基于CASPER平台的射电频谱仪设计与实现

发布时间：2018-10-13 17:09

【摘要】：在第二次世界大战之后,人们仿造雷达的结构做成由天线系统、接收系统和记录设备系统构成的射电望远镜,用于接收天体发射出的无线电波,射电天文学也算是由此诞生。射电天文通常通过对电磁波的接收处理来实现观测,所有宇宙空间中的天体和物质都可以被作为对象,比如我们所在的太阳系和尺度稍微扩展一些的银河系都可以找到观测的对象,再到更远的银河系以外的观测目标。射电天文学是使用射电望远镜系统在无线电波段研究宇宙中各类天体的一门学科。随着时代的发展和科学技术的不断进步,用于天文观测的设备也在不断地提升和更新换代。特别是数字技术和计算机技术的发展,使得射电天文技术的发展得到了新的契机。现在正在建设中的FAST工程是在建射电望远镜项目中单口径最大的设备,本文课题的提出是基于射电波段的前沿天体物理课题及FAST早期科学研究计划的从属内容,是对于接收机频谱终端的早期研究和设计工作。本文的主要工作内容和目标分为两部分,分别是针对ADC量化过程对于谱线观测的影响进行分析和讨论,以及在数字化硬件平台上进行频谱终端的设计与实现,最后实现中性氢观测测试。首先针对本文的课题内容、预期目标进行调研和学习,并根据已有条件进行了技术路线和可行性分析。第一部分研究工作中针对ADC量化对于谱线观测的影响进行了分析和讨论,通过理论推导与实际观测数据处理相结合的方式来对这个问题进行讨论分析。通过推导证明ADC量化位数不足带来的对于观测系统灵敏度的影响可以通过提高积分时间得到补偿和优化的结论,使用了联合实验室天线平台的观测数据,用实测数据处理结果来证明讨论和推导结果的正确性。第二部分主要研究工作中首先对进行谱线观测的实现中所涉及到的数字信号处理的理论背景知识进行了学习和研究,主要包含采样理论,傅里叶变换和快速傅里叶变换理论,以及多相滤波器算法结构。之后通过使用CASPER硬件开发平台和MATLAB以及simulink组件等软件联合开发设计实现谱线终端。最后,使用设计编译通过的谱线终端成功实现了中性氢观测。
[Abstract]:After World War II, radio telescopes made up of antenna systems, receiving systems and recording systems were constructed to receive radio waves emitted from celestial bodies, and radio astronomy was born. Radio astronomy is usually observed by receiving and processing electromagnetic waves. All objects and objects in space can be used as objects. For example, our solar system and the slightly expanded Milky way galaxy can find objects of observation, and then beyond the Milky way. Radio astronomy is a subject that uses radio telescope systems to study various celestial bodies in the universe. With the development of the times and the progress of science and technology, the equipment for astronomical observation is constantly upgraded and updated. Especially with the development of digital technology and computer technology, the development of radio astronomy technology has got a new opportunity. The FAST project, which is under construction, is the largest single aperture equipment in the project of radio telescope under construction. In this paper, the advanced astrophysics project based on radio band and the subordinate content of FAST early scientific research project are proposed. Is for the receiver spectrum terminal early research and design work. The main contents and objectives of this paper are divided into two parts: the analysis and discussion of the influence of ADC quantization on spectral line observation, and the design and implementation of spectrum terminal on the digital hardware platform. Finally, the neutral hydrogen measurement is realized. First of all, according to the content of this paper, the expected goal of research and learning, and according to the existing conditions of the technical route and feasibility analysis. In the first part, the influence of ADC quantization on spectral line observation is analyzed and discussed, and the problem is discussed by combining theoretical derivation with practical observation data processing. It is proved by derivation that the influence of insufficient quantization bits of ADC on the sensitivity of the observation system can be compensated and optimized by increasing the integral time. The observation data from the antenna platform of the joint laboratory are used. The correctness of the discussion and derivation is proved by the experimental data processing results. In the second part of the main research work, we first study and study the theoretical background knowledge of digital signal processing involved in the realization of spectral line observation, mainly including sampling theory, Fourier transform and fast Fourier transform theory. And the algorithm structure of polyphase filter. After that, the spectral line terminal is designed by using CASPER hardware development platform, MATLAB and simulink software. Finally, the neutral hydrogen observation is successfully realized by using the designed compiled line terminal.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH751

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