Cellular terminal location using GPS signals in the cellular band
First Claim
1. A position location system for determining a geographic position comprising:
- a plurality of cellular network base stations positioned at predetermined locations; and
a communications network that communicates with said plurality of cellular network base stations, wherein at least one of said plurality of cellular network base stations comprises a generator that generates a global positioning system pseudosatellite signal independent of receiving global positioning system satellite signals.
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Accused Products
Abstract
Aspects of global positioning system (GPS) technology and cellular technology are combined in order to provide an effective and efficient position location system. In a first aspect of the invention, a cellular network is utilized to collect differential GPS error correction data, which is forwarded to a mobile terminal over the cellular network. The mobile terminal receives this data, along with GPS pseudoranges using a GPS receiver, and calculates its position using this information. According to a second aspect, when the requisite number of GPS satellites are not in view of the mobile terminal, then a GPS pseudosatellite signal, broadcast from a base station of the cellular network, is received by the mobile terminal and processed as a substitute for the missing GPS satellite signal. A third aspect involves calculating position using GPS when the requisite number of GPS satellites are in view of a GPS receiver, but when the requisite number of GPS satellites are not in view of the GPS receiver, then position is calculated using the cellular network infrastructure. When the requisite number of GPS satellites come back into view of the GPS receiver, then position is again calculated using GPS. A fourth aspect involves using cellular signals already being transmitted from base stations to terminals in a cellular network to calculate a round trip delay, from which a distance calculation between the base station and the terminal can be made. This distance calculation substitutes for a missing GPS satellite signal.
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Citations
26 Claims
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1. A position location system for determining a geographic position comprising:
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a plurality of cellular network base stations positioned at predetermined locations; and
a communications network that communicates with said plurality of cellular network base stations, wherein at least one of said plurality of cellular network base stations comprises a generator that generates a global positioning system pseudosatellite signal independent of receiving global positioning system satellite signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A position location system for determining a geographic position comprising:
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a cellular antenna that receives a cellular signal having a frequency in a cellular frequency band, wherein said cellular signal contains global positioning system pseudosatellite data;
a first converter connected to said cellular antenna, wherein said first converter converts said received cellular signal into a first intermediate frequency signal having a first frequency;
a global positioning system receiver antenna that receives global positioning system satellite signals having frequencies in a satellite frequency band from a plurality of global positioning system satellites;
a second converter connected to said global positioning system receiver antenna, wherein said second converter converts said received global positioning system satellite signals into a second intermediate frequency signal having a second frequency, wherein said first frequency of said first intermediate frequency signal is substantially equal to said second frequency of said second intermediate frequency signal;
a selector connected to said first converter and to said second converter, wherein said selector selects one of said first intermediate frequency signal and said second intermediate frequency signal; and
a control processing unit connected to said selector, said control processing unit configured to utilize said first intermediate signal and said second intermediate signal when a requisite number of global positioning system satellites are not in view of the global positioning system receiver antenna, to calculate global positioning system pseudoranges. - View Dependent Claims (10, 11, 12, 13)
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14. A method for determining a geographic position of a mobile terminal comprising the steps of:
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receiving global positioning system satellite signals having frequencies in a satellite frequency band at the mobile terminal from a plurality of global positioning system satellites that are in view of the mobile terminal;
converting said global positioning system satellite signals into a first intermediate frequency signal;
receiving a cellular signal having a frequency in a cellular frequency band at the mobile terminal, wherein said cellular signal contains global positioning system pseudosatellite data;
converting said cellular signal into a second intermediate frequency signal; and
calculating the geographic position using both said first intermediate frequency signal and said second intermediate frequency signal when a requisite number of global positioning system satellites are not in view of the mobile terminal. - View Dependent Claims (15, 16)
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17. A method for determining a geographic position of a mobile terminal comprising the steps of:
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receiving global positioning system satellite signals having frequencies in a satellite frequency band at the mobile terminal from a plurality of global positioning system satellites that are in view of the mobile terminal;
receiving a cellular signal having a frequency in a cellular frequency band at the mobile terminal, calculating a cellular distance measurement representing a distance between the mobile terminal and a cellular network base station using said cellular signal;
calculating the position of the mobile terminal using said received global positioning system signals when a requisite number of global positioning system satellites are in view of the mobile terminal; and
calculating the position of the mobile terminal using said received global positioning system signals and the cellular distance measurement when the requisite number of global positioning system satellites are not in view of the mobile terminal. - View Dependent Claims (18, 19, 20, 21)
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22. A method for determining a geographic position of a mobile terminal comprising the steps of:
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receiving global positioning system satellite signals having frequencies in a satellite frequency band at the mobile terminal from a plurality of global positioning system satellites that are in view of the mobile terminal;
receiving a cellular signal having a frequency in a cellular frequency band at the mobile terminal, calculating a cellular distance measurement representing a distance between the mobile terminal and a cellular network base station using said cellular signal;
correcting said cellular distance measurement using a cellular correction term, to obtain a corrected cellular distance measurement;
calculating the position of the mobile terminal using said received global positioning system signals when a requisite number of global positioning system satellites are in view of the mobile terminal; and
calculating the position of the mobile terminal using said received global positioning system signals and said corrected cellular distance measurement when the requisite number of global positioning system satellites are not in view of the mobile terminal. - View Dependent Claims (23, 24, 25, 26)
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Specification