I’ve got a boat that’s using a Holybro UM982 GNSS. Since this is a dual antenna setup for heading yaw, is there any reason to connect the SDA and SCL? Currently, I only have a 6-conductor exiting a waterproof connector, and I wanted to retain the status led. But every so often, I get an EKF error, usually concerning yaw or position. In my Orange + params, I’ve set not to use a compass. Is it cool to keep it disconnected?
GPS yaw only works when it has a RTK fix so the compass is generally used as a backup.
Being a moving baseline, it always has a fix solution. But it would seem the autopilot doesn’t like something lol. No corrections are being sent for navigation though. I could, but given the existing setup is either GPS status 3 or 4, there has to be something conflicting with the UM982. All my Holybro DroneCAN H-RTK F9P and non CAN work flawless for heading. I just thought I’d save some money with the boat. Maybe no a good idea.
Dual RTK GNSS yaw should work, even if there is no RTK fix. See Ardupilot’s documentation: GPS for Yaw (aka Moving Baseline) — Copter documentation
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It needs both receivers to have a RTK fix, when using moving baseline one receiver on the rover acts as the base for the other. so if one looses fix then you loose heading. It just doesn’t need external RTK corrections since absolute accuracy doesn’t matter. for heading its just looking at the relative position of the 2 receivers on the rover but it needs to know where they are very accurately from each other, and it can only do that with a high precision fix.
This works even if the GPSs do not have an RTK fix (RTCM data from a fixed RTK station or NTRIP server).
I have asked for that to be clarified to say
This works even if the GPSs do not have RTCM data from a fixed RTK station or NTRIP server.
Incorrect. The moving base need not have an RTK fix.
Isn’t the corrections provided by the other GPS on the vehicle so it’s RTK but without the absolute accuracy of using external corrections and it needs both GPS receivers to communicate corrections for moving baseline to work with enough accuracy for heading to work. So it’s RTK but without absolute accuracy?
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To get heading, the system only needs the relative accuracy provided by the (self-contained) corrections from the moving base to the rover.
Yes but that would still be RTK as it’s still getting corrections just not externally.
I never claimed otherwise.
You suggested both modules need an RTK fix. That is not true.
The moving base simply needs a 3D fix. It then provides RTCM3 to the rover for the relative correction that makes heading calculation possible.
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