Location determination system and method using television broadcast signals
First Claim
1. A location determination system in which mobile units are in an area of at least three geographically fixed commercial television stations, each of which broadcasts television signals having horizontal sync, vertical sync and chrominance carrier burst sync signals, comprising,each mobile unit includes television receiver means including detection means for receiving television signals from a predetermined number of said television stations and measuring the times of arrival of at least one of said sync signals of each of said predetermined number of said television stations, respectively, and producing mobile unit signals corresponding thereto,a geographically fixed reference station having means for storing the frequency and geographic positions of said plurality of geographically fixed commercial television stations, means for receiving said television signals and measuring frequency and wavelength drift in said television signals from each of said geographically fixed television stations, respectively, and producing reference receiver correction signals corresponding thereto, andlocation determining means for receiving said mobile unit signals and said referenced receiver correction signals and determining the respective location of each said mobile units therefrom.
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Accused Products
Abstract
A location determination system and method in which mobile receiver units are in an area of at least three fixed commercial television stations, each television station broadcasting standard television signals, including horizontal, vertical and chrominance burst synchronizing signals. The standard television signals from selected ones of said television station are received at the mobile receiver unit and the times of arrival synchronizing signals of the selected ones of the television stations, respectively, are measured to produce mobile receiver unit signals corresponding thereto. A fixed reference station receives the television signals and detects any frequency and wavelength drift in the standard television signals from each of the fixed commercial television stations, respectively, and produces reference receiver correction signals. A processor, which may be at the reference station or at the mobile receiver units, computes the location of the mobile receiver units from the mobile receiver unit signals and the reference receiver correction signals.
253 Citations
11 Claims
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1. A location determination system in which mobile units are in an area of at least three geographically fixed commercial television stations, each of which broadcasts television signals having horizontal sync, vertical sync and chrominance carrier burst sync signals, comprising,
each mobile unit includes television receiver means including detection means for receiving television signals from a predetermined number of said television stations and measuring the times of arrival of at least one of said sync signals of each of said predetermined number of said television stations, respectively, and producing mobile unit signals corresponding thereto, a geographically fixed reference station having means for storing the frequency and geographic positions of said plurality of geographically fixed commercial television stations, means for receiving said television signals and measuring frequency and wavelength drift in said television signals from each of said geographically fixed television stations, respectively, and producing reference receiver correction signals corresponding thereto, and location determining means for receiving said mobile unit signals and said referenced receiver correction signals and determining the respective location of each said mobile units therefrom.
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8. A method of determining position of a mobile receiver within a geographical area having a plurality of commercial television (TV) broadcast stations and wherein the mobile receiver from time-to-time is in a building or other obstructed environment, comprising:
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providing said mobile receiver with means for receiving said plurality of commercial television (TV) broadcast signals having synchronizing signals therein, and detecting the relative times of arrival of said TV broadcast signals and producing mobile receiver signals corresponding thereto, receiving said TV broadcast signals at a geographically fixed reference station having stored thereat the geographic positions of said plurality of commercial TV broadcast stations and measuring the wavelength drift of each of said TV broadcast signals and producing reference receiver correction signals corresponding thereto, and determining the location of said mobile receiver from said mobile receiver signals and said reference receiver correction signals, including when said mobile receiver is in a building.
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9. A method of determining position of a mobile GPS receiver within a geographical area wherein the mobile GPS receiver from time-to-time is in a building or other obstructed environment, said mobile GPS receiver producing a GPS location signal, comprising:
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providing said mobile GPS receiver with means for receiving a plurality of commercial television (TV) broadcast signals having synchronizing signals therein, and detecting the relative times of arrival of said TV broadcast signals and producing mobile receiver TV location signal corresponding thereto, and logic means for selecting one of said GPS and TV location signals for presentation to a utilization device. - View Dependent Claims (10)
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11. A location finding navigation system for operating in an environment of GPS satellite signals and commercial television (TV) broadcast signals, comprising:
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first receiver means for receiving a predetermined number of GPS satellite signals and producing a GPS location signal, second receiver means for receiving a predetermined number of said TV broadcast signals and producing a TV location signal, and logic means connected to receive said location signal and selecting one of said location signals and presenting the selected location signal to a utilization device.
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Specification