GPS corrections injected into custom control software?

Hi, after a few months of trying to work it out by myself, I’ve decided to just ask…

I’m super envious of the ability to inject the correction messages - Mission Planner’s MAVLink message injection. Would I be able to do something like that?

I’m 2 years into building a self-driving robot that runs on custom autopilot software (written in C), and is controlled from a (C#) Windows program. The radio telemetry is sent over a custom binary radio protocol that I wrote myself. Switching radio protocols to MAVLink and using Mission Planner are not an option for my robot.

So far, I’ve tried to read correction data from message byte (0xD3) up to the byte before the next (0xD3) byte; wrapping and transmitting that array to the robot, and having it send that array to the GPS… but that doesn’t seem to work. Maybe I messed up somewhere, though. Binary message packet assembly and disassembly is hard to debug. I’m not a pro… yet.

Any help is welcome:
Is there some documentation on what bytes mark the end of a message? I can maybe improve or debug my current code.
Or better yet, can anybody link me to a document that describes how to decode the messages? I’m mostly interested in 1002 1006 1010
How exactly does it work in Mission Planner?
Where can I learn more about rtcm3 message structure? Is there an introductionary book at least?

If my method sounds right and you think I just missed a bug in my code, let me know! I’m going to keep trying.

Hi Johandre,

Great stuff! What is the application for your custom autopilot?

You can actually buy RTCM3 specification for a $100 or something. But wouldn’t it be easier to peek into MP or RTKLIB’s source code?

Hi Egor,

Thanks for the tip. I think you might be right. It’s time to dig in again and reverse engineer something from source code. I actually forgot to check out MP’s source up to this point. If all else fails, I’ll get the book I guess.

My robot is just for research right now, but may have a future in automated agriculture. Fingers crossed!

Good luck :slight_smile:

Thanks :+1:

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