ardusimplertk2b-rasberry-pi-base-unit-paired-with-rasberry-pi-rover-moving-base-rtcm-over-wifi-tcp

Q&A forumCategory: Questionsardusimplertk2b-rasberry-pi-base-unit-paired-with-rasberry-pi-rover-moving-base-rtcm-over-wifi-tcp
weedinator asked 8 months ago
Hi, I have built a (ArdusimpleRTK2B + Rasberry pi + Pi hat ) base station unit using this method https://www.youtube.com/watch?v=lKr6w_LjnGE&t=461s its uses str2str.c to forward correction data over WIFI/TCP. This is working well extremely well as our farm has a long range wifi mesh network, which is high bandwidth, high quality and low latency, with transparent roaming. ūüôā We have a success with the rover using a ArdusimpleRTK2B , again connected via raspberry pi and pi hat and feeding the RTCM back into the f9p using this method outlined here https://www.youtube.com/watch?v=qlkN70bBfFQ&t=66s This is working very well. We would like to get the rover + moving base , so the ArdusimpleRTK2B + simpleRKKBlite board, but were not sure how to provide the RTCM correction data to it using strstr, obviously the advise is to stack a radio module on top of simpleRKKBlite, but this will not work with our WIFI mesh network. Hopefully this can be achieved by clever configuration of the USB/UART1/UART2 of the two f9p Boards. I hope somewhere here can help us achieve this configuration. Cheers, ¬† ¬† ¬† ¬† ¬† ¬† ¬† ¬† ¬†
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Ardusimple
Staff replied 8 months ago

Hi weedinator,
Great project and thanks for the summary and the links, sure someone else will use this post.

About your question, it is possible, the simpleRTK2B UART2 is designed so it can be used to talk with the zed-f9p or with the device connected on the xbee socket (in your case a simpleRTK2Blite). You can use this feature:

TX1: ZED-F9P UART1 TX in simpleRTK2B
RX1: ZED-F9P UART1 RX in simpleRTK2B
TX2: simpleRTK2Blite UART TX (this pin is also connected to simpleRTK2B ZED-F9P UART2 RX).
RX2: simpleRTK2Blite UART RX (this pin is also connected to simpleRTK2B ZED-F9P UART2 TX, make sure you disable any protocol out).

weedinator
replied 8 months ago

Thank you for you quick reply, however, I’m having trouble visualising this configuration? Could a wiring digram from you help me? I’m trying basically understand the flows of data between, the two F9P chips, what UARTS sits where, and when to inject my RTCM data from the base station. It’s very hard to conceptualise the input and output messages on each UART/USB? Thanks again!

weedinator
replied 8 months ago

I also think i’ve got my terminology a little mixed up. I think it’s not a moving BASE, as our base unit is stationary. on our rovers moves. Sorry for the confusion.!

Ardusimple
Staff replied 8 months ago

Hi weedinator,
Did I understand correctly that you have a static base, and then you want a simpleRTK2B and a simpleRTK2Blite as a rover, so they can calculate heading information?
If we understood you correctly this rover with 2x GPS will have:
– one unit working as “rover” from your static base station but at the same time as a “moving base”
– a second unit that will be “rover” of the moving base, that will be able to calculate heading.

Unfortunately we can’t make a custom diagram for you, thank you for your understanding, but have a look at the moving base application note: https://www.u-blox.com/en/docs/UBX-19009093
And also you will find useful info in the simpleRTK2B+heading hookup guide: https://www.ardusimple.com/simplertk2heading-hookup-guide/

weedinator
replied 8 months ago

The terminology that ublox and and by proxy to ardusimple is confusing and misleading a best. Having read more ublox documentation. It’s confusing. My application is a STATIC base unit , providing RTK data to a moving rover. Moving rover has the simpleRTK2B and a simpleRTK2Blite. The question is which UART do i provide RTCM messages to this configuration and which GPS chip do i send the data to…what communication port confiugrations and what messages need to be sent between the two rover GPS units… , and what configuration can i use to help me do this, without using your integrated wireless shields.I hope this clears things up. I will look more closely into your configurations for this type of GPS configuration and see if that can give me UARTS/USB Input and Output messages and how the data flow is occurring.

Ardusimple
Staff replied 8 months ago

Hi weedinator,
If your rover is formed by a simpleRTK2B and a simpleRTK2Blite, your rover is actually a “rover + moving base” and “rover from moving base”. Don’t mix these with your static base.
The RTCM stream is as follows:
– Static base sends static RTCM to “rover + moving base”
– “rover + moving base” sends moving base RTCM to rover