Research On Transmitting Waveform Design And Adaptive Receiving Processing Based Target Detection

With the developments and advances in hardware technology and signal processing, the transmitting waveform design and adaptive receiving processing becomes popular research area in radar. This technology breaks the limit of implementing fixed transmitting waveform and receiving processing in traditional radar system, by which the degree of freedoms in transmitting and receiving are used to improve the radar target detection performance in complex environments.This dissertation investigates the transmitting waveform design and adaptive receiving processing based radar target detection. The main results are as follows:1. Aiming at the range sidelobe and band limited interference in single pulse compression system, we develop and simplify the cost function based on the weighted integrate sidelobe level(WISL) and the stopband energy. We propose optimized phase modulated(PM) waveform design methods based on the pattern search method(PS) and the subspace Newton method, respectively. Aiming at the problem of suppression of the both band limited interference and the range sidelobe, we propose a PS based optimize waveform design method. The proposed methods reduce the computation load for at least two orders of magnitude for the same optimizing performance with respect to conventional method.2. Aiming at the PM orthogonal waveform set design for the shared spectrum multi-static radar system, we develop and simplify the cost function based on the WISL and weighted cross-correlation integrate sidelobe level(WCISL) and propose optimized waveform design methods based on the PS and the band distributing(BD) method, respectively. The proposed multi-waveform PS method is superior to the WeCAN method in both the optimizing performance and computation complexity for the range limited sidelobe suppression optimizing problem. In optimizing problem that the auto correlation mainlobe is allowed to broaden, the multi-waveform BD method further reduced the computation load of the multi-waveform PS method, for similar performance.3. Aiming at the adaptive pulse compression(APC) algorithm, we prove its convergence and propose methods to calculate the probability density function of the APC estimate for multi-target scenario and detection performance of the APC based detector in clutter scenario, respectively. We prove that the estimating method for each recursion in several existing variations of APC and the CLEAN algorithms are special cases of the linear Bayes(LB) estimating method. Based on these results, we propose the recursive modified LB method. Simulations show that the proposed method has better performance over existing APC methods.4. For the range-Doppler estimating for the non fluctuating targets in coherent multi-pulse system, the computational efficiency and the estimating performance are two goals hard to meet simultaneously. We propose the modified fast adaptive multi-pulse compression(MFAMPC). The MFAMPC has similar estimating performance to the adaptive multi-pulse compression(AMPC) at the computation load similar to the existing fast AMPC method. Aiming at the clutter parameter estimating for coherent multi-pulse system in fluctuating scenario, we analytically derived the simplified expectation maximum(EM) algorithm and several special cases of the EM algorithms that reduce the computation load without performance degradation.