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:
May. 13, 1997
Filed:
Apr. 18, 1996
Eric B Rodal, Cupertino, CA (US);
Dominic G Farmer, Milpitas, CA (US);
Chung Y Lau, Sunnyvale, CA (US);
Trimble Navigation Limited, Sunnyvale, CA (US);
Abstract
A GPS receiver having a rapid acquisition of a GPS satellite signal when a normal operational mode is entered after a low power standby mode. The GPS receiver includes an RF section for receiving the GPS satellite signal and providing an GPS IF signal, a correlator section for providing a correlation signal for the correlation between the GPS IF signal and an internally generated replica signal, and a microprocessor section for receiving the correlation signal and calculating a geographical location of the GPS receiver. The replica signal is based upon a reference frequency from a reference oscillator and a reference time of arrival (TOA) from a timer. In order to increase acquisition speed, the microprocessor section provides the correlator section with an initial frequency adjustment and an initial TOA adjustment to correct for drift in the reference frequency during the standby mode. The initial adjustments are based upon a learned corrections to the initial adjustments that result in acquisition of the GPS satellite signal after alternating one or more times between the standby mode and the normal mode or from stored temperature relationships and measured temperatures of the reference oscillator.