Fast acquisition of a phase-coherent DSFH satellite signal

A hybrid direct sequence and frequency hopping (DSFH) spread spectrum signal can greatly improve ranging precision and jamming resisting capability in spacecraft TT and C (Tracking, Telemetry and Command). The frequency hopping adds another searching dimension to acquisition and increases the acquisition complexity. Therefore, this paper designs a phase-compensating-based acquisition algorithm. First, the model DSFH signal is introduced. Then the auto-correlation function and the acquisition problem are analyzed. Finally, a phase-compensating-based acquisition algorithm is proposed, its computation complexity is analyzed, and the signal-to-noise ratio (SNR) losses due to necessary approximations are shown. Simulations validate the advantageous performance of our algorithm. The proposed method can be modified to adapt to different PN chip rates and frequency hopping rates.