Patent ID: 7522100

Claim:
In a navigational system utilizing a plurality of satellites that transmit radio-frequency signals containing time and orbit information of said satellites, a method of acquiring said satellite signals at a receiver, the method comprising: receiving a satellite signal at the receiver; performing short-length correlations between the received satellite signal and locally generated reference codes, wherein each short-length correlation spans approximately 1 ms; performing block accumulating coherent integration of said short-length correlations over a preset extended length, wherein performing the block accumulating coherent integration includes: reducing frequency error for a block of short-length correlations prior to integrating said block with preceding blocks over said preset extended length; adding said frequency error reduced block of short-length correlations to partial sums of previous blocks of short-length correlations, thereby updating said partial sums, wherein each partial sum is added for a different possible data bit edge and a corrected bit sign of said block; and making a decision based upon said updated partial sums to ascertain the presence or absence of said satellite signal up to this point.