Research On Airborne Radar Clutter Real-time Simulation Technology

With the rapid development of radar technology,radar simulator has been more and more important for the evaluation of radar performance.In addition to simulating target and various interference signals,radar simulator can also simulate clutter signals reflected by the environment,which will directly affect the performance of radar target detection.Therefore,through simulating clutter signals from various kinds of environment,radar simulator can be utilized to test the detection ability of radar.Particularly,for airborne radar clutter,considering the movement of platform,there will be extra Doppler frequency and broadening phenomenon in its spectrum.This is quite different from that of the clutter received by ground-based radar.As a result,we should pay much attention to the study of airborne radar clutter simulation.When simulating airborne radar clutter,the real-time requirement need to be taken into consideration.This thesis carries out the research from the following aspects:1.Radar clutter based on statistical characteristics is modeled and simulated.Firstly,the distribution characteristics of amplitude and power spectrum of radar clutter are simulated and analyzed,and then two methods,ZMNL and SIRP,are discussed in detail.At last,the ZMNL method is used to analyze the correlated coherent Rayleigh distribution clutter sequence and the correlated coherent Weibull distribution clutter sequence.2.Modeling and simulation of ground clutter based on flat airborne radar.A meshing method is proposed to mathematically model the power spectrum of airborne radar clutter.The clutter power spectrums in the modes of low,medium and high pulse repetition frequency are simulated and analyzed,and the influence of related parameters on the clutter power spectrum are discussed.Through the simulation analysis,it can be concluded that the grid division method can well simulate the airborne radar ground clutter.3.In order to solve the problem that grid division method needs integrating calculations when modeling airborne radar clutter,which consumes a large amount of computing time,a simplified model of airborne radar clutter is proposed.Firstly,we establish the simplifie models of main lobe clutter,height line clutter,and side lobe clutter,and then combine them with the sampling rate of the hardware implementation to generate clutter reduced model data and analyze different interception methods.Finally,by analyzing and comparing clutter power spectrums obtained by the reduced model and grid division,it can be concluded that the simplified model not only simulates the clutter well,but also reduces the computation greatly,which meets the real-time requirement.4.Using clutter simplifie model data as clutter raw data input when clutter simulator hardware is implemented,a system solution for airborne radar clutter simulator is proposed.We utilize Vivado and Verilog to design and test digital channel module,clutter raw data generation module,waveform-based real-time convolution module and digital up-conversion module.Finally,the hardware system as a whole is tested and analyzed.