KMS of Xinjiang Astronomical Observatory, CAS
| 基于射电天文台址的电波环境测量与分析 | |
| Alternative Title | Measurement and Analysis of Electromagnetic Environment Based on Radio Astronomy Site |
张群涛
| |
| Subtype | 硕士 |
| Thesis Advisor | 孙正文 |
| 2016 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 天文技术与方法 |
| Keyword | 射电天文 电波环境 干扰测量 频谱分析 |
| Abstract | 射电望远镜具有极高的系统灵敏度，而国内现有的射电望远镜在建设过程中缺乏电磁兼容性设计及屏蔽防护方面的考虑，随着空间无线电技术的发展以及台站内电子设备的不断增多，电磁环境变得尤为复杂，各类电子设备电磁辐射通过天线旁瓣进入接收系统，降低系统信噪比，恶化观测数据，加大观测时间、处理数据的复杂性。有效的电波环境测试方法及频谱分析对射电天文台站频谱管理、屏蔽防护、消干扰策略提供重要依据。首先，深入调研了SKA 选址RFI测试方法及数据处理方法，研究了频谱分析原理及噪声测试的基本要求，给出了频谱分析仪关键参数设置依据，确保了频谱测试精度。其次，基于现有电波环境测试系统，提出一种相对实时电波环境测试方法；该测试方法在保证测试精度的基础上，测试位置的选取接近馈源口面，此位置功率值可直接用于评估干扰对射电天文观测的影响；测试时间安排方面，考虑覆盖人们活动的主要时间，将每个白天12小时划分为8个时间段，每个时间段覆盖台站每个方向的测试频谱，从而实现每1.5小时的频谱覆盖率，可有效分析台站每个方向频谱随着时间的变化趋势。针对相对实时的电波环境测试方法，运用matlab 软件，开发了基于电波环境频谱的数据处理程序，实现了同一时间不同方向和同一方向不同时间的频谱成图；基于电波环境频谱特征，提取并统计频谱中的干扰信号，为分析频谱中干扰信号特征奠定基础。最后，运用相对实时的电波环境测试方法对南山台站进行详细的电波环境测试，通过数据处理与有效成图分析了台站电波环境频谱随着时间的变化趋势，给出了台站不同方向的干扰信号特征；依据台站内部设备区域划分，给出了台站主要干扰来源。运用对着设备区域和隔过设备区域的方法对台站内部关键设备区域方向进行诊断，通过频谱分析确定了电波环境频谱中大量的窄带干扰来自台站自身设备。运用便携式仪器设备对台站内关键仪器设备区域进行干扰诊断，确定了关键仪器设备区域主要的干扰源。基于电波环境频谱，分析了2G、3G等无线通讯业务的干扰特征及频谱趋势，为台站周围的无线电协调提供测试依据。 |
| Other Abstract | As is well-known that radio telescope has extreme system sensitivity, but the existing radio telescope lacks of electromagnetic compatibility and does not take electromagnetic shield into account during construction at home. With the development of space radio technology and the increasement of electronic equipment inside the station, the electromagnetic environment becomes more complex. The electromagnetic radiation of all kind of electronic equipment enter into receiving system by antenna sidelobe, and reduce the LNR of system, and worsen the observation data, and increase the observation time and complexity of data processing. So, the valid electromagnetic environment measurement method and spectrum analysis can provide important evidences for spectrum management, shielding method and interference mitigation strategies.Firstly, we studied RFI measurement method and data processing method for candidate SKA sites, and researched spectrum analysis principle and basic requirements of noise measurement, and presented parameters setting for spectrum analyzer, and make certain spectrum measurement accuracy.Secondly, based on existing electromagnetic environment measurement system, we present a relatively real time electromagnetic environment measurement method. On the basis of making certain measurement accuracy, we choose the measurement position near to the feed source, because in this position the power can be directly used in assessing the influence of interference for radio astronomy observation. In the aspect of measurement time, taking covering people’s activity time into account, we divide 12 hours of daytime into 8 period, and every period covers all directions of measurement spectrum, then the time resolution of spectrum is 1.5 hours, so, it can effectively analyze the time trends of spectrum from each direction. We exploit data processing program based on electromagnetic environment spectrum by matlab software, presents the measurement result of the same direction and different time and the same time different direction. Based on the characteristic electromagnetic environment spectrum, we pick up and count interference of spectrum data, and lay the foundation of analyzing interference signal from spectrum.Lastly, we use the relatively real time electromagnetic environment measurement method to measure electromagnetic environment of Nanshan station in detail, and analyze electromagnetic environment spectrum as the trends of time by data processing and figure, and present the characteristic of interference signal from different directions. According to the distribution of main equipment of station interior, this paper presents main interference source. We diagnose the interference from key equipment region by facing toward key region and not facing toward it, and find the narrow-band interference of electromagnetic environment spectrum from our own instruments. So, we use portable measurement instruments to diagnose the region of key instruments, and find main interference source in these regions. Based on electromagnetic environment spectrum, we analyze the interference characteristic and change trends of radio communication service of 2G and 3G, and provide measurement evidences for radio coordinating around our station. |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/1727 |
| Collection | 研究生学位论文 射电天文研究室 |
| Affiliation | 中国科学院新疆天文台 |
| Recommended Citation GB/T 7714 | 张群涛. 基于射电天文台址的电波环境测量与分析[D]. 北京. 中国科学院大学,2016. |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| 张群涛-学位论文.pdf（4426KB） | 学位论文 | 暂不开放 | CC BY-NC-SA | Application Full Text | ||
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