GPS Modules not tracking above 12.5km in altitude

GPS/GNSS Development Boards
1

I have tried 2 different Sparkfun GPS modules for my high altitude ballooning experiments. I tried one with the built in antenna and one with an external antenna and received similar results:

SparkFun GPS Breakout - NEO-M9N, Chip Antenna (Qwiic) - GPS-15733

SparkFun GPS Breakout - NEO-M9N, U.FL (Qwiic) - GPS-15712

Both GPS modules stopped tracking at ~12.5km in altitude, which is below the typical 18km limit for civilian GPS units. However the reason I bought these modules is because the datasheet specifies a limit of 50km; so a 12.5km dropout is significantly below this theoretical limit.

Has anyone had success using these for high altitude experience or have a similar product recommendation?

Thanks!

2

Hi @trizzle,

I’ve successfully flow u-blox modules - usually the MAX-M8Q - multiple times to 30km and beyond. The only non-standard setting I use is to change the dynamic model to “airborne <1G”. There’s an example here:

https://github.com/sparkfun/SparkFun_u- … cModel.ino

If you need more proof, send me a private message and I’ll send you a link to a paper that documents the flights.

Cheers,

Paul