Position determination and message transfer system employing satellites and stored terrain map
US4965586A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1988 |
| Grant date | Oct 23, 1990 |
| Priority date | — |
| Expiry date | Oct 31, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S7/4091
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A radio position determation and message transfer system is implemented using a pair of satellites in geostationary orbit for replaying interrogation and replay signals between a ground station and a user-carried transceiver. The user portion is calculated based on the arrival times of replay signals received at the ground station via the two satellites, the known transmission time of the interrogation signal from the ground station, and the user's elevation on the surface of the earth. The elevation is derived from a stored terrain map providing local terrain elevations at a plurality of points of the earth's surface. The stored terrain map allows accurate position fixed to be obtained for surface users regardless of the deviation of the local terrain from the spherical or ellipsoidal model of the earth's surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.