System and method for location-finding using communication signals
First Claim
1. A receiver for receiving code division multiple access (CDMA) signals and determining the location of the receiver at least in part from the CDMA signals, comprising:
- an antenna for receiving transmitted CDMA signals;
a circuit for converting the frequency of the CDMA signals and digitizing the CDMA signals into in-phase and quadrature signals;
a variable length pseudorandom code generator to generate a pseudorandom code;
an early, late and true correlator to correlate the in-phase and quadrature signals with the pseudorandom code; and
a processor to compute the location of the receiver.
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Accused Products
Abstract
A method and system for location-determination of a mobile comprising of a receiver with a variable processor gain of up to 45.15 dB for detecting signals transmitted from transmitters that at a farther distance as well as from transmitters that are situated in sparsely populated areas. The system also includes a plurality of terrestrially deployed transmitters known as “pseudolites” that broadcast GPS-like signals, and in addition implementing the use of existing, available information from modulated signals, such as phase, amplitude and convolution with pseudorandom codes.
39 Citations
10 Claims
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1. A receiver for receiving code division multiple access (CDMA) signals and determining the location of the receiver at least in part from the CDMA signals, comprising:
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an antenna for receiving transmitted CDMA signals;
a circuit for converting the frequency of the CDMA signals and digitizing the CDMA signals into in-phase and quadrature signals;
a variable length pseudorandom code generator to generate a pseudorandom code;
an early, late and true correlator to correlate the in-phase and quadrature signals with the pseudorandom code; and
a processor to compute the location of the receiver. - View Dependent Claims (2)
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3. A method for locating an object utilizing CDMA and GPS signals comprising:
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receiving a GPS signals from a GPS signal transmitter at a receiver;
receiving a CDMA signal at the receiver;
digitizing the CDMA signal into in-phase and quadrature components;
locally generating a variable pseudorandom code (PN);
correlating the in-phase and quadrature components with early, true and late correlators;
multiplying the generated variable PN code with the early, true and late correlator; and
processing the product of the early, true and late correlator and the PN code to determine the receiver location. - View Dependent Claims (4, 5)
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6. An apparatus for locating an object utilizing CDMA and GPS signals comprising:
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a receiver for receiving a CDMA signal from a base station;
an antenna for receiving the CDMA signals;
an amplifier for amplifying the received signal;
a digitizer for digitizing the CDMA signal into in-phase and quadrature components;
a variable pseudo random code (PN) generator for locally generating a PN code;
a correlator for correlating the in-phase and quadrature components by early, true and late correlators;
a multiplier for multiplying the generated variable PN code with the early, true and late correlator; and
a processor for processing the product of the early, true and late correlator and the PN code to determine the location of the receiver. - View Dependent Claims (7, 8, 9, 10)
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Specification