Patent ID: 7180446

Claim:
A method implemented in a global satellite navigation receiver for acquisition of signals received from navigational satellites, the method comprising: in a coarse acquisition phase: for a selected dwell in a list of code-frequency dwells, calculating a non-coherent accumulated power from the signals, if the non-coherent accumulated power is less than a low threshold value then eliminating the selected dwell from the list of code-frequency dwells and continuing the coarse acquisition phase, if the non-coherent accumulated power is greater than a high threshold then initiating a fine acquisition phase using the selected dwell; if a number of integration intervals for the selected dwell exceeds a predetermined duration then initiating the fine acquisition phase using the list of code-frequency dwells in the fine acquisition phase: for a given dwell, calculating a fast Fourier transform of a set of recent signal samples to determine coherent accumulated powers for a set of frequencies, and discarding frequencies whose coherent accumulated powers are less than an average power.