The Low Intercept Probability Of Four-phase Coded Radar Reconnaissance

This paper disscusses the interception methods of quadrature phase shift keying (QPSK) radar signal, which include spectral correlation detection and wavelet analysis. Spectral correlation theory rises from cyclic stable signal model, buiding a more reasonable mathematic model than regular spectral analysis and exceeding in detecting signal in noise. From simulation, it is discussed how spectral correlation detection is affected by selecting the width of window of spectrum smoothing. Wavelet transform is a powerful method to unstable signal analysis, which is allergic to singularity of signals. Relation between singularity index of signal and coefficient of signal抯 wavelet transform is discussed. Signal is detected by the method of maximum module, and the requirement of wavelet function is discussed. The variation of variance of noise under different scales is analysed, and it is compared with that of coefficient of signal抯 wavelet transform. Character of quardrature phase shift keying signal is analysed too. Afterward, a scheme of distinguishing the maximum module points from signal and noise. The ability of the signal parameter extraction and the signal identification in multi-signal environment are discussed in the paper. The interception system are studied here, too. A compitable system between SCD system and wavelet analysis system.