Optimized GPS & PPS config for u-blox NEO-M8N

[geoffreyheller]

Thanks for providing this great script for setting up the RPi Stratum One time server!

In addition to your script, I thought you might want to add some documentation for how to optimally set up the common u-blox NEO-M8N as a time source.

The following are the notes I used to configure my own M8N. I was hoping to share this and potentially get some feedback / questions. Once the config is agreed we could make an automated configuration script to set up the GPS devices themselves.

The following instructions are for u-center v21.09 and the NEO-M8N:

The following assumes that for configuration purposes you are connecting your PC to the M8N using a USB cable, and that your Raspberry Pi's ttyAMA0 UART is connected directly to UART1 on your M8N.

FIRST RESET TO FACTORY DEFAULTS Tools > Firmware Update Utility Check "Program FIS only" FIS file: C:\Program Files (x86)\u-blox\u-center_v21.09\flash.xml Check "Use chip erase" GO

-or-

UBX > CFG > CFG Reset to defaults Send

CONFIGURATION View > Configuration View

UBX > CFG > PRT Target: 1 - UART1 Protocol out: 1 - NMEA Change Baudrate to 115200 Send

UBX > CFG > CFG Save current configuration Send

NOTE: U-center won't show a baud change since we are connected with USB and not UART1

UBX > CFG > GNSS Enable GPS only (32 channels) Send

UBX > CFG > SBAS Subsystem: Disabled Send

UBX > CFG > NAV5 Dynamic Model: 2 - Stationary Send

UBX > CFG > TP5 Check Active Pulse Period: 1000000 Check Align to TOW=0 Set: 0-UTC Time Check Rising Edge on TOS Send

UBX > CFG > PMS Setup ID: 0-Full Power Check: Save configuration Send

UBX > CFG > RATE Time Source: 0 - UTC Time Send

UBX > CFG > MSG Uncheck all boxes for: F0-01 NMEA GxGGL F0-02 NMEA GxGSA F0-03 NMEA GxGSV F0-04 NMEA GxRMC F0-05 NMEA GxVTG

Check all boxes for: F0-00 NMEA GxGGA F0-08 NMEA GxZDA

(Summary: Keep only the GPGGA and GPZDA messages)

UBX > CFG > CFG Save current configuration Send

[geoffreyheller]

Update: I'm going to see if I can get the same settings using ubxtool

[beta-tester]

thanks,

but i do not plan to add documentations for a specific device (i not own). i think the u-blox documentation / Interface Manual 'u-blox8-M8_ReceiverDescrProtSpec_UBX-13003221.pdf' is good enough.

i will keep you feedback open for a while