| Although MIMO technology has been widely applied to fight against multiple-patheffects for communication system, MIMO radar is a relatively new field to be furtherstudied. MIMO radar is a new radar system that employs multiple transmiting antennasand multiple receiving antennas. So far there exist two definitions of MIMO radars. Thefirst one is proposed by Lincoln Laboratories, transmitting orthogonal signals, whichhas much in common with the traditional phased-array radar. The second one isstatistical MIMO radar using spatial diversity at both the receiving-array andtransmitting-array, which is more different from the traditional phased-array radar. Andit employs spatial diversity gain instead of coherent gain to fight against targetfluctuation.With the key study of the second one mentioned above—statistical MIMO radar,the contributions of this work are:(1) Comprehensive research of signal model of MIMO radarThis article introduces the signal models of phased-array radar, orthogonal signalMIMO radar and statistical MIMO radar in detail, including the general and individualcharacteristics. Special stress is given on three signal models of statistical MIMO radar,and evolution process from distributed target model to ideal point-source model is alsodiscussed as well as the principle of how to realize spatial diversity gain. Throughanalysis of influence of RCS on target detection performance, the limitations oftraditional phased-array radar and the advantages of MIMO radar are also presented.(2) Analysis of contributions of spatial diversity gain on detection performanceThe detection performances of statistical MIMO radar and the traditionalphased-array radar play a dominant role under different conditions, the contributions ofspatial diversity gain on detection performance is analyzed and compared with that ofphased-array, and it is concluded that the former is beneficial to increase the number ofindependent channels and the latter can increase SNR of each channel. Throughtheoretical analysis and simulation experiments on MISO, SIMO and sub-array MIMO,it is concluded that the detection performance can be effectively enhanced by rationally adjusting the proportion of two kinds of gain.(3) Analysis of influences of non-ideal factors on detection performanceThis article discusses the approximate expression of detection performance underthe condition that the RCS of target is partially correlated. In addition, with comparisonbetween statistical MIMO radar and phased-array radar, it is concluded that thecorrelation of clutter has more influence on phased-array radar.(4) Research on polarization statistical MIMO radarSpatial diversity is not the only technique to mitigate target RCS fluctuation. Withthe combination of polarization diversity and spatial diversity, the article derives thesignal model and average detection performance of polarization statistical MIMO radar.In addition, the transmitting power distribution of each polarizing direction is discussed,and a linear optimization algorithm is presented to find approximate optimal solution.(5) Research on robust detection system of CFAR and anti-jammingBased on requirements for robustness, research on CA-CFAR and OS-CFARdetectors of MIMO radar is included in this article. And the waveform design ofdetection system is also discussed in order to guarantee the lower limit of detectionperformance in jamming background.
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