Design Of Array Radar Baseband Echo Simulation System

During the development of the radar system,a large number of radar performance indicators need to be tested to find problems and deficiencies in the radar system and make improvements in a timely manner.The on-site test requires a flight test,and the test efficiency is low and the flexibility is insufficient.The accuracy of the test results will also be significantly affected by the interference of external environmental factors,and debugging is difficult.The difference is that the radar echo simulator is produced by the combination of digital simulation technology and radar technology.It can not only simulate the radar echo signal in real time,but also allow the radar system test to obtain almost the same input signal as the real situation.Radar system development and testing has a more efficient and convenient operating environment.The method of using radar signal simulator as a radar system verification tool is an inevitable trend of future radar system development.First,the baseband echo simulation system of the array radar is analyzed according to different functional requirements and performance requirements,and then according to the characteristics and actual requirements of the array radar,the overall design scheme of the array radar simulation system is proposed and the overall process is designed.The system first simulates the radar echo signal according to various parameters set by the control software,and then simulates the echo according to the different gains of the antenna surface,and adds ground clutter,meteorological clutter and interference,respectively signals form the reference echo data,and then multiply by the directional weighting coefficient to obtain the echo data of each array element.The parameters to be calculated include the doppler frequency,range delay,and radial delay of the target relative to the radial velocity of the radar.In order to reduce the amount of calculation and improve real-time performance,the channel receiver's output power and angle caused by the phase difference of each channel can generate reference data in the program initialization phase according to the input parameters.Then the wave position table compatible with phase scanning and machine scanning of the array radar was designed,and the main control interface of the graphical user interface(GUI)and various functional modules in the echo simulation system were developed.The wave position table stores the beam center direction of N wave positions and the waveform information of each wave position radar transmitting signal,which can be combined with the target route to judge the intersection of the target and the beam.Functional modules include noise module,transmitting signal module,antenna module,interference module,clutter module,and target module.(1)The noise module can generate gaussian and randomly distributed noise signals with specified noise power;(2)The transmit signal module can generate chirp or non-linear frequency modulation signals with a specified time bandwidth;(3)The antenna module can be set to form an array.Structure,transmit beam width and antenna scanning method,and generate steering vector and transmit antenna pattern;(4)The interference module can generate multiple interference signals with uniform linear motion,including radio frequency noise interference signals,spot frequency interference signals,and pulse interference signals,dense false target interference signals;(5)The clutter module can generate up to two clutter signals with uniform linear motion.The clutter distribution statistics include rayleigh distribution,lognormal distribution,weibull distribution,and K distribution;(6)The target module can generate echoes of multi-target ideal linear,circular and figure eight trajectories.Finally,a test case is designed for typical parameters,and the generated simulation data is processed in a coherent manner through pulse compression(PC),moving target detection(MTD),constant false alarm rate(CFAR)processing and spot condensing.After processing,obtain the position and doppler information of the target in the echo,and compare and analyze it with the theoretical setting value.The distance error of the simulation result is within a distance gate and the angle error is within 0.2°,which verifies the simulation data.Array radar baseband echo simulation system has the advantages of strong real-time,high flexibility,accurate processing results,simple operation and friendly human-computer interaction,etc.It has certain engineering reference significance for the test and improvement of actual array radar system.