共查询到20条相似文献,搜索用时 93 毫秒
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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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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的 1 0m口径抛物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/Server原理与模糊逻辑控制思想相结合 ,对 1 0m口径天线实施自动控制 ,并开发了用于现场控制、远程控制的网络控制软件。 相似文献
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本通过对上海、乌鲁木齐两台Φ25m天线轨道基础结构的分析测量和比较,说明了只有改造上海Φ25m天线轨道枕板结构,才能有效地控制天线的指向精度。 相似文献
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本文提出了低纬子午环 (LLMC)配备CCD后的CCD芯片跟踪运动的控制方案 ,讨论了CCD芯片的预置位置及跟踪扫描速度的计算问题 ,并介绍了实现这一控制方案的系统硬件构成及软件设计方法。 相似文献
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R. L. Forward 《Earth, Moon, and Planets》1976,16(1):3-26
Simulations of the gravity data to be expected from a Lunar Polar Orbiter spacecraft utilizing either a Doppler velocity tracking system or a gravity gradiometer instrument system are generated using a point mass model that gives an excellent representation of the types of gravity anomalies to be found on the Moon. If the state of the art in instrumentation of both systems remain at the level of ±1 mm/sec at 10 sec integration time for the Doppler velocity system accuracy and at ±1 Eotvos at 10 sec integration time for the gravity gradiometer system accuracy, inspection of the simulations indicates that a gravity gradiometer system will give science data with better resolution and higher amplitude-to-measurement noise ratio than the Doppler velocity system at altitudes below 100 km. The error model used in the study is one where the system errors are assumed to be dominated by the point measurement noise and data quantization noise. The effects of other, more controllable, systematic error sources are not considered in this simplified analysis. For example, both systems will be affected by errors in LPO orbital altitude and position knowledge, spacecraft maneuvers, and data reduction errors. In addition, a Doppler tracking system will be sensitive to errors produced by spacecraft acceleration (from outgassing or solar pressure) and poor relative position of the LPO, Relay Satellite and ground tracking station, while a gravity gradiometer system will be sensitive to errors from spacecraft attitude and angular rates. These preliminary study results now need to be verified by a more complete error analysis in which all the uncertainties of the data gathering process are formally mapped into uncertainties in the resulting gravity maps. 相似文献
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Abdel-Fattah Attia 《Experimental Astronomy》2004,18(1-3):93-108
This paper presents a novel application of fuzzy logic (FL) controller driven by an adaptive fuzzy set (AFS) for position
tracking of the telescope driven by electric motor. Also, the proposed FL controller, driven by AFS, is compared with a classical
FL control, driven by a static fuzzy set (SFS). Both FL controllers algorithm use the position error and its rate of change
as an input vector. The mathematical model of the telescope driven by electric motor is highly nonlinear differential equations.
Therefore the use of the artificial intelligent controller, such as FL is much better than the conventional controller, to
cover a wide range of operating conditions. So, the output of FL control is utilized to force the electric drives, of the
telescope, to satisfy a perfect matching of the predefined desired position of the telescope arms. Both of FL controllers,
using AFS and SFS, are simulated and tested when the system is subjected to a step change in reference value. In addition,
these simulation results are compared with the conventional Proportional-Derivative (PD) controller, driven by fixed gain.
The proposed FL, using an adaptive fuzzy set, improve the dynamic response of the overall system by improving the damping
coefficient and decreasing the rise time and settling time compared with other two controllers. 相似文献
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Spacecraft Doppler tracking with possible violations of LLI and LPI: a theoretical modeling 总被引:1,自引:0,他引:1
Currently two-way and three-way spacecraft Doppler tracking techniques are widely used and play important roles in control and navigation of deep space missions.Starting from a one-way Doppler model,we extend the theory to two-way and three-way Doppler models by making them include possible violations of the local Lorentz invariance(LLI) and the local position invariance(LPI) in order to test the Einstein equivalence principle,which is the cornerstone of general relativity and all other metric theories of gravity.After taking the finite speed of light into account,which is the so-called light time solution(LTS),we make these models depend on the time of reception of the signal only for practical convenience.We find that possible violations of LLI and LPI cannot affect two-way Doppler tracking under a linear approximation of LTS,although this approximation is sufficiently good for most cases in the solar system.We also show that,in three-way Doppler tracking,possible violations of LLI and LPI are only associated with two stations,which suggests that it is better to set the stations at places with significant differences in velocities and gravitational potentials to obtain a high level of sensitivity for the tests. 相似文献
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《天文和天体物理学研究(英文版)》2016,(8)
In this paper, a cascade acceleration feedback control(AFC) enhanced by a disturbance observation and compensation(DOC) method is proposed to improve the tracking precision of telescope systems.Telescope systems usually suffer some uncertain disturbances, such as wind load, nonlinear friction and other unknown disturbances. To ensure tracking precision, an acceleration feedback loop which can increase the stiffness of such a system is introduced. Moreover, to further improve the tracking precision, we introduce the DOC method which can accurately estimate the disturbance and compensate it. Furthermore,the analysis of tracking accuracy used by this method is proposed. Finally, a few comparative experimental results show that the proposed control method has excellent performance for reducing the tracking error of a telescope system. 相似文献
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Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible violations of the local Lorentz invariance(LLI) and the local position invariance(LPI), we analyze the post-fit residuals of three-way Doppler tracking data of Mars Express. These Doppler observations were carried out from August 7th to 8th in 2009, with an uplink station administered by the European Space Agency at New Norcia in Australia and three downlink stations at Shanghai, Kunming and Urumqi in China. We find that, although these observations impose preliminary bounds on LLI at the level of 10-2, they are not suitable for testing LPI because of the configuration of these stations and the accuracy of the observations.To our knowledge, this is one of the first attempts in China to apply radio science to the field of fundamental physics. 相似文献
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