Global positioning system tag system
US6611757B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 28, 2002 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | May 28, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.