quote:

---

Next, I visited with TruePosition, a company that makes location-based-technology products. Their uplink-time difference-of-arrival (U-TDOA) technology is widely used in the cell phone industry to implement the E911 location system mandated by the FCC for all carriers. U-TDOA is the E911 technology used by AT&T and T-Mobile. Roughly 75K U-TDOA basestations are part of the estimated 200K+ basestations in the U.S. This system uses special receivers from three basestations to triangulate on a handset to compute its location usually to within 50 meters. Other cell sites of the cdma2000 variety use a handset solution that requires each handset have a GPS receiver that reports its location back to the carrier for E911 service. A version that helps predict location when the GPS antenna is indoors and out of touch with the satellites is called Assisted GPS.

TruePosition announced their new Hybrid Location Solution at the show. It combines the best features of U-TDOA and A-GPS. New algorithms combine the two technologies to provide higher location accuracy and increased reliability. As it turns out, U-TDOA is better in those locations where lots of cell sites exist and indoors while A-GPS works best when it is in a location with a clear view of the sky like in rural areas. The new hybrid approach is expected to improve overall location capability that will promote better location-based services (LBS).

---