Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： Pulsars have significant academic and application value in fields such as astrophysical evolution, physics, timing, deep space autonomous navigation, and gravitational wave detection, making pulsar survey and application one of the current hot topics in the astronomical community. In order to explore the current research status and future development trends in the field of pulsar survey and application, 964 relevant articles were screened from the Web of Science (WOS) database. Building upon the analysis of core articles, in-depth exploration was conducted utilizing data analysis and visualization methods. The study results reveal that research in the field of pulsar survey and application has progressed through initial exploration and steady development phases, and is currently experiencing vigorous growth. Close collaboration among nations has led to the formation of three major research groups in this field. Pulsar survey and application research are anticipated to yield significant scientific research value and practical application outcomes in the future, such as direct detection of gravitational waves and advancements in deep space autonomous navigation, thereby further enriching and diversifying the research domain of pulsars.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-06-07 Cooperative journals: 《天文学进展》
Abstract： Phased array feed is a new array antenna receiving system in the field of radio astronomy in recent years. It is a kind of small electric antenna unit array arranged in rect#2;angular, hexagonal and other ways on the focal plane of radio telescope. It applies different excitation to each array element through beam combination, and regulates the amplitude and phase of each array element, so that each beam overlaps with each other and the phase center is close to each other. In order to improve the efficiency of sky survey, the focal plane area can be fully sampled to achieve continuous field of view coverage. Starting from focal plane array, this paper introduces the phased array feed and multi-beamed technology, and then describes in detail the advanced research of phased array feed technology development in the world, including NRAO in the United States, ASTRON in the Netherlands, DRAO in Canada and CSIRO in Australia, etc. And then introduces the technology pre-research and engineering practice of phased array feed which are carried out under the promotion of large scientific device and projects such as SKA. Finally, according to the development of existing phased array feed technology, the future research difficulties and development direction of this technology are proposed.
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：快速射电暴（Fast Radio Burst，FRB）是目前射电天文领域的主要热点前沿。其相关研究被《自然》（Nature）杂志评选为2020年十大科学发现之一。FRB爆发时间极短且鲜少重复的特点，使其观测捕捉到的概率极低。由人工从海量的天文观测数据中识别FRB事件是件耗时费力的工作。机器学习技术的蓬勃发展为实时搜寻与多频段联合跟踪观测FRB带来了可能。该文从传统机器学习方法和深度学习方法两个方面，对该研究已有的成果进行了分析与总结，并探讨了基于机器学习的FRB搜寻技术目前存在的问题和面临的挑战，分析了其未来发展趋势。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-06-18 Cooperative journals: 《天文研究与技术》
Abstract： 射电天文是通过接收和处理无线电波以此研究宇宙天体的一门学科，微波接收机则是射电天文观测的核心接收设备。结合中国科学院新疆天文台南山25米射电望远镜现有K波段制冷接收机及未来Q波段毫米波观测需求，本论文提出一种K波段常温接收机研制，该接收机射频工作频率22-24.2GHz，经混频最终输出3.95-6.15GHz的中频信号，主要用于在K波段开展强度校准方法实践及大气不透明度测量。最终采用冷热负载法测试K波段常温接收机噪声温度为402.2K（理论计算为410.6K），标准噪声源为166.3K也满足设计需求，结合斩波轮校准机械结构，该K波段接收机已经具备开展强度校准及大气不透明度测试功能，相关工作也可为南山25米射电望远镜未来Q波段毫米波观测做技术预研。
Subjects: Astronomy >> Astrophysical processes submitted time 2020-05-12 Cooperative journals: 《天文研究与技术》
Abstract：噪声注入定标方法作为厘米波段一种常规强度校准方式而被广泛使用。通过组建K波段常温接收机及其定标平台，在室内20℃下使用传统冷热负载法标定接收机噪声温度及噪声源温度，之后在室外-7℃中使用同样方法再次标定上述参数，并利用室内标定的噪声源去进一步标定室外环境中接收机的噪声温度。测试结果表明，在环境温度变化约27度时，接收机噪声温度定标差异约为50.5%，标准噪声源定标差异约为41%。故此得知，如若将噪声注入法应用于常温接收机定标中，首先需考虑对接收机进行恒温处理，另外可采取对注入的标准噪声源进行温度补偿，使其可以更加精确的应用于二次定标当中，这也是本论文下一步计划开展的工作。
Subjects: Astronomy >> Astrophysical processes submitted time 2017-10-20 Cooperative journals: 《天文研究与技术》
Abstract：射电天文台址内仪器设备众多，电磁环境复杂，电磁兼容设计、屏蔽设计及辐射评估均依赖基于测试的数据处理与分析，而程序化是提高测试及数据分析效率的唯一手段。浅析了电磁辐射评估系统的硬件组成、评估流程、软件开发目标及关键技术点;基于软件需求分析及评估过程中的数据传递、数据处理及数据存储，给出了评估软件的设计流程图、数据流图及二维差值算法流程图;分析了电磁辐射评估过程中主要数据特征，开发了基于数据源、数据库的数据存储及管理模块。其次，基于Microsoft Visual Studio 2010开发平台，通过大量的程序调试与界面优化，完成了电磁辐射评估软件开发，能够对仪器设备辐射特性进行快速测试、分析与评估，为射电天文台址电磁兼容性改造和射电望远镜系统兼容性设计提供重要的参考依据。
Subjects: Astronomy >> Astrophysical processes submitted time 2017-09-26 Cooperative journals: 《天文研究与技术》
Abstract：南山25 m射电望远镜经过一年多的升级改造现已全面完成，主反射面直径增加至26 m，为保证Q波段(30 } 50 GHz)接收机的工作效率，望远镜的表面精度需达到较高的水平，微波全息法可对天线面形进行精确测量和调整，是望远镜面形首次和定期精调的首选，基于新南山26 m天线建立了一套全息法测量系统。整个系统包括参考天线、接收机、相关机、传输链路、时频参考、扫描控制和全息法处理软件等几部分，采用带通采样技术直接采集中频信号，减少了基带信号转换环节;采用高性能外部本振并利用氢钟输出的参考信号进行锁相，达到了极高的相位稳定度。目前整个系统已通过测试并取得了初步的测量结果，经处理分析，该系统工作正常，已达到应用要求。
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