• DEFENCE ELECTRONICS TECHNOLOGY •

### Short-range clutter suppression method combining oblique projection and interpolation in airborne CFA radar

Yili HU(), Yongbo ZHAO*(), Xiaojiao PANG(), Sheng CHEN()

1. 1 National Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, China
• Received:2019-12-11 Online:2021-02-18 Published:2021-03-16
• Contact: Yongbo ZHAO E-mail:huyili66@126.com;ybzhao@xidian.edu.cn;1964230291@qq.com;842561535@qq.com
• About author:|HU Yili was born in 1994. He received his B.S. degree in signal and information processing from Yangtze University, Jingzhou, China, in 2017. He is currently purpusing his Ph.D. degree in the National Laboratory of Radar Signal Processing, Xidian University. His research interests include processing of airborne conformal arrays radar, clutter suppression and MIMO radar signal processing. E-mail: huyili66@126.com||ZHAO Yongbo was born in 1972. He received his M.E. and Ph.D. degrees in electrical engineering from Xidian University, Xi’an, China, in 1997 and 2000, respectively. He is currently a professor with the National Laboratory of Radar Signal Processing, Xidian University. His research interests include adaptive signal processing, array signal processing, multiple input multiple output radars, and target tracking. E-mail: ybzhao@xidian.edu.cn||PANG Xiaojiao was born in 1993. She received her B.S. degree from Xidian University, Xi’an, China. She is currently pursuing her Ph.D. degree in the National Laboratory of Radar Signal Processing, Xidian University. Her research interests are space time adaptive processing and compress scene. E-mail: 1964230291@qq.com||CHEN Sheng was born in 1993. He received his B.S. degree from Xidian University, Xi’an, China, in 2017. Currently, he is pursuing his Ph.D. degree in the National Laboratory of Radar Signal Processing, Xidian University. His current research interest is measure height of metrewave radar. E-mail: 842561535@qq.com
• Supported by:
This work was supported by the Fund for Foreign Scholars in University Research and Teaching Programs (the 111 Project) (B18039)

Abstract:

The airborne conformal array (CFA) radar’s clutter ridges are range-modulated, which result in a bias in the estimation of the clutter covariance matrix (CCM) of the cell under test (CUT), further, reducing the clutter suppression performance of the airborne CFA radar. The clutter ridges can be effectively compensated by the space-time separation interpolation (STSINT) method, which costs less computation than the space-time interpolation (STINT) method, but the performance of interpolation algorithms is seriously affected by the short-range clutter, especially near the platform height. Location distributions of CFA are free, which yields serious impact that range spaces of steering vector matrices are non-orthogonal complement and even no longer disjoint. Further, a new method is proposed that the short-range clutter is pre-processed by oblique projection with the intersected range spaces (OPIRS), and then clutter data after being pre-processed are compensated to the desired range bin through the STSINT method. The OPIRS also has good compatibility and can be used in combination with many existing methods. At the same time, oblique projectors of OPIRS can be obtained in advance, so the proposed method has almost the same computational load as the traditional compensation method. In addition, the proposed method can perform well when the channel error exists. Computer simulation results verify the effectiveness of the proposed method.