this post was submitted on 08 Jul 2025
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Why would you need an Internet connection to use GPS?
I didn't say you need internet connection. But you do need a satellite uplink. So, I wouldn't call that offline. Clearly, many others do so maybe I'm wrong.
Nah, GPS isn't a two-way thing. There's no way for the GPS system to track devices.
Your phone figures out where itself is using the satellites as markers, the phone doesn't emit any signals for this. It's offline.
Basically the way it works is GPS satellites broadcast a very accurate time signal, (and occasionally data about the satellites exact orbit). Your phone sees this and uses signals from at least four satellites to find it's location. It does this by measuring the delay in the signal between them. (Due to the speed of light, each signal will be delayed slightly). Knowing the delay in the signal you will know how far away you are from the satellite, and knowing the exact time along with it's orbit info will tell you where exactly the satellite is. But knowing that you're 13,000mi away from a satellite doesn't help much. But then if you look at the other signals you can see you're 16,000mi from another satellite, and so on which when you use 4 satellites will leave you with one possible spot you can be.
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Jaw drop moment for me... I did not know that.
I'd have probably expected that your phone automatically sends the device ID, but that's of course not necessary.