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:
Aug. 04, 2009
Filed:
Dec. 29, 2005
Chi-shin Wang, Half Moon Bay, CA (US);
Zongde Qiu, Shishi, CN;
Shridhara A. Kudrethaya, Cupertino, CA (US);
Jun MO, San Jose, CA (US);
Chi-Shin Wang, Half Moon Bay, CA (US);
Zongde Qiu, Shishi, CN;
Shridhara A. Kudrethaya, Cupertino, CA (US);
Jun Mo, San Jose, CA (US);
SiRF Technology, Inc., San Jose, CA (US);
Abstract
The present invention provides GPS receivers capable of tracking very weak GPS signals particularly in an indoor environment without assistance from an external server or a network. In a preferred embodiment, a GPS receiver initially acquires and locks onto GPS satellite signals to compute receiver position outdoors. The GPS receiver then tracks at least one satellite signal indoors to maintain acquisition parameters for quick acquisition of GPS signals. To save power, the receiver automatically goes to the sleep state and periodically wakes up, i.e., powers up, to maintain the at least one satellite signal tracking. During the wakeup state, the receiver collects ephemeris data from the at least one satellite signal when the ephemeris data needs to be updated for quick acquisition of GPS signals.