Signature matching for location determination in wireless communication systems
First Claim
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1. In a system for wireless transmitter location finding, a method for calculating a set of likely locations of a transmitter, the method comprising:
- (a) measuring at a base station a signal covariance R associated with the transmitter;
(b) evaluating a function B(θ
) that measures an energy of the signal covariance R in an angular direction θ
relative to the base station, wherein the evaluation of B(θ
) uses an antenna array vector a(θ
);
(c) calculating a distance G between the function B(θ
) and a function Bk (θ
), where Bk (θ
) measures an energy of a calibrated signal covariance Rk in the angular direction θ
relative to the base station, wherein the evaluation of B(θ
) uses an antenna array vector a(θ
), and wherein Rk is a calibrated signal covariance associated with a location index k; and
(d) selecting a set of location indices k such that the distance G between B and Bk is small.
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Abstract
A method and apparatus for wireless location finding determines a set of likely locations from a signal covariance matrix R, a set of array calibration vectors {a(θ)}, and a set of calibrated signal covariance matrices {Rk } corresponding to calibrated locations. From these quantities, an angular energy distribution function B(θ) is calculated from R and a(θ), and compared to a set of calibrated angular energy distribution functions B1 (θ), . . . , BN (θ) corresponding to the set of calibrated signal covariance matrices R1, . . . , RN. The function B(θ) is then compared with each of the calibrated functions B1 (θ), . . . , BN (θ) to determine those calibrated functions that most closely match the calculated function B(θ). From these calculations a set of likely locations is then determined.
159 Citations
10 Claims
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1. In a system for wireless transmitter location finding, a method for calculating a set of likely locations of a transmitter, the method comprising:
-
(a) measuring at a base station a signal covariance R associated with the transmitter; (b) evaluating a function B(θ
) that measures an energy of the signal covariance R in an angular direction θ
relative to the base station, wherein the evaluation of B(θ
) uses an antenna array vector a(θ
);(c) calculating a distance G between the function B(θ
) and a function Bk (θ
), where Bk (θ
) measures an energy of a calibrated signal covariance Rk in the angular direction θ
relative to the base station, wherein the evaluation of B(θ
) uses an antenna array vector a(θ
), and wherein Rk is a calibrated signal covariance associated with a location index k; and(d) selecting a set of location indices k such that the distance G between B and Bk is small. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for location finding in a wireless communications system, the apparatus comprising:
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(a) a multichannel receiver for coherently receiving signals originating from a transmitter; (b) a signal processor connected to the multichannel receiver for determining a set of likely locations from the received signals; and (c) a memory device accessible by the processor for storing signal signature calibration data; wherein the signal processor determines the set of likely locations from the received signals in accordance with the following procedure; i) determining a signal covariance R from the signals received at the multichannel receiver; ii) evaluating a function B(θ
) that measures an energy of the signal covariance R in an angular direction θ
relative to the apparatus, wherein the evaluation of B(θ
) uses an antenna array vector a(θ
);iii) calculating a distance G between the function B(θ
) and a function Bk (θ
), where Bk (θ
) measures an energy of a calibrated signal covariance Rk in the angular direction θ
relative to the apparatus, wherein an evaluation of B(θ
) uses an antenna array vector a(θ
), and wherein Rk is a calibrated signal covariance associated with a location index k; andiv) selecting a set of location indices k such that the distance G between B and Bk is small. - View Dependent Claims (7, 8, 9, 10)
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Current AssigneeMotorola, Inc. (Motorola Solutions, Inc.)
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Original AssigneeUS Wireless Corp. (Vontier Corp.)
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InventorsWax, Mati, Hilsenrath, Oliver
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Primary Examiner(s)Bost, Dwayne D.
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Assistant Examiner(s)CONTEE, JOY KIMBERLY
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Application NumberUS09/115,460Time in Patent Office777 DaysField of Search455/456, 455/457, 455/67.1, 455/115, 455/560, 455/63, 370/334, 370/335, 370/342, 370/310, 342/457, 342/372, 342/387, 342/458US Class Current455/456.1CPC Class CodesG01C 21/26 specially adapted for navig...G01S 1/022 Means for monitoring or cal...G01S 1/026 of associated receiversG01S 5/021 Calibration, monitoring or ...G01S 5/0218 Multipath in signal receptionG01S 5/02521 using a radio-mapH04L 67/04 specially adapted for termi...H04L 67/51 Discovery or management the...H04L 67/52 specially adapted for the l...H04L 67/535 Tracking the activity of th...H04L 69/329 in the application layer [O...H04L 9/40 Network security protocolsH04W 4/02 Services making use of loca...H04W 4/023 using mutual or relative lo...H04W 4/029 Location-based management o...H04W 4/20 Services signaling; Auxilia...H04W 64/00 Locating users or terminals...
