M9N GPS not detected satellite

Basant · July 28, 2023, 2:52pm

Hello,

We have try to connect M9N GPS to my Pixhawk but the gps not fix and also not provided any type of RX and TX signal

Please tell us how to fix this problem

==.> GPS Fix ==> Only Blue Led flashing
==> GPS RGB Led ==> Yellow Led flashing

Please give me any solution

roman-dvorak · July 30, 2023, 5:22pm

Hi, what version of FW do you use? Because I observe very similar behavior with two days old Master FW.

roman-dvorak · August 1, 2023, 12:34pm

A have recognised this issue in main and beta branches:

github.com/PX4/PX4-GPSDrivers

Fix unsupported message with NEO-M9N Ublox module.

PX4:main ← ThunderFly-aerospace:tf/fix-unsupported_message

opened 12:25PM - 01 Aug 23 UTC

roman-dvorak

+2 -2

The current GPS driver in the autopilot system contains an issue when attempting… to initialize communication with the NEO-M9N UBLOX module, which is integrated within the [TFGPS01](https://github.com/ThunderFly-aerospace/TFGPS01/). During communication, the GPS driver receives NACK (negative acknowledgment) when trying to configure the following messages: 1. `UBX_CFG_KEY_MSGOUT_UBX_NAV_HPPOSLLH_I2C` 2. `UBX_CFG_KEY_MSGOUT_UBX_NAV_RELPOSNED_I2C` After a reading of the [NEO-M9N documentation](https://content.u-blox.com/sites/default/files/u-blox-M9-SPG-4.04_InterfaceDescription_UBX-21022436.pdf), i have discovered that these specific message types are not supported by the NEO-M9N receiver. Consequently, the GPS driver fails to establish proper communication with the module, leading to the inability to retrieve GPS data and compromising the autopilot's navigation and positioning capabilities. **Testing** The proposed changes have been tested using NEO-M9N and CUAV FMUv5. The GPS driver was successfully initialized, and the autopilot shows correct functionality in receiving GPS data after implementing the exception for these messages. More detailed description is here: https://github.com/PX4/PX4-Autopilot/issues/21914