Patent ID: 6975690

Claim:
A simplified, weak GPS C/A code coherent acquisition method comprising the steps of: receiving a weak global positioning system C/A code digitized data signal of a length of N ms, where N is an integer greater than 1 generating a complex radio frequency digitized signal with a length of N ms as a local reference signal; first multiplying said digitized data signal from said receiving step with said digitized complex radio frequency signal; dividing a product from said multiplying of digitized data signal with digitized complex radio frequency signal into N equal sections of data signals; adding said data signals in N equal sections together from said dividing step; first applying a fast Fourier transform to a sum of data signals from an output of said adding step acquiring 1 ms of length of digitized C/A code of a preselected GPS satellite; second applying a fast Fourier transform to said 1 ms of digitized C/A code of a preselected GPS satellite from of said acquiring step; taking a complex conjugate of said fast Fourier transformation from said second applying step; second multiplying said complex conjugate from said taking step with said fast Fourier transformation from said first applying step; and taking an inverse fast Fourier transform of a product from said second multiplying steps, an index of the maximum of said inverse fast Fourier transform being an initial phase of the C/A code.