Does the iPhone's GPS Use Up Data?by Jacob Andrew
The iPhone is equipped with an integrated GPS antenna which, when combined with the native “maps” app, can create a rudimentary GPS. GPS operates outside of the cellular signal, communicating directly with satellites to determine your position. Every other feature on the iPhone, however, relies on cellular towers or Wi-Fi networks to transmit data. This can result in the GPS using a portion of your allotted cellular data.
Differentiating GPS From Other Data
The GPS antenna in the iPhone and other smartphones can only locate your whereabouts at a particular moment. Once this data is obtained, it can be used to mark your position on a map. This map is a graphic file that must be downloaded through a data network. If you have not accessed a map recently for your current location, it must be downloaded by the Apple Maps app using your data connection. If you are connected to a Wi-Fi network at the time, it should not affect your overall data usage with your provider.
Occasionally, data usage on the iPhone occurs not just from the maps but also from a feature called “Assisted GPS.” Because GPS signals can take some time to determine your location, some devices use bits of data sent to three different cell towers to help pinpoint your location faster. The amount of data is small, but it can add up if the feature is used frequently.
High Data Volumes
The biggest data usage comes from using the iPhone as a GPS when you drive a long distance. This is because new sections of the map are downloaded as you travel. If you have a limited data plan, you should avoid using the GPS feature too often while driving.
How to Avoid Data Downloads
If you have a Wi-Fi connection available, you may be able to avoid some data charges from your cellular network. Open the maps program and navigate to the area where you expect to need the GPS. Zoom in and out on this area, pausing with each step of the zoom to allow the map to load. Doing this will place these maps in a temporary cache on the iPhone, so they won't have to be downloaded over a cellular connection when you are using the GPS. Version 6 of the iOS offers enhanced functionality for caching these maps.
Some third-party GPS applications save you data charges by including the maps. GPS manufacturer TomTom makes an app for the iPhone that uses built-in maps for navigation. The downside to such an app is that it tends to be more costly. Another caveat is that downloading the maps requires over 1.4GB of storage on the phone.