宽带流星雷达硬件系统的设计与实现

发布时间：2018-01-14 13:42

本文关键词：宽带流星雷达硬件系统的设计与实现　出处：《武汉大学》2017年硕士论文　论文类型：学位论文

【摘要】：流星雷达技术用于流星观测始于上世纪30年代,当时流星雷达主要用于研究流星天文学。随着科学技术的不断发展,流星雷达系统也在不断更新换代,应用方面也逐渐由最初的流星观测拓展至流星雨的观测、流星速度的观测和流星区大气动力学的研究。到上世纪90年代末,国外的流星雷达研制已经日臻完善,其中澳大利亚研制的流星雷达尤为突出,它采用最新的全天空流星雷达技术,可获得流星区大气动力学的各种参量。2000年以后,我国一些地区虽然引进了流星雷达,如武汉、昆明、三亚等,并且利用观测数据取得了流星天文学、大气动力学等方面的研究成果。然而,目前国内仍没有自主研发的流星雷达设备。因而本文首次开展了国内流星雷达研制的工作,完成了宽带流星雷达硬件系统的整体设计和实现,并使用该雷达做了初步的实验和数据分析。首先,介绍了激励源中常用几种频率合成方法,使用直接数字频率合成(DDS)技术作为发射系统的激励源。发射系统以DDS芯片AD9958为核心,设计工作频段为30MHz-100MHz,结合雷达系统的探测指标,选用了二相编码调制信号作为发射波形设计,给出了软硬件实现的方法,并对DDS输出信号进行了调整,使得其输出能满足功放单元的需求且抑制了信号的失真以及谐波干扰。其次,完成了宽带流星雷达接收系统的设计。在分析了接收系统的几个重要指标后,接收系统采用数字中频结构,并对该结构展开了整体设计和实现,包括了模拟接收前端电路、模数转化器、数字下变频、数据传输以及通道校准的设计和实现,并对灵敏度、动态范围、增益等指标进行了测试,测试结果表明该接收系统满足设计指标。最后,利用发射系统和接收系统进行了闭环实验和开环实验。其中,开环实验分别使用互补码和巴克码进行了探测,并对探测的流星回波进行了初步分析,获取了流星的速度大小、位置以及空间分布情况。实验结果验证了流星雷达的正确性和可行性。综上所述,本文首次开展了国内的流星雷达硬件系统的研制,实现的雷达具有工作频带宽(可覆盖目前国外流星雷达的所有工作频段)、控制参数可灵活配置等特点。尽管初步实验结果验证了流星雷达设计的可行性和正确性,但该系统仍需根据未来长期观测中的问题进行参数的调整和进一步完善。
[Abstract]:Meteor Radar Technology for meteor observations began in the last century in 30s, when the meteor radar is mainly used to study the meteor astronomy. With the development of science and technology, the meteor radar system is also constantly upgrading, the application has gradually expanded to the meteor meteor rain observation first, observation and research area of atmospheric dynamics meteor meteor speeds. To the end of 90s, Meteor Radar foreign development has been more and more perfect, which developed in Australia meteor radar is particularly prominent, it uses all sky meteor radar technology, the meteor District atmospheric dynamics parameters.2000 years later, some areas in our country although the introduction of meteor radar, such as Wuhan, Kunming. Sanya, and the use of observational data obtained meteor astronomy, atmospheric dynamics and other aspects of the research results. However, the current domestic is still not independent Meteor radar equipment research and development. So this paper is carried out for the first time the meteor radar research work, completed the design and implementation of broadband meteor radar hardware system, and use the radar made a preliminary analysis of the experiment and data. First, introduces several common frequency synthesis method of excitation source, the use of direct digital frequency synthesis (DDS) technology as the excitation source transmitting system. Transmission system using DDS chip AD9958 as the core, the design of working frequency is 30MHz-100MHz, with the detection index of the radar system, the phase encoding modulation signal as the transmitting waveform design, gives a method of realization of hardware and software, and the output signal of DDS is adjusted, so that the output can to meet the demand of power amplifier unit and suppress the signal distortion and harmonic interference. Secondly, completed the design of broadband meteor radar system. In the analysis of the receiving system Several important indexes, the receiving system adopts digital intermediate frequency structure, and the structure of the overall design and implementation, including the analog front-end circuit, analog-to-digital converter, digital down conversion, data transmission and the design and implementation of channel calibration, and the dynamic range of gain, sensitivity, and other indicators to test the test results. That meet the design index of the receiving system. Finally, the closed loop experiment and open loop experiment using the transmitter and the receiver system. The open-loop experiments were made using complementary code and Barker code were detected, and the detection of meteor echoes are analyzed, the meteor speed, location and spatial distribution.. the experimental results verify the correctness and feasibility of the meteor radar. To sum up, this paper first developed the hardware system of domestic meteor radar, the radar has Wide frequency band (which can cover all the foreign meteor radar working frequency), the control parameters can be configured flexibly. Although preliminary experimental results verify the feasibility and correctness of the design of the meteor radar, but the system is still need long-term observation parameters according to the problems in the future in the adjustment and perfection.

【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P185.82;TN959

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