Global positioning tag system and method
First Claim
1. A communications system for determining the position of an object, said system comprising:
- an interrogator remote from the object and including circuits that;
receive GPS signals from GPS satellites;
for one of the GPS satellites associated with the GPS signals, transmit pre-positioning data for the GPS satellite, including a pseudorandom noise (PRN) code number, a Doppler frequency offset and a code phase offset and a tracking signal including reference time and frequency information; and
determine a pseudorange associated with a received correlation snapshot, wherein the correlation snapshot comprises correlator sums and a range offset in chips; and
a transponder positioned on the object and including circuits that receive;
receive the pre-positioning data and the tracking signal;
collect RF samples of the GPS signals;
correlate the RF samples of the GPS signals against replicas of a GPS signal based on the PRN code number, the Doppler frequency offset, and the code phase offset in the prepositioning data and the reference time and frequency information in the tracking 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.
29 Citations
8 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 including circuits that; receive GPS signals from GPS satellites; for one of the GPS satellites associated with the GPS signals, transmit pre-positioning data for the GPS satellite, including a pseudorandom noise (PRN) code number, a Doppler frequency offset and a code phase offset and a tracking signal including reference time and frequency information; and determine a pseudorange associated with a received correlation snapshot, wherein the correlation snapshot comprises correlator sums and a range offset in chips; and a transponder positioned on the object and including circuits that receive; receive the pre-positioning data and the tracking signal; collect RF samples of the GPS signals; correlate the RF samples of the GPS signals against replicas of a GPS signal based on the PRN code number, the Doppler frequency offset, and the code phase offset in the prepositioning data and the reference time and frequency information in the tracking signal to produce the correlation snapshot; and transmit the correlation snapshot to the interrogator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification