Research On Modeling And Simulation Of Sea Clutter And Implementation On FPGA

Radar signal simulator becomes an indispensable part of radar system designing for its versatility, flexibility, scalability. As a key part of radar signal simulator, clutter simulation imposes a crucial impact on the overall performance of the radar signal simulator. The accuracy of sea clutter model becomes an important criterion when accessing the radar signal simulator's performance. The research work of this paper presents three problems at the background of radar signal simulator, including the statistic modeling and simulation of sea clutter, the real-time generation of sea clutter based on FPGA, and the system implementation of sea clutter's echo signal. The results of the researches mainly involve:Chapter 1 firstly introduces the background and significance of the research work. Secondly, current development status and future trend of radar signal simulator and sea clutter are presented. The latest progresses of key components are also introduced. Finally, content of the research work and overall framework of the paper are given.Chapter 2 focuses on the statistical modeling and simulation of sea clutter and the selection of sea clutter model. Firstly, the concepts of sea clutter are outlined. Secondly, commonly used statistical models of sea clutter are introduced, including the amplitude distributed model, the backscattering coefficient model and the power spectrum model. On the basis of these, two common methods of simulating the sea clutter are presented, Zero Memory Non-Linearity (ZMNL) and Spherically Invariant Random Process (SIRP). Thirdly, combined with the practical application of the radar signal simulator scenarios and based on the analysis of measured data, the problem of selecting the sea clutter model is solved and the way to generate the model is also given. Lastly, the model is simulated and the simulation result is given.Chapter 3 focuses on the specific methods of the model implementing on FPGA, which is based on the theoretical foundation of the previous chapter. Firstly, the principle and immplementation method of Coordinate Rotation Digital Computer (CORDIC) algorithm is introduced. Triangle function is implemented using the CORDIC algorithm. Secondly, the methods of generating random number are proposed. The simulation result is analyzed and then compared with the theoretical values. Thirdly, Finite Impulse Response (FIR) filter is introduced, which is commonly used in the field of digital signal processing. A simplified hardware implementation of FIR filter structure is given. Finally, the statistical model of sea clutter is implemented on the platform of FPGA and experimental results of the simulation are analyzed. The results show that the model is correct.Chapter 4 focuses on the system implementation of sea clutter echo signal. Firstly, the method of compartmentalizing sea clutter area under the radar beam irradiation is proposed and the calculation of antenna pattern is also given. Secondly, the method of generating sea clutter echo signal and implementation flowchart is proposed. The results of simulation is given and analyzed. Lastly, the hardware implementation platform of sea clutter echo signal and system performance indicators is discussed. The results show the effectiveness of the system. The method based on FPGA platform for sea clutter echo signal has some guiding significance for other radar signal simulators.