Spoofing is a big topic in the GNSS world (which is the broader set of satellite constellations like GPS). There's a lot of stuff happening to prevent spoofing.

Spoofing is a big topic in the GNSS world (which is the broader set of satellite constellations like GPS). There's a lot of stuff happening to prevent spoofing. One of those things is using digital signatures that you can use to authenticate the signal. Another thing is using signals from multiple satellite constellations and correlating those. And of course the way these things work you need to talk 3-5 satellites from each network at least to be able to reliably interpolate the position. Even older networks, like GPS, change over time as satellites get replaced and software is updated. The advantage Starlink has is that there are a lot more satellites that are also in a much lower orbit. There has been some talk about using their satellites for positioning. I think they look at that as a bit of a low value market so far.