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1.
针对FAST的馈源运动控制要求,对馈源支撑系统的控制软件进行了设计与开发。该系统的特色在于基于网络通讯的模块化设计以及采用了完全开源的操作系统与开发工具,操作系统为完全免费且社区化的Ubuntu Linux,开发工具为免费并可跨平台的Qt4。介绍了在上述平台与工具下,整个控制软件的设计与开发过程,关键技术与实现。 相似文献
2.
As an engineering demonstrator for SKA, the Five-hundred-meter Aperture Spherical Telescope (FAST) is proposed in China. This paper is focused on one of the most critical components of FAST, the feed support system. The engineering concept, the configuration and results from model experiments are presented. The mechanical characteristics of the structure are analyzed. The performance of the feedback control system of the model is described. The feasibility of the design is tentatively confirmed by the experiments described at the end of the report. 相似文献
3.
Five-hundred-meter Aperture Spherical Telescope project 总被引：2，自引：0，他引：2
A Five hundred meter Aperture Spherical Telescope (FAST) is proposed to be built in the unique karst area of southwest China,
and will act, in a sense, as a prototype for the Square Kilometer Array (SKA). It will be over twice as large as the Arecibo
telescope coupled with much wider sky coverage. Some results from site surveys for such a SKA concept are briefly reported.
Technically, FAST is not simply a copy of the existing Arecibo telescope but has rather a number of innovations. Firstly,
the proposed main spherical reflector, by conforming to a paraboloid of revolution in real time through actuated active control,
enables the realization of both wide bandwidth and full polarization capability while using standard feed design. Secondly,
a feed support system which integrates optical, mechanical and electronic technologies will effectively reduce the cost of
the support structure and control system. Pre-research on FAST has become a key project in the CAS.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
First feed support system, which is one of the key technologies of Five hundred meter Aperture Spherical Telescope (FAST)
was discussed in this paper. A 1:30 scaled model (20 m × 20 m × 6 m) has been built to make systemic research on the feasibility
of the system. The root mean square of pointing error of moving cable car was measured and the displacements of cable car
within the wind speed of 8 m/s, which is the maximal wind speed of the place where the FAST will be located, were evaluated.
Then the total maximal pointing error of cable car was computed. Experimental results demonstrate that the total pointing
error of the cable car is less than 50 cm, the required pointing accuracy error of the system.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) is by far the largest telescope of any kind ever built. FAST produced its first light in September 2016 and it is now under commissioning, with normal operation to commence in late 2019. During testing and early science operation, FAST has started making astronomical discoveries, particularly pulsars of various kinds, including millisecond pulsars, binaries, gamma-ray pulsars, etc. The papers in this mini-volume propose ambitious observational projects to advance our knowledge of astronomy, astrophysics and fundamental physics in many ways.Although it may take FAST many years to achieve all the goals explained in these papers, taken together they define a powerful strategic vision for the next decade. 相似文献
6.
Ru-Rong Chen Hai-Yan Zhang Cheng-Jin Jin Zhi-Shen Gao Yan Zhu Kai Zhu Peng Jiang You-Ling Yue Ji-Guang Lu Bo Zhang Wu Jiang Ren-Jie Zhu Shao-Guang Guo Bo Xia Rong-Bing Zhao FAST Collaboration 《天文和天体物理学研究(英文版)》2020,(5):165-170
The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-dish radio telescope in the world,and is now being commissioned after the first light in September 2016.Very long baseline interferometry(VLBI)is among the key science topics according to the original design.The FAST VLBI system has been established,and the first VLBI fringe has been successfully obtained.FAST will significantly improve the sensitivity of the existing VLBI networks in the future,and some science projects in need of high sensitivity will benefit from its participation. 相似文献
7.
《New Astronomy》2022
Radio frequency interference (RFI) identification is a key step in radio data processing. In order to efficiently process huge volumes of data produced by modern large radio telescopes, such as the Five-hundred-meter Aperture Spherical radio Telescope (FAST), exceptional balance between accuracy and performance (throughput) is required for RFI flagging algorithms. RFI-Net is a single-process RFI identification package based on deep learning technique, and has achieved a higher flagging accuracy than the classical SumThreshold method. In this paper, we present a scalable RFI flagging toolkit, which can drive parallel workflows on multi-CPU and multi-GPU clusters, with RFI-Net as its core detector. It can automatically schedule the workload and aggregate itself after errors according to the running environment. Moreover, its main components are all pluggable, and can be easily customized according to requirements. The experiments with real data of FAST showed that using eight parallel workflows, the toolkit can process sky survey data at a speed of 66.79 GB/h, which means quasi-real-time RFI flagging can be achieved considering the data rate of FAST extragalactic spectral line observations. 相似文献
8.
