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. 19, 2009
Filed:
Jun. 07, 2007
Shaowei Han, Palo Alto, CA (US);
Shaowei Han, Palo Alto, CA (US);
SiRF Technology Holdings, Inc., San Jose, CA (US);
Abstract
Provided herein are systems and methods that enable a navigation receiver to determine receiver position using a low ppm (Parts Per Million) Real Time Clock (RTC) under weak satellite signal reception conditions without the need for timing information from navigation satellites or aiding systems. Under weak signal conditions, the receiver is unable to demodulate navigation data bits but may be able to synchronize with the one ms PN sequences and 20 ms data bit edges of a received signal. In this case, the receiver is unable to determine the signal travel time from the navigation data bits resulting in one ms and/or 20 ms integer ambiguities in the travel time. Systems and methods are provided for resolving these one ms and/or 20 ms integer ambiguities and correct or reconstruct the pseudorange measurements accordingly. The reconstructed pseudorange measurements are used to accurately determine the receiver position.