Costas编码信号高分辨动态二维成像方法研究
doi: 10.3724/SP.J.1146.2013.00829
Study on Two-dimensional High Resolution Dynamic ImagingAlgorithm of Costas-coded Signal
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摘要: Costas编码信号是一种对速度敏感的信号形式,在多目标的情况下,速度补偿不精确时,其较高的旁瓣会淹没较小的目标。论文针对Costas编码信号的这种特点,结合稀疏成份分析的方法,研究了一种高分辨的2维成像方法。该方法根据目标回波在距离-速度是2维稀疏的这一先验信息构造词典,引入波形熵作为信号稀疏性的度量函数,通过对推广的正则化FOCUSS算法进行改进,并采用卡尔曼滤波器进行状态预测,迭代寻找最优原子,实现了动态的距离和速度的高分辨。最后,通过仿真验证了这种方法的有效性,并对算法的容噪性和时效性进行了分析。Abstract: Costas-coded Frequency Hopping (FH) signal is very sensitive to velocity changes. As a result, in multi- targets scenario, sidelobe pedestal arisen induced by inaccuracy compensation will make possible masking if one target is much stronger than the others. Based on this property of Costas-coded FH signal a high resolution rang- velocity two-dimensional imaging algorithm is studied by using sparse component analysis. Echoes can be regarded to be sparse in rang-velocity dimensions, and a sparse dictionary is constructed based on the sparsity feature, where the waveform entropy is used as the sparse measuring function. By improving the generalized regularized FOCUSS algorithm and making use of Kalman filter, the best atom can be found iteratively and high resolution in rang and velocity is realized. The algorithm is validated by simulations, and the noise tolerance as well as the time effectiveness are analyzed.
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