GPS receiver apparatus and receiving method
First Claim
1. A GPS receiver comprising:
- a frequency conversion means for converting a high-frequency GPS signal into an intermediate frequency GPS signal, wherein the high-frequency GPS signal is transmitted as transmission data from an artificial satellite by modulating a carrier wave through a signal spectrum-spread by a spread code;
a synchronization hold means for obtaining the transmission data by receiving the intermediate frequency GPS signal supplied from the frequency conversion means and acquiring and holding synchronization of the carrier wave and phase synchronization of the spread code;
a control means for controlling repetition of an intermittent operation which operates the synchronization hold means to obtain the transmission data, then stops operating the synchronization hold means, and again operates the synchronization hold means after lapse of a specified time by using, as initial values, a carrier wave frequency and a spread code phase valid for the most recent stop condition; and
a positioning operation means for performing a positioning operation by using the transmission data obtained through the synchronization hold means and finding and outputting positioning information indicative of a current position.
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Accused Products
Abstract
A GPS receiver can periodically obtain range data without degrading the performance such as positioning sensitivity and positioning speed and conserve energy consumption. Supplied with IF data from a frequency conversion section 4, a synchronization hold section (6) acquires synchronization of a carrier frequency and phase synchronization of a C/A code, holds the acquired state, and obtains necessary information such as range data. When range data is obtained, a switch (23) is turned off to stop supplying the power to the synchronization hold section (6). A control section (7) executes a positioning operation using the obtained range data and the like, finds and outputs positioning information indicative of a current position. Thereafter, the switch (23) is turned on to restart the synchronization hold section (6). In this manner, control is provided to repeatedly start and stop the synchronization hold section (6).
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Citations
14 Claims
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1. A GPS receiver comprising:
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a frequency conversion means for converting a high-frequency GPS signal into an intermediate frequency GPS signal, wherein the high-frequency GPS signal is transmitted as transmission data from an artificial satellite by modulating a carrier wave through a signal spectrum-spread by a spread code;
a synchronization hold means for obtaining the transmission data by receiving the intermediate frequency GPS signal supplied from the frequency conversion means and acquiring and holding synchronization of the carrier wave and phase synchronization of the spread code;
a control means for controlling repetition of an intermittent operation which operates the synchronization hold means to obtain the transmission data, then stops operating the synchronization hold means, and again operates the synchronization hold means after lapse of a specified time by using, as initial values, a carrier wave frequency and a spread code phase valid for the most recent stop condition; and
a positioning operation means for performing a positioning operation by using the transmission data obtained through the synchronization hold means and finding and outputting positioning information indicative of a current position. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A GPS signal reception method comprising the steps of:
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sequentially converting frequencies of a high-frequency GPS signal transmitted as transmission data from an artificial satellite by modulating a carrier wave through a signal spectrum-spread by a spread code to form an intermediate frequency GPS signal;
obtaining the transmission data by performing a synchronization hold process for the intermediate frequency GPS signal so as to acquire and hold synchronization of the carrier wave and phase synchronization of the spread code;
using, as initial values, a carrier wave frequency and a spread code phase valid for the most recent stop condition of the synchronization hold process to repeat an intermittent operation which temporarily stops the synchronization hold process after obtaining the transmission data and restarts the synchronization hold process after lapse of a specified time; and
using the obtained transmission data to perform a positioning operation and finding and outputting positioning information indicative of a current position. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification