Satellite-based localization has attracted ever growing attention in the last few years. In this work, we present a signal processing technique for initial code acquisition and synchronization of satellite signals, such as the one used by position location techniques. Conventional approaches are based on the interpolation, usually carried out by (time-consuming) narrow-band over-sampling or (fast) fitting of few samples of a smoothed function of the ambiguity function around its coarse maximum. Conversely, the devised detector exploits a fast parabolic interpolation, running on three estimated ambiguity samples in the neighborhood of the coarse estimate. Performance analysis is carried out in comparison with the conventional power detector method. The obtained results have evidenced that the devised method is well suited for satellite spread-spectrum communications such as the GALILEO system.