• Journal of the Optical Society of Korea
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• v.15 no.1
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• pp.52-55
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• 2011

We discuss the effect of stray light on a high-precision camera in an LEO(Low Earth Orbit) satellite. The critical objects and illumination objects were sorted to discover the stray light sources in the optical system. Scatter modeling was applied to determine a noise effect on the surface of a detector, and the relative flux of a signal and noise were also calculated. The stable range of reflectivity of the beam splitter was estimated for various scattering models.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.278-282
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• 2011

We discuss two possible optical noise sources in an electro-optic camera loaded on a low earth orbit satellite. The first noise source was a reflection at the window for signal rays incident upon the window which is placed before the FPA plane. The second noise source came from a reflection at the surface of the FPA cell when the signal flux is not entirely absorbed. We investigate the noise generation processes for two optical noise sources, and a parametric solution is used to estimate the optical noise effects.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.68-68
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• 2000

In this paper a very brief review of historical development of optical science and technology in China is presented. More attention has been pain on Modem Optics, which developed since 1950s. The recent development of optical science and technology in following fields are introduced. 1. Optical engineering and instrumentation (tracking theodolites, high speed cameras, satellite laser ranging systems, satellite flying attitude control, cameras for remote sensing, astronomical optical instrument) 2. Applied optics (adaptive optics, optical metrology, infrared optics, optical processing, optical holography) 3. Laser science and technology (ultrashort pulse lasers, UV-X ray lasers, high power laser facilities and laser fusion, laser isotope separation) 4. Laser and nonlinear materials (rare earth elements doped laser glasses and crystals, tunable laser crystals, borate series and organic nonlinear crystals) 5. Optoelectronic science and technology (Optical communication, optical data storage, optical computing) The current situation and developing prospect of optical and optoelectronic industry in China are presented. Furthermore it points out that the optical industry could be developed vigorously only if products development capacity is enhanced and new products industrialization is heightened. The main research and education institutions in the optics field in China, as well as the Chinese Optical Society (COS) are introduced.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1240-1247
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• 2010

This paper describes the study on the electrical design of a multi-beam large antenna for a satellite payload. This satellite antenna provides the universal communication and broadcasting services to personal portable terminals over the Korean Peninsula. The structure of the hybrid antenna fed by a feed array is proper to provide multi-beams. The amplitude and phase of each feed element should be optimized for a required beam and they can be obtained by GO (Geometrical Optics) and PO(Physical Optics) method. The number of feed elements are also optimized to meet the specification of EIRP(Effective Isotropically Radiated Power). The optimally designed antenna with the limited reflector size and minimum number of feed elements is shown in this paper.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.64-67
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• 2004

The optics and opto-mechanics are disigned for imaging the sun at Lyman-${\alpha}$ line for scientific satellite. The optics are composed of conic mirrors. In order to block stary light. the new baffle design method is suggested. And we will present the opto-mechanics for this scientific satellite.

• Proceedings of the Optical Society of Korea Conference
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• 1995.06a
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• pp.53-58
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• 1995

Examples of advanced digital electro-optic imaging systems for the satellite remote sensing applications are introduced including multispectral focal plane assembly for newly proposed 1-m spatial resolution capability.

• Current Optics and Photonics
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• v.5 no.2
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• pp.101-113
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• 2021

Adaptive optics (AO) systems are becoming more complex to improve their optical performance and enlarge their field of view, so it is a hard and time consuming process to set up and optimize the components of AO systems with actual implementation. However, simulations allow AO scientists and engineers to experiment with different optical layouts and components without needing to obtain and prepare them physically. In this paper, we introduce a new AO simulation named the Korea Adaptive Optics Simulation (KAOS), independently developed by LIG Nex1. We verified the performance of KAOS by comparing with other AO simulation tools. In the comparison simulation, we confirmed the results from KAOS and other AO simulation tools were very similar. Also, we proposed a laser tomography AO system with five Rayleigh laser guide stars (LGSs) optimized by using KAOS to overcome the disadvantages of the AO system with a single sodium LGS for the satellite imaging system. We verified the performance of the proposed AO system using KAOS, and the simulation result showed averaged Strehl ratio of 0.37.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.45-49
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• 2010

This paper presents the study on multi-beam large aperture antenna systems for a satellite payload. Multi-beam large antenna provides the universal communication and broadcasting services to personal portable terminals. The hybrid antenna composed of a large reflector and a feed array forms multi-beams. The feed cluster consists of a group of feed elements and each element should be optimized for the appropriate amplitude and phase. The optimization progress for amplitude and phase was performed by GO (Geometrical Optics) and PO (Physical Optics) method. The number of feed elements as well as the power level per element were also optimized to meet the required EIRP (Effective Isotropically Radiated Power). In conclusion, 30m-class reflector and twenty five elements for fifteen beams over Korean Peninsula were designed through the optimization process.

• Korean Journal of Optics and Photonics
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• v.25 no.2
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• pp.78-84
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• 2014

In this paper secondary optics for an LED lamp with a narrow beam angle of $15^{\circ}$ were optimized by using a two-reflector system, to reduce both its size and the occurrence of satellite rings. The conic constant and the curvature of the primary reflector were determined by considering the relation of the source size to the beam angle, and the optimal position and radius of the secondary reflector were found for reducing the occurrence of satellite rings. Luminous flux efficiency was about 80%.

• Bulletin of the Korean Space Science Society
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• 2005.10a
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• pp.71-71
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• 2005