Patent ID: 7782252

Claim:
A method for acquiring a GPS signal having a predefined coarse acquisition frame period, the method comprising: receiving a GPS signal portion over the coarse acquisition (C/A) frame period; storing the received GPS signal portion; correlating the received GPS signal portion to each of a plurality of versions of a reference coarse acquisition (C/A) code to obtain a respective plurality of autocorrelation values; and selecting a peak value among the autocorrelation values, wherein correlating the received GPS signal portion comprises: (i) correlating the received GPS signal portion to a reference coarse acquisition code to obtain a first autocorrelation value; (ii) circularly-shifting the reference coarse acquisition code to obtain a shifted reference coarse acquisition code; (iii) correlating the received GPS signal portion to the circularly-shifted reference coarse acquisition code to obtain a second autocorrelation value and repeating (ii) and (iii) until the reference C/A code has shifted through one complete revolution, whereby the received GPS signal portion is correlated to each of the reference and shifted versions of the C/A code.