The reflector of the Five-hundred-meter Aperture Spherical radio Telescope(FAST)consists of 4450 reflector units.Installation of the reflector faces the challenges of large span,complex terrain,serious interference,complex processes,high position and inability to use conventional equipment.The installation technology for the flexible reflector with a large span was specially studied and designed.Two half-span arc-moving cable cranes and two transfer trucks were jointly operated along a path that follows a circular beam.After installation of the reflector was completed,two half-span cable cranes were merged into a set of full-span cable cranes for maintenance of the reflector.Installation of the reflector combines features of unit and site topography of FAST.The installation technology follows scientific and reasonable practices,and is highly efficient and convenient.It represents a breakthrough in many key technologies in construction and maintenance techniques.It has promoted related technical progress in the construction and maintenance of complex projects.It has also provided an important reference for the construction and maintenance of similar projects,and has strong significance and applicability. 相似文献
9.
A cross bow-tie dipole feed with cavity and symmetrical E and H plane pattern is presented for the Five hundred-meter Aperture Spherical radio Telescope(FAST).In this paper we describe the design,optimization and simulation results of a wide-band cross dipole feed with cavity covering the frequency range from 300 MHz to 600 MHz for FAST.The main goals of our design are to ensure that,(1)we cover the octave bandwidth,(2)the feed has symmetrical E and H plane pattern,and(3)the physical dimension is suitable for mounting it in the reserved position of the FAST feed cabin.The initial results indicate that we have met most of our design goals.This kind of feed had been equipped with the multi-beam receiver to carry out observation on the platform of FAST cabin. 相似文献
10.
The Five-hundred-meter Aperture Spherical radio Telescope(FAST)will be fully commissioned later in 2019.Once commissioned,operation and maintenance of FAST will be the most prominent task.The unique working mode of active shape-changing of FAST cable-net structure makes the traditional maintenance way,which combines routine inspection with preventive maintenances not only expensive,but also unable to effectively avoid potential risks in operations.Therefore,it is necessary to develop an economical and reliable operation/maintenance technology for FAST cable-net structure.In this paper,a Prognostics and Health Management(PHM)system is proposed based on the advanced Digital Twin(DT)technology.Through the finite element analysis of DT model,the current safety status of FAST cablenet is evaluated,and the fatigue life of components in the cable-net is predicted.Hence Condition-Based Maintenance(CBM)of FAST cable-net structure can be realized.The PHM system described in this paper can effectively guarantee the healthy and safe operation of the FAST cable-net structure,greatly improve the maintenance efficiency and reduce the cost for maintenance works. 相似文献
11.
500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST),整体结构处于复杂的喀斯特地貌上,反射面承受风载荷作用,需要进行抗风设计。建立了FAST反射面及其周边山地地形的计算流体动力学(Computational Fluid Dynamics,CFD)计算模型,计算域范围为40 km×10 km×5.5 km。确定了入口风速剖面的基准高度为海拔810 m。计算了不同风向下反射面风压系数分布特征,得出了不利风向。对挡风墙的研究结果表明,挡风墙高度选择的效果优于位置选择。该研究结果可为FAST工程提供抗风设计的初步参考。 相似文献
12.
《Chinese Astronomy and Astrophysics》2023,47(2):335-352
Thanks to the excellent performance of FAST (Five-hundred-meter Aperture Spherical radio Telescope), the number of pulsars has increased rapidly. It is very important to analyze the physical parameters of known pulsars. The overall properties of pulsars are studied by analyzing the related physical parameters such as spatial position, period, surface magnetic flux density and so on. A large number of pulsars were detected by FAST near the galactic disk, which reflect the superiority of its detection ability. The diagram of the relationship between the period and the time derivative of period of pulsars has been updated. At present, 57 pulsars have crossed the classical “death line”, and five were discovered by FAST. Finally, the physical parameters of the binary pulsar systems are statistically analyzed, the binary pulsar systems are evolving towards the direction of low eccentricity and the decrease mass of the companion star. Moreover, 9 are located above the “spin-up line”. FAST is making China into the golden age of pulsar discovery, which will further promote the rapid development of pulsar physics. 相似文献
13.
