Research On Low-Grazing Angle Detection And Parameter Estimation With MIMO Radar

Low-grazing angle flying targets are difficult to detect and track is one of the four great threats propelling radar development, and this has failed to effectively solve. Recent years, a new radar conception based on Multi-Input Multi-Output(MIMO) array configuration has drawn much attention. MIMO radar using diversity gain in target detection,parameter estimation, target tracking, target recognition and anti-jamming, and et al, compared with the traditional radar has obvious advantagets. Encouraged by the success in radar, MIMO radar can do to solve the low altitude flight to target detection technique approach. In recent years the domestic and foreign scholars have conducted extensive research on the MIMO radar in target detection, imaging identification, parameter estimation, but the low altitude target in MIMO radar technology based on the detection and parameters are rarely involved. We try to solve the low altitude target detection and parameter estimation problem, the dissertation on key issues of low altitude MIMO radar theory model, low altitude MIMO radar detector design and low altitude MIMO radar parameter estimation. The main contents of this thesis are arragemented as follows:In Chapter 1, background and siginificance of this paper are first expounded. Introduces the low altitude target detection and tracking the status and research on MIMO radar concept, classification and its application in the field of target detection; Summary of some key technologies of low altitude target detection.Baed on the widely used at present Swerling model, research detection performance of MIMO radar for low Swerling target. Firstly, considering the atmospheric refraction and reflection coefficient of the curvature of the earth; Introduced the MIMO radar low altitude multipath signal model; The detection probability and false alarm probability are derived low non-fluctuating targets and fluctuating targets, respectively, and analyze the detection performance of MIMO radar for low Swerling target model through the simulation experiment.In order to prove that MIMO radar in the low altitude target detection advantage in theory, the third chapter mainly analysis and comparison of the performance of the MIMO radar and phased array radar in low altitude target detction. Firstly, the MIMO radar and phased array radar low altitude multipath signal model are derived. The probability of low altitude detection probability and false alarm of MIMO radar and phased array radar based on the Neyman-Pearson criterion are derived respectively. Finally, analyzes the system design problems of MIMO radar and phased array radar based on the relative entropy,respectively. Both theory analysis and simulated experiments have demonstrated that: for the problem of low altitude target detection, MIMO radar is superior to the pahsed array radar, and the detection performance of MIMO radar are concerned with the number of array and the height of target.Low altitude radar clutter model often uses the compound gaussian model, the fourth chapter studies the low altitude detector design based on compound gaussian clutter model with MIMO radar. First of all, the MIMO radar multipath vctor signal model are derived.On this basis, design generalized likelihood ratio test-Linear quadratic detector(GLRTLQ), generalized likelihood ratio test(GLRT) detector and Rao detector, and analysis of low altitude detection performance of the detector. It is found out that, the GLRT and Rao detector has the constant false alarm rate(CFAR) properties, generalized likelihood ratio test-Linear quadratic detector of low altitude detection performance is better than the generalized likelihood ratio detector and the Rao detector, and the multipath effect on the importance of low altitude detection. The number of radar antenna and the height of the target of low altitude detection performance has a significant influence.In Chapter 5, we proposed based on the parameter expanded expectation maximization(PX-EM) parameters estimation method of low altitude moving target in MIMO radar. Firstly, the low altitude moving target in MIMO radar multipath signal model is derived, which laid a theoretical foundation for the low parameter estimation. We develop maximum likelihood(ML) methods for jointly estimating the target and clutter parameters in compound gaussian clutter using MIMO radar measurements. For unknown parameters, proposed a maximum likelihood estimation algorithm based on PX-EM algorithm. The texture components obey Gamma and inverse Gamma distribution Cramer–Rao bounds(CRB) are derived.In Chapter 6, we make a summary of the thesis, and several problems which are still needed to be exploited are proposed.Tosummarize, the MIMO radar has attracted more and more attention in recent years as the research object,has carried on the preliminary exploration in the aspect of system concept, theory model, system design, detector and parameter estimation etc. The research may enrich system info of MIMO radar, and provide some constructive reference for recognizing, understanding the future low altitude detection and parameter estimation.