宽带雷达目标使得接收回波产生时延和尺度伸缩,宽带模糊函数是分析该类目标回波并进行目标时延和尺度因子估计的一种常用手段。但是该方法计算量大、实时性差,且难以有效分析扩展目标。梅林匹配滤波器是基于梅林变换发展而来的一种变换域匹配滤波器,可以有效估计出目标的尺度因子,但尺度因子的估计精度对目标时延非常敏感。为了消除目标时延对尺度因子估计的影响,文中利用发射信号的幅度谱构造冲击响应函数,提出一种改进型梅林匹配滤波器用于估计目标的尺度因子。在利用该滤波器估计出目标尺度因子后,再根据尺度因子估计值构建目标回波时延匹配滤波字典,实现目标时延估计。仿真结果表明:相对于宽带模糊函数与梅林匹配滤波器,改进型梅林匹配滤波器对目标尺度因子的估计精度有所改善,且能够有效估计出扩展目标参数。

In wideband radar, the echoes backscattered from a target undergoes translation and dilation. The wideband ambiguity function is a common approach to analyze this type of echoes and estimate the translation and dilation parameters. However, this approach has high computational complexity and poor real-time capability. Moreover, this approach does not work well in the case of extended targets due to low precision. The Mellin matched filter is a transform-domain matched filter, which is based on the Mellin transform. Although this filter can estimate the scaling parameter effectively, the estimation accuracy is very sensitive to the time delay of the target. To overcome this drawback, a modified Mellin matched filter is proposed, which exploits the amplitude spectrum of the transmitted signal to construct the filter impulse response function. In this paper, the scaling factor is estimated by the proposed filter, and then a time-delay matched waveform dictionary is constructed with the estimated scaling to further estimated time delay. Simulation results suggest that the parameter estimation accuracy of the proposed filter is more precise than those of the Mellin matched filter and the wideband ambiguity function. In addition, the parameters of extended targets can be efficiently estimated by the proposed filter.

TN957. 52

国家自然科学基金资助项目(61671245)