Trueposition, Inc.

Rashidus S Mia

Robert J Anderson

Pete A Boyer

Matthew L Ward

Simon Issakov

Ronald Lefever

Edward Joseph Segall

Jeffrey Francis Bull

Pitchaiah Soma

Edward J Gander

Benjamin H Cohen

Robert Binion, Ii

Robert Ii Binion

In an overlay, network-based, wireless location system, LMUs typically co-located with BTSs are used to collect radio signaling both in the forward and reverse channels for use in TDOA and/or AOA positioning methods. Information broadcast from the radio network and by global satellite navigation system constellations can be received by the LMU and used to reduce the difficulty of initial system configuration and reconfiguration due to radio network changes.

Network-based location of mobile transmitters

In an overlay, network-based, wireless location system, passive network probes and Location Measurement Units, typically co-located with eNodeB's, are used to collect identity information and radio signaling both in the forward and reverse channels for use in power-based, timing-based and/or angle-based positioning methods in Long Term Evolution (LTE) and LTE-Advanced wireless communications networks.

Overlay network-based location of E-UTRAN devices

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. By using historical network and real-time data about the radio signal and/or radio channel, the segmentation and computation scheme may be optimized to reduce latency and enhance capacity while maximizing location accuracy.

Optimization of variable coherence integration for the location of weak signals

For Wireless Communications Networks (WCNs) that support soft handover, cooperator receiver selection for a TDOA, AOA, TDOA/AOA, or hybrid network-based or network-overlay Wireless Location System (WLS) must contend with one or more network base stations as a serving cell. When the active set contains more than one member, two techniques for determining a set of cooperating and demodulating receivers to use in the signal collection for location estimation is disclosed. In one embodiment, the active set members are constructively reduced to a single member that is used as a proxy serving cell. In another embodiment, the information contained in the active set membership is retained and a new set of demodulating and cooperator receivers are generated based on the entire membership of the active set.

Cooperating receiver selection for UMTS wireless location

In an overlay, network-based, Wireless Location System, LMUs typically co-located with BTSs, are used to collect uplink radio signaling for use in TOA, TDOA and/or AoA positioning methods. In a UMTS, the dual nature of the uplink allows for identification of the correct uplink signal even in the presence of co-channel interference from other UMTS mobile devices.

Identification and isolation of radio signals for a wireless location system

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 an overlay, network-based Wireless Location System, Location Measurement Units (LMUs) are used to collect radio signaling both in the forward and reverse channels for use in TDOA and/or AoA positioning methods. Information broadcast from the radio network and by global satellite navigation system constellations can be received by the LMUs and used to reduce the difficulty of initial system configuration and reconfiguration due to radio network changes.

Automated configuration of a wireless location system

In an LTE environment, the sensitivity of wireless location system receivers to narrowband transmissions, and the resolution of the receivers to wideband transmissions, may be improved by using tailored uplink transmission parameters, thereby increasing location accuracy and decreasing latency in developing a location. A first method for increasing TDOA performance allows LMU receivers to integrate TDOA and/or AOA measurements over longer periods of time, and thus achieve higher sensitivity. This method employs the Semi-Persistent-Scheduling (SPS) feature of the LTE communications system. A second method for increasing TDOA performance allows LMUs to collect signals over a broader bandwidth, and thus achieve higher resolution. This method uses the Sounding Reference Signal (SRS) feature of the LTE system. Using both the SPS and SRS functions for U-TDOA locations provides the benefit of increased sensitivity and greater resolution, thereby providing the potential for significantly improved location performance.

Network based location of mobile transmitters

A large volume of high accuracy location data is determined in many commercial wireless networks from location based services (LBS) and, in the United States, for E911. Uplink-Time-Difference-of-Arrival (UTDOA) and Assisted GPS (AGPS) are the predominant geolocation technologies providing these high accuracy locations. In the US alone over 10 million wireless subscribers are located every month because they dial the national emergency number '911' on their mobile phones. This rich set of location data provides an a priori distribution of the location of subscribers in the wireless network. All digital wireless communications networks have a mechanism for the subscribers to time synchronize their handsets to the network. This mechanism provides a band of ranges from the serving cell site to the handset. An a posteriori location estimate can be determined very quickly by considering the a priori distribution of callers in the range band that the current subscriber is in.

Location accuracy improvement using a priori probabilities

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.

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Phoenixville, PA, United States of America

Rashidus S Mia