AT&T has launched assisted-GPS technology (A-GPS) on its network to add location-based services (LBS) on its cell phones last week with two more navigation applications on the way: MapQuest Navigator and AAA Mobile navigator, underscoring its focus on GPS services.

AAA Mobile navigator will offer audible turn-by-turn directions as well as AAA TourBook travel guide information such as Diamond Ratings for restaurants and lodgings, gas prices, movie reviews and show times.

MapQuest Navigator will give turn-by-turn, voice-guided driving and walking directions, 3D moving maps, and access to 16 million points of interest from MapQuest's database. Users can get real-time traffic alerts, gas prices, gas station locations and AOL's City's Best restaurant and venue ratings.

Conventional GPS often encounters difficulty providing reliable positions in poor signal conditions. For example when surrounded by tall buildings (as a result of multipath), or when the satellite signals are weakened by being indoors or under trees. Unlike true GPS, which searches satellites for latitude and longitude coordinates, A-GPS triangulates locations of cell phone customers using nearby landmarks to identify actual position.