Patent ID: 8509362
Filing Date: 2013-08-13
Classification: G01S,H04L

Abstract:
1. A method of acquiring a Global Positioning System (GPS) satellite signal, the method comprising: setting a coherent integration period; performing coarse coherent integration for the set coherent integration period to determine a first correlation value; determining whether the first correlation value is greater than a high threshold, wherein the high threshold corresponds to a strong positive correlation between a received GPS signal and each of one or more of a coarse acquisition code, a code phase, and an estimated Doppler frequency; when the first correlation value is greater than the high threshold, then performing fine coherent integration to refine the coarse acquisition code, the code phase, and the estimated Doppler frequency to acquire the GPS signal; when the first correlation value is not greater than the high threshold, then determining whether the first correlation value is greater than a low threshold, wherein the low threshold corresponds to a weak positive correlation between the received GPS signal and each of one or more of the coarse acquisition code, the code phase, and the estimated Doppler frequency; when the first correlation value is not greater than the low threshold, then determining whether the set coherent integration period is at a maximum duration; and when the set coherent integration period is not at the maximum duration, then increasing the set coherent integration period and returning to performing coarse coherent integration.