@thoyo wrote:
Dear all,
I have connected the U-Blox Neo M8M GNSS receiver to my Pixhawk, and ONLY the COMPASS output of 3DR's GPS+MAG module as an external compass to the I2C port. (edit: The 3DR module is connected to Vcc and GND via its GPS port, it has the status LED on, and is visible to Mission Planner on compass calibration).
After that, I fly an octacopter, and set it to go in Loiter mode, but although the GNSS signal quality is OK, after few seconds it ends up in toilet bowl effect.
Then, I replace the M8M by the 3DR GPS and do the same test, and Loiter mode works fine. Like this, I can discard compass calibration and interferences as the sources of error.
I have been sniffing the data written by 3DR GPS, and I see the following U-Blox messages:
- NAV-SOL
- NAV-STATUS
- NAV-DOP
- NAV-VELNED
- NAV-POSLLH
While my M8M was only writting RXM-RAWX, and RMC, VTG and GGA NMEA messages.
My questions are:
- Can it be that the lack of this NAV-* messages is causing the error in the Loiter mode?
- Why is Pixhawk not configuring the M8M to write this messages?
Right now I don't have a UAV to test the M8N with the new configuration, and would like to be sure I have figured out the problem before next flight.
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