频率分集阵列雷达空时距信号处理方法研究

Frequency Diverse Array （FDA） greatly improves the flexibility of beamforming and signal processing, which has drawn much attention of researchers home and abroad. Compared with the traditional phased array transmitting fixed carrier frequency, the FDA introduces frequency increment across the array elements, which results in range-dependent beampattern and enjoys additional controllable degree-of-freedom in range domain. It is verified that FDA radar has many advantages compared with its fixed-frequency phased-array radar counterpart. However, opportunities and challenges come together. The core problem is that the range information of target in the FDA framework exists in the radar transmit port while the transmit steering vector of target contains coupled linear phase term of range and angle, quadratic phase term of angle, and cross-correlated phase term of angle and Doppler. So, it results in defocused target in spatial and temporal domains. This proposal aims at the range-angle coupling relationship and defocused target in spatial-temporal domains in FDA radar, and explores innovative approaches for system design and signal processing of the FDA radar framework. We will develop effective solutions to realize range-angle decoupling and target focusing in spatial-temporal domains, and make use of the additional controllable degree-of-freedom in range domain for range ambiguity processing. This proposal is of great value in supporting the development of the novel FDA radar framework and the breakthroughs in fundamental theories and crucial techniques.

频率分集阵列雷达以其灵活的波束控制和信号处理性能引起国内外学者的广泛关注。所谓频率分集阵列，是指相对于传统相控阵雷达各阵元发射相同频率信号而言，其阵元间发射信号引入了一个微小的频率差，将导致天线发射方向图随距离变化而变化，从而引入额外的距离维可控自由度，给雷达带来诸多优势。然而，机遇与挑战并存，其核心问题就是频率分集阵雷达的目标距离维信息存在于发射端，发射导向矢量中不仅存在距离和角度的一次相位耦合项，还存在角度的二次相位和角度多普勒耦合相位项，造成目标空时二维散焦问题。本项目将针对频率分集阵列的距离角度信息耦合与目标空时二维散焦的难题，探索频率分集阵列雷达的系统设计与信号处理新方法，实现距离角度解耦合和目标空时二维聚焦，研究利用频率分集阵列距离维可控自由度的距离模糊处理方法，以提升雷达性能，为频率分集阵列雷达系统理论与关键技术的突破奠定基础。

不同于当前广泛应用的相控阵天线，频率分集阵天线通过改变发射天线单元之间的载波频率，形成空时二维远场方向图，其研究工作很快得到了国内外学者的广泛关注。本项目针对频率分集阵雷达所面临的距离-角度信息耦合和目标空时二维散焦的科学问题，开展了频率分集阵雷达系统设计与信号处理方法的系统研究工作。研究频率分集阵列的距离角度解耦合方法，研究目标空时二维散焦情况下的稳健约束和空时频处理方法，研究利用频率分集阵列距离维可控自由度的距离模糊处理方法。通过本项目的研究工作，初步形成了频率分集阵的基本理论框架，提出了频率分集阵雷达目标参数估计、模糊杂波抑制、高分辨宽测绘成像、主瓣抗干扰等一系列新方法和新技术，为机载雷达预警探测、雷达动目标和场景成像功能一体化等应用问题提供了新思路。