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:
Jan. 13, 2009
Filed:
Mar. 30, 2007
Chi-shin Wang, Half Moon Bay, CA (US);
Zhike Jia, San Jose, CA (US);
Yue-meng Chen, Shanghai, CN;
Jian Cheng, Guangzhou, CN;
Enyuan Tu, Shanghai, CN;
Chi-Shin Wang, Half Moon Bay, CA (US);
Zhike Jia, San Jose, CA (US);
Yue-Meng Chen, Shanghai, CN;
Jian Cheng, Guangzhou, CN;
EnYuan Tu, Shanghai, CN;
SiRF Technology Holdings, Inc., San Jose, CA (US);
Abstract
Provided herein are systems and methods for achieving long coherent integration in a navigational receiver to improve the sensitivity of the receiver and enable the receiver to acquire, reacquire and track signals under very weak signal conditions. In an embodiment, phase compensation is computed based on estimated Doppler frequency, rate of change of the Doppler frequency with time, and second order rate of change of the Doppler frequency. The Doppler frequency may be computed from an orbital model or ephemeris. This phase compensation is used to compensate samples of the input signal for changes in the phase due to the Doppler frequency. Frequency components of the phase-compensated samples are then computed using a frequency analysis such as a Fast Fourier Transform (FFT). The maximum frequency component is taken as an error frequency and used to compensate the samples of the input signal for residual frequency error.