Navio+/2 GPS problems (hopefully) solved


I write this to help others, who might experience the same problems I did.
My problem in short was a very unreliable GNSS fix, with my Navio+ and now with my Navio2 board, using various versions of Arducopter. Emlids customer support is really great and they provided me with replacement antennenas and even a replacement Navio+ board.

Here is a video showing the problem (Navio2):

I now got it working by setting the following parameters for Arducopter:

GPS_GNSS_MODE 67 (default 0)

this enables GPS, SBAS, GLONASS
you might have to change that, depending on where you live.

GPS_SBAS_MODE 1 (default 0)

GPS_TYPE 2 (default 1)

with those settings, I have a GNSS fix with 12 sats and a HDOP of 1,02 at the moment.
That means, indoors ca. 1 meter away from the window, overhanging balkony and thin, but fully overcast.
My theory is, that Arducopter does not use the M8s given config right, if you leave the above parameters at default.

1 Like

Here is antother thing I found:
I tested GPS with Arducopter only, using a UDP connection to my PC running missionplanner.
After it was working, I installed mavproxy on the RPi and channeled the telemetry connection through it.
After a few tests, I can say, the copter never gets a GPS fix, if mavproxy is running.
Yesterday (heavy overcast, snowfall) I started just Arducopter and had a GPS fix after 15min indoors.
I then started Arducopter with mavproxy and even after three hours (weather improved over time), no GPS fix.
Arducopter alone, GPS fix after 7min.
Today again with mavproxy, 4 hours, no GPS fix. Arducopter alone, GPS fix after 5min.
I have absolutely no idea how mavproxy might interfere with the GPS, but it does.

Was this an issue ONLY with using mavproxy? I am wondering if I should change my GPS settings to make sure they are correct but my gut tells me, if it ain’t broke, don’t fix it. My GPS is working just fine now, perhaps it could be better?

Do not change anything, if it is working. I really had bad GPS performance. 8 sats max under a clear blue sky, with frequent drops to zero/no fix. With an Ublox 6 receiver, I got a fix with 10-12 sats in the same spot.