Geolocation method and apparatus for satellite based telecommunications system
US6020847A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1996 |
| Grant date | Feb 1, 2000 |
| Priority date | — |
| Expiry date | Apr 25, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/1855
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for determining the geolocation of a user terminal within a telecommunications system having a constellation of satellites which relay communications signals between earth stations and user terminals over preassigned channels. The method performs synchronization upon the telecommunications signals to calculate timing and frequency update information for the user terminals. The timing and frequency update information is also used within the earth station to calculate the geoposition of the user terminal. To do so, the earth station calculates a distance between the satellite and a user terminal based on the corresponding propagation time therebetween which is obtained from the timing information. Once the satellite to user terminal distance is obtained, a range solution line may be calculated therefrom. In addition, the frequency update information is used to calculate a Doppler solution line upon which the user terminal is positioned. Thereafter, the range and Doppler solution lines are combined to obtain points of intersection therebetween. These points of intersection represent potential geolocations of the user terminal. The earth station discriminates between these int…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.