Hybrid acousto-opto-electronic correlator for rapid acquisition and tracking of GPS codes

The advantages of acoustooptic techniques over classical electronic ones for signal correlation are reviewed. The limitations of these techniques and their drawbacks as compared to electronic systems are analyzed. By an appropriate association of the two systems it is possible to retain the advantages of both electronic and acoustooptic processing. The solution consists of making an appropriate interface between an acoustooptic correlator for rapid acquisition and tracking electronics which track the signal in a continuous way which is not possible in the acoustooptic correlator. This interface allows both acquisition and tracking in quasi-real time