I can’t believe I’ve never thought about this and that no one is really talking about it. GPS is a system that everyone uses everyday on there phone and is constantly tracking your location. Many people here (including myself) use airplane mode to block mobile data signals so that mobile data companies cannot track your location and sell it to data brokers. But airplane mode doesn’t block GPS (I just tested this now on my phone, maybe your phone works differently). Is GPS somehow designed in a way so that it’s private?

It’s not as clear-cut as most people here are saying. In short, GPS itself is just listening to satellites, and nothing is leaked that way, but most modern phones use “Assisted GPS” of some sort. The most common (I believe) AGPS is SUPL, which seems to be used by most phones. This involves sending your approximate location to an Internet server, which returns satellite data based on that approximate location. To nobody’s surprise, in Android this is a Google server. I’m pretty sure most Android distros don’t give you any control over when it’s used, or which servers it uses. Anecdotally, my phone without Google Play services has a horrible time obtaining a GPS fix, so I suspect without GPlay it’s only using raw GPS, but I’ve not bothered to actually dig into it. As I understand it, SUPL means even if you’re in aeroplane mode, if you have an Internet connection over WiFi you might still be leaking (approximate) location data when using GPS. I learned about this from this excellent series of blog posts, which is a very thorough comparison of various Android ROMs’ privacy. It has a background section (search for “Assisted GPS”) in each of the ROM-specific posts which explains it better than I can.

Thanks. One question though: is this assistet GPS the same as RTK services?

My first answer is “WTF is RTK?”; my answer after consulting Wikipedia is “no, they’re separate things”. RTK doesn’t sound like it broadcasts any data out but I barely understood what I just read. The Wikipedia coverage on this whole topic seems rather poor quality, I don’t think it’s just because I’m dumb.