多维波形编码信号大测绘带成像

Wide swath imaging with multidimensional waveform encoding

提出一种基于MIMO-SAR(Multiple-Input Multiple-Output Synthetic Aperture Radar)体制的多维波形编码大测绘带成像的方法.首先介绍了多维波形编码信号.在信号发射过程中,利用俯仰阵列进行波束形成,控制波束方向使其在不同子脉冲时间内照射不同子测绘带,通过适当的参数设计可以将远近不同场景回波时间限定在一小段时间范围内.由于各子测绘带回波信号混叠导致了距离模糊,利用俯仰方向阵列天线进行数字波束形成解距离模糊.该方法实现的大测绘带是连续的,克服了传统方法中利用俯仰波束实现宽测绘带存在盲区的缺陷.同时该方法具有灵活的功率分配能力和多距离分辨能力.克服了传统大测绘带成像中回波能量偏低的缺点,同时也突破了传统成像过程中单一分辨率的不足.

A novel approach described in the paper is the Wide Swath Imaging with Multidimensional Waveform Encoding Based on Multiple-Input Multiple-Output Synthetic Aperture Radar （MIMO-SAR）. First, the concept of Multidimensional Waveform Encoding is introduced; then in the process of signals transmission, arrays in elevation is used to generate beamforming to scan different subswaths, and they can properly design the system parameters in order to restrict time-delay of the echoes from the near subswaths to the far sub- swath, As a result, the radar echoes from different subswaths would overlap in the receiver; range ambiguities must occur; finally digital beamforming is used to remove range ambiguities. The approach can be used to realize consecutive wide swath, and it overcomes the disadvantage that non-consecutive wide swath occurs by the conventional elevation multi-beam. At the same time it holds the abilities of flexible power distribution and of the multiple range resolution. It not only overcomes the shortcoming of low echoes power which appears in traditional wide swath imaging, but also breaks through the disadvantage of single range resolution in the processing of traditional imaging.