A New Fast Doppler Shift and Doppler Rate Joint Acquisition Method for Hypersonic Vehicle Communications

For communications with hypersonic vehicles, high-speed relative movement between the transmitter and the receiver causes a very large and rapidly changing Doppler shift, which imposes a great challenge for the fast signal recovery. In this paper, a new fast Doppler shift and Doppler rate joint acquisition algorithm is proposed to increase the acquisition probability and to reduce the acquisition time simultaneously. The Doppler rate is matched with equally spaced Doppler rate over a wide range. The spectrum peaks of the matched results in different branches are then compared with each other. The maximum is the Doppler shift and the Doppler rate can be jointly obtained by the corresponding branch. Simulation results indicate that one hundred percent successful acquisition can be achieved under -30dB with only 300 symbols and the processing time is less than 90 ms.