  A point cloud enhancement method for 4D mmWave radar imagery is proposed in
this paper. Based on the patch antenna and MIMO array theories, the MIMO array
with small redundancy and high SNR is designed to provide the probability of
high angular resolution and detection rate. The antenna array is deployed using
a ladder shape in vertical direction to decrease the redundancy and improve the
resolution in horizontal direction with the constrains of physical factors.
Considering the complicated environment of the real world with non-uniform
distributed clutters, the dynamic detection method is used to solve the weak
target sensing problem. The window size of CFAR detector is assumed variant to
be determined using optimization method, making it adaptive to different
environments especially when weak targets exist. The angular resolution
increase using FT-based DOA method and the designed antenna array is described,
which provides the basis of accurate detection and dense point cloud. To verify
the performance of the proposed method, experiments of simulations and
practical measurements are carried out, whose results show that the accuracy
and the point cloud density are improved with comparison of the original
manufacturer mmWave radar of TI AWR2243.
