Radio determination using satellites transmitting timing signals with correction by active range measurement
US4161730A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1977 |
| Grant date | Jul 17, 1979 |
| Priority date | — |
| Expiry date | Oct 17, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S2013/466
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The time-of-arrival of timing signals transmitted by two satellites is measured relative to a crystal clock, and an approximate position fix is computed for the ship or other object being located. Because of clock error the position fixes are displaced along a hyperbolic line of position. A two-way active range measurement through a third satellite or one timing signal satellite enables computation of an independently determined line of position, the true position fix being at its intersection with the hyperbolic line of position. The clock error is corrected and the method of position fixing from two timing satellites is repeated until the clock drift exceeds acceptable limits. A continuous navigation service and also position surveillance are realized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.