Abstract: A method and apparatus for position determination is provided using measurements from both Global Positioning System (GPS) receivers and terrestrial-based Uplink Time Difference of Arrival (UTDOA) receivers. The method involves the transformation of downlink satellite measurements into equivalent UTDOA measurements by computing comparable cross-correlation coefficients and time differences of arrival with respect to a UTDOA reference station. The method includes a weighting operation whereby the relative weights of the UTDOA measurements and the relative weights of the GPS measurements are adjusted based on a theoretical scaling followed by empirical adjustments. The method further involves the efficient computation and combining of metrics that are used to minimize the weighted error between candidate location solutions and the UTDOA and GPS measurements.

Abstract: In an overlay, U-TDOA-based, Wireless Location System, LMUs typically co-located with BTSs, are used to collect radio signaling both in the forward and reverse channels. Techniques are used to compensate for sparse LMU deployments where sections of the U-TDOA service area are uplink demodulation or downlink beacon discovery limited.

Abstract: A method and apparatus for position determination is provided using measurements from both Global Positioning System (GPS) receivers and terrestrial-based Uplink Time Difference of Arrival (UTDOA) receivers. The method involves the transformation of downlink satellite measurements into equivalent UTDOA measurements by computing comparable cross-correlation coefficients and time differences of arrival with respect to a UTDOA reference station. The method includes a weighting operation whereby the relative weights of the UTDOA measurements and the relative weights of the GPS measurements are adjusted based on a theoretical scaling followed by empirical adjustments. The method further involves the efficient computation and combining of metrics that are used to minimize the weighted error between candidate location solutions and the UTDOA and GPS measurements.

Abstract: A method and apparatus for position determination is provided using measurements from both Global Positioning System (GPS) receivers and terrestrial-based Uplink Time Difference of Arrival (UTDOA) receivers. The method involves the transformation of downlink satellite measurements into equivalent UTDOA measurements by computing comparable cross-correlation coefficients and time differences of arrival with respect to a UTDOA reference station. The method includes a weighting operation whereby the relative weights of the UTDOA measurements and the relative weights of the GPS measurements are adjusted based on a theoretical scaling followed by empirical adjustments. The method further involves the efficient computation and combining of metrics that are used to minimize the weighted error between candidate location solutions and the UTDOA and GPS measurements.

Abstract: In an overlay, U-TDOA-based, Wireless Location System, LMUs typically co-located with BTSs, are used to collect radio signaling both in the forward and reverse channels. Techniques are used to compensate for sparse LMU deployments where sections of the U-TDOA service area are uplink demodulation or downlink beacon discovery limited.

Abstract: In a network-based Wireless Location System (WLS), geographically distributed Location Measurement Units (LMUs) must be able to detect and use reverse channel (mobile to network) signals across multiple BTS coverage areas. By using Matched Replica correlation processing with the local and reference signals subdivided into discrete segments prior to correlation, the effects of mobile clock drift and Doppler shifts can be mitigated allowing for increased processing gain.

Abstract: Iterative geolocation of a stationary RF emitter through the use of TDOA may include the use of a single portable geolocation (e.g., TDOA) sensor, a pair of portable geolocation sensors and three of more portable geolocation sensors. Adding portable geolocation sensors to the iterative process reduces the constraints on the signals to be located as well as providing a reduction in the number of iterations required to obtain improved location accuracy.

Abstract: In a Wireless Location System (WLS) deployed in connection with a CDMA-based wireless communications system, Location Measurement Units are used to collect multi-path corrupted radio signaling for use in time difference of arrival (TDOA) and hybrid positioning methods. Signal processing techniques are used to enhance the WLS's ability to determine the minimally time-delayed multi-path component and thus increase the accuracy of the TDOA location in CDMA-based wireless communications systems. The signal processing includes a filtering technique for reducing the leading sidelobes of the cross-correlation function as well as a leading edge discovery procedure.

Abstract: In a network-based Wireless Location System (WLS), geographically distributed Location Measurement Units (LMUs) must be able to detect and use reverse channel (mobile to network) signals across multiple BTS coverage areas. By using Matched Replica correlation processing with the local and reference signals subdivided into discrete segments prior to correlation, the effects of mobile clock drift and Doppler shifts can be mitigated allowing for increased processing gain.

Abstract: A method and apparatus for position determination is provided using measurements from both Global Positioning System (GPS) receivers and terrestrial-based Uplink Time Difference of Arrival (UTDOA) receivers. The method involves the transformation of downlink satellite measurements into equivalent UTDOA measurements by computing comparable cross-correlation coefficients and time differences of arrival with respect to a UTDOA reference station. The method includes a weighting operation whereby the relative weights of the UTDOA measurements and the relative weights of the GPS measurements are adjusted based on a theoretical scaling followed by empirical adjustments. The method further involves the efficient computation and combining of metrics that are used to minimize the weighted error between candidate location solutions and the UTDOA and GPS measurements.

Abstract: In a Wireless Location System (WLS) deployed in connection with a CDMA-based wireless communications system, Location Measurement Units are used to collect multi-path corrupted radio signaling for use in time difference of arrival (TDOA) and hybrid positioning methods. Signal processing techniques are used to enhance the WLS's ability to determine the minimally time-delayed multi-path component and thus increase the accuracy of the TDOA location in CDMA-based wireless communications systems. The signal processing includes a filtering technique for reducing the leading sidelobes of the cross-correlation function as well as a leading edge discovery procedure.

Abstract: In an overlay, U-TDOA-based, Wireless Location System, LMUs typically co-located with BTSs, are used to collect radio signaling both in the forward and reverse channels. Techniques are used to compensate for sparse LMU deployments where sections of the U-TDOA service area are uplink demodulation or downlink beacon discovery limited.

Abstract: In an overlay, U-TDOA-based, Wireless Location System, LMUs typically co-located with BTSs, are used to collect radio signaling both in the forward and reverse channels. Techniques are used to compensate for sparse LMU deployments where sections of the U-TDOA service area are uplink demodulation or downlink beacon discovery limited.