The Detection Of Remote And Weak Signal In The Strong Sea Clutter

Sea clutter is the backscattering echo from the sea surface which is irradiated by the radar transmitted signal. As the sea clutter restrict the detection of radar echo which include the" point" target from the sea surface (include ships, maritime buoyage and civilian fishing boats, etc.), so the detection of remote and weak signal in the strong sea clutter not only have theoretical importance, but also have practical importance. This paper brings the Tsallis distribution into the sea clutter nonstationary model, and presents a mothod of goodness-of-fit to Tsallis distribution using K-S, through combining Nelder-Mead. At the same time, let the Tsallis distribution fit the data measured by the IPIX radar, through the analysis of the different of the the parameters, present a method of target detecion using the single parameter, providing a new method for the detection of remote and weak signal in the strong sea clutter.The main work in this paper includes the following:1,State the cause of rising research on the sea clutter from domestic and foreign, and expound present research situation in three aspects of sea clutter modeling, sea clutter simulation and target detection in the sea clutter; Introduce the IPIX radar, data format measured by the IPIX rader and the method of processing the sea clutter data using Matlab; Analyze the sea clutter characteristics from sea clutter scattering coefficient, sea clutter statistical distribution, sea clutter spectrum and tim、spatial correlation; Compare the two kinds of sea clutter simulation method of zero memory nonlinearity method and spherically invariant random process method.2,Realize the amplitude fitting of Rayleigh distribution, Lognormal distribution, Weibull distribution and K distribution, four sea clutter models based on statistical distribution relative the date measured by the IPIX rader, using the Maxinum likelihood estmation, and moment estimation, and analyzes the impact of the parameters for each statistical distribution model based these experments.3,Research the the sea clutter characteristics of nonlinearity using the date measured by the IPIX rader. Do experiments from there aspects of doppler spectrum, doppler centroid and sea clutter texture. The result proves that the sea clutter has the characteristics of nonlinearity.4,Bring the Tsallis distribution into the sea clutter nonstationary model through the analysis of the relationship between Shannon entropy, Renyi entropy and Tsallis entropy, and propose a mothod of goodness-of-fit to Tsallis distribution using K-S combining the Nelder-Mead. The result proves that the sea clutter nonstationary model based on the Tsallis distribution is better than the sea clutter models based on statistical distribution.5,Propose the target detection methods based on single parameter. Using the date measured by the IPIX rader, the result of the experiment proves that the method of basing on the single parameter can complete the task of the detection of remote and weak signal in the strong sea clutter. Discuss the parameter q from the definition of the Tsallis entropy, the analysis shows that the sea clutter has rate sensitivity between the chaos system and random system.