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> GPS isn't possibly tracking mechanism because it works via passive reception of a satellite signal. That's only one component of the GPS system. It also pull

> GPS isn't possibly tracking mechanism because it works via passive reception of a satellite signal. That's only one component of the GPS system. It also pulls data from the network based on your location; look up Assisted GPS. EDIT: I don't mind the downvotes, but someone please educate me and everyone else if the statement is incorrect.

diggernet 10y ago
GPS works entirely through passive reception from satellites. No other connectivity is required. With true GPS, it is impossible for the satellites to know where you are, or even that you are using it. (That also makes it infinitely scalable, as users consume no satellite resources.) Assisted GPS is an "improvement" which depends on additional data from the cellular network. Which means the cellular network knows you are using it, knows where you are, and can track you. Edit: Back in my Nokia days, I had phones with true GPS and 100% offline maps, which would work perfectly well for navigation far from any hint of connectivity. No idea whether Android's "Device only" mode is GPS or aGPS.
- hackuser 10y ago
  AFAIK, Assisted GPS is almost universal, so almost anyone using GPS uses that component too.
- duskwuff 10y ago
  There's two types of assisted GPS. In one type, the cellular network (or some other network) is used to download a copy of the GPS almanac faster than it would have been received from the satellites. The almanac is globally valid (it's just a bunch of high-precision data about the GPS satellite orbits, the signals they're transmitting, and ionospheric conditions), so this doesn't leak any information about the receiver's location, beyond what's inherent from being active on a cell network. In another type, the receiver sends a portion of the GPS signal it's received to a server, which calculates a position fix and returns it. Obviously, this lets the server discover the client's location. My understanding is that the second approach is largely obsolete -- modern GPS chipsets are small and cheap enough that there is no advantage to offloading the calculations.
- tinus_hn 10y ago
  The fact that data is downloaded for A-GPS doesn't cause the ability for the mobile network to track you. A-GPS just downloads some information that you would otherwise get from the satellites, which describes where the satellites are along with some technical data. This information doesn't depend on your location and in fact, as your phone is requesting it, it doesn't know where it is yet. That's the whole point! The mobile network can track you because you have a constant connection to it. Not because of A-GPS.

diggernet 10y ago

GPS works entirely through passive reception from satellites. No other connectivity is required. With true GPS, it is impossible for the satellites to know where you are, or even that you are using it. (That also makes it infinitely scalable, as users consume no satellite resources.) Assisted GPS is an "improvement" which depends on additional data from the cellular network. Which means the cellular network knows you are using it, knows where you are, and can track you. Edit: Back in my Nokia days, I had phones with true GPS and 100% offline maps, which would work perfectly well for navigation far from any hint of connectivity. No idea whether Android's "Device only" mode is GPS or aGPS.

hackuser 10y ago
AFAIK, Assisted GPS is almost universal, so almost anyone using GPS uses that component too.
duskwuff 10y ago
There's two types of assisted GPS. In one type, the cellular network (or some other network) is used to download a copy of the GPS almanac faster than it would have been received from the satellites. The almanac is globally valid (it's just a bunch of high-precision data about the GPS satellite orbits, the signals they're transmitting, and ionospheric conditions), so this doesn't leak any information about the receiver's location, beyond what's inherent from being active on a cell network. In another type, the receiver sends a portion of the GPS signal it's received to a server, which calculates a position fix and returns it. Obviously, this lets the server discover the client's location. My understanding is that the second approach is largely obsolete -- modern GPS chipsets are small and cheap enough that there is no advantage to offloading the calculations.
tinus_hn 10y ago
The fact that data is downloaded for A-GPS doesn't cause the ability for the mobile network to track you. A-GPS just downloads some information that you would otherwise get from the satellites, which describes where the satellites are along with some technical data. This information doesn't depend on your location and in fact, as your phone is requesting it, it doesn't know where it is yet. That's the whole point! The mobile network can track you because you have a constant connection to it. Not because of A-GPS.