Design And Development Of Test System For SAR Echo Simulation Of The Sea Targets

The synthetic aperture radar(SAR) is an all-day and all-weather two-dimension remote sensing imaging radar. It has been served as an effective technique in many applications like battlefield surveillance, attack on sea targets, terrain mapping, and ocean observation, etc. With regard to this fact, this paper focuses on the study of SAR echo simulation, especially on sea scene and target signal returns simulation. Besides, a test system is designed for SAR echo simulation. The remainder of this paper is organized as follows.Firstly, the SAR signal model is analyzed. Based on this model, the ideas of Range Time domain Pulse Coherence and Range Frequency domain Pulse Coherence are discussed respectively. Then the efficiency and accuracy of the two methods are compared by simulation experiments. With practicability, efficiency, and accuracy under consideration, the range-frequency method is adopted in the following experiments.Secondly, the meaning of classic ocean wave spectrum is introduced, followed by several classical models of it. Based on this, a simulation method for physical sea surface is presented. Then the physical sea surface at different wind speed is simulated, which is divided into small scattering cells. Finally, the DS model, combined with the backscattering coefficients of those scattering cells calculated by electromagnetic method, is used to simulate the echoes of sea scenes. The correctness of the proposed method is validated by comparing the statistical characteristics of simulated sea echo with theory.Thirdly, the basic idea of ship target scattering center model is explained. In experiment, the scattering center model of a real ship is established, based on which the ship echo is simulated. And the echo is proved correct by imaging algorithm. Then the multi-path scattering model of time-variant sea target is analyzed. Finally, a flowchart is proposed to simulate echoes of time-variant sea targets, which is verified by imaging processing.Finally, the basic structure of the digital simulation and test system is introduced, including the software design requirements, the basic idea of software design, and its realization. Then there follows the design solution and realization of several modules, such as the main interface, login interface, Demo testing module, and echo generation module. Finally, several key techniques used in the system are introduced, including VC++ and Matlab mixed programming, network programming, and public data storage. Those techniques have already been widely used in practice.