Method and apparatus for self-calibration and adaptive temperature compensation in GPS receivers
US7459984B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 2005 |
| Grant date | Dec 2, 2008 |
| Priority date | — |
| Expiry date | Jul 23, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/235
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention provides a method and apparatus to optimally estimate and adaptively compensate the temperature-induced frequency drift of a crystal oscillator in a navigational signal receiver. A Read-Write memory encodes two tables, one for looking up frequency drift values versus temperature readings and another one for valid data confirmation on the first table. The initially empty look-up table is gradually populated with frequency drift values while the receiver computes the frequency drift along with its position. During initial start of the receiver or re-acquisition of satellite signals, the stored frequency drift value corresponding to the current temperature is used. If no valid frequency drift value is available, the frequency drift value is computed based on the existing frequency drift values in the table. This invention reduces the Time-To-First-Fix (TTFF) of the receiver and enables the receiver to self-calibrate, thus no additional factory calibration would be necessary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.