A Weak Target Detection Method in Sea Clutter Based on Joint Space-time-frequency Decomposition

The target on the sea destroys the movement of the sea and affects an area around the target. Therefore, radar echoes from a target on the sea can be found in several successive range cells. Analysis of the echoes shows that the echoes of the target have a long range correlation in space. In this paper, we propose a target detection method by using the joint space-time-frequency decomposition, according to the diffidence between the target echoes and the sea clutter. Therein, the cross S-Method is proposed, which can be considered as the summation of the cross Wigner-Ville representations of the signal components and the sea clutter components, respectively. By using the inverse transform of the cross Wigner-Ville representation, we decompose the echoes from successive range cells. Then a signature, revealing the cross time-frequency concentration, is used to find the signal component in the decomposed signal components. The proposed method is evaluated by the X-band sea echoes with a simulated target or a real target. Results demonstrate that the proposed method not only detects the weak target in high accuracy, but also provides its instantaneous state.