Multi-parameters Estimation Method Of High Speed Target Based On Bistatic MIMO Radar

High-speed weapons have a particularly strong penetration ability and are more and more popular in modem military war.The high-speed weapons play a significant role in modem military war,which can effectively break through the existing radar defense system and bring a great threat to national security,posing a serious challenge to the traditional system of radar.Bistatic MIMO radar is a new radar system,which has got the wide attention of the scholars.The bistatic radar has the advantages of resisting anti-radiation missile and anti-jamming;Multiple input multiple output signal has the characteristics of expanding the antenna aperture,improving the target detection performance and parameter measurement performance.Owning to the fact that the high-speed moving target moves across several range cells during the long coherent observation period,the energy of the target is scattered over multiple range cells and the estimation of angle,Doppler and other parameters with the echo data located at the single rang cell has considerable error for the high speed moving targets.One of the problems that cannot be ignored when detecting the high-speed moving target is the Doppler frequency sensitivity of the waveform.The pulse width of the radar emitted waveform in modern warfare is becoming wider and wider,which leads to the problem that the Doppler sensitivity becomes more prominent.So the waveform designed requires a good Doppler tolerance so that there are as little as possible loss of Doppler while matching in the filter of the receiver.In this thesis,the joint parameters estimation method with multiple range cells and the waveform design are studied for the above-mentioned problems.The main work is divided into the following two aspects:Focused on the range walk of high-speed targets,a method for estimating parameters combing multiple range cells based on bistatic MIMO radar is proposed.Firstly,according to the characteristics of the echo of the signal,the echo signal model of bistatic MIMO radar is established.By making the rough estimate of the targets in each range cell,the number of range cells that target moves across is obtained,and then pulse compression to every range cell with the corresponding reference signal and using the traditional super-resolution algorithm for joint angle and Doppler estimation are is exploited to obtain the high precision estimation of velocity and location.The simulation results indicate that the parameter estimation accuracy of the proposed method for the high speed moving targets,which is independent of the number of range cells that target moves across,is better than that of the existence approaches,and is close to that of the existence approaches with no range migration occurrence.Focused on the Doppler sensitivity of radar signal,a phase-coded stepping frequency signal is designed.The carrier frequency of different elements is changed at a fixed step frequency interval,and the sub-pulse is modulated with polyphase code.Then,the GA algorithm and the SA algorithm are combined by making use of the correlation energy of the polyphase code as cost function.The strong global search capability of GA and strong local search capability of SA are beneficial to the optimization of polyphase code to obtain good autocorrelation performance and cross-correlation performance.Based on the derivation and simulation of the fuzzy function of the phase coded stepping frequency signal,it is proved that the waveform has good distance resolution performance and good Doppler tolerance,which is helpful to the detection and parameter estimation of high speed target.