No GPS lock with Neo-M9N

[n-snyder]

I am using the Control Zero H7 loaded with the PX4 v1.12.3 release with the mRo Neo-M9N GPS. The PX4 GPS_1_CONFIG is configured to use GPS 1 (201). After booting and waiting 5-10minutes, the GPS just blinks blue lights; no GPS lock in QGC. After setting and rebooting several times, the problem persisted.

I connected to the device using Ublox's U-Center, and it showed 29 satellites. I also loaded ArduCopter 4.1 onto the Control Zero, and the M9N acquired a GPS fix.

[dagar]

I'm not sure if any of the PX4 developers have this board to assist with testing. Do you know which version of the board it is? https://github.com/PX4/PX4-Autopilot/tree/master/boards/mro

Through a console could you run gps status?

We should also check if these serial ports are correct.

PX4-Autopilot/boards/mro/ctrl-zero-h7/default.px4board

Lines 4 to 7 in a548c94

	CONFIG_BOARD_SERIAL_GPS1="/dev/ttyS2"
	CONFIG_BOARD_SERIAL_TEL1="/dev/ttyS0"
	CONFIG_BOARD_SERIAL_TEL2="/dev/ttyS1"
	CONFIG_BOARD_SERIAL_TEL3="/dev/ttyS4"

@ryanjAA which version of the Control Zero were you using?

[ryanjAA]

An f7 but I have a few h7s here as well. Let me give it a try (all of them are running 1.11.3 so I’ll get current stable on one and test).

[ryanjAA]

Doesn’t work on stable 1.12.3. I’ll check the port mappings and figure out why but iirc I remapped them on the f7 release for 1.11.3 and then have them remapped for out 1.12 release. I have an h7 and h7 oem so will figure it out.

[ryanjAA]

Stable is causing random reboots but temp is crazy high. Maybe related.

[dagar]

Stable is causing random reboots but temp is crazy high. Maybe related.

I'll lower the default cpu frequency on these H7 boards, there's no reason to run at the max rate (mostly idling) and get this hot. #18198

[rousselmanu]

Hi, same problem here with Control Zero H7 with latest stable firmware 1.12.3: no GPS communication.
"gps status" returns:
status: NOT OK, port: /dev/ttyS2

[rousselmanu]

We managed to establish the communication with the GPS by connecting the GPS to USART3 (ttyS1) and following config:

• GPS_1_CONFIG: TELEM2
• SER_TEL2_BAUD: 115200
  see: https://mrobotics.io/wp-content/uploads/2020/10/control-zero_straight.jpg
  USART4 seems to have a configuration issue.

[rousselmanu]

We managed to establish the communication with the GPS by connecting the GPS to USART3 (ttyS1) and following config:

* GPS_1_CONFIG: TELEM2

* SER_TEL2_BAUD: 115200
  see: https://mrobotics.io/wp-content/uploads/2020/10/control-zero_straight.jpg
  USART4 seems to have a configuration issue.

In fact SER_TEL2_BAUD should be put to "auto".

[n-snyder]

I just returned from field testing another setup. The workaround of using TELEM2 is providing a GPS fix (14 satellites in an obscured environment). However, the LED on the GPS pulses blue, which I understanding is to mean "No GPS".

[benjinne]

This may be related: #18968 (comment)