Research And Implementation Of High-speed Target Detection Technology Using LFM Rada

In the application of missile-borne radar,prolonging the coherent accumulation time is an effective method to improve the detection ability of weak maneuvering target,but the detection performance is affected by the fluctuation of range and Doppler frequency caused by long-time accumulation.In this paper,the signal processing method of high-speed target is studied on the background of the radar research project of a space research institute,and the realization of active linear frequency modulation(LFM)radar signal processor Digital Signal Processing(DSP)is completed.The main work of this paper is as follows:1.For the range walk of the constant speed target,according to the characteristics of radar receiving ground guidance station signal,the echo frequency domain energy accumulation algorithm under the condition of velocity binding is proposed.This method compensates the velocity phase term in the frequency domain according to the time-frequency characteristics of the signal,and corrects the envelope walk of the echo.2.For the phase fluctuation of acceleration target,two acceleration estimation algorithms are designed.Under the condition of velocity binding,the double orthogonal fourier transform(BFT)is used to estimate the acceleration by using the slope density spectrum under the double orthogonal basis.The algorithm can estimate the acceleration of multiple targets due to its linear characteristics.Under the condition of unknown velocity,the difference cancellation transform is used to cancel the quadratic phase term of the signal conjugate multiplication between adjacent pulses,and the acceleration is estimated by fast fourier transform(FFT).The simulation shows that the target acceleration estimation error of the algorithm is less than0.2% in the signal-to-noise ratio(SNR)0d B environment.3.For the complex coupling effect caused by the third-order phase fluctuation of maneuvering target,a third-order parameter estimation algorithm based on Taylor transform is proposed.After correcting the linear range walk of the signal and combining with the Taylor series expansion,the two-dimensional parameter matching search is carried out in the range frequency domain.The simulation results show that the estimation error of velocity,acceleration and acceleration rate is less than 0.1% in the SNR-10 d B environment,and the algorithm can effectively focus on multiple weak targets.3.For targets with acceleration rate,a three-order parameter estimation algorithm based on keystone transform is proposed.Two-dimensional parameter search is carried out by Taylor series expansion.The estimation error of parameter is less than 0.1 %,and multiple targets can be effectively processed due to the linear characteristics of the algorithm.4.The engineering scheme of LFM radar signal processor DSP is designed,including the realization of real-time signal processing,instruction communication and data transmission.Finally,the signal processing test results of the equipment in the microwave anechoic chamber are given to verify the ability of radar to track the target.