Study On Joint Multi-target Parameter Estimation Methods For MIMO Radar With Non-uniform Linear Arrays

As a new radar system,multiple-input-multiple-output(MIMO)radar has drawn a lot of attention from scholars at home and abroad by virtue of its many advantages compared to the traditional radar system.Moreover,as the key technology of target localization and imaging,target parameter estimation is an important aspect of study on MIMO radar and it possesses a very important practical significance.However,the traditional MIMO radar system is configured by uniform linear array(ULA).Taking the transmit diversity MIMO radar as an example,its maximum number of identifiable targets is the number of its receiver array minus one,meanwhile,its spatial resolution is proportional to its receive array aperture.In the case of insufficient number of receive array elements,the spatial resolution of the MIMO radar is very limited.The non-uniform linear array(NLA)is a recently emerging array shape,typically including the coprime array,the nested array,etc.The NLA has unequal inter-element spacing which is an integer multiple of the half carrier wavelength and meets certain conditions.Meanwhile,the NLA possesses large array aperture and a large number of virtual array elements,which makes it become one of the hot spots of the array signal processing.The MIMO radars in this paper are configured by NLAs,which can enlarge the maximum number of identifiable targets of MIMO radars and enhance the spatial resolution and target parameter estimation accuracy of MIMO radars.By configuring different kinds of MIMO radars with coprime arrays and nested arrays,the problem of joint multi-target parameter estimation for MIMO radar with non-uniform linear arrays is investigated in this paper.The research work of this paper is funded by the national natural science foundation of China(No: 61371158 and No: 61071140).The innovation work of this paper is as follows:By configuring the receive array of the transmit diversity MIMO radar with coprime array and nested array,two improved transmit diversity MIMO radars are proposed in this paper.The signal models are built,and the corresponding target direction finding algorithms are proposed.The simulation results show that the two improved transmit diversity MIMO radars both can achieve accurate target localization when the number of the targets are far more than the number of thereceive array elements.Meanwhile,the two improved transmit diversity MIMO radar possess higher spatial resolution compared with the traditional transmit diversity MIMO radar.By configuring both the transmit array and receive array of the bistatic MIMO radar with nested arrays,an improved bistatic MIMO radar is proposed in this paper.The signal model is built and a joint DOD/DOA estimation algorithm is proposed.The simulation results show that the improved bistatic MIMO radar possesses higher two-dimensional angle resolution.By configuring both the transmit array and receive array of the polarimetric MIMO radar with coprime arrays and adopting the coprime sampling method in time domain,an improved polarimetric MIMO radar is proposed.The signal model is built while two target multi-parameter estimation algorithms that based on PARAFAC-TALS and PARAFAC-QALS are proposed,respectively,which can achieve the estimation of DOD,DOA,polarimetric parameters and Doppler frequency of targets.To further extend the array aperture,both the transmit array and receive array of the poparimetric radar are configured with the nested array,and the nested sampling method is adopted in time domain.Two target multi-parameter estimation algorithms that based on PARAFAC-TALS and PARAFAC-QALS are proposed,respectively,which can achieve the estimation of DOD,DOA,polarimetric parameters and Doppler frequency of targets.The simulation results show that the two algorithms both can achieve higher spatial resolution and multi-parameter estimation accuracy.