Pixracer GPS: NO GPS

None of my pixracers will identify a gps. I’ve tried an M8N, a BN-880 and nothing works. Both of those gps receivers will work with a regular pixhawk. Wiring is per the user manual, I’ve tried the gps port and telem2 with the baud on 38 and input set to gps. Is this some problem with the hardware?

I’ve not had any problems w/ gps and pixracers. I’m on 3.4, but not the latest beta.

I also never had GPS problems with the Pixracer (3.4.1 rc2, 3.4.3, actual beta 3.4.4 rc1). Are you really sure you have wired properly (TX and RX are connected crosswise) ?


After sitting for about an hour with it connected .suddenly picked up and started reading 13-14 satellites indoors. No problems since…

When connecting a new GPS a cold boot to acquire the first satellites can take a long time especially if you are inside …

I thought that, but it connected immediately when attached to the pixhawk. The pixracer was having the issue on the same gps.

Was this ever looked into any further?
I have a Pixracer clone that is currently doing the same thing.
Will eventually get satellites, but still show No GPS in the HUD and takes forever to initialise.

Able to supply some logs if anyway cares to take a look into this.

I have GPS problems with the Pixracer as well (3.4.4 and 3,4,5).
QGroudControl shows me the location of the drone and tells me it sees up to 14 satellites and “3D Lock”, but when I try to arm in a flight modus that needs GPS it says “Need 3D Fix”.
Can anybody explain the difference between a 3D Fix and a 3D Lock? Or point in a direction how to further debug GPS?

edit: screenshot from QGroundControl http://imgur.com/a/rpAhu

Since you are inside it’s quite normal you won’t get a good 3D fix. The GPS might even report a 3D fix, but we check for a consistent/stable fix before allowing arming.

It’s quite strange that you are getting a “Need 3D Fix” message, you should get the detailed reason. In any case, you need to go out and see if you really have a problem or it’s just a bad fix inside the house.

I litetally left my pixracer on for about an hour and when i came back it had sorted itself out. Also, i generally get about 13 satellites with this receiver indoors. Usmile Beitian NEO-M8N GPS Module with Built-in HMC5883L Compass Protective Case for Ublox PX4 PIX APM2.5/2.6 Pixhawk https://www.amazon.com/dp/B01EH3819W/ref=cm_sw_r_cp_apa_b1SXyb296SVD2

Btw, you also need to make sure your compass is facing the same way as the fc, or have the orientation set correctly

I have the same problem outside, I just didn’t have a screenshot from when I tried then. I just found the message really confusing. Sometimes I get a more specific error like “GPS speed is 1.2 but needs to be 1.0”, but this only happens inside.
Is there any way to monitor the GPS status better than what QGroundControl tells me? I’ve been playing with the Nuttshell over mavlink, but did not find any GPS related stuff in there yet. Currently I’m trying to get some more infos via MissionPlaner and u-center, but I have to mess with Windows for that :-(.

I should mention though that I’ve compiled from source and get a warning that my compiler version is too high (5.4.1). I’m not sure if that has any influence, but wanted to mention it nonetheless. Also I’m only using the internal compasses of the Pixracer, the compass which is part of the GPS module is not connected.

Ok, so that specific error is clear. You are getting GPS speeds that are too high given that you should be stationary - that usually means your GPS fix isn’t very good. Make sure that you have a good open area to do these tests. Also buying GPS from trusted stores is better than cheap (maybe cloned) ones from wholesale chinese websites :wink:

Regarding more info: ArduPilot sends a pretty complete message with GPS info, what a GCS shows is up to them.

Since you are having issues I suggest you start with a verified stable firmware version provided by us instead of your own.

Well, the “fix” mentioned earlier eventually worked for me as well. Just let it sit outside for a while (about 30 minutes for me) and everything just started working as expected. Oh well.