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Abstract

A global positioning system (GPS) receiver apparatus using time and frequency information derived from a radio signal other than the GPS satellite signal for improving the time to first fix (TTFF). The GPS receiver apparatus includes a GPS signal receiver for receiving a GPS satellite signal modulated with data bits and a radio signal receiver for receiving a radio signal having a standard time and/or a standard frequency. The radio signal receiver provides standard time information to the GPS signal receiver. The GPS signal receiver uses the standard time information to resolve a GPS time for a time of arrival of a data bit. The GPS signal receiver includes a propagation delay calibrator for correcting the standard time for the travel time due to the path length for the radio signal. The radio signal receiver uses a reference clock signal provided by the GPS signal receiver for determining a frequency error between a frequency of the reference clock signal and the standard frequency. The GPS signal receiver uses the frequency error for pre-tuning to the carrier frequency of the GPS satellite signal.

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First Claim