An Assisted-GPS (A-GPS) receiver dramatically improves the performance of GPS receivers using an assistance server, to enable the transfer of data that receivers would ordinarily have to download from the GPS satellites.

Conventional standalone GPS also has difficulty providing reliable positions in poor signal conditions. For example when surrounded by tall buildings or when the satellite signals are weakened when a GPS device is indoors or under trees. With network assistance, the receiver operates quicker and more efficiently than it would unassisted since tasks are shared with the more powerful assistance server. The performance of an A-GPS system is greater than that of the same receiver in standalone mode.

Provision of assistance data to a GPS receiver greatly improves the Time To First Fix (TTFF) and increases the sensitivity of the GPS receiver. A-GPS offers significant performance advantages over autonomous GPS, particularly at low power levels often associated with consumer applications.

Spirent test systems for A-GPS development, range from provision of assistance data to the device under test through to integrated wireless network and GPS environment simulation with full conformance and performance test capabilities. Spirent also offers production test systems for A-GPS devices. Testing can simulate both UE-Based and UE-Assisted operating modes and synchronization to other systems such as network location servers. Conformance testing is often in accordance with standards from organizations such as 3GPP (IS-916), the Open Mobile Alliance (OMA) and leading carriers.