Research And Implementation Of PD Radar Pulse Pressure Sidelobe Suppression And Moving Target Accumulation Algorithm

Pulse Doppler radar is a kind of fully coherent radar which detects the distance and relative velocity of moving target based on Doppler effect of moving body.The paper introduces and studies the basic signal processing flow of pulse Doppler radar,focusing on the design technology of digital down conversion module and pulse compression module.Based on the characteristics of band-pass sampling,a timing control extraction module is designed for the digital down conversion module,which directly extracts IF echo to form I/Q two orthogonal IF echo,greatly reducing the consumption of resources on the board.In order to solve the high distance sidelobe problem after pulse compression,a new "three-term Gaussian window" for weighting is proposed by comparing the existing methods at home and abroad.The weighted window function can reduce the peak sidelobe by about3.7d B compared with the traditional matched filtering under the condition that the main lobe does not expand after pulse compression.By introducing variable adjustment to the window function,it can adjust the main lobe expansion and peak suppression ability.Compared with the existing Kaiser window method,under the same main lobe broadening condition,the "three Gaussian window" can further suppress the peak sidelobe by about 5d B.Then,on the basis of the above theoretical research,the paper based on FPGA simulation software to achieve the digital down conversion module and pulse compression module software simulation,and based on the development board to achieve the hardware platform algorithm module verification.The causes of migration problems in phase-coherent accumulation of moving targets are firstly analyzed.The first-order Keystone algorithm is introduced and studied to correct the range migration problems of phase-coherent accumulation of uniform velocity targets,and the second-order Keystone algorithm is introduced to correct the range bending and Doppler frequency migration problems of phase-coherent accumulation of uniformly accelerated targets.Aiming at the shortcomings of the second-order Keystone algorithm with large errors and large computation,this paper proposes to correct the migration problem in phase-coherent accumulation of uniform acceleration target based on the slow time axis reverse sequence +first-order Keystone algorithm.The simulation results show that the accuracy of velocity measurement is improved while the processing computation is significantly reduced.