Study On Polarized Waveform Design Methods For MIMO Radar With Distributed Antennas

Since MIMO (Multiple Input Multiple Output) radar rises, its system strengthshave been recognized by many scholars. It has more tremendous advantages over thetraditional radar in many aspects, such as the capability of target detection and theaccuracy of localization. Its waveform diversity is the main difference to ordinaryphased array radar.As the development of the polarization measurement techniques, the MIMOradar based on polarization diversity has been concerned. It has the abilities to capturethe polarization information in target echo signals and to transmit waveform withdifferent polarizations. By changing the polarization of the transmitted waveform, theperformance of MIMO radar target detection can be significantly improved. However,the polarization characteristics of waveform hardly be taken into account in traditionalMIMO radar waveform design. Thus, the polarization diversity advantages of suchMIMO radar could not be fully exploited.Firstly, a traditional method of MIMO radar waveform design is analyzed, andthe results are verified by simulation. On this basis, to address the above problem, themethods of polarized waveform design for distributed MIMO radar is investigated.And a method of polarized waveform design for distributed MIMO radar is proposedbased on information theory, which improved the ability of MIMO radar to obtaintarget information. Then, base on game theory, a method of polarized waveformdesign for distributed MIMO radar in the clutter environment is proposed. And thepolarized waveform designed based on this theory improved the radar target detectioncapability in complex environments. The work is supported by the project “Jointparameter estimation and target localization based on polarization diversity in MIMOradar”（No.61071140）, which is a National Natural Science Foundation project.The main innovative work is as follows:With to distributed MIMO radar, an adaptive method of polarized waveformdesign base on mutual information theory is proposed. In this method, the designcriterion is minimizing the mutual information of target echo signals at current time and the next time. According to this criterion, the polarized waveform to betransmitted is dynamically designed, such that, at the next time MIMO radar canobtain more new information about the target. For solving the problem of jointoptimization of multi-dimensional polarized parameters, an alternating projectionoptimization algorithm in multi-dimensional space is proposed, which will reduce theproblem that multi-variables are jointly optimized to the problem that a plurality ofsingle variables are alternately optimized. And it greatly reduces the complexity ofdata processing.As the method based on information theory can not be used for complexenvironmental. A polarized waveform design method for MIMO radar with clutterexistence is further proposed based on game theory. First, the received signal model ofdistributed MIMO radar with clutter is described. Then, the problem of designingpolarized waveform can be taken as the strategy issues that the waveform designershould consider in the game with his opponent, and the received signal to clutter ratiois chosen as the payoff function, so that the polarized waveform design under thecomplex environment is accomplished. The polarized waveform designed by thismethod enhances the target detection capability of MIMO radar in clutter environment.Moreover, since there is no need to know specific target characteristic, the step can besaved that acquiring the characteristics of the target in real time by doing experiments,which reduces the cost and difficulty of the radar waveform design.