Time-frequency Methods for Period Identification of Loran-C
罗兰C周期识别时频分析方法研究

Based on the analysis of Short Time Fourier Transform(STFT) and Wigner-Vill Transform(WVT) for Loran-C signal, influence of SNR at the antenna input, SGR(Sky-wave to Ground-wave Ratio) and phase difference on STFT and WVT for Loran-C signal are analyzed and simulated. The results show that peak values of STFT and WVT for Loran-C signal are steady, and noise can be restrained successfully. But they both have the issue of multi-values, moreover, the issue of multi-values of Loran-C signal’s WVT can be removed successfully and effectively because frequency points of its negative peak values are different when the arrival time interval of sky-wave and ground-wave is different, so a new period identification based on WVT for Loran-C is presented.