E-OTD augmentation to U-TDOA location system
First Claim
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1. A method of locating a mobile appliance in a network overlay geolocation system having a plurality of base stations and a second plurality of wireless location sensors comprising:
- measuring the time of arrival (TOA) of a reverse signal from the mobile appliance at one or more of the second plurality of wireless location sensors (WLS) to create time difference of arrival (TDOA) measurements;
synchronizing the TDOA measurements of the reverse signal to a common time base and;
measuring the TOA of a forward channel from one or more of the plurality of base stations at the mobile appliance to create enhanced observed time difference (E-OTD) measurements; and
,determining a location estimate based on the TDOA measurements of the reverse signal and the E-OTD measurements.
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Abstract
A method for use in a wireless communication system with a network overlay geolocation system having a sparse deployment network in which base stations of the wireless communication system may or may not have a co-located wireless location sensor (WLS). The method uses U-TDOA measurements on the uplink (reverse) signal and E-OTD measurements on the downlink (forward) signals to estimate a location for a mobile appliance.
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Citations
31 Claims
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1. A method of locating a mobile appliance in a network overlay geolocation system having a plurality of base stations and a second plurality of wireless location sensors comprising:
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measuring the time of arrival (TOA) of a reverse signal from the mobile appliance at one or more of the second plurality of wireless location sensors (WLS) to create time difference of arrival (TDOA) measurements; synchronizing the TDOA measurements of the reverse signal to a common time base and; measuring the TOA of a forward channel from one or more of the plurality of base stations at the mobile appliance to create enhanced observed time difference (E-OTD) measurements; and
,determining a location estimate based on the TDOA measurements of the reverse signal and the E-OTD measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In a sparse geo-location network overlay system having a plurality of base stations and at least two wireless location sensors (WLS), wherein uplink signals are received by the at least two wireless location sensors and downlink signals are received by a mobile appliance, a method of locating the mobile appliance comprising:
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synchronizing the time of arrival of the uplink signal at the at least two wireless location sensors to a common clock; synchronizing the time of arrival of a downlink signal from one or more of the plurality of base stations at the mobile appliance to a second common clock; determining a location estimate based on the synchronized time of arrival of the downlink signal and the synchronized time of arrivals of the uplink signals. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for estimating the location of a mobile appliance operating in a wireless communication system comprising:
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measuring a time of arrival (TOA) of an uplink signal from the mobile appliance received at a plurality of wireless location sensors; determining a location estimate based at least in part on the TOA of the uplink signal; determining a location accuracy of the location estimate; comparing the location accuracy to a predetermined threshold; if the location accuracy is less that the predetermined threshold; measuring TOAs of downlink signals from a plurality of base stations at the mobile appliance; determining a second location estimate based at least in part on the TOAs of the downlink signals; determining a second location accuracy of the second location estimate; comparing the second location accuracy to the predetermined threshold; if the second location accuracy is less than the predetermined threshold; determining a third location estimate based at least in part on the uplink TOA and the downlink TOAs. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. In a wireless communication system having a sparse deployment of wireless location sensors wherein one or more base stations of the wireless communication system are not associated with a co-located wireless location sensor and wherein a geographic area served by the wireless communication system has a no location area, a method of determining the location of a mobile appliance comprising:
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determining if the mobile appliance is in the no location area as a function of time difference of arrival measurements of the reverse link, and; using enhanced observed time difference (E-OTD) measurements from the forward link and time of arrival (TOA) measurements from the reverse link to estimate the location of the mobile appliance. - View Dependent Claims (31)
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Specification