Research On Digital Signal Processing System Of High Performance Digital Beamforming Array Radar

Digital beamforming(DBF)is a combination of antenna beamforming and digital signal processing,which is widely used in array signal processing.Digital beamforming technology can maximize the signal gain in one direction and effectively suppress the signal interference in other directions.The construction of digital signal processing system of array radar based on digital beamforming is the hot spot and key point in the development of modern radar technology.Based on the narrowband digital beamforming principle,a digital signal processing system for array radar is systematically implemented in this thesis.Firstly,the narrowband digital beamforming algorithm is simulated,the effect of the digital beamforming algorithm is verified,and the factors that affect the effect of the digital beamforming algorithm are discussed,which establishs a theoretical foundation for the implementation of the subsequent system.Then,the hardware platform of the whole system is built.The whole hardware platform is divided into modules according to functions,and the hardware implementation is carried out,including for the power module,the main control platform module,the analog-to-digital converter(ADC)signal acquisition module,the digital-toanalog converter(DAC)signal output module and the Gigabit Ethernet communication module.Then,on the basis of the hardware platform,the digital signal processing process is realized.According to the order of signal processing,the signal acquisition,high frequency and high sampling rate signal preprocessing based on field programmable logic gate array(FPGA),gigabit Ethernet transmission,digital beamforming algorithm realization based on FPGA and baseband digital signal conversion into analog IF signal output are studied and realized.Finally,the digital signal processing system of array radar based on digital beamforming technology is verified.In order to test the whole digital signal processing system in this thesis,the sinusoidal wave of 137.5MHz generated by the signal source is transmitted through the antenna as the received signal of the whole system.By comparing the SNR of the 16-channel synthetic beam with the SNR of the single-channel beam,it is found that the gain of the synthetic beam is at least 11.3d B and the average gain is 11.8d B.The analog output is connected to the spectrometer,and it is found that the analog IF output is 70.2MHz.The whole digital signal processing system can work normally and meet the equipment requirements.