Lora examples or libraries for piping RTCM correction data to rover.

GPS/GNSS Development Boards
1

Does anyone know of any examples of c code, preferably using radiohead, for sending RTCM correction data via loRa?

The rover in this case is a Stihl robotic lawn mower. I currently have a feather Fona sending gps/accelerometer/ temperature/ humidity data via cellular to Firebase. There using nodejs I can process the data using a kalman filter and made a little website showing the rovers location. I’d like to use the GPS-RTK Board - NEO-M8P-2 (Qwiic) as the new gps chip in the rover.

The SparkFun GPS-RTK Board - NEO-M8P-2 (Qwiic) is configured as per the excellent Sparkfun guide, using the Sparkfun Serial Basic and the chip immediately pulls the rtk led to low and the ucenter program shows 3d/gnss fix and has .25 meter accuracy on average.

The current (not working) set-up is a feather mo rfm95 accepting data from the Serial Basic via serial1, pushing it using radio head to a second feather mo rfm95 which then pushes via Serial1 to the - NEO-M8P-2, gnd rx pins. I’ve tried various sprintf, char* casting, etc. to no avail. I’m guessing it’s a through put problem?

The feather’s use the same samd21 as the Sparkfun product. Sorry about all the Adafruit, but Sparkfun products just started showing up at the local store.

I’m interested seeing how or if the three antennas interfere. Also I have pizero that snaps pictures of the lawn and sending the image to a google automl vision library and identifies whether weed is present in the lawn. In theory a second rover could travel to gps points and spray the weed individually and thus spare the planet from the over use of pesticides.

Anyway, If there is some sample code out there that could point me in the right direction to get over my LoRa hurdle I’d appreciate the links.

2

Hi imeanttodothat,

I would agree that it is most likely a throughput problem like we mention in the note at the bottom of [this section of our Hookup Guide for the NEO-M8P. It is technically possible to send RTCM correction data via a LoRa connection but you’ll need to adjust some settings in your LoRa device to achieve it. I assume you are using the example from that section (or a modified version of it) in your tests? You may need to sacrifice one or more RTCM channels to reduce the size of the data package you are sending via LoRa.

We do not really have any example code specifically for sending RTCM data via LoRa, unfortunately. I’ll try and do some more digging to see if there are either examples out there or some resources that will help you configure your LoRa radios and the NEO-M8P to optimize this connection.](https://learn.sparkfun.com/tutorials/gps-rtk-hookup-guide#setting-up-a-base-station)