How can Raspberry PI receive RTK corrections over the internet and forwart them to Pixhawk?

I have a rover with a Pixhawk4 running Ardurover 3.5.1 with an Ardusimple RTK gps board. I have successfully used Mission Planner (running on a windows ground control computer) to receive and inject RTK messages which get sent over the 900 mhz radios to the rover. My Ardusimple is running in RTK Float and RTK Fixed modes.

To get the ground control computer out of the equation (at least for the RTK corrections), I put a Raspberry PI onboard the rover. RPi is talking to the Pixhawk4 as per http://ardupilot.org/dev/docs/raspberry-pi-via-mavlink.html.

The RPi has its own internet connection (through a Huawei 3372 USB stick and a Google FI data-only SIM card; worked flawlessly on the first try!).

So my question (@stephendade ?) is, how is the best way to run an NTRIP client on the RPi that will connect over the internet to the NTRIP server, receive corrections from that server, and forward them (presumably using some mavlink feature) to the Pixhawk? Is this already coded up in Mavlink? Or, do I need to run an NTRIP client on the RPi that somehow sends the corrections to mavproxy running on the RPi which in turn forwards the corrections to the Pixhawk4?

Thanks in advance for any pointers in the right direction…

Chris

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MAVProxy has the DGPS module which may work grabbing the NTRIP data and forwarding it to the Pixhawk.

[I’ve not used the DGPS module in some time, so not 100% sure if it’ll work with your particular NTRIP server]

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Hello everyone,

We are trying to achieve a similar implementation so after a small research this topic came up to me. Is there any update you would like to share?

Thanks in advance.

this is how we do it:

git clone https://github.com/tomojitakasu/RTKLIB.git --branch rtklib_2.4.3

cd RTKLIB/app/str2str/gcc

make

./str2str -in ntrip://USER:PASSWORD@CORS_IP:2101/MOUNT_POINT -b 1 -out serial://ttyAMA1:115200:8:n:1

I have my F9 connected to pixhawk trough serial one of the gps module and send corretion to the serial 2 of the gps module. Serial 2 of the module has NMEA and RTCM 3 enabled. Serial 2 of the module is connected to serial 2 of the raspberry (ttyAMA1).

I also made a service so that correction starts when raspberry starts and i can start, stop and look at the status of it. If you know how to make a service on raspberry it is really simple, just start the software as described above (./str2str -in ntrip…)

Hope it is clear enough, if you need more infos please ask.

Hi,

I’m trying to make exactly the same : provide the RCTM3 frame by a RPI and Mobile connexion (so, without Mission planer).

But I’m not sure about the architecture : where I need to send the RTCM3 frame : to the pixhawk or to the F9P GPS Module ?

It is written in my previous post, read it.

More discussion here: ArduRover + PixHawk + GPS RTK WITHOUT telemtry : 4G connexion - #3 by myozone