Patent ID: 8472504

Claim:
A method for optimizing an acquisition of a spread-spectrum signal originating from a satellite by a mobile receiver, said method comprising: receiving a signal transmitted by at least one transmitter, the signal being modulated by a pseudo-random code; generating a local replica of the pseudo-random code of the signal transmitted; determining a plurality of assumptions relating to a frequency f i of the signal received at an initial instant t 0 and to a trend of the frequency f i over time up to a final instant t n corresponding to an integration time, each assumption in the plurality of assumptions relating to the trend of the frequency f i of the signal between the initial instant t 0 and the final instant t n being a trend path; calculating a plurality of correlation functions s(f i , t k , τ) of all pairs of frequency-time assumptions (f i , t k ) using at least the local replica; choosing a first initial frequency assumption f 1 out of the plurality off assumptions relating to the frequency f i corresponding to the initial instant t 0 ; acquiring at least one information item concerning the movement of the receiver, and deducing therefrom, for the first initial frequency assumption f 1 , the trend assumptions for a frequency of the signal over time; determining a respective total energy, corresponding to a maximum of the correlation function, as a correlation peak, of all the possible trend paths of the frequency of the signal between the instants t 0 and t n , the total energy of each possible trend path being obtained by coherently aggregating correlation results between the initial t 0 and final t n instants, the frequency taking in succession all the frequency values located on the chosen trend path; selecting the trend path whose total energy is the strongest; choosing in succession all the other remaining possible initial frequency assumptions in the plurality of assumptions relating to the frequency f i and, for each remaining initial frequency assumption, selecting the trend path whose total energy is the strongest; and deciding that, out of all the trend paths selected on each frequency assumption in the plurality of assumptions relating to the frequency f i , the trend path which has the strongest energy is the most likely path and substantially corresponds to a real path followed by the receiver.