宽带数字阵列雷达试验系统设计与仿真

发布时间：2018-09-04 07:18

【摘要】：数字阵列雷达的出现标志着相控阵雷达系统的设计进入数字化时代,射频模拟信号直接数字化,在提升系统稳定性的同时也对数字信号的处理能力提出了更高的要求。多通道宽带数字阵列雷达的数据率高、运算量大、算法设计也相对复杂。为此,本文主要研究了宽带数字阵列雷达系统设计中的一些关键问题,包括射频采样技术的分析与设计,宽带恒定束宽波束形成器的凸优化设计及宽带通道均衡技术分析,和宽带数字阵列雷达系统的通用信号处理平台软硬件设计。并采用MATLAB仿真及实测数据分析验证了相关技术实现的可行性与有效性。论文首先阐述了宽带数字阵列雷达的发展意义及背景。采用模块化的设计思想将宽带数字阵列雷达系统划分成若干独立且完备的功能模块,包括天线前端、数字阵列模块、宽带数字波束形成、常规信号检测处理及终端显示等,论述了宽带数字阵列系统中各个功能模块的关键技术。从雷达威力、收发辐射方向图以及模糊函数理论对宽带数字阵列雷达系统的参数选取及波形选择进行研究。深入分析了P波段宽带射频采样的软硬件设计,重点说明了模数转换(Analog to Digital Converter,ADC)性能的理论计算和实际测试方法。从采样率、信噪比、有效转换位及动态范围四方面分析了射频采样对ADC性能的要求。介绍了射频采样硬件设计,包括硬件平台结构、现场可编程门阵列(Field Programmable Gate Array,FPGA)芯片选型、高速ADC芯片选择、及ADC前端设计。基于JESD2048协议设计了射频采样的FPGA程序,解决了多片ADC芯片之间的同步问题。基于某技改雷达实测数据,给出了实测噪声法及注入信号法下的信噪比分析。针对宽带数字波束形成存在的空间色散和时间色散问题,提出基于凸优化的恒定束宽波束形成器设计。与现有优化方法不同的是,本文采用待优化频段内的某一频点作为参考频点,引入调和因子,构造了以全方位最小均方误差和参考频点上波束辐射方向图的Minmax旁瓣电平准则的凸组合为目标函数的恒定束宽波束形成器最优化设计问题,并可通过线性约束,实现指向不变、干扰置零及最大平坦波束形成器等设计。仿真分析验证了本文设计的有效性。采用线性调频信号分析了宽带通道失配对信号脉压的影响,并分析了频域最小二乘算法的通道均衡性能。最后,论文分析了通用信号处理平台的设计。针对现代雷达系统通用化、标准化、模块化和数字化的要求,提出对通用信号处理平台的设计要求。研究了目前主流的标准传输协议,包括cPCI标准、VPX标准、PCIe、Rapid IO、RocketIO GTX传输、光纤、及以太网等。基于以上标准协议,给出了针对宽带数字阵列雷达系统的通用硬件平台设计思路和规范,以及数据传输拓扑结构等。结合某具体的宽带数字阵列雷达系统,分析了系统传输带宽要求。从工程设计角度出发,对一些常规检测算法的运算量进行了分析。
[Abstract]:The emergence of digital array radar indicates that the design of phased array radar system has entered the digital era, the RF analog signal is digitized directly, which not only improves the stability of the system, but also puts forward higher requirements for the processing ability of digital signal. Multi-channel wideband digital array radar has high data rate, large computation and complex algorithm design. Therefore, this paper mainly studies some key problems in the design of wideband digital array radar system, including the analysis and design of RF sampling technology, the convex optimization design of broadband constant beamwidth beamformer and the analysis of wideband channel equalization technology. And the hardware and software design of general signal processing platform for wideband digital array radar system. The feasibility and effectiveness of the related technology are verified by MATLAB simulation and the analysis of measured data. Firstly, the development significance and background of wideband digital array radar are described. The wideband digital array radar system is divided into several independent and complete functional modules, including antenna front end, digital array module, wideband digital beamforming, conventional signal detection and processing, terminal display, etc. The key technology of each function module in wideband digital array system is discussed. The parameter selection and waveform selection of wideband digital array radar system are studied based on radar power, radiation pattern and ambiguity function theory. The hardware and software design of P-band broadband RF sampling is analyzed in depth, and the theoretical calculation and practical testing method of analog-to-digital conversion (Analog to Digital Converter,ADC) performance are emphasized. The requirements of RF sampling for ADC performance are analyzed in terms of sampling rate, signal-to-noise ratio (SNR), effective conversion bit and dynamic range. This paper introduces the hardware design of RF sampling, including the structure of hardware platform, the selection of field programmable gate array (Field Programmable Gate Array,FPGA) chip, the selection of high speed ADC chip, and the design of ADC front-end. The FPGA program of RF sampling is designed based on JESD2048 protocol, which solves the synchronization problem between multiple ADC chips. Based on the measured data of a technical modified radar, the signal-to-noise ratio (SNR) analysis of the measured noise method and the injection signal method is given. Aiming at the spatial and temporal dispersion problems in wideband digital beamforming, a new design of constant-beamwidth beamforming based on convex optimization is proposed. Different from the existing optimization methods, a certain frequency point in the frequency band to be optimized is used as the reference frequency point in this paper, and the harmonic factor is introduced. The optimization design problem of constant beamwidth beamforming based on the convex combination of the Minmax sidelobe level criterion of the beam radiation pattern on the omnidirectional minimum mean square error and the reference frequency is constructed, and the direction invariant can be realized by linear constraints. Interference zero setting and maximum flat beamforming design. The effectiveness of the design is verified by simulation analysis. The linear frequency modulation (LFM) signal is used to analyze the influence of Wideband channel mismatch on pulse compression, and the channel equalization performance of frequency domain least square algorithm is analyzed. Finally, the design of general signal processing platform is analyzed. In order to meet the requirements of generalization, standardization, modularization and digitization of modern radar system, the design requirements of general signal processing platform are put forward. The current mainstream standard transmission protocols, including cPCI standard VPX standard, PCI Rapid IO,RocketIO GTX transmission, fiber optic, Ethernet and so on, are studied. Based on the above standard protocol, the design idea and specification of the general hardware platform for wideband digital array radar system and the data transmission topology are given. Combined with a specific wideband digital array radar system, the transmission bandwidth requirement of the system is analyzed. From the point of view of engineering design, the computation of some conventional detection algorithms is analyzed.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN955

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