Locating radar echo centers in coherent radar imaging based on grey clustering algorithm

Coherent radar imaging (CRI) using multiple-receiver technique has been applied successfully to a variety of atmosphere researches actualizing with VHF radar. It is well known an accurate and automatic locating approach for angular center (direction-of-arrival or DOA) of the radar echoes is fundamental for CRI research, especially for the situation of multiple DOAs. Thus, this paper presents an automatic approach to DOA estimation in CRI based on grey clustering algorithm (GRA). The proposed approach consists of three stages: segmentation, clustering and merging. First, the bright areas in input image are segmented. Then, the coordinates of segmented areas are clustered by GRA. Finally, the clusters are merged to find the DOAs of the radar echoes. The proposed approach is justified by several examples. Simulation results indicate that the proposed approach is able to locate DOAs of the radar echoes in CRI accurately.