Why does Project Lifesaver use radio frequency technology when the newer, more modern GPS is available?

GPS is the most accurate navigation system in the world, but the navigation signals are very weak and can be difficult to locate in blocked environments. The clients that are registered with Project Lifesaver do not exhibit traditional lost person characteristics and often do not realize they are, in fact, lost. Oftentimes, they will wander into areas where GPS signal penetration is very poor such as underground parking, dense bush or inside structures.

The transmitter used by Project Lifesaver has an approximate 1.5 km range under ideal conditions. The transmitter uses pulse carrier wave frequency technology to emit a signal once every second. The receiver and antennae are used to detect the signal and then to physically locate the transmitter worn by the client.