Characteristic Analysis And Simulation Of Sea Clutter

The modeling and analysis on the characteristic of sea clutter are of great significance for the estimation of radar performance, designation of radar system, detection of targets and remote sensing. Two kinds of theoretical methods of sea clutter modeling are discussed. Based on the experimental data from IPIX radar, the statistical characteristic of the amplitude distribution, time correlation, power spectrum and time-frequency property are under analysis in detail. The following topics are addressed in the study:1. Two kinds of theoretical methods of the sea clutter modeling are organized in the context. One is implemented with the help of some mathematical tools, like SIRP(Spherically Invariant Random Processes) and ZMNL(Zero Memory Nonlinearity). The other is completed based on one kind of the sea surface scattering theories. Besides, some experimental data from the IPIX radar are introduced and analyzed.2. The PDF of the amplitude of the real data are estimated and compared with some common empirical models, like Lognormal, K-distribution, ect. It is found that the K-distribution and LN-distribution could fit the real data well. In addition, we also found that the I- or Q-component of the data seems not in accordance with the Gaussian distribution well. The distribution difference between VV and HH polarization is also studied. For the real data used in this thesis, The probability of low amplitude of HH polarization is much larger than that of VV polarization.3. Due to analyze the spectrum of the real data at both low and high sea state, and the real data with target and without target, we include two kinds of power spectrum analysis methods: one is the traditional method: periodogram method; and the other is the modern one: AR model method.There is frequency shift.The frequency shift of the data of the HH polarization is larger than that of the data of the VV polarization.4. Short Time Fourier Transform (STFT) and Wigner Viller distribution (WVD) are simply introduced to explore the time-frequency characteristic of high and low sea state data of sea clutter. The data with and excluding target are also studied using STFT and WVD.