Septentrio GPS & PreArm: AHRS: Waiting for home

Dear Ardupilot community,
I recently completed the assembly of a quadcopter using Cube Orange+ and a Septentrio GNSS receiver that is set as heading source.

I installed Arducopter v4.3.7 from Septentrio that adds SBF heading support and configured it. In Mission Planner and on the GCS I can see all GPS-related data correctly (photo) and the vehicle icon appears accurately on the map. If the drone is manually moved the icon seems to accurately follow the UAV movements.

The problem is that, even with a reported “3D DGPS Lock” when switching to “Position Mode” flight mode I get stuck with the error message “PreArm: AHRS: Waiting for home”.

I also noticed that although the indicated “GPS Yaw (deg)” corresponds with my smartphone compass readings (pictures), and the vehicle’s icon on the GCS and Mission Planner “spins” precisely accordingly to the vehicle yaw changes when manually moved, the heading displayed on Mission Planner’s map is completely off (photo).

I’m not sure if the two issues are related one to the other, but I would greatly appreciate if anyone could help me figure out this two issues. I literally cannot wait to start flying!!! :star_struck:

I also uploaded a log that I hope can be useful: Log link

Thank you very very much!

Update to the latest 4.4 firmware (support remains in the updated versions).

I found this guide very helpful:

Wow, that’s a lightning fast feedback @Yuri_Rage ! Thank you! :heart_eyes:

We did initially try with v4.4, but didn’t seem to work. Then we downloaded from Septentrio GitHub their latest v4.3.7 and got it working.

Tomorrow morning I will try to update to v4.4 and update! Do you know “what is the problem”? Even in a very short description, just for my further understanding.

Thanks again.

Probably incorrect antenna orientation, which can be changed via the USB interface.

Good morning @Yuri_Rage !
We updated to v4.4 using Mission Planner and now we’re getting “GPS: No GPS” and “EKF3 waiting for GPS config data”.

If we install Septentrio Arducopter firmware the GPS works just fine. Same settings.

Do you have clue why this is happening?
Are you sure that @WickedShell 's SBF-heading patch (included in the Septentrio firmware) still remains after the update?

At this link the v4.4 log (quite big, 100MB)

Actually, it appears I was incorrect. That patch is still ahead of AP master and is not yet included in the ArduPilot repo or builds. I mistakenly thought that it had been merged.

The guide from ArduSimple overcomes this by using NMEA formatting, and I can confirm that it works.

@Yuri_Rage good morning!
So, last night we switched to Cube Orange (instead of Orange +), loaded the same settings and GPS+heading seems to be working correctly.

The problem we’re facing now is that the GCS running QGroundControl is not showing us any GPS data in the “GPS Status” window. I can see from Mission planner that “satcount” is “0” while “satcount 2” shows the right number of satellites.

Do you know how we can set “GPS2” as the source of GPS data for system/QGroundControl?

Glad to hear you got it working. I can’t explain why you’re experiencing different results on the Orange vs Orange+.

I don’t use QGC, so I’m afraid I’m no help there.


I’m not familiar with the Septentrio modifications of the firmware, so I assume that the parameters are following the normal ArduCopter description.

I went through your parameters of both files and saw something odd with the GPS_PRIMARY. The only serial port that is configured as GPS is SERIAL4 (aka the port with label GPS2). So, I assume that’s your first (and only) detected GNSS system. However, the GPS_PRIMARY (Complete Parameter List — Copter documentation) is set to ‘1’, the second detected GNSS system.

Can you set GPS_PRIMARY to ‘0’? Maybe this will switch the GPS and GPS2 data.

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