Multitarget Parameter Identifiability Of MIMO Radar

Multiple-Input Multiple-Output(MIMO)radar takes advantages of waveform diversity to enhance multitarget parameter estimation.As a basic characteristic of a radar system,parameter identifiability is one of the main research directions of MIMO radar multitarget parameter estimation.However,current researches mainly consider the parameter identifiability of MIMO radar on different directions,which can also be influenced by the distance and speed of targets.Therefore,this dissertation aims to provide the theoretical criterion of parameter identifiability of MIMO radar based on different signal models which include the impact of direction,range and speed.According to the number of varieties,MIMO radar can be divided into three types: space-only MIMO radar which only considers the direction of targets,space-time MIMO radar considering direction and range and space-time-doppler MIMO radar considering direction,range and speed.Firstly,the signal model of traditional space-only MIMO radar and the derivation of its parameter identifiability are introduced in this paper,and the limitation of space-only MIMO radar is also presented.The maximum identifiable number of targets of space-only MIMO radar is M times that of its counterpart phase array radar,where M is the number of transmit antennas.Then,the influence of target range of is added into the MIMO radar signal model,and space-only MIMO radar is extended into space-time MIMO radar.The parameter identifiability of space-time MIMO radar is analyzed and the maximum identifiable number of targets is derived to be N times that of a space-only MIMO radar,where N is the number of range bins.The independence of the parameter identifiability of different range bins is also pointed out.The lower bounds of the number of antennas is presented under a certain number of targets and range bins,which can be used as guidelines for radar system design and algorithm application.Finally,the doppler shift caused by target speed is added into MIMO radar signal model and space-time MIMO radar is further extended into space-time-doppler MIMO radar.Via separating the signals in different doppler bins apart,the maximum identifiable number of targets of space-time-doppler MIMO radar is derived,and it is Q times of its counterpart space-time MIMO radar due to its further extended information in doppler dimension.The results are validated by the simulations.Moreover,it's also pointed out that different doppler bins can not compensate each other,namely,the parameter identifiability of a single doppler bin cannot be enhanced by other doppler bins.