Reflector surface distortion on a sub-reflectarray Cassegrain system: Simulations, measurements, and microwave holographic diagnostics

GIS are closely related to mathematical cartography, as they work with spatially coordinated data. Practical course in mathematical cartography should meet the requirements of time and include tasks involving the use of modern GIS technologies. The functionality of GIS packages allow you to easily create maps in a given map projection, draw graticules and measured grids, perform dimensions on maps. This article is devoted to the research of map projection properties on the basis of GIS technologies in a practical course of mathematical cartography. The focus is on visual way to display local and regional distortions on maps. To create lines of equal distortion should use special software tools that allow to build digital models of surface distortion distribution directly on formulas or be interpolated both discretely located nodal points and isolines.

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An examination of yield surface distortion and translation

Acta Mechanica ◽

10.1007/bf01175962 ◽

1984 ◽

Vol 52 (1-2) ◽

pp. 15-40 ◽

Cited By ~ 23

Author(s):

D. W. A. Rees

Keyword(s):

Yield Surface ◽

Surface Distortion ◽

Yield Surface Distortion

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Real-time Closed-loop Active Surface Technology of a Large Radio Telescope

Publications of the Astronomical Society of the Pacific ◽

10.1088/1538-3873/ac32af ◽

2022 ◽

Vol 134 (1031) ◽

pp. 015003

Author(s):

Yong Zhang ◽

Guoping Li ◽

Guohua Zhou ◽

Qishuai Lu ◽

Heng Zuo ◽

...

Keyword(s):

Real Time ◽

Radio Telescope ◽

Closed Loop ◽

Preliminary Test ◽

Active Surface ◽

Angle Measurement ◽

Quality Data ◽

Surface Accuracy ◽

Surface System ◽

Reflector Surface

Abstract The surface accuracy of a large radio telescope’s primary reflector is easily affected by gravity and temperature change during observations. An active surface system is crucial to ensure the regular operation and high-quality data output of the radio telescope. We propose a real-time closed-loop active surface system including two components. The first component, a new type of photoelectric edge sensor, detects the angle change of the adjacent panels. The second component, the displacement actuator, adjusts the panels’ position and posture to compensate for the angle changes. So, over the entire observation, the closed-loop surface control system with these two components could actively maintain the primary reflector’s accuracy in real time. Using this approach, we constructed an experimental active surface system for the Xinjiang Qitai 110 m Radio Telescope (QTT) to test the maintenance of the surface accuracy. The angle measurement accuracy is better than 0.″2, and the positioning accuracy of the displacement actuator could achieve ±15 μm over the whole 50 mm stroke. The preliminary test results show that the accuracy requirements of the QTT’s primary reflector surface can be met using the active surface system we propose.

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Fabrication of electrically-pumped resonance-cavity membrane-reflector surface-emitters on silicon

2013 IEEE Photonics Conference ◽

10.1109/ipcon.2013.6656459 ◽

2013 ◽

Author(s):

Wenjuan Fan ◽

Deyin Zhao ◽

Santhad Chuwongin ◽

Jung-Hun Seo ◽

Hongjun Yang ◽

...

Keyword(s):

Electrically Pumped ◽

Reflector Surface ◽

Resonance Cavity

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