GNSS time fraction calibration of a real time clock
US7791534B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 2009 |
| Grant date | Sep 7, 2010 |
| Priority date | — |
| Expiry date | Mar 13, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/23
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A generic navigation satellite system (GNSS) signal receiver having a fast time to first fix by calibrating a low power always-on real time clock (RTC). The receiver includes an RTC calibrator having a fraction calculator. The RTC calibrator may also include a time expander. Before the receiver is powered off, the fraction calculator uses the fine resolution of GNSS time for determining a time fraction for RTC time. When the receiver is powered back on, the time expander uses an estimate of RTC time drift during the time that GNSS receiver had power off and the time fraction for calibrating and increasing the resolution of the RTC time for an RTC time tick. A signal navigation processor uses the calibrated RTC time for assisting a first fix with code phase search, integration time periods, resolution of epoch integer and/or location-in-space of GPS satellites.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.