A method for acquiring a code phase shift between an input sequence and a reference sequence is provided. The method is to be implemented using an acquisition device that includes a mapping unit configured to transform the input sequence and the reference sequence respectively into an input signal and a reference signal each with a complex phase, a comparison unit configured to compare the input signal with the reference signal so as to obtain a phase coherent indicator, and calculating unit configured to obtain the code phase shift between the input sequence and the reference sequence based on a phase of the phase coherent indicator and a number of bits of the input sequence.