[Rebelgecko]

GPS is a bit different. It's uses multiple frequencies, so receivers can correct from some of the water vapor attenuation. I suspect that GPS satellites also broadcast at a much higher power than the starlink terminals will. Starlink is also using a much higher frequencies: GPS is around 1ghz. Starlink is in the 12-40 range since it used Ku and Ka band. Ku and Ka are much more susceptible to problems from moisture in the atmosphere. That's actually why K Band was split into Ku(under) and Ka(above). The middle parts around 22ghz are not useful for communicating through lots of atmosphere because so much of the signal gets absorbed by water (sidenote-- NASA and NOAA use signals around 22ghz to measure water vapor in the atmosphere. That's why they're pissed that the FCC auctioned off 24ghz spectrum for 5G-- it's going to interfere with forecasting things like hurricanes).