A robust switching-beam algorithm designed for long range underwater acoustic communication

The SNR (signal to noise ratio) of the received signal in long range UUV underwater communication system can be increased by using beamforming technology. But owing to the moving of the UUV, a switching-beam algorithm is needed to detect the beam pointing to the DOA of incident signal. The traditional time domain switching-beam (TDSB) algorithm is incapable of tracing the DOA while the SNR of the received signal is low. In order to solve this problem, a frequency domain switching-beam (FDSB) algorithm is proposed. In the proposed algorithm, the beam output is converted into frequency domain by FFT. The beam pointing to the DOA of the incident signal is judged by comparing the peak values of signal spectrums. Computer simulation is done with channel model based on sea test data. The simulation results show that compared with the TDSB algorithm, the proposed FDSB algorithm has better performance when the SNR of the received signal is very low.