I have an APM2 with the in-built mediatek GPS. This is disabled (confirmed through
the mission planner). When I connect the uBlox GPS it is not detected by the APM board.
The uBlox itself is running - the red power led is on and the blue "fix" led is flashing.
I have tried various resets, re-attached cables and more, but no change.
"test gps" in Terminal only outputs "G!" repeatedly.
I use the ArduCopter v2.7.1 Quad firmware.
Is there anything I missed, any ideas how to troubleshoot this further ?
did you reset the apm2?
Ok, it sounds like you've followed the steps pretty well so let's go over how it works.
When you power the APM, the current code checks for the type of GPS attached via a query sent to the GPS. It then configures the APM firmware to accept the data coming from the GPS.
When you did the check from command line, you got nothing but G.
In general, this indicated we failed at the first step to identify the GPS from query at boot thus no "driver" in the firmware is runnning and we see no data stream.
This still could be a wiring issue between the GPS and the APM (crossed tx and rx lines). I say this because we know you have power to the GPS and it says it got lock, but there is a communication error.
This could be that your GPS module has the wrong firmware, so when the query happens at boot, your GPS return the wrong info and thus the APM cannot load a known driver.
Both of these are possible root causes of the problem.
To test the GPS
I would connect a FTDI or other UART (serial) connection directly to the GPS and see what it's sending. This would also be the way to upgrade or change the firmware of the GPS to the correct version to work with the APM.
Sorry, I don't have the detail behind what firmware works, but I'm sure some searching would find it.
Also "uBlox GPS" is a bit generic. Exactly which model and where you got it from would help us hone in on what firmware it likely has loaded and what firmware needs to be on it. We really need this info to help you.
Can I jump in here and ask if you know what uBlox modules will work with the APM2? I know the LEA-6 comes configured to work but would a NEO-6 work as well?
I can't find a list so I guess most will work, but I wanted to ask before I solder the pins on my built in Mediatek
thanks for your help
How did you disable the onboard GPS?
I just noticed that I had short-cut the wrong pins of the mediatek gps. All fine now, sorry for wasting your time.