They can’t shut down the satellites over Iran. That’s not how GPS works. They aren’t geostationary with tight beams like comm satellites. Every GPS satellite goes around the earth twice a day and has a beam that covers the entire earth plus something like 10 degrees on the sides out into space (circular, not actually side to side). While the US can turn off broadcasting while directly over very large swaths at a time (like, say, China and Russia), it isn’t actually turned off on the ground because there will still be satellites over Europe or northern Africa that will be on and sending data at a higher angle to that large swath. It will be lower powered in that region because the signal power is lower at the edges, but it isn’t off. Also, Iran is in the same region as US allies and US military bases: Turkey, Saudi Arabia, Israel, etc; so the US would be unlikely to want to lower GPS power in that region.
Starlink is very different in how it sends signals to the earth, which is why it can shut off services to areas.
bjoern_tantau@swg-empire.de 3 weeks ago
It’s stupid to not just use all the available systems. Don’t just support Beidou. Use Beidou, Galileo (European), GLONASS (Russia) and GPS. Makes lock on faster, increases precision and helps if one doesn’t work for whatever reason.
The US cannot just shutdown Iran’s usage. That would impact all other countries as well. GPS consists of only about 30 satellites for the whole world. Starlink satellites are much much lower and can thus be more easily associated with one country.
Glitchvid@lemmy.world 3 weeks ago
Echoing this, civilian GNSS is a passive system, and I’m all for redundancy, you should be using all four constellations for the highest accuracy and fastest lock.
themurphy@lemmy.ml 3 weeks ago
Yes, you should use it for the fastest lock, but if your interest is to keep the US out of influence, ofc they would do it.
Either that, or they do it to please China hoping for an ally. Second option might be their played hand, even if it doesnt work.
WhyJiffie@sh.itjust.works 3 weeks ago
this article just makes 0 sense. they didn’t “disable” GPS and they most probably didn’t just start using beidou today