共查询到18条相似文献，搜索用时 187 毫秒
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本文从当前天文观测所受自然环境的影响入手,提出远程控制观测是解决目前观测所遇到的困扰的好方法,并介绍了中科院云南天文台太阳射电组原１０m口径持面天线的计算机远程 控制系统。本文着重讨论了远程控制的实施方案,包括天线当前的性能测试、如何安全地做到远程通信、前端控制（即现场控制）等问题,把ＴＣＰ／ＩＰ协议族原理和Ｃｌｉｅｎｔ／Ｓｅｒｖ 相似文献
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本文简要介绍了云南天文台１０ 米口径的太阳射电望远镜天线的远程控制系统中局域网控制和通过电话线控制的实现方案 相似文献
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天马13 m射电望远镜是专为空间大地测量的新一代甚长基线干涉测量(Very Long Baseline Interferometry, VLBI)天线,即VGOS(VLBI Global Observing System)系统。VGOS观测将从调度、相关、观测策略到分析各方面改变甚长基线干涉测量。与传统测地观测相比,VGOS观测将数据精度提高1～2个数量级。天马13 m射电望远镜安装了3～15 GHz宽频制冷接收机,一般要求天线指向偏差小于最高频率波束宽度的1/10。为满足高精度指向要求,详细介绍了建立指向的方法和天线控制扫描策略,给出了系统误差修正模型的完全表达式,明确了指向修正模型中的参数意义。基于该天线指向扫描的实测数据,实测评估了望远镜的指向精度。采用最小二乘法对覆盖全天区的数据样本进行拟合,得到天马13 m射电望远镜指向模型,并加载到天线伺服控制系统进行验证,得到了优于10″的盲指误差。 相似文献
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射电天线指向精度通常要求小于主波束宽度的1/10, 对于短厘米波段或毫米波段的大口径反射面天线, 指向精度要求高达几个角秒, 对于天线性能目标的实现是个巨大的挑战, 因此对于大口径高频段的反射面天线来说指向问题成为天线性能实现的重要关注焦点. 在众多影响天线指向精度的结构子系统因素中, 对主反射面变形因素的研究很少. 文章结合天线的结构特点建立了反射面空间坐标系统, 并基于变形后主面点的空间坐标值, 提出了3自由度下的非线性最小二乘吻合的方法去精准预测天线指向. 最后利用空间几何关系严格推导出了服务于天线指向误差修正的俯仰和方位的精确调整量, 从而构建了主面变形同指向误差之间的间接关系, 这对大型射电天线指向精度的提升具有一定的指导意义. 相似文献
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苏定强 《紫金山天文台台刊》2003,(1)
目前 ,已有 1 0架口径 8～ 1 0m的地面大望远镜建成并投入科学观测。在近红外波段 ,自适应光学和干涉术已在大望远镜上获得成功。Hubble空间望远镜发射至今已逾 1 2年。为了研究早期宇宙 ,探测类地行星等 ,2 0 0 2年 9月NASA已与TWR公司签约 ,研制口径≥ 6m的下一代空间望远镜JWST ,计划2 0 1 0年发射。许多口径 30～ 1 0 0m的地面未来巨型望远镜FGT项目已经提出。本报告 ,也介绍了我国正在研制或预研中的三个大项目 :LAMOST、FAST和SST ,这些项目虽较小 ,但完成后都会对天文学的一个方面作出有份量的贡献。最后 ,报告人建议我国参与到与国外合作研制FGT或NGST的工作中 ,特别强调要有天文学家和工程专家参与进去 相似文献
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《天文研究与技术》2015,(4)
简述了基于ROACH和Xilinx System Generator平台的接收机数字后端系统的设计与实现。介绍了Zoom-PFB算法原理,讨论了该算法的核心部分低通滤波和抽取的现场可编程门阵列(Field-Programmable Gate Array,FPGA)实现。针对谱线观测局部高精度分辨率的需要,给出了将400 MHz带宽分为带宽25 MHz的16个通道,对其中任一通道做通道数为6 k、频率分辨率为4 k Hz的频谱细化系统的具体设计方案。在实验室条件下,对该数字后端的性能进行了分析和测试,并以4.5 m口径X/Y结构天线进行银道面中性氢谱线观测检验其应用效果,验证了方案的可行性。 相似文献
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《天文研究与技术》2021,(3)
500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope, FAST)在观测时,将球形反射面内部照明区域的形状变为300 m口径抛物面,实现望远镜的主焦天线功能。照明口径(球面变位到抛物面的口径)对望远镜的观测性能起决定作用。为了望远镜潜在的性能提升及后续发展,在500 m口径球面射电望远镜照明口径300 m及大于300 m的情况下,通过不同焦距抛物面与基准球面变位距离的计算,进行球面到不同口径抛物面变位分析,对望远镜增大照明口径的可行性进行探讨。给出了在500 m口径球面射电望远镜反射面变位驱动促动器最大运动行程范围内,增大口径抛物面变位时抛物面焦距及焦径比的选取。在驱动行程方面初步说明了变位的理论可行性,相关分析同样适用于其他口径的抛物面。 相似文献
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文中所作的主要工作是为云南天文台十米抛物面设计、制造一付好的对数周期偶极子天线（ＬＰＤＡ）作馈源。工作有：（１）设计一对交叉的ＬＰ－ＤＡ；（２）分析ＬＰＤＡ特性；（３）估算抛物面的电特性；（４）讨论线极化向园极化转换的问题；（５）天线测量。ＬＰＤＡ的测量结果比较满意。该天线的方向图、平均输入阻抗、三分贝和十分贝波瓣宽度都在从０．５－１．５ＧＨｚ的频率范围内比较一致和稳定，变化很小。天线理论上的许多成就都是与数子计算机有关的。在文中，我们充分利用了计算机的功能来设计天线，分析天线特性，并从测量所得的所有数据文件中计算天线的参数。所编ＦＯＲＴＲＡＮ程序使这一切工作变得容易。最后，我们还讨论了用功率合成器实现线极化向园极化转换的各种情况 相似文献
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The surface accuracy of a large parabolic antenna is an important indicator to evaluate the quality of the antenna.It not only directly affects the antenna’s aperture efficiency,thereby determining the shortest wavelength that the antenna can work,but also affects the main lobe width and side lobe structure of the antenna pattern.Microwave holography is an important method for parabolic antenna profile detection.In this article we adopt a new algorithm to adjust the panels for the large radio telescope with an active main reflector through the TM65 m antenna’s aperture phase profile.The panels of the TM65 m radio telescope is in a radial pattern with 14 rings.Each corner of the panel is fixed on the screw of the actuator to move up and down,and the adjacent corners of the four panels share an actuator.We use the method of plane fitting to calculate the adjustment value of every panel’s corner.But one actuator,which simultaneously controls the common corner of the adjacent panels,will have different adjustment values according to the different plane fitting equation based on adjacent panels.In this paper,the adjustment value of the adjacent panels’crosspoints are constrained to be equal to the constraint condition to calculate each actuator’s adjustment value of the TM65 m radio telescope.Through multiple adjustments and application of the new algorithms,the accuracy of the TM65 m antenna reflector profile has been improved from the original 0.28 mm to the current 0.19 mm. 相似文献
