Frequency aiding method and system for navigation satellite receiver with crystal oscillator frequency hysteresis
US7956804B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 2008 |
| Grant date | Jun 7, 2011 |
| Priority date | — |
| Expiry date | Aug 19, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/25
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for estimating oscillator signal variation due to temperature and for providing an estimated frequency to a GPS receiver in order to assist the GPS receiver to acquire the signals quickly is disclosed. A temperature sensor is closely thermally coupled with the crystal oscillator in the GPS receiver and during GPS tracking mode, when the error in the oscillator signal is known with precision, outer bounds of TCXO frequency at given temperatures are maintained, which may correspond to rising and falling temperature conditions. During acquisition mode, an estimated frequency value is provided to the GPS receiver based on a determined average of these bounds. Optionally, an uncertainty factor associated with the frequency estimated may also be provided. The two bounds take into account the hysteresis effects of the oscillator signal drift due to temperature so that a more accurate initial frequency estimate can be provided to the GPS receiver, thus reducing its average time to first fix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.