High-sensitivity infrequent use of servers
US6559795B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Feb 19, 2002 |
| Grant date | May 6, 2003 |
| Priority date | — |
| Expiry date | Feb 19, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/235
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A navigation-satellite receiver depends on a network server to occasionally provide key pieces of information needed during its initialization. The navigation-satellite receiver critically maintains its position uncertainty, sigmaPos, to under 150-km. Therefore, at least every five minutes, the navigation-satellite receiver uses a network connection to download all the ephemeris information for all the operational SV's. The power-off time uncertainty, sigmaTime, is kept under one millisecond by running a real-time clock with a software-compensated crystal oscillator reference. Such information is instantly available at power-up to reduce the time necessary to produce a first fix when receiver signal levels are under −150 dbm even for the strongest SV.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.