GPS fixes, cell towers, and Wi-Fi networks
The Location Services iOS API uses a collection of technologies known as Assisted GPS (A-GPS) to determine the device's position. The main reason why mobile devices use A-GPS instead of only traditional satellite GPS is that the latter does not perform well inside buildings; it is also slower than other technologies and quickly drains a device's battery. A-GPS works by augmenting satellite GPS by using external sources (such as cell towers) that enhance the speed, quality, and precision of satellite signals. Data received by external sources is then consolidated to figure out the device's precise location.
The following is a list of sources that power A-GPS:
- Satellite GPS
- Cell towers
- Wi-Fi networks
- Bluetooth devices
We will look into these in more detail in the following sections.
You may be wondering how an iOS device manages to resolve locations from Wi-Fi networks or cell towers; this is implemented...
