Patent ID: 8331422

Claim:
A method for high-sensitivity GPS/GNSS signal acquisition in a stationary GPS/GNSS receiver including a front end section and a signal processing section, the front end section receiving GPS/GNSS signals from satellites and producing a digitized complex baseband signal, the method comprising: partitioning a range of uncertainty in frequency of the received signal due to apparent Doppler shift into a plurality (P) of contiguous frequency bins having a center frequency f 0p ; partitioning a range of uncertainty in location of navigation data bit boundaries of the received signal to obtain equally spaced trial bit boundary locations t 0s ; and for each combination of the trial bit boundary location and the frequency bin, performing a search process including: capturing a segment of the baseband signal including navigation data using start time corresponding to the selected trial bit boundary location; Doppler-compensating the captured baseband signal segment using a phase rotator; partitioning the segment of the baseband signal into successive sub-segments, each having a length of one navigation data bit; synchronously summing samples of each sub-segment with a periodicity of one period of C/A code, so as to produce a compressed sample block having N samples, each compressed sample block having the length of one period of C/A code; cross-correlating each compressed sample block with one period of reference C/A code for a selected satellite to produce an N-value correlation function per compressed sample block; calculating a magnitude of each value of the N-value correlation function to produce a correlation magnitude function for each N-value correlation function, the correlation magnitude function having N values; and stack-accumulating a number of the N-value correlation magnitude functions into an array with precession compensation so as to determine a correlation peak having a largest value in the array.