由于方位分辨性能受限和多普勒模糊问题,高频地波雷达(HFSWR)难以分辨编队内的子目标。该文将逆合成孔径原理应用于HFSWR,提出横向距离成像方法。该方法首先在运动补偿处理中消除径向运动分量、保留旋转运动,实现聚焦的多普勒谱,并分辨多个子目标。然后,横向距离定标处理将频率坐标转化为横向距离,进而估计子目标间的间距。其中,由最小熵准则来估计径向速度和径向加速度,由分段数字波束形成来估计旋转角度。为了在有限积累时间条件下提升分辨效果,采用基于数据复用方式的重叠相干积累来增加扫频周期数。仿真实验表明,所提方法的理论分辨率在几百米至几千米范围内,运动补偿和横向距离定标实现了单纵队的分辨及其间距估计,重叠积累具有缩窄主峰和降低旁瓣水平的效果。

Due to the limited azimuth resolution and spreading Doppler frequency, group targets within the formation are difficult to be resolved for high frequency surface wave radar (HFSWR). In this paper, the inverse synthetic aperture principle is employed for HFSWR, and a cross-range imaging method is proposed. First, the motion compensation processing is performed to eliminate the radial motion and preserve the rotational motion, which enables the realization of a focused Doppler spectrum with resolved multiple sub-targets. Then, the cross-range scaling process converts the Doppler coordinates into cross-range which allows the spacing between sub-targets to be estimated. Specially, the radial velocity and radial acceleration are estimated by the minimum entropy criterion, and the rotational angle is estimated by the fragment digital beamforming. To further enhance the resolution performance under limited integration time, overlapping coherent integration based on the data multiplexing approach is used to increase the

TN957. 51

国家自然科学基金资助项目(61701263);国家重点研发计划资助项目(2017YFC1405200)