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. 13, 1990
Filed:
Mar. 27, 1989
Paul E Braisted, San Jose, CA (US);
Ralph F Eschenbach, Redwood City, CA (US);
Trimble Navigation, Ltd., Sunnyvale, CA (US);
Abstract
To reduce error introduced by the local oscillator in the velocity calculations, the receiver has two 'tracking channels' and a microcomputer. With numbers required to, simultaneously, lock each of the 'tracking channels' each to a respective satellite signal, the microcomputer employs a differential doppler technique to calculate the receiver velocity. The microcomputer calculates a number which represents the difference between the apparent doppler frequency shift of the carrier signal which is transmitted by the first 'tracking channel' satellite and which is measured over a specific time period and the apparent doppler frequency shift of the carrier signal which is transmitted by the second 'tracking channel' satellite and which is measured over substantially the same time period.