System and method for CDMA geolocation
First Claim
1. A method of determining the location of a first mobile appliance in a wireless communication system, comprising the steps of:
- (a) providing a reverse pilot channel;
(b) transmitting from said first mobile appliance a reverse pilot signal over said reverse pilot channel wherein said reverse pilot signal is different from reverse pilot signal emitted by other mobile appliances;
(c) recieving said first mobile appliance reverse pilot signal at a wireless location sensor;
(d) determining an attribute of said first mobile appliance reverse pilot signal at said wireless location sensor; and
,(e) determining the location of said first mobile appliance as a function of said attribute,wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, and wherein said first mobile appliance reverse pilot signal is quadrature scrambled by a pseudo-random sequence that is a function of the ESN of said first mobile appliance.
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Accused Products
Abstract
A system and method is disclosed for determining the location of a mobile appliance using the reverse pilot channel provided in CDMA 2000 communication systems to determine an attribute (e.g., time of arrival, angle of arrival, time difference of arrival, received power level) of a reverse pilot signal at one or more wireless location sensors. A network overlay of wireless location sensors monitors the reverse pilot channel for a target mobile'"'"'s reverse pilot signal. The monitored signal may be compared to a reference signal to determine a correlation and thereby determine an attribute of the target mobile'"'"'s reverse pilot signal. The method may be performed independently from the communication system and without requiring retrieval of information bits from the mobile appliance. The reference signal may be generated from the unique long spreading code mask of the target mobile appliance which is typically a function of the ESN of the target mobile appliance.
65 Citations
72 Claims
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1. A method of determining the location of a first mobile appliance in a wireless communication system, comprising the steps of:
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(a) providing a reverse pilot channel; (b) transmitting from said first mobile appliance a reverse pilot signal over said reverse pilot channel wherein said reverse pilot signal is different from reverse pilot signal emitted by other mobile appliances; (c) recieving said first mobile appliance reverse pilot signal at a wireless location sensor; (d) determining an attribute of said first mobile appliance reverse pilot signal at said wireless location sensor; and
,(e) determining the location of said first mobile appliance as a function of said attribute, wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, and wherein said first mobile appliance reverse pilot signal is quadrature scrambled by a pseudo-random sequence that is a function of the ESN of said first mobile appliance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. The method of determining the location of a first mobile appliance in a wireless communication system, comprising the steps of:
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(a) providing a reverse pilot channel; (b) transmitting from said first mobile appliance a reverse pilot signal over said reverse pilot channel wherein said reverse pilot signal is different from reverse pilot signals emitted by other mobile appliances; (c) receiving said first mobile appliance reverse pilot signal at a wireless location sensor, said receiving comprising; (c)(i) providing a reference signal at said wireless location sensor; and (c)(ii) detecting the presence of the first mobile appliance reverse pilot signal by cross-correlating in the time domain the received reverse pilot signal with said reference signal, (d) determining an attribute of said first mobile appliance reverse pilot signal at said wireless location sensor; and
,(e) determining the location of said first mobile appliance as a function of said attribute, wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, and wherein step (c)(i) comprises the steps of; (c)(i)(A) generating a sequence of zeros; (c)(i)(B) generating a long spreading code using the long code mask of said first mobile appliance; and (c)(i)(C) applying said long spreading code to an I channed short code and applying said long spreading code to a Q channel short code.
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13. A method of determining the location of a first mobile appliance in a wireless communication system, comprising the steps of:
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(a) providing a reverse pilot channel; (b) transmitting from said first mobile appliance a reverse pilot signal over said reverse pilot channel wherein said reverse pilot signal is different from reverse pilot signals emitted by other mobile appliances; (c) receiving said first mobile appliance reverse pilot signal at a wireless location sensor; (d) determining an attribute of said first mobile appliance reverse pilot signal a said wireless location sensor; and
,(e) determining the location of said first mobile appliance as a function of said attribute, wherein the reverse pilot signal of each mobile appliance is a pseudo-random sequence that is substantially orthogonal to the pseudo-random sequence generated by each of the other mobile appliances. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of determining the location of a first mobile appliance in a wireless communication system, comprising the steps of:
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(a) providing a reverse pilot channel; (b) transmitting from said first mobile appliance a reverse pilot signal over said reverse pilot channel wherein said reverse pilot signal is different from reverse pilot signals emitted by other mobile appliances; (c) receiving said first mobile appliance reverse pilot signal at a wireless location sensor including the steps of (c)(i) providing a reference signal at said wireless location sensor by generating a sequence of zeros, generating a long spreading code using the long code mask of said first mobile appliance, and applying said long spreading code to an I channel short code and applying said long spreading code to a Q channel short code; and (c)(ii) detecting the presence of the first mobile appliance reverse pilot signal by cross-correlating in the time domain the received reverse pilot signal with said reference signal; (d) determining an attribute of said first mobile appliance reverse pilot signal a said wireless location sensor; and
,(e) determining the location of said first mobile appliance as a function of said attribute. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. The method for estimating the location of a mobile appliance in a wireless communication system including at least one base station and a plurality of geolocation receiver sites, comprising the steps of:
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transmitting from said mobile appliance a known spread spectrum sequence for establishing synchronization between said mobile appliance and said at least one base station; receiving said sequence at ones of said plural geolocation receiver sites; cross-correlating in the time domain and the frequency domain the received sequence with a reference sequence to thereby determine an attribute of said receiced sequence at said ones of said plural geolocation receiver sites; and
,estimating the location of the mobile appliance as a function of said attribute, wherein the known spread spectrum sequence of the mobile appliance is a pseudo-random sequence that is substantially orthogonal to the pseudo-random sequence generated by other mobile appliances. - View Dependent Claims (35, 36, 37, 38, 39)
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40. A method for estimating the location of a mobile appliance in a wireless communication system including at least one base station and a plurality of geolocation receiver sites, comprising the steps of:
