Can't set GPS_GNSS_MODE for Galileo on Ublox SAM-M8Q


I have an Ublox SAM-M8Q GPS module from Drotek, which works quite good so far.
In u-center UBX-CFG-GNSS configration I activated Galileo GNSS in and saved it.
Then ArduCopter was using GPS, GLONASS, GALILEO and SBAS at 10 Hz update rate.
Got 23 sats with HDOP of 0.55, which is quite good I think.

Unfortunately SAM-M8Q has no flash to permanent save the settings, just a battery backup RAM.
The battery is too weak, so the settings are lost after some hours and Galileo is off again.

Then in Mission Planner I set Parameter GPS_GNSS_MODE to 71, which should activate GPS, GLONASS, GALILEO and SBAS at ArduCopter boot time.
But the UBX-CFG-GNSS setting did not change! I verified with MAVSerial-Pass and u-center.
It also did not work with a different Drotek NEO-M8N module, which I updated to ublox firmware 3.01. Also other values for GPS_GNSS_MODE did not work.
GPS_AUTO_CONFIG is set to “1”.

Is GPS_GNSS_MODE working at all?
How can I activate Galileo with ArduCopter?


Why not exchange the battery?
I am using a Drotek m8n with full Galileo support on Arducopter for over 16 months now. No issues. Up to 27 sats locked.
I initially enabled Galileo in ucenter.

A bigger battery yould be an option.
My hope was to find a way to activate Galileo via ArduCopter.

@RainerW last time I tested all the GPS_GNSS_MODE stuff was working on a M8N, it’s been awhile since I’ve tested that though so I will try and retest it here sometime today/tommorow and let you know if it’s functioning correctly.

I would like to bring this subject up again, because I now also have the Problem with a NEO M8N.
GPS, GLONASS, SBAS can correctly be set via Mission Planner GPS_GNSS_MODE parameter.

But as soon as I activate Galileo, the GNSS configuration is not written in the NEO M8N any more.
Also the GPS, GLONASS, SBAS configuration is no longer written.
I checked this with “MAVserial pass” and U-Center after rebooting the FC.

Could anyone verify that?
Or does anyone have any idea how activating Galileo via GPS_GNSS_MODE works?

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I have the same problem, there is a bug in gps driver,After changing the code, my gps can be configured correctly,I will give a pull request recently

How have you fixed the issue?

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This is now fixed in the latest 4.1.0-dev master.
With GPS_GNSS_MODE = 71 my SAM M8Q shows this configuration in U-Center