【作者】 王胜；

【导师】 陈曾平； 付强；

【作者基本信息】 国防科学技术大学 ， 电子科学与技术， 2011， 博士

【摘要】 为了对雷达系统的功能与性能进行全面验证,需要获得目标和环境具有遍历性和代表性的试验数据,但这往往因需要消耗巨大的时间和经济成本而难以实现,因此雷达回波模拟就成为雷达系统、特别是其信号处理系统研制过程中重要的验证测试手段。随着先进雷达工作体制及其信号处理技术的发展,雷达可观测并提取到微多普勒等许多更为精细的目标动态特征,这对雷达回波模拟技术也相应地提出了更高要求。如何高保真地实时模拟目标多维雷达特征信号以及环境杂波,并研制相应的雷达回波模拟器,就成为推动雷达技术发展的一项重要课题。本文针对此问题,对动态目标雷达回波模拟算法及其实现技术展开研究,并在此基础上研制成功了一个可用于雷达半实物仿真测试的回波模拟器。绪论部分首先阐明了本课题研究的背景和意义,概述了雷达回波模拟技术的研究背景、主要研究内容、关键技术及其发展趋势,然后介绍了雷达回波模拟技术所面临的问题与发展方向,最后给出了本文的主要研究内容。第二章对动态雷达目标的运动仿真方法和电磁散射的快速算法进行研究。首先对影响动态目标电磁散射计算精度的目标模型剖分、曲面散射、动态仿真和快速计算等关键环节进行了深入分析,提出了电磁计算动态目标模型面元剖分的准则。随后重点针对目标非刚体运动,对雷达电磁散射的快速计算方法进行研究,提出了动态目标雷达散射序列的插值算法,并推导了该方法的误差上界。针对大平板面元的全等分割算法的提出进一步提高了插值算法的效率并扩展了插值算法的应用范围,通过与直接采用原始算法比较该方法的计算量为原始算法的十分之一。最后针对采用平板面元逼近曲面给散射计算引入的“面元噪声”问题,提出了一种基于神经网络的修正方法,极大地提高了曲面的电磁计算精度。第三章对动态目标回波建模问题展开研究。首先系统分析了目标的运动形态对雷达特征的影响,并给出了高分辨相参雷达体制下点目标振动的显著性条件,该显著性条件为动态目标散射中心的提出提供了理论依据。在此基础上,提出了可用于动态目标雷达回波建模的动态散射中心模型。目标的动态散射中心模型既体现振动目标的高分辨结构特征,又可以体现目标的随机性动态特征,为进一步实现雷达信号的实时模拟提供了理论基础。第四章对应用超大规模集成电路(VLSI,Very Large Scale Intergrated)对回波实时模拟系统的设计与优化技术展开研究。首先应用多CORDIC(Coordinate Rotational Digital Computer)单元共享正切查找表优化方法,设计并实现了基于动态散射中心模型的目标回波模拟可复用IP(Intellect Property)核。随后针对杂波实时模拟问题,提出了一种基于球不变随机过程(SIRP,Sphere Invariance RandomProcess)的任意时长全相参可变参数K分布杂波模拟算法,并实现了杂波模拟可复用IP核。该IP核的研制解决了K-分布杂波随场景和环境变化所引起的频谱及尺度参数和形状参数的时变问题,极大地简化了雷达杂波生成系统的硬件结构。第五章针对某典型应用对本文提出的模拟方法和实现技术进行了应用研究,设计并实现了用于雷达半实物实时跟踪仿真系统的动态目标实时回波模拟器。首先分析了雷达半实物实时跟踪仿真系统的总体结构及其关键技术。然后设计并实现了以VLSI片上系统(SOC,System on Chip)为核心器件的雷达回波实时模拟器,它采用基于动态散射中心模型的目标回波模拟技术,并配合高速并行的系统结构和流水式的数据处理,具有良好的保真度、实时性与交互性。最后,将动态目标实时回波模拟器成功应用于某雷达半实物实时跟踪仿真系统。更多还原

【Abstract】 In order to perform a comprehensive validation of function and performance for radar systems, ergodic and typical experiment data of targets and environments under different conditions are needed. However, it is usually time-consuming and costly, even unrealizable. Therefore, radar echo simulation is an important testing approach for advanced radar system design, especially for the signal processing system design. Due to the development of radar operating system and its signal processing techniques, it is possible to measure and extract many more elaborate dynamic features, e.g., micro-Doppler. Hence, the requirements for radar echo simulation technology accordingly rise. It is an important issue for radar system development to simulate target multi-dimension features and environment clutter in real-time operation with high precision and develop a corresponding radar echo simulator. Aiming at solving this problem, these dissertation studies echo simulation algorithms and implementation techniques for moving targets, and develop a radar echo simulator successfully, which can be used in Hardware-in-the-loop simulation.The background and significance of this work are presented in the introduction chapter. We first survey the background, contents, key techniques and their developing directions of radar echo simulation technology. An introduction of challenging difficulties and developing goals is then proposed. The main researching contents are given finally.In chapter 2, the motion simulation approaches for moving targets and the fast algorithms for electromagnetic scattering computation are studied. Firstly, we perform an in-depth analysis for key components which affect the precision of electromagnetic scattering computation, e.g., model partition, surface scattering, dynamic simulation, fast computation, etc. Secondly, fast algorithms for electromagnetic scattering computation are studied aiming at nonrigid body motion. An interpolation algorithm is proposed to compute scattering series for moving targets, and the error upper bounds of the algorithm are derived. Finally, a modified approach based on the neural network is introduced to decrease the“facet noise”, which is induced by approximating surface by flat facets. The computation precision is improved significantly.In chapter 3, the modeling of moving target echoes is studied. Firstly, a systemic analysis for the impacts of motion forms on radar signatures is performed, and vibration significance curves for high resolution radar are given. Based on this, a dynamic scatterer model is introduced to modeling radar echoes for moving targets. The model reflects both high resolution structural features of vibrating targets and stochastic features. It provides theoretical foundation for the implementation of radar echo simulation in real-time operation. In chapter 4, the design and optimization techniques based on very large scale integration (VLSI) in real-time echo simulation are studied. Firstly, applying the optimization method of multiple CORDIC units to share look-up table of tangent, we design a reusable intellect property (IP) for echo simulation based on dynamic scatter model. Secondly, aiming at real-time clutter simulation, a K-distributional clutter simulation algorithm is proposed based on the sphere invariance random process, which can simulate arbitrary time period, coherent, and variable parameter clutter. The reusable clutter generating IP is designed successfully.In chapter 5, the application of the proposed simulation and implementation techniques are studied in a typical scenario. An echo simulator is designed for hardware-in-the-loop simulation. Firstly, the global architecture and key techniques of radar tracking systems are analyzed. Secondly, an echo simulation system is designed and implemented using VLSI system on a chip (SOC) as the key components. The system possesses a high precision, real-time operation, and interaction, which are due to the simulation technique based on dynamic scatter model, high speed parallel system architecture, and pipelining data processing. Finally, the system is applied to a target tracking Hardware-in-the-loop simulation system.更多还原