• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2008년도 공동학술대회
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• pp.73-78
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• 2008

지각구조 연구 및 연안 속도구조 등의 조사를 위해 한국해양연구원에서 제작된 광각 탄성파 탐사기록 장비인 해저면지진계 및 소노부이 시스템의 특징을 살펴보았으며, 실해역 시험 탐사를 통해 그 유용성을 살펴보았다. 해저면 지진계 및 소노부이 시스템은 정상적으로 작동하였으며, 전형적인 광각 탄성파기록을 얻을 수 있었다. 특히 소노부이 기록상에서 기반암 등 지하구조에 의한 초기 굴절파의 이벤트가 나타났으며, 이는 굴절법 탐사 혹은 토모그래피 등을 통해 지하속도 구조 탐사가 가능함을 보여준다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1992년도 한국우주과학회보 제1권1호
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• pp.12-12
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• 1992

Results from the Earth Radiation Budget Experiment (ERBE) will help interpret the data from the operational satellite system. However, a major problem exists because a follow-on experiment to ERBE is not planned until the late 1990`s. Meanwhile, it will be necessary to provide OLR estimates from the operational satellite system. Since 1973the outgoing long wave radiation(OLR) data have been obtained by the 10#m window radiance(AVHRR) estimation technique from he observation NOAA operational satellites. However, those data have not been universall if accepted because they are estimated from the radiance in but one narrow spectral regiou. However , this type of technique has not been exploited for use with data from the ]fIRS multispectral radiometer. Since the radiance data measured by HIRS contains more: information on atmospheric variables than the AVHRR, it is a potentially better instrument for operational estimates of the OLR In this study, results from model are better flux estimates than the AVHRR, The technique is then tested by comparing simultalleous AVHRR and HIRS OLR estimations with a radiation model flux calculation froml homogeneous atmospheric scenes at the regions of desert and subtropic ocean.

• International Journal of Aerospace System Engineering
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• 제5권2호
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• pp.8-15
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• 2018

For small earth observation satellites, alignment between the optical components is important for precise observation. However, satellite cameras are structurally subject to misalignment in the launch environment where vibration excitations and impacts apply, and in space environments where zero gravity, vacuum, radiant heat and degassing occur. All of these variables can cause misalignment among the optical components. The misalignment among optical components results in degradation of image quality, and a re-alignment process is needed to compensate for the misalignment. This process of re-alignment between optical components is referred to as a refocusing process. In this paper, we proposed a 3 - axis focusing mechanism to perform the refocusing process. This mechanism is attached to the back of the secondary mirror and consists of three piezoelectric inertia-friction actuators to compensate the x-axis, y-axis tilt, and de-space through three-axis motion. The fabricated focus mechanism demonstrated excellent servo performance by experimenting with PD servo control.

• 한국환경과학회지
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• 제33권7호
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• pp.547-552
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• 2024

Satellite technology has emerged as a powerful tool in modern agriculture, offering capabilities for Earth observation, land-use pattern analysis, crop productivity assessment, and natural disaster prevention. This mini-review provides a concise overview of the applications and benefits of satellite technologies in agriculture. It discusses how satellite imagery enables the monitoring of crop health, identification of land-use patterns, evaluation of crop productivity, and mitigation of natural disasters. Farmers and policymakers can make informed decisions to optimize agricultural practices, enhance food security, and promote sustainable agriculture by leveraging satellite data. Integrating satellite technology with other advancements, such as artificial intelligence and precision farming techniques, holds promise for further revolutionizing the agricultural sector. Overall, satellite technology has immense potential for improving agricultural efficiency, resilience, and sustainability in the face of evolving environmental challenges.

• 대한원격탐사학회지
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• 제26권2호
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• pp.277-285
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• 2010

