Near-Field Imaging Algorithm of MIMO Radar with the Aid of Reference Points

In the near field of multiple-input multiple-output (MIMO) array, the spatial phase that targets relative to MIMO array does not satisfy a linear relationship, so imaging algorithm based on fast Fourier transform (FFT) can result in high side lobes in the directional diagram. In this paper, a near-field imaging algorithm with the aid of reference points is proposed to solve this problem, and the principle of the algorithm and its applicable extent are given. Within the applicable extent, the spatial phase can be regarded to be linear approximately. A single reference point is suitable for near-field imaging in interested local area. For the need of global near-field imaging, a selection method of multiple reference points and the imaging steps are given. Simulated and measured show that this algorithm is able to suppress the high side lobes, and global near-field imaging can be achieved through a reasonable choice of reference points.