Aiming at the problem that the correlation peak difference of copy correlation synchronous detection is large in different channel environments in the process of underwater acoustic communication，and the signal false detection rate and missed detection rate are high through a single fixed threshold synchronous detection，a signal synchronous detection frame structure is designed. Three tone signals are added before the traditional copy correlation synchronous detection signal. Combined with morphological filtering technology，a new synchronous detection method of underwater acoustic communication signal is proposed，which realizes the synchronous detection of underwater acoustic communication signal with a single fixed threshold detection value under different channel environment and communication distance，and reduces the probability of false detection and missed detection. The actual sea trial results show that this method can achieve signal synchronous detection under different channel environments and at communication distances of 5km，7km and 10km，and the probability of false detection and missed detection are both 0.
[6] STOJANOVIE M.OFDM for underwater acoustic communications:adaptive synchronization and sparse channel estimation[C]//IEEE International Conference on Acoustics,Speech and Signal Processing.Las Vegas:IEEE,2008.
