Method and apparatus for covariance matrix estimation in a weighted least-squares location solution
First Claim
1. In a wireless communication system comprising a fixed infrastructure in wireless communication with a plurality of mobile units, the fixed infrastructure comprising a location processor, a method for the location processor to estimate a location of a mobile unit of the plurality of mobile units, the method comprising steps of:
- determining M channel quality metrics corresponding to the mobile unit, wherein M≧
3;
determining M time of arrival variances based on the channel quality metrics;
determining M-1 time of arrival differential variances based on the time of arrival variances; and
determining a weighted least squares solution using the time of arrival differential variances to estimate the location of the mobile unit.
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Abstract
Signals exchanged between a fixed infrastructure (110-116) and a mobile unit (160) give rise to M channel quality metrics. The channel quality metrics are mapped, via predetermined relationships (501-503), in to M corresponding time of arrival variances, which in turn are used to derive M-1 time of arrival differential variances. A time of arrival differential weighting matrix including, in part, the time of arrival differential variances, is used to calculate a WLS solution, which solution is an estimate of a location of the mobile unit. This procedure may be implemented using an infrastructure-based location processor (130) operating in conjunction with the mobile unit, or may be performed by either the location processor or mobile unit alone.
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Citations
48 Claims
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1. In a wireless communication system comprising a fixed infrastructure in wireless communication with a plurality of mobile units, the fixed infrastructure comprising a location processor, a method for the location processor to estimate a location of a mobile unit of the plurality of mobile units, the method comprising steps of:
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determining M channel quality metrics corresponding to the mobile unit, wherein M≧
3;determining M time of arrival variances based on the channel quality metrics; determining M-1 time of arrival differential variances based on the time of arrival variances; and determining a weighted least squares solution using the time of arrival differential variances to estimate the location of the mobile unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. In a wireless communication system comprising a fixed infrastructure in wireless communication with a plurality of mobile units, the fixed infrastructure further comprising a plurality of geographically-diverse fixed transceivers and a location processor, a method for a mobile unit of the plurality of mobile units to estimate a location of the mobile unit, the method comprising steps of:
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receiving M signals from M transceivers of the plurality of geographically-diverse fixed transceivers, wherein each of the signals uniquely corresponds to one of the transceivers, and wherein M≧
3;determining M channel quality metrics, wherein each of the channel quality metrics uniquely corresponds to one of the signals; sending, to the location processor, the channel quality metrics; and receiving, from the location processor, the location of the mobile unit, wherein the location of the mobile unit is based on the channel quality metrics. - View Dependent Claims (15, 16, 17, 18, 19)
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20. In a wireless communication system comprising a fixed infrastructure in wireless communication with a plurality of mobile units, the fixed infrastructure further comprising a plurality of geographically-diverse fixed transceivers and a location processor in communication with the plurality of geographically-diverse fixed transceivers, a method for estimating a location of a mobile unit of the plurality of mobile units, the method comprising steps of:
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receiving, by M transceivers of the plurality of geographically diverse transceivers, M representations of a signal sent by the mobile unit, wherein each of the representations uniquely corresponds to one of the transceivers, and wherein M≧
3;determining, by the transceivers, M channel quality metrics, wherein each of the channel quality metrics uniquely corresponds to one of the representations; sending, from the transceivers to the location processor, the channel quality metrics; determining, by the location processor, M time of arrival variances based on the channel quality metrics, wherein each of the time of arrival variances uniquely corresponds to one of the channel quality metrics; determining, by the location processor, M-1 time of arrival differential variances based on the time of arrival variances; and determining, by the location processor, a weighted least squares solution using the time of arrival differential variances to estimate the location of the mobile unit. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. In a wireless communication system comprising a fixed infrastructure in wireless communication with a plurality of mobile units, the fixed infrastructure further comprising a plurality of geographically-diverse fixed transceivers, a method for a mobile unit of the plurality of mobile units to estimate a location of the mobile unit, the method comprising steps of:
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receiving M signals from M transceivers of the plurality of geographically-diverse fixed transceivers, wherein each of the signals uniquely corresponds to one of the transceivers, and wherein M≧
3;determining M channel quality metrics, wherein each of the channel quality metrics uniquely corresponds to one of the signals; determining M time of arrival variances based on the channel quality metrics, wherein each of the time of arrival variances uniquely corresponds to one of the channel quality metrics; determining M-1 time of arrival differential variances based on the time of arrival variances; and determining a weighted least squares solution using the time of arrival differential variances to estimate the location of the mobile unit. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A location processor comprising:
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a digital computing device; a memory coupled to the digital computing device, the memory having stored thereon executable instructions that, when executed by the digital computing device, cause the digital computing device to comprise; a variance determiner, responsive to M channel quality metrics corresponding to a mobile unit, that produces M time of arrival variances, wherein M≧
3;a differential variance determiner, responsive to the time of arrival variances, that produces M-1 time of arrival differential variances; and a location determiner, responsive to the time of arrival differential variances, that calculates a weighted least squares solution to estimate a location of the mobile unit.
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47. A mobile unit comprising:
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a receiver, responsive to M signals from M transceivers of a plurality of geographically-diverse fixed transceivers, that produces M channel quality metrics, wherein each of the signals and each of the channel quality metrics uniquely corresponds to one of the transceivers, and wherein M≧
3;a location processor, coupled to the receiver, comprising; a digital computing device; a memory coupled to the digital computing device, the memory having stored thereon executable instructions that, when executed by the digital computing device, cause the digital computing device to comprise; a variance determiner, responsive to the channel quality metrics, that produces M time of arrival variances; a differential variance determiner, responsive to the time of arrival variances, that produces M-1 time of arrival differential variances; and a location determiner, responsive to the time of arrival differential variances, that calculates a weighted least squares solution to estimate a location of the mobile unit.
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48. A communication system comprising:
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at least M geographically diverse transceivers that each receive a corresponding one of M representations of a signal sent by a mobile unit, and that each determine a channel quality metric for the corresponding one of the representations, wherein M≧
3;a location processor, coupled to the transceivers, comprising; a digital computing device; a memory coupled to the digital computing device, the memory having stored thereon executable instructions that, when executed by the digital computing device, cause the digital computing device to comprise; a variance determiner, responsive to the channel quality metrics, that produces M time of arrival variances; a differential variance determiner, responsive to the time of arrival variances, that produces M-1 time of arrival differential variances; and a location determiner, responsive to the time of arrival differential variances, that calculates a weighted least squares solution to estimate a location of the mobile unit.
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Specification