US Patent 7499710 Integrity monitoring for geo-location systems

Weighted ridge regression (WRR) processing is applied to three or more distance measurements to determine the location of a terminal. For example, in an integrated satellite-based navigation system/wireless network, the location of a mobile unit can be determined by applying WRR processing to at least three distance measurements, where one or more of the distance measurements are satellite-based distance measurements (e.g., GPS pseudorange measurements) and one or more are wireless network-based distance measurements (e.g., round-trip delay or pilot phase offset measurements). WRR processing provides improved accuracy in the determination of mobile unit position over conventional least mean square techniques.