Global positioning system tag system
First Claim
1. A communications system for determining the position of an object, said system comprising:
- an interrogator remote from the object and adapted to;
receive GPS signals from GPS satellites;
transmit pre-positioning data for each of the received GPS signals including the pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset and a tracking signal including reference time and frequency information; and
determine the pseudorange associated with at least one of the GPS signals using a subsequently received correlation snapshot; and
a transponder positioned on the object and adapted to;
receive the pre-positioning data and tracking signal;
collect RF samples of at least one of the GPS signals associated with one of the PRN code numbers;
correlate the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot; and
transmit the correlation snapshot to the interrogator.
1 Assignment
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Accused Products
Abstract
A system for determining the location of an object includes an interrogator remote from the object and a transponder located at the object. The interrogator receives GPS signals and transmits pre-positioning data and a tracking signal to the transponder. The pre-positioning data includes pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset while the tracking signal includes reference time and frequency information. The transponder collects RF samples of at least one of the GPS signals associated with one of the PRN code numbers and correlates the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot. The transponder transmits the correlation snapshot to the interrogator and the interrogator determines the pseudorange associated with the GPS signal using the correlation snapshot.
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Citations
19 Claims
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1. A communications system for determining the position of an object, said system comprising:
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an interrogator remote from the object and adapted to;
receive GPS signals from GPS satellites;
transmit pre-positioning data for each of the received GPS signals including the pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset and a tracking signal including reference time and frequency information; and
determine the pseudorange associated with at least one of the GPS signals using a subsequently received correlation snapshot; and
a transponder positioned on the object and adapted to;
receive the pre-positioning data and tracking signal;
collect RF samples of at least one of the GPS signals associated with one of the PRN code numbers;
correlate the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot; and
transmit the correlation snapshot to the interrogator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 15, 16, 17, 18, 19)
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10. A method of determining the position of an object comprising:
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receiving, at a location remote from the object, GPS signals from GPS satellites;
transmitting, at the location remote from the object, pre-positioning data for each of the received GPS signals including the pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset and a tracking signal including reference time and frequency information;
receiving, at the object, the pre-positioning data and tracking signal;
collecting, at the object, RF samples of at least one of the GPS signals associated with one of the PRN code numbers;
correlating, at the object, the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce a correlation snapshot;
transmitting, at the object, the correlation snapshot;
receiving, at the location remote from the object, the correlation snapshot; and
determining, at the location remote from the object, the pseudorange associated with at least one of the GPS signals using the correlation snapshot. - View Dependent Claims (11, 12, 13)
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14. A transponder adapted to be associated with an object and for use in providing data to an interrogator remote from the object, the data for use in determining the location of the object, said transponder comprising:
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a transceiver adapted to receive signals from the interrogator, the signals including pre-positioning data for GPS signals received by the interrogator including the pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset and a tracking signal including reference time and frequency information; and
a plurality of correlators adapted to collect RF samples of at least one of the GPS signals associated with one of the PRN code numbers and correlate the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce a correlation snapshot;
wherein the transceiver is further adapted to transmit the correlation snapshot to the interrogator.
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Specification