Weak Target Detection In Strong Clutter Algorithm

The detection of dim target is one of the hot-spot aspects in the research field of modern radar technology.Its application helps radar to solve the increasingly serious challenges. In order to deal with the threats of the super-low altitude intruding weapons and dim targets in strong clutter environments, the correlative research is urgently needed in the field of radar detertion. Such as the corresponding effective clutter suppression methods to the complex strong land/sea clutter and the target detection and tracking algorithms to the modern weak target of the invsion.In this thesis, the basic mechanisms of radar target detection and clutter model and the suppression techniques have been analyzed. Then the joint method based on constant-false-alarm rate(CFAR) processing and the Hough-transform-based track-before-detect(TBD) algorithm is proposed and the detection of weak target in strong clutter environments based on this method is explored and investigated for radar detection..The main results are as follows:1. the basic principle of radar target detection is discussed. several statistic models of target widely used in radar and the basic mechanism of radar target detection is analyzed in detail, then the TBD algorithm of dim target detection is introducted from accumulation of signal to provide a theoretical basis for research.2. Clutter suppression methods are investigated in detail. Firstly, several classic clutter statistical models are analyzed and then two typical clutter suppression methods are studied in detail: adaptive moving target indication (AMTI) and space-time adaptive processing (STAP) technique. the principle of AMTI and Optimal STAP have been analyzed, then simulations verify the validity of AMTI and the reduced-dimension STAP based on Joint-Domain Localized method (JDL) algorithm.3. An improved two-dimensional CFAR is proposed. the principles and performances of various of CFAR approachs are analyzed, then an improved two-dimensional CFAR processing technology is proposed based on the magnitude characteristic of sea clutter; finally, a performance comparison of these methods for radar real data verify the superiority of the improved two-dimensional CFAR.4. The improved TBD algorithm based on Modified Hough transform and Viterbi algorithm(MHT&VA) is proposed. Firstly, the objectives and echo measurement models are generalized. the TBD algorithm based on Hough transform are analyzed and process is summarized; and then the improved TBD algorithm based on MHT&VA is proposed; Finally, Simulations verify the validity of the proposed algorithms. In addition, a new joint detection method is proposed, which is constituted by improved two-dimensional CFAR and the proposed TBD algorithm, and then the experimental data verify the better property of joint method for the weak target detection.