Trueposition, Inc.

Pete A Boyer

Rashidus S Mia

Robert J Anderson

Pitchaiah Soma

Ronald Lefever

Edward Joseph Segall

Matthew L Ward

Jeffrey Francis Bull

Disclosed is a method for processing readily available radio network, timing and power information about cellular networks and typical measurements made by the mobile device and network. A probabilistic method is disclosed that uses both time (i.e., range) and power differences with known downlink transmitter antenna characteristics to locate mobiles with accuracy better than cell-ID with ranging, with high capacity, and without the need for field calibration.

Time and power based wireless location and method of selecting location estimate solution

A method for combining a plurality of individual location measurements, for use in a wireless location system, includes the following steps. A quality metric for a single location estimate is computed along with individual quality metrics and individual weightings for each individual location measurement. In addition, weighting operations incorporating a quality metric for a single location are performed, and the measurement weights are adjusted based on information about co-location groups; and a decision metric and common bias accounting for multiple reference measurements are computed.

Combination of multiple baselines for location estimation

In a wireless location system configured to use a baseline correlation method, an iterative approach to increasing location accuracy is disclosed. The quality of received signals is ordered from highest to lowest and used to calculate an initial location. The initial location is modified using the lower quality signals as constrained by the time and frequency deviation from the initial location and velocity estimate.

Position estimation through iterative inclusion of measurement data

Time and power based wireless location detection system

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.

Hybrid GNSS and TDOA wireless location system

A method for improving the results of radio location systems that incorporate weighted least squares optimization generalizes the weighted least squares method by using maximum a posteriori (MAP) probability metrics to incorporate characteristics of the specific positioning problem (e.g., UTDOA). Weighted least squares methods are typically used by TDOA and related location systems including TDOA/AOA and TDOA/GPS hybrid systems. The incorporated characteristics include empirical information about TDOA errors and the probability distribution of the mobile position relative to other network elements. A technique is provided for modeling the TDOA error distribution and the a priori mobile position. A method for computing a MAP decision metric is provided using the new probability distribution models. Testing with field data shows that this method yields significant improvement over existing weighted least squares methods.

Method for position estimation using generalized error distributions

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. This is done efficiently in two dimensions for UTDOA and in three dimensions for GPS measurements by increasing the complexity of searching operations as the optimal location solution is approached. A technique is also described that improves upon a particular location solution by changing the measurement weightings using criteria specific to GPS and UTDOA.

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Chesterbrook, PA, United States of America

Pete A Boyer