Search method for acquisition of time synchronization between a spreading sequence of a receiver and that of a transmitter

A search method for acquisition of time synchronization between a spreading sequence of a receiver and a spreading sequence of a transmitter, the receiver receiving a spread signal and demodulating the signal using the spreading sequence of the receiver includes a test step consisting in measuring the energy of the demodulated signal by integrating the demodulated signal during a time interval Tobsi and comparing that energy with a threshold value to determine if the threshold value is exceeded, for a given hypothesis as to the time shift between the spreading sequences, and modifying the time shift hypothesis if the threshold value is not exceeded and incrementing the value of a counter. Steps a and b are repeated until the value of the counter reaches a predetermined value. When the predetermined value is reached, the time interval Tobsi is replaced with a time interval Tobsi+1, with Tobsi+1=m.Tobsi and m>1, and the process resumes at step a replacing Tobsi with Tobsi+1. The process ends when the predetermined value has been reached a predetermined number of times. The invention applies to the reception of spread signals with an unknown signal-to-noise ratio.