Sea Clutter Covariance Matrix Estimation and Its Application to Whitening Filter

• Published in: Journal of Electromagnetic Engineering and Science Vol. 21; no. 2; pp. 134 - 142
• Main Authors: Choi, Sanghyun, Yang, Hoongee, Song, Jimin, Jeon, Hyeonmu, Kim, Jongmann, Chung, Yongseek
• Format: Journal Article
• Language: English
• Published: 한국전자파학회JEES 01.04.2021; The Korean Institute of Electromagnetic Engineering and Science; 한국전자파학회
• Subjects: clutter suppression; covariance matrix estimation; doppler frequency; whitening filter; 전자/정보통신공학; Clutter Suppression; Covariance Matrix Estimation; Doppler Frequency; Whitening Filter
• ISSN: 2671-7255; 2671-7263; 2671-7263
• DOI: 10.26866/jees.2021.21.2.134

The accurate estimation of clutter covariance matrix (CCM) is essential in designing a radar detector/filter to suppress sea clutter. This estimation might not be easily accomplished because of the scarcity of valid training vectors adjacent to the range cell under test (CUT). We propose a new CCM estimation algorithm that is derived by modeling time-series clutter returns into a clutter Doppler spectrum in the frequency domain and exploiting mutual independence among spectral components. To justify its excellence over the conventional sample covariance matrix (SCM) algorithm, we design two filters—a maximum signal-to-interference-plus-noise ratio (SINR)-based filter and a whitening filter—that use the estimated CCMs and compare their performance in a numerically simulated sea clutter scenario. Comparisons are made by showing the eigenvector spectra of the estimated CCMs and the frequency responses and outputs of the filters. Moreover, SINRs at the target Doppler bin are examined and compared with a theoretical, analytically derived SINR.