Lpi Radar Signal Detection Method

Recently, Low Probability of Intercept (LPI) radar technique has improved rapidly due to the signals modulation has been changed from simple to complex. Because the traditional intercept receiver devices are difficult to detect LPI radar signals, therefore, the development of new methods for detecting LPI radar signals is of great significance. In this paper, we investigate the LPI radar signals and the methods for LPI radar signals detection, the main contents are as follows.Firstly, we introduce the four LPI radar signals, including the Linear Frequency Modulation Continuous Wave (LFMCW) signal, the Costas frequency hopping (FH) signal, the Bi-phase Coding/LFM signal and the Frequency Shift Keying /Phase Shift Keying (FSK/PSK) Costas FH signal. Then, we analyze the periodic ambiguity function (PAF) of those LPI radar signals. The results show that the complexly modulated radar signals have better distance and speed resolutions than those of the simply modulated signals. Therefore the complexly modulated signals are more suitable for the LPI radar signals.Secondly, we study two LPI radar signals detection methods: the first one is based on the Wigner distribution and the second one is based on the parallel filter arrays and high order statistics (third-order cumulant estimator). The analysis results show that the Wigner distribution based method is an effective method to detect the simply modulated radar signals, whereas, the parallel filter arrays and high order statistics based method has better performance for detecting complexly modulated radar signals. Incidentally, the parallel filter arrays and high order statistics based method is also effective to detect simply modulated radar signals.