摘要
Most operating radar systems don′t have sufficient frequency bandwidth to produce high range resolution(HRR) profile of a target. But we can use stepped frequency waveform in a narrow band coherent radar to obtain the HRR profile of a target. For moving targets which are of great importance in practical radar usage, autofocusing,i.e. phase correction, is a necessary and critical step of the synthetic HRR processing. The purpose of autofocusing is to remove the radial motion effect of the target from radar echoes, and only reserve the stepped frequency effect which is the basis of synthetic HRR capability. We investigate two autofocusing approaches for synthetic HRR radars using stepped frequency waveform in this paper. The first is motion fitting method. This method depends on a certain parametric model, and is computationally expensive. Then we propose the iterative dominant scatterer method. It is robust, non parametric and simple in computation in comparison with the motion fitting method. Experimental results based on data acquired by using a metallised scale model B 52 in a microwave anechoic chamber reveal the validity and effectiveness of the method.
大多数现役雷达频带不够宽，不能直接得到目标的高距离分辨（ＨＲＲ）剖面，但是窄带相参雷达可采用步进频率波形得到目标合成的ＨＲＲ剖面。在雷达实用中重要的是运动目标，对于运动目标，自聚焦即相位校正是合成ＨＲＲ处理必需和关键的步骤。自聚焦的目的是从雷达回波中消除目标径向运动的影响，只保留步进频率的影响，而后者是合成ＨＲＲ能力的基础。本文研究步进频率波形合成ＨＲＲ雷达的两种自聚焦方法。第一种是运动拟合，这种方法依赖于某种参量模型，而且计算复杂。本文提出迭代强散射点法，它是一种鲁棒和非参量的方法，而且计算简单。在微波暗室中用Ｂ－５２金属缩比模型采集了数据，实验结果表明，此方法是正确和有效的。