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《天文和天体物理学研究(英文版)》2017,(5)
The design of the Qitai 110 m Radio Telescope(QTT) with large aperture and very high working frequency(115 GHz) was investigated in Xinjiang, China. The results lead to a main reflector with high surface precision and high pointing precision. In this paper, the properties of active surface adjustment in a deformed parabolic reflector antenna are analyzed. To assure the performance of large reflector antennas such as gain and boresight, which can be obtained by utilizing an electromechanical coupling model, and satisfy them simultaneously, research on active surface adjustment applied to a new parabolic reflector as target surface has been done. Based on the initial position of actuators and the relationship between adjustment points and target points, a novel mathematical model and a program thatdirectly calculates the movements of actuators have been developed for guiding the active surface adjustment of large reflector antennas. This adjustment method is applied to an 8 m reflector antenna,in which we only consider gravity deformation. The results show that this method is more efficient in adjusting the surface and improving the working performance. 相似文献
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介绍一种天线口面温度定标的方法．当用这个方法对目标源进行温度定标时,由于定标源讯号和目标源讯号均由天线口面同路输入,因此波导和微波器件的传输损耗在定标的过程中被自动消除,因而这种温度定标方法能大大地提高观测资料的精度．目前无线口面温度定标方法除了在射电天文和微波天线测量中应用外,还广泛应用于雷达和无线电技术测量及微波遥感控制等． 相似文献
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正在发展中的云南天文台０．５ＧＨｚ—１．５ＧＨｚ快速射电频谱分析仪的接收天线部分是计划在现有的十米口径抛物面天线的焦点上安装两付互相垂直的对数周期偶极子天线作为馈源。本文介绍了设计一个ＦＯＲＴＲＡＮ语言程序对对数周期偶极子天线电特性进行分析的过程，它可以在整个工作频段范围内计算出任意频率点上一副对数周期偶极子天线两个主平面内的方向图、波瓣宽度、增益和输入阻抗，并把结果以数据文件的形式记录下来，结合绘图软件，就可给出直观的结果，从而为对数周期偶极子天线的设计方案提供了可靠的理论判据。本文最后针对为云南天文台抛物面所设计的馈源作具体的分析。 相似文献
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Maroulis D. Dumas G. Caroubalos C. Bougeret J. L. Moussas X. Alissandrakis C. Patavalis N. 《Solar physics》1997,172(1-2):353-360
We present the new digital solar radio spectrograph located at the Thermopyles station, Greece, operated by the University of Athens. Observations cover the range from 110 to 600 MHz, using a 7-m parabolic antenna. The reception system uses two techniques in parallel: sweep frequency and multi-channel, the latter being based on the Acousto-Optical technique. The data acquisition system is based on two subsystems, a Sun Sparc-5 workstation and a front end based on a VME Motorola system. The two subsystems are connected through the Ethernet and are operated using the VxWorks real-time package. The daily operation is completely automated: pointing of the antenna to the sun, starting and stopping the observations at pre-set times, acquiring data, compressing data by silence suppression in real time, and archiving the data on a routine manner on DAT tapes. Apart from its usual function, this instrument will be used in conjunction with other instruments, including the Nançay decameter array and the low frequency radio receivers on the Wind spacecraft. 相似文献
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Low frequency Radio Astronomy instruments like LOFAR and SKA-LOW use arrays of dipole antennas for the collection of radio signals from the sky. Due to the large number of antennas involved, the total data rate produced by all the antennas is enormous. Storage of the antenna data is both economically and technologically infeasible using the current state of the art storage technology. Therefore, real-time processing of the antenna voltage data using beam forming and correlation is applied to achieve a data reduction throughout the signal chain. However, most science could equally well be performed using an archive of raw antenna voltage data coming straight from the A/D converters instead of capturing and processing the antenna data in real time over and over again. Trends on storage and computing technology make such an approach feasible on a time scale of approximately 10 years. The benefits of such a system approach are more science output and a higher flexibility with respect to the science operations. In this paper we present a radically new system concept for a radio telescope based on storage of raw antenna data. LOFAR is used as an example for such a future instrument. 相似文献