GPS receiver

Abstract

A GPS receiver for shortening the time for locking onto a satellite includes a detector having an oscillator and plural reception channels, a navigational-message-receiver for analysing the message demodulated at the detector from a signal transmitted by a GPS satellite, a position-determiner for acquiring information of the receiver's position, a satellite-selector for selecting a receivable GPS satellite, a stationary-satellite-receiver for receiving a signal from a stationary satellite and measuring an offset frequency of the oscillator. The satellite selector sets a scanning range on a center frequency for each channel, the scanning range being formed by adding the Doppler-shift frequency to the offset frequency of the oscillator, the offset frequency being measured by the stationary-satellite-receiver. The stationary-satellite-receiver always receives signals from the stationary satellite to measure the offset frequency of the oscillator while a main power source is turned off. Therefore, the satellite selector immediately sets a correct frequency scanning range for the satellites upon turning on the main power source, thereby shortening the time for locking onto the satellite.

Dependencies are inferred from the claim text.