传统铷原子钟和铯原子钟已在卫星导航定位系统中作为星载原子钟获得重要应用.卫星导航定位系统的更新和新发展要求更高精度更小型的新型星载原子钟.该文介绍采用新物理原理和先进技术在下-代卫星导航定位系统有应用前景的新原子钟的产生和发展以及它们目前的进展. 相似文献
14.
George Hobbs Shi Dai Richard N.Manchester Ryan M.Shannon Matthew Kerr Ke-Jia Lee Ren-Xin Xu 《天文和天体物理学研究(英文版)》2019,(2)
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will become one of the world-leading telescopes for pulsar timing array(PTA) research. The primary goals for PTAs are to detect(and subsequently study) ultra-low-frequency gravitational waves, to develop a pulsar-based time standard and to improve solar system planetary ephemerides. FAST will have the sensitivity to observe known pulsars with significantly improved signal-to-noise ratios and will discover a large number of currently unknown pulsars. We describe how FAST will contribute to PTA research and show that jitter-and timing-noise will be the limiting noise processes for FAST data sets. Jitter noise will limit the timing precision achievable over data spans of a few years while timing noise will limit the precision achievable over many years. 相似文献
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16.
相控阵馈源(Phased array feeds, PAFs)接收机作为下一代微波接收机,为大口径射电天文望远镜的射电干扰(Radio Frequency Interference, RFI)缓解工作带来了新的解决方法. PAFs接收机对射电望远镜焦平面的电磁波进行空域采样,返回时域阵列信号,使用最小方差无失真响应(Minimum Variance Distortionless Response, MVDR)波束合成器可以自适应地识别RFI的方向,同时抑制RFI在输出信号中的功率,从而达到提升射电望远镜灵敏度的效果.仿真结果表明MVDR波束合成器对有源高能量的射电干扰有很强的识别能力和一定程度的缓解能力,同时,该波束合成器对各阵元信道中加性噪声累积引起的无源干扰有很强的抑制能力,因此, PAFs接收机的MVDR波束合成器可以增强日益复杂电磁波环境下射电望远镜的抗干扰能力. 相似文献
17.
18.
Similarity model of feed support system for FAST 总被引：1，自引：0，他引：1
A new design of feed support system for Five hundred meter Aperture Spherical Telescope (FAST) is proposed in this paper.
According to the similarity theory, a 1:15 scale model of feed support system has been built to make systemic research on
the feasibility of the system. Then the control system and hardware structure of the feed support system are illustrated.
A complete astronomical observation track is run by the scale model and the experiments results demonstrate that the new feed
support system can satisfy the observation accuracy requirement of FAST. 相似文献
19.
The paper relates to a motion planning algorithm for the feed support system of the Five-hundred-meter Aperture Spherical radio Telescope(FAST).To enhance the stability of the feed support system,the start/termination planning segments are adopted with an acceleration and deceleration section.The source switching planning adopts a combination of a line segment and focal segment to realize stable control of the feed support system.Besides,during the observation trajectory,a transition segment which is not used for observation data is planned with a required time.Through an example simulation,a smooth change is realized via the motion planning algorithm and presented in this paper. 相似文献
20.
Xin-Xin Zhang Ran Duan Xin-Ying Yu Di Li Ning-Yu Tang Tao-Chung Ching 《天文和天体物理学研究(英文版)》2020,(5):155-164
The Five-hundred-meter Aperture Spherical radio Telescope(FAST)was launched on 2016 September 25.From early 2017,we began to use the FAST wideband receiver,which was designed,constructed and installed on the FAST in Guizhou,China.The front end of the receiver is composed an uncooled Quad Ridge Flared Horn feed(QRFH)with the frequency range of 270 to 1620 MHz,and a cryostat operating at 10 K.We have cooperated with the Institute of Automation of the Chinese Academy of Sciences to develop the China Reconfigurable ANalog-digital backEnd(CRANE).The system covers the 3 GHz operating band of FAST.The hardware part of the backend includes an Analog Front-end Board,a wideband high precision Analog Digital Converter,and a FAST Digital Back-end.Analog circuit boards,field programmable gate arrays,and control computers form a set of hardware,software,and firmware platforms to achieve flexible bandwidth requirements through parameter changes.It is also suitable for the versatility of different astronomical observations,and can meet specific requirements.This paper briefly introduces the hardware and software of CRANE,as well as some observations of the system. 相似文献