Patent ID: 7791534

Claim:
A global navigation satellite system (GNSS) receiver, comprising: an always-on real time clock to maintain an RTC time having RTC time ticks of a certain time period; an RTC calibrator to determine a time fraction of said certain time period while the receiver has power on wherein said time fraction is a difference at a one of said RTC time ticks between GNSS-based time at a fine resolution and said GNSS-based time at a time resolution of said certain time period; and to combine said time fraction with a turn on said RTC time corresponding to turn-on of the receiver at a one of said time ticks after a power down time of the receiver to calibrate said turn-on RTC time when the receiver is switched from power off to power on; and a signal navigation processor to use said calibrated RTC time to assist in determination of a GNSS-based fix.