地基双基地MIMO成像雷达空间分辨特性分析

地基MIMO（Multiple-Input Multiple-Output，多输入多输出）成像雷达是一种新体制雷达系统，相比于传统的地基合成孔径雷达具有便携性好、无需运动补偿及图像帧频高等优势，在滑坡等地质灾害预警方面具有广阔的应用前景。在利用多部MIMO雷达系统进行三维形变监测时，采用双基地MIMO雷达构型能够对传统单基地观测进行有效补充，可大大提高系统的整体观测自由度，但目前尚无有效的双基地MIMO成像雷达成像性能评估方法。针对这一问题，本文通过广义模糊函数对双基地MIMO成像雷达的空间分辨特性进行了分析。首先，根据系统的几何构型推导了地基双基地MIMO成像雷达的广义模糊函数表达式并分析了等效阵列特性，然后根据广义模糊函数对系统的旁瓣走向、两维分辨率和栅瓣位置进行了分析，给出了系统空间分辨率的计算公式，最后利用Matlab仿真验证了分析结论的正确性。 

Analysis on spatial resolutions of ground-based bistatic MIMO imaging radar

Ground-based MIMO (Multiple-Input Multiple-Output) imaging radar is a new kind of radar that has broad application prospects in geological disaster warning such as landslide. It has the advantages of good portability, freedom of motion compensation and high image frame rate compared with the traditional ground-based synthetic aperture radar. When using multiple MIMO radar systems for three-dimensional deformation monitoring, the bistatic MIMO radar configuration can effectively supply the traditional monostatic observation and greatly improve the overall observation degree of the system. However, there is no effective imaging performance evaluation method for bistatic MIMO imaging radar now. Aiming at solving this problem, this paper analyzes the spatial resolution property of bistatic MIMO imaging radar by generalized ambiguity function. Firstly, the expression of generalized ambiguity function and equivalent array for ground-based bistatic MIMO imaging radar is derived according to the geometry of the system. Then the side lobe’s direction, two-dimensional resolution of the system and the position of grating lobes are analyzed according to the generalized ambiguity function, and the spatial resolution of the system is derived. The correctness of the calculation is finally verified by two Matlab simulations.