Extern GPS with compass, NMEA messages

I have connected a Hemisphere V103 GPS Compass to BBBlue ttyO1.
ArduPilot receives GPS messages fine.
The GPS Compass delivers higher quality heading information than the internal.
How can I get ArduPilot to accept the Compass NMEA messages (GPHDT) ?
If nessecary we can send GPHDT messages to another serial port.

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@bok555, so I guess the GPS_TYPE parameter has already been set to “5” (for NMEA)? Re adding support for the GPHDT message, our driver is here. I don’t immediately see that we accept “GPHDT” but I’m not much of an expert in this area. I guess the driver could be enhanced. The first step for that would be to create an enhancement request in our issues list… or if you’re a developer we’re happy to accept pull requests!

I could extend the AP_GPS_NMEA module to accept GPHDT messages, but I don’t know how to pass it on to the back-end of ardupilot.

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Will the Hemisphere V103 GPS Compass work with RTK correction messages? Just curious, looking for a decent GPS compass with RTK support. I am looking at something like this maybe…


But ArduPilot would have to accept the messages being passed.

@Vincent_Miceli, I think the vectornav products are much more than just a GPS, they’re a full IMU + GPS + EKF. There’s a request on the issues list to add support and at least one developer tried (but then gave up for lack of time it seems) to add support to AP.

My view is that for most users these external systems won’t make a significant improvement over AP’s position and attitude estimates but that’s just a guess.

For the moment, I don’t have any advice on which RTK GPSs are best to use besides what’s on the wiki. Perhaps other developers with more experience of RTK GPSs might have some more ideas.