Mr. Feng Qian Profile

Feng Qian

at Shanghai Institute of Technical Physics

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Publications (2)

Proceedings Article | 21 August 2013 Paper

The research of adaptive-exposure on spot-detecting camera in ATP system

Feng Qian, Jian-jun Jia, Liang Zhang, Jian-Yu Wang

Proceedings Volume 8906, 89060L (2013) https://doi.org/10.1117/12.2032633

KEYWORDS: Cameras, Telecommunications, Laser communications, Imaging systems, Acquisition tracking and pointing, Sensors, Signal detection, Laser systems engineering, Detection and tracking algorithms, Satellites

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High precision acquisition, tracking, pointing (ATP) system is one of the key techniques of laser communication. The spot-detecting camera is used to detect the direction of beacon in laser communication link, so that it can get the position information of communication terminal for ATP system. The positioning accuracy of camera decides the capability of laser communication system directly. So the spot-detecting camera in satellite-to-earth laser communication ATP systems needs high precision on target detection. The positioning accuracy of cameras should be better than ±1μ rad . The spot-detecting cameras usually adopt centroid algorithm to get the position information of light spot on detectors. When the intensity of beacon is moderate, calculation results of centroid algorithm will be precise. But the intensity of beacon changes greatly during communication for distance, atmospheric scintillation, weather etc. The output signal of detector will be insufficient when the camera underexposes to beacon because of low light intensity. On the other hand, the output signal of detector will be saturated when the camera overexposes to beacon because of high light intensity. The calculation accuracy of centroid algorithm becomes worse if the spot-detecting camera underexposes or overexposes, and then the positioning accuracy of camera will be reduced obviously. In order to improve the accuracy, space-based cameras should regulate exposure time in real time according to light intensity. The algorithm of adaptive-exposure technique for spot-detecting camera based on metal-oxide-semiconductor (CMOS) detector is analyzed. According to analytic results, a CMOS camera in space-based laser communication system is described, which utilizes the algorithm of adaptive-exposure to adapting exposure time. Test results from imaging experiment system formed verify the design. Experimental results prove that this design can restrain the reduction of positioning accuracy for the change of light intensity. So the camera can keep stable and high positioning accuracy during communication.

Proceedings Article | 21 August 2013 Paper

Real time basis-deviation measurement system based on BB84 module

Ming Zhang, Jin-cai Wu, Liang Zhang, Jian-jun Jia, Zhi-pin He, Shi-ji Yang, Feng Qian, Jian-yu Wang

Proceedings Volume 8906, 890629 (2013) https://doi.org/10.1117/12.2034937

KEYWORDS: Quantum communications, Polarization, Quantum key distribution, Photon polarization, Satellites, Optical components, Time metrology, Telecommunications, Photon counting, Signal detection

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