The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 20, 2001
Filed:
Apr. 26, 2000
Masahiro Sasaki, Kanagawa, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
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.