해상 환경 측정 및 해상 표적 탐색에 대한 연구

Abstract

The performance of high resolution radars in the detection of targets with low radar cross sections may be seriously affected by the strong returns from the sea, often referred to as sea spikes, that can occur at low grazing angles. Characteristic analysis of sea clutter is important in utilizing radar observations and detecting sea-surface targets. Measurement data signals are analyzed to determine the fractal characteristics of sea clutter signals. Sea clutter is a nonlinear, nonstationary radar echo signal. A novel method that detects targets in sea clutter is proposed by utilizing the complex empirical mode decomposition (CEMD) and combining it with fractal characteristics. The CEMD method is applied to decompose sea clutter signals into several intrinsic mode functions (IMFs). Fluctuation analysis is utilized to calculate the Hurst exponent for the main functions of IMF after which real sea clutter data are used for training and testing. Results show that targets in sea clutter can be effectively observed and detected through the proposed method, the performance of which is better than that of the target detection method for EMD and Hurst exponent under typical time.