baseline length from u-center via UBX-NAV-RELPOSNED (also enabled on the Base), which seemed somewhat accurate. The heading on the other hand seems to be off a bit, and I can’t reproduce it. From what I understand, the heading being output is relative to the base stations’ antenna, is that correct or how do I need to interpret the heading?
My question is, if that’s the correct way to configure a moving base application and if it’s possible to set up a moving base application to get the heading and position of my rover without using the simpleRTK2Blite board? Otherwise I need to think about buying the simpleRTKBlite kit.
Thank you for your help, I appreciate it.
Best regards,

1 Answers

Best Answer

Ardusimple Staff answered 4 weeks ago
Hi thehari,
In moving base configuration, the base should not be in TIME mode. We recommend starting from our configuration files: http://www.ardusimple.com/configuration-files
About your extra questions:

  • Yes the heading under RELPOSNED is relative to the base station
replied 3 weeks ago

Thank you for your answer.

Which configurations would that be if I don’t own a simpleRTK2Blite board? “1Hz simpleRTK2B (Rover) of a simpleRTK2B+heading kit” configuration file for the rover? Which config file do you recommend for the base?

Staff replied 3 weeks ago

You can use the configuration files of the simpleRTK2B+heading kit even if you don’t have a lite.

replied 3 weeks ago

Ok, thank you! I’ll give it a try again tomorrow when I’m back in the office.
I’ll configure my system as follows:
– Base: upload “1Hz simpleRTK2Blite (Moving Base) of a simpleRTK2B+heading kit”
– Rover: upload “1Hz simpleRTK2B (Rover) of a simpleRTK2B+heading kit”
With the messages enabled as described above.

I have an additional question regarding the wired connection. Next to the USB connection to POWER+GPS of both boards, I need to connect TX2 (base) and RX2 (rover) between the two boards (wired / wireless) right ?

Staff replied 3 weeks ago

Make sure you check the hookup guide for the connection, you need to enable IOREF and check the correct direction of this pins:
IOREF: this is an input that will define the voltage levels of the next pins. If you input 1.8V, the next pins will be 1.8V level. It supports from 1.2V to 5.5V.
TX2: XBee UART TX (this pin is also connected to ZED-F9P UART2 RX).
RX2: XBee UART RX (this pin is also connected to ZED-F9P UART2 TX).

replied 3 weeks ago

I configured my base and rover with the simpleRTK2B+heading configuration files as mentioned above. After enabling UBX-NAV-RELPOSNED, I’m not able to receive the RELPOSNED message on my rover (only zeros are being received).

Regarding the wired connection: I’m aware of the hookup guide, but I’m still not sure if and which pins need to be connected when I want to get the position and heading? Is it correct, that the moving base application requires a wired / wireless connection between TX / RX ?

Staff replied 3 weeks ago

moving base configuration with our configuration files, requires that ZED-F9P (moving base) UART1 TX is connected to ZED-F9P (rover) UART2 RX.

replied 3 weeks ago

Ok I will give it a try and see if it works.
For my actual application, a wired connection between the moving base and rover isn’t possible. As I understand, a wireless connection between both boards is also possible, right?

Would it be an easier alternative, to buy the simpleRTK2Blite board if I want to get the accurate position and heading of my vehicle withou having a wired connection between the moving base and rover?

Staff replied 2 weeks ago

Yes wireless connection is also possible, with some degradation on performance and maximum update rate due to latency.

Yes with lite it’s easier, then you can just plug in the socket and upload configuration files.

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