Research On Moving Target Detection Technology Of Frequency Diverse Array Radar

In recent years,the combination of frequency-diverse array(FDA)radar and multiple input multiple output(MIMO)technology for target detection and parameter estimation has attracted particular attention.But FDA-MIMO radar in the detection of moving targets,due to the frequency offset between the transmitting array coupling the motion parameters of the target,Doppler spread appears,which degrades the coherent accumulation of the signal energy of each channel of the receiver and reduces the detection performance of the system.In this thesis,the Doppler spread of FDA-MIMO radar in detecting moving targets is analyzed in detail,and the problem of simultaneous multi-moving target detection is also studied.Finally,the corresponding solution is proposed.The main research work is summarized as follows:1.The FDA-MIMO radar echo signal model of moving target is established,and the fuzzy function of FDA-MIMO radar is deduced,and the application potential of FDA-MIMO radar in target detection is analyzed.At the same time,the maximum likelihood receiver model of FDA-MIMO radar is also given.The Doppler spread effect caused by the frequency offset is analyzed theoretically and simulatively.2.In order to solve the Doppler spread problem of FDA-MIMO radar in detecting moving targets,the moving target detection algorithms for FDA-MIMO radar based on Doppler spread compensation are proposed to achieve coherent accumulation of echo energy.For uniform velocity target detection,a joint compensation function algorithm based on keystone transform and a joint interpolation filter algorithm based on resampling are proposed to suppress the Doppler spread effect caused by array frequency offset,and to compensate the cross cell movement of sub-target echo in range dimension.For uniformly accelerating target detection,a algorithm based on resampling combined with LVD is proposed,which could eliminate the Doppler spread caused by velocity and frequency offset and the range-dimensional cross cell walking problem.Meanwhile,LVD was used to estimate the target acceleration,and the compensation function was constructed to suppress the Doppler spread caused by acceleration,so as to realize the coherent accumulation of signal energy.The numerical simulation results show that the proposed algorithms can suppress the Doppler spread effect in FDAMIMO radar moving target detection and correct the target's travel in the range dimension,which can obtain high signal processing gain and achieve good detection performance.3.In the multi-moving target detection of FDA-MIMO radar,multiple target velocities and frequency offset coupling produce Doppler spread effect superposition with different degrees,and it is difficult to obtain the number of targets from the detection results.A multi-moving target detection algorithm of FDA-MIMO radar based on DBSCAN density clustering is proposed.Firstly,according to the resampling joint interpolation filtering,the coherent accumulation of signals is realized by self-adaptive compensation of Doppler spread effect of multiple targets.Then,without the need to set the number of clusters in advance,the data set obtained after constant false alarm detection of coherent accumulation results is clustered and divided into clusters,so as to realize the adaptive estimation of the number of multi-moving targets.The simulation results show that the multi-target Doppler spread effect is effectively suppressed,and the proposed algorithm can filter the detected noise points effectively,and achieve good clustering performance.