GPS reception method and GPS receiver
First Claim
1. A GPS (Global Positioning System) reception method comprising the steps of:
- if a signal received from at least one GPS satellite is a synchronization hold state, an intermediate frequency carrier frequency of said signal is known, orbit information about said GPS satellite in the synchronization hold state is stored in a storage section, and a position and a current time of a receiver of said signal are known, computing an intermediate frequency carrier error as an error of said intermediate frequency carrier frequency on the basis of an oscillation frequency error of a reference oscillator of said receiver from said intermediate frequency carrier frequency of said signal, a position and a velocity of said GPS satellite in the synchronization hold state obtained from said orbit information and said current time, and said position of said receiver;
correcting said intermediate frequency carrier frequency by said computed intermediate frequency carrier error; and
acquiring signals received from other GPS satellites by use of said corrected intermediate frequency carrier frequency.
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Accused Products
Abstract
The present invention is intended to provide the synchronization acquisition of signals received from four GPS satellites in a short time and with stability by the time in which an intermediate frequency carrier error of good accuracy can be obtained at the time of power-on sequence, for example. Prerequisites are that at least one GPS satellite signal be in the synchronization hold state, its intermediate frequency carrier frequency be known, the orbit information about that GPS satellite be stored in a storage section, and the position and current time of the GPS receiver be known. Under these prerequisites, an intermediate frequency carrier error is computed from the intermediate frequency carrier frequency, the position and velocity of the GPS satellite obtained from the orbit information and the current time, and the position of the GPS receiver. The intermediate frequency carrier frequency is corrected by the computed intermediate frequency carrier error. The signals received from other GPS satellites are acquired by use of the corrected intermediate frequency carrier frequency.
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Citations
10 Claims
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1. A GPS (Global Positioning System) reception method comprising the steps of:
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if a signal received from at least one GPS satellite is a synchronization hold state, an intermediate frequency carrier frequency of said signal is known, orbit information about said GPS satellite in the synchronization hold state is stored in a storage section, and a position and a current time of a receiver of said signal are known, computing an intermediate frequency carrier error as an error of said intermediate frequency carrier frequency on the basis of an oscillation frequency error of a reference oscillator of said receiver from said intermediate frequency carrier frequency of said signal, a position and a velocity of said GPS satellite in the synchronization hold state obtained from said orbit information and said current time, and said position of said receiver;
correcting said intermediate frequency carrier frequency by said computed intermediate frequency carrier error; and
acquiring signals received from other GPS satellites by use of said corrected intermediate frequency carrier frequency. - View Dependent Claims (2, 3, 4, 5)
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6. A GPS receiver comprising:
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synchronization unit for synchronously acquiring a signal received from a GPS satellite by use of a given intermediate frequency carrier frequency and synchronously holding said acquired signal;
error computation unit for computing an intermediate frequency carrier error as an error of said intermediate frequency carrier frequency on the basis of an oscillation frequency error of a reference oscillator of said receiver from said intermediate frequency carrier frequency of said signal, a position and a velocity of said GPS satellite in the synchronization hold state obtained from said orbit information and said current time, and said position of said receiver if a signal received from at least one GPS satellite is a synchronization hold state, an intermediate frequency carrier frequency of said received signal is known, orbit information about said GPS satellite in the synchronization hold state is stored in a storage section, and a position and a current time of a receiver of said signal are known; and
correction unit for correcting said known intermediate frequency carrier frequency by said intermediate frequency carrier error computed by said error computation unit and supplying said corrected intermediate frequency carrier frequency to said synchronization unit. - View Dependent Claims (7, 8, 9, 10)
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Specification