New to Ardupilot - GPS not working

Hey Guys,

First time using Ardupilot and I have got myself a bit stuck.

I have removed all the electronics from an old TBS Discovery as I was having wierd video issues so I am replacing it with new hardware - A Matek H743-Wing v3 Flight Controller and a Matek M8Q-5883 GPS unit.

It seems the GPS is detected as I am getting “No Fix” on the OSD and not “No GPS”?

I have connected the GPS via the MSP instructions, using tx/rx2 Serial3, the compass is responding but I seem to be getting no activity from the GPS or barometer.

I have confirmed there is connectivity to every pin with a multimeter.

I have confirmed the unit is getting a 3d fix with a blinking blue LED.

The wiring is as follows:
GPS - Flight Controller
SDA - SDA
SCL - SCL
TX - RX2
RX - TX2
GND - GND
5v - 4v5

Ardupilot Configuration so far:

MSP

  • SERIALx_PROTOCOL = 32 (MSP) where x is the SERIAL port used for connection on autopilot
  • GPS_TYPE = 19 (MSP)
  • BARO_PROBE_EXT = 4096 (MSP Baro)
  • BARO_PRIMARY = 1 (If you want to use MSP baro as primary baro, otherwise leave as default)
  • COMPASS_TYPEMASK = 0 (or make sure MSP bit is not checked)

I have been trawling the discource for a number of hours and set baud rates and other different parameters for gps protocol types etc but have had no luck.

These are some of the things I have tried

GPS_DRV_OPTIONS = 4 as suggested by another post
Also tried: SERIAL_BAUD = 9600, 57600, 115200

Where can I go from here? What are they key things to check being new to Ardupilot.

Not sure about MSP but if the GPS is connected to the Flight Controller and you are using the primary barometer then:
GPS_TYPE=2 (for that GPS module)
BARO_PROBE_EXT=0 (default)
BARO_PRIMARY=0 (default)

Thank you very much for your reply.

I dont think I have changed the GPS_TYPE yet as I have been going off the documentation, I will try that and see if anything else changes.

The barometer settings are already set (I am using the H743 onboard barometer).

No dice with that change unfortunately.

I get “No GPS” on the OSD and gpsstatus reports 0.

With the GPS_TYPE set to 19 it seems to be aware that a GPS is present, but I am not getting any stats from it.

Disable your VTX and re-test

I have no VTX plugged in or enabled yet.

I just connected the GPS to the u-center software and it is picking up sats, I changed the update rate to 10hz and the baud rate to 5700 as a test - no change.

EDIT:

After a bit of tinkering and making the changes above I changed the SERIAL3_PROTOCOL to 5 - GPS.

I am now getting data from the GPS it seems…

These are my final settings that are getting some random number is some GPS fields, going to put it near a window now…

Well yea the serial protocol needs to be GPS. Don’t bother with Ucenter. The settings will be overwritten by Arducopter on boot. Use Mission Planner to confirm GPS and Baro are working and the troubleshoot the MSP/OSD issue seperaty.

I forgot to add the other thing I changed was the Output protocol from “UBX+NMEA” to just “UBX” in the u-center software.

I also changed the GPS settings back to defaults and it stopped working again in Ardupilot, even with the new settings advised in this discussion and the recommended from the documentation, so it definitely seems these setting were the issue.

Do you recommend I change the baud, update rate and output protocols back?

I now get a GPS fix, even inside my house.

MSP aside, the default settings work for sure. I have 2 of those same combinations (Slim and Mini version of the H743) and the Matek GPS module. And another of the same Matek GPS module with a Kakute FC.

You are absolutely right, it should work with default settings but it doesn’t… only the changes above allowed it to function correctly for me.

At first I thought it was a faulty GPS unit as I was confident after reading through the documentation, checking my wiring and double checking with you guys here that I had things correct but after connecting to u-center finding it was working perfectly there…

Would it be worth dumping my config in case there is something funky going on with some other parameter? The only parameters I have changed though are the ones above, this is a brand new flight controller that has not had any previous config freshly flashed with arducopter.

Attached is a parameter file for a Matek H743-Mini (same as Wing for most things) and the Matek M8Q-5883 Module. Perhaps you will see something.
Matek H743-Mini.param (18.0 KB)

Thank you very much for this, I will compare and see if you have anything that stands out.

Still trying to figure out why it is not working on documented settings.

I couldnt see much difference to be honest in the two configs, your GPS setup is as you say, out of box and should just work.

Out of frustration I wiped the FC and flashed Arducopter again and the GPS was detected perfectly! The Compass and Barometer is now also behaving.

Maybe was a bad flash or some parameters were messed up that were not cleared when I was re-flashing.