Reseach On Algorithm And Implementationthe Of Cfar Under Clutter Interference In Radar

The signal detection under complex clutter background has always been a major component of the signal processing. The technology of Constant False Alarm Rate gains the ability of target detection, while keeping the false alarm rate being constant. Although CFAR has been widely used, but due to variation and edge of the clutter background, there are many problems and challenges waiting to be solved. This thesis is based on the classical CFAR theory. CFAR theory in frequency-domain and also under the K distribution of sea clutter is discussed in it. In combination with the research on theory, implementation on FPGA is conducted too.At first, the classical CFAR theory is researched. There are some analyses and compares between Mean-level and Ordered Statistics detector about detection performance under homogeneous clutter and the edge of the clutter. The thesis provides the theory basis for implementation by analyzing the influence of the parameters.Then, CFAR in frequency domain is investigated. Combining with MTD-CFAR Processing structure, the thesis studies the distribution of the clutter and signal after DFT. Influence by MTD is also discussed in it. In order to prevent the phenomenon of “signal pollution” which is caused by the extension of the frequency domain signal, treatment schemes are proposed.The correlation of sea clutter is a significant factor which affects the detection performance. Based on the foundation of classical theory under homogeneous clutter background, this thesis expands the Mean-level and Ordered statistics detector under K distribution and analyzes their detection performance. Through simulation and theory analysis, their detection performance is compared with the optimal detector under Rayleigh distribution. What’s more, to further validate the theoretical analysis, the thesis is discussed combined with simulation data.Finally, the specific scheme of the implementation of CFAR is provided, and according to the characteristics of the platform itself, it is designed by FPGA in the actual signal processing system. The process and steps of the implementation is discussed too. On the basis of CFAR which is one-dimensional, the CFAR of two-dimensional is further derived. Through the analysis about the process of data processing, the structure of implementation has been optimized.. The system is tested though the experiment and compare between the experimental results and the theoretical value id done. The experimental result of two-dimensional CFAR which is adopted in this thesis shows that. The two-dimensional CFAR does not only detect the target effectively, but also keep the false alarm in an effective way.Through the analysis of CFAR under complex clutter background, the detection performance of classical detector is achieved. What’s more, the Implementation of a two-dimensional CFAR of Range-Doppler domain is accomplished.