基于加权循环算法的高分辨成像波形设计

High resolution imaging waveform design based on weighted cycle algorithm

为实现感兴趣区域目标的高分辨成像,MIMO-SAS声呐(Multiple Input Multiple output SyntheticAper-tureSonar,MIMO-SAS)一般采用长的发射信号对目标进行照射,但发射信号过长会导致近距离目标和远距离目标回波产生混叠,从而引起距离模糊,影响目标成像质量。为了抑制距离向的模糊,通常的做法是降低脉冲重复率,然而脉冲重复率过低会导致MIMO-SAS方位向欠采样,使回波信号频谱相互混叠,声呐成像时会在方位向出现珊瓣,很难把目标回波有效分离出来。针对这个问题,提出一种基于加权循环算法(Muti-sequenceWeightedCyclic Algorithms,Multi-WeCAN)的阵列发射波形设计方法,通过计算机仿真发现,相比传统的发射波形,在不改变脉冲重复率的情况下,通过Multi-WeCAN波形设计方法能够有效抑制回波混叠,提高MIMO-SAS目标的成像质量。

To achieve high-resolution imaging of objects of interest,MIMO-SAS(Multiple Input Multiple output Syn-thetic Aperture Sonar)generally uses long transmitted signals to irradiate targets.However,too long transmitted signals will result in aliasing of the echoes of short-range tagets and long range targets,causing range ambiguity and affecting the ima-ging quality of tagets.In order to suppress range-derection ambiguity,the usual method is to reduce the pulse repetition rate.However,too low pulse repetition rate will lead to azimuth under sampling in MIMO-SAS,resulting in mutual aliasing of echo spectrum.In addition,there will be Shanlob in azimuth in Sonar imaging,making it difficult to effectively separate target echo.To slove this problem,a transmission waveform design method based on weighted cycle algorithm is proposed in this paper can suppress echo asiasing and effectively improve the imaging quality of Sonar targets without changing the pulse re-petition rate.