基于折射波静校正的未知参数穿墙成像合成延迟时算法

在穿墙雷达实际应用中，墙体一般由两层不同介质构成，且各层墙体参数未知。若对墙后目标直接成像，会产生目标散焦或位置偏移。针对该问题，提出了基于折射波静校正的合成延迟时方法对墙后目标进行聚焦成像。首先读取每根接收天线回波数据确定电磁波的折射回波时刻，通过基本折射方程得到延迟时超定方程组，解此超定方程组可得电磁波在外层墙体内的传播时延，再运用相邻发射天线和相邻接收天线延迟时之差估计内层墙体中电磁波的传播时延，最后各个通道内传播时延依次相加后运用后向投影算法获得目标精确成像。对成像位置精度、图像熵，以及输入输出目标杂波比等性能的分析和比较证明了该算法的有效性。

A through-the-wall radar imaging composite delay time algorithm for wall with unknown parameters based on refraction static correction

In the practical application of through-the-wall radar,the wall generally consists of two layers of different media and the parameters of the wall are unknown.The problem of image defocusing and displacement of the target behind multi-layered wall will arise when the target is directly imaged.To solve this problem,a composite delay time method based on refraction static correction is proposed to focus the image of the target behind the wall.Firstly,the method reads the echo data of each receiving antenna to determine the refraction echo time of the electromagnetic wave,and then obtains the time delay overdetermined equations through the basic refraction equation.Solving the overdetermined equations can obtain the propagation delay of the electromagnetic wave in the outer wall.The propagation delay of the electromagnetic wave in the inner wall is estimated by the difference between the adjacent transmitting antenna and the adjacent receiving antenna.The propagation delay in each channel is added successively and then the backward projection algorithm is used for imaging.Finally,the imaging position accuracy,image entropy and target clutter ratio of the algorithm are analyzed to demonstrate the effectiveness of the proposed algorithm.