Study on cycle identification compensation method for underwater receiving Loran-C signal

Because of the influence of dispersion effects, phase variation of each frequency component is different when Loran-C signal is propagating underwater, the result is that envelop of composite signal is altered and envelop cycle difference (ECD) compensation is needed in processing. Therefore, after the analysis of the dispersion characteristics of underwater receiving Loran-C signal, the prime five half-cycle peak ratios (HCPR) under different depths when standard signal propagates from air into the water are given by simulation. After that, with the simulation results, a cycle identification method contained ECD compensation which used for underwater receiving Loran-C signal is designed according to minimum mean square. The experiment results show that the designed cycle identification compensation method can identify the underwater receiving signal exactly and enhance the position precision, which has great significance to underwater applications of Loran-C receivers.