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transmitting from said mobile appliance a known spread spectrum sequence for establishing synchronization between said mobile appliance and said at least one base station; receiving said sequence at ones of said plural geolocation receiver sites including the steps of providing a reference sequence by generating a sequence of zeros, generating a long spreading code using the long code mask of said mobile appliance, and applying said long spreading code to an I channel short code and applying said long spreading code to a Q channel short code; and detecting cross-correlating in the time domain and the frequency domain the received sequence with the reference sequence to thereby determine an attribute of said received sequence at said ones of said plural geolocation receiver sites; and
,estimating the location of the mobile appliance as a function of said attribute. - View Dependent Claims (41, 42, 43, 44, 45)
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46. A system for estimating the location of a first mobile appliance, comprising:
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said first mobile appliance including means for emitting a reverse pilot signal different from pilot signals emitted by other mobile appliances; at least one wireless location sensor including means for receiving said first mobile appliance reverse pilot signal; and a geolocation control server operatively connected to said at least one wireless location sensor for determining an attribute of said received reverse pilot signal and estimating the location of said first mobile appliance as a function of said attribute, wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, wherein said first mobile appliance is operating in a wireless communication system having at least one base station for communicating with said mobile appliance, and where said reverse pilot signal emitted from said first mobile appliance is used by said at least one base station to coherently demodulate a traffic signal emitted by said first mobile appliance. - View Dependent Claims (47, 48, 49, 50, 51, 52)
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53. A system for estimating the location of a first mobile appliance, comprising:
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said first mobile appliance including means for emitting a reverse pilot signal different from pilot signals emitted by other mobile appliances; at least one wireless location sensor including means for receiving said first mobile appliance reverse pilot signal; and a geolocation control server operatively connected to said at least one wireless location sensor for determining an attribute of said received reverse pilot signal and estimating the location of said first mobile appliance as a function of said attribute, wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, and wherein said reverse pilot signal emitted from said first mobile appliance is generated as a function of a long spreading code for said first mobile appliance.
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54. A system for estimating the location of a first mobile appliance, comprising:
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said first mobile appliance including means for emitting a reverse pilot signal different from pilot signals emitted by other mobile appliances;
at least one wireless location sensor including means for receiving said first mobile appliance reverse pilot signal; anda geolocation control server operatively connected to said at least one wireless location sensor for determining an attribute of said received reverse pilot signal and estimating the location of said first mobile appliance as a function of said attribute, wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, and wherein said geolocation control server includes; a reference signal generator for generating a reference signal; a cross-correlation or ambiguity function device for determining said attribute of said received reverse pilot signal; and a location estimator for estimating the location of said first mobile appliance as a function of said attribute. - View Dependent Claims (55)
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56. A system for estimating the location of a first mobile appliance, comprising:
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said mobile appliance including means for emitting a reverse pilot signal different from pilot signals emitted by other mobile appliances; at least one wireless location sensor including means for receiving said first mobile appliance reverse pilot signal; and a geolocation control server operatively connected to said at least one wireless location sensor for determining an attribute of said received reverse pilot signal and estimating the location of said first mobile appliance as a function of said attribute, wherein said first mobile appliance reverse pilot signal is a digital signal generated from an information bit data sequence of zeros, and wherein the location of the first mobile appliance is determined independent of the state of said first mobile appliance.
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57. A system for estimating the location of a first mobile appliance, comprising:
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said first mobile appliance including means for emitting a reverse pilot signal different from pilot signals emitted by other mobile appliances; at least one wireless location sensor including means for receiving said first mobile appliance reverse pilot signal; and a geolocation control server operatively connected to said at least one wireless location sensor for determining an attribute of said received reverse pilot signal and estimating the location of said first mobile appliance as a function of said attribute, wherein the reverse pilot signal of each mobile appliance is a pseudo-random sequence that is substantially orthogonal to the pseudo-random sequence generated by each of the other mobile appliances. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A system for estimating the location of a first mobile appliance, comprising:
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said first mobile appliance including means for emitting a known spread spectrum sequence for establishing synchronization between said mobile appliance and said at least one base station; plural geolocation receiver sites including means for receiving said sequence; and a geolocation control server operatively connected to said at least one receiver site for cross-correlating in the time domain and the frequency domain the received sequence with a reference sequence to thereby determine an attribute of said received sequence at said ones of said plural geolocation receiver sites and estimating the location of said mobile appliance as a function of said attribute wherein said mobile appliance spread spectrum sequence is a digital signal generated from an information bit data sequence of zeros.
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72. A location system for estimating the location of a first mobile appliance, comprising:
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said first mobile appliance including means for emitting a known spread spectrum sequence for establishing synchronization between said mobile appliance and said at least one base station; plural geolocation receiver sites including means for receiving said sequence; and a geolocation control server operatively connected to said at least one receiver site for cross-correlating in the time domain and the frequency domain the received sequence with a reference sequence to thereby determine an attribute of said received sequence at said ones of said plural geolocation receiver sites and estimating the location of said mobile appliance as a function of said attribute wherein the known spread spectrum sequence of the mobile appliance is a pseudo-random sequence that is substantially orthogonal to the pseudo-random sequence generated by other mobile appliances.
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Specification