Study On Velocity Measurement And Ranging Method Of Air-Based LFMICW Radar For High Velocity Moving Targets

The research and development of high-velocity aircraft directly contributed to the development of air-based radars,and the air-based radar plays an important role in safeguarding own security and enemy detection.However,the Linear Frequency Modulation Interrupted Wave(LFMICW)is a kind of radar system which has the characteristics of both pulse radar and continuous wave radar.It has the advantages of low peak power,long range,good transceiver isolation and low interception rate.These advantages make it ideal for the air-based radars applied for complex battlefield environments,high concealment requirements,and high detection performances.This thesis focuses on the problems of detection for high-velocity moving targets by air-based LFMICW radar.It mainly studies the problems of velocity measurement,ranging and tracking for high-velocity moving targets.The main research works are summarized as follows:1.According to the high-velocity relative motion between the radar and target,the single-cycle and multi-cycle echo signal models of the point target are built.Based on the model,analyzed the range aliasing,range velocity coupling and range migration which affect the accuracy of velocity measurement and ranging.2.Aiming at the range aliasing problem which introcduces the false targets into the range profile,the method for removing range aliasing by using LFMICW transmitting signal with staggered interrupted pulse is adopted.This method can completely eliminate the range aliasing phenomenon in single-target or multi-target environments.3.Aiming at the range migration problem caused by high-velocity relative motion,the migration correction algorithm based on velocity compensation and based on keystone transform are studied,the algorithms not only correct the migration but also achieve the coherent accumulation at the Doppler dimension.4.Aiming at the problem of velocity and range acquisition,a two-dimensional FFT method based on velocity defuzzification is studied when the velocity ambiguity is small,a method based on frequency domain pairing is studied when the velocity ambiguity is large.Both can acquire the velocity and range.5.Aiming at the problem of the velocity measurement and ranging continuously for high velocity target,the tracking method of high-velocity target based on Kalman filtering and ?-? filtering are studied,which can effectively track the uniform high velocity moving target.The above work has been verified by simulation.The results show that the air-based LFMICW radar can achieve velocity measurement and ranging accurately and track the high-velocity moving targets.