세계 최초로 개발된 정지궤도 해색탑재체(GOCI-I, Geostationary Ocean Color Imager-I)이 2010년 6월에 발사될 예정이다. GOCI-I의 수명은 약 7년 이므로 위성개발 소요기간 약 6년을 고려하면 제2호 정지궤도 해색탑재체의 개발을 위한 임무 및 이용자 요구사양을 준비해야할 시점이 되었다. 제2호의 임무는 우선 1호의 임무를 승계하는 것이므로 제1호와 유사한 관측 임무를 갖지만 가장 큰 차이점은 장기 기후 변화에 대응한 지구규모적 관측에 있다. 그리고 기존의 Local 관측은 그 공간해상도의 성능을 더 향상시킨 $250m{\times}250m$로 하였고, 1호에 비하여 부족한 band 수를 보강하여 12 개로 하였다. 어장정보를 위한 야간 관측을 위한 Panchromatic band를 추가하였다. 동시에 한반도 주변 고정된 영역 관측기능을 구름이 없는 해역 혹은 special event area로 신축적으로 변경 시킬 수 있는 기능을 갖게 함으로써 위성자료의 활용도를 크게 높이었다. 위성 운용은 1호와 같은 일 8회 관측, 그리고 Global mode인 full disk 관측에서는 일 1-2회 정도 관측할 수 있도록 하였다. 그리고 본 연구에서는 지금까지 위성개발 추진방법의 문제점을 해소한 개선된 개발 추진 방안에 대하여서도 제시하였다. 그 외 제2호의 하드웨어적인 구조 및 디자인에 대하여서는 국내외 개발사와의 상호협의가 필요하다.

• 전기학회논문지
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• 제57권3호
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• pp.403-408
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch. The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply (HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.231-236
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• 1999

Accurate ocean surface fluxes with high resolution are critical for understanding a mechanism of global climate. However, it is difficult to derive those fluxes by using ocean observation data because the number of ocean observation data is extremely small and the distribution is inhomogeneous. On the other hand. satellite data are characterized by the high density, the high resolution and the homogeneity. Therefore, it can be considered that we obtain accurate ocean surface by using satellite data. Recently we constructed ocean surface data sets mainly using satellite data. The data set is named by Japanese Ocean Flux data sets with Use of Remote sensing Observations (J-OFURO). Here, we introduce J-OFURO. The data set includes shortwave radiation, longwave radiation, latent heat flux, sensible heat flux, and momentum flux etc. Moreover, sea surface dynamic topography data are included in the data set. Radiation data sets covers western Pacific and eastern Indian Ocean because we use a Japanese geostationally satellite (GMS) to estimate radiation fluxes. On the other hand, turbulent heat fluxes are globally estimated. The constructed data sets are used and shows the effectiveness for many scientific studies.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.11-13
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• 2005

The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) concluded that many collective observations gave a aspect of a global warming and other changes in the climate system. Future earth observation using satellite data should monitor global climate change, and should contribute to social benefits. Especially, human activities has given the big impacts to earth environment This is a very complex affair, and nature itself also impacts the clouds, namely the seasonal variations. JAXA (former NASDA) has the plan of the Global Change Observation Mission (GCOM) for monitoring of global environmental change. SGLI (Second Generation GLI) onboard GCOM-C (Climate) satellite, which is one of this mission, is an optical sensor from Near-UV to TIR. This sensor is the GLI follow-on sensor, which has the various new characteristics. Polarized/multi-directional channels and 250m resolution channels are the unique characteristics on this sensor. This sensor can be contributed to clarification of coastal change in sea surface. This paper shows the introduction of the unique aspects and characteristics of the next generation satellite sensor, SGLIIGCOM-C, and shows the preliminary research for this sensor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1488-1490
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch, The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• Journal of Astronomy and Space Sciences
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• 제19권3호
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• pp.197-206
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• 2002

NORAD Two Line Elements (TLE) are widely used for the increasing number of small satellite mission operations and analysis. However, due to the irregular periodicity of generation of the NORAD TLE, a new TLE that is independent of NORAD is required. A TLE type Orbit Determination (TLEOD) has been developed for the generation of a new TLE. Thus, the TLEOD system can provide an Antenna Control Unit (ACU) with the orbit determination result in the type of a TLE, which provides a simple interface for the commercialized ACU system. For the TLEOD system, NORAD SGP4 was used to make a new orbit determination system. In addition, a least squares method was implemented for the TLEOD system with the GPS navigation solutions of the KOMPSAT-1. Considering both the Orbit Propagation (OP) difference and the tendency of $B^{*}$ value, the preferable span of the day in the observation data was selected to be 3 days. Through the OD with 3 days observation data, the OP difference was derived and compared with that of Mission Analysis and Planning (MAPS) for the KOMPSAT-1. It has the extent from 2 km after sit days to 4 km after seven days. This is qualified enough for the efficiency of an ACU in image reception and processing center of the KOMPSAT-2.