• Journal of Satellite, Information and Communications
• /
• v.1 no.1
• /
• pp.20-25
• /
• 2006

The link of Geostationary Communication Satellite has transit delay and noise environments by physical distance. This situation exerts an influence on the degradation of baseband performance of Earth Station. Therefore, it is very important that degradation of baseband performance is grasped previously. This paper is presented that developed the simulator which can evaluate the baseband performance of earth station of a military satellite communication system during the current development. The simulator can mock delay on a satellite channel and bit errors without being used actual satellite links.

• Journal of Astronomy and Space Sciences
• /
• v.30 no.4
• /
• pp.321-326
• /
• 2013

The modulation transfer function (MTF) is a widely used indicator in assessments of remote-sensing image quality. This MTF method is also used to restore information to a standard value to compensate for image degradation caused by atmospheric or satellite jitter effects. In this study, we evaluated MTF values as an image quality indicator for the Geostationary Ocean Color Imager (GOCI). GOCI was launched in 2010 to monitor the ocean and coastal areas of the Korean peninsula. We evaluated in-orbit MTF value based on the GOCI image having a 500-m spatial resolution in the first time. The pulse method was selected to estimate a point spread function (PSF) with an optimal natural target such as a Seamangeum Seawall. Finally, image restoration was performed with a Wiener filter (WF) to calculate the PSF value required for the optimal regularization parameter. After application of the WF to the target image, MTF value is improved 35.06%, and the compensated image shows more sharpness comparing with the original image.

• Korean Journal of Remote Sensing
• /
• v.26 no.4
• /
• pp.387-394
• /
• 2010

There has been an increasing trend in damaging by the Asian dust in spring. The continuous monitoring of the dust event with IR channels in geostationary satellite is very useful for forecasting and preventing the event. However, the monitoring with the IR channels revealed various problems associated with sensitivity. To eliminate these problems, we introduced a new concept of monitoring by constructing the background threshold values (BTV) and aerosol index (AI). This paper is about to test the reliability of this concept by applying to geostationary satellite, MTSAT-1R.

• Korean Journal of Remote Sensing
• /
• v.35 no.1
• /
• pp.195-201
• /
• 2019

The Outgoing Longwave Radiation (OLR) is an important satellite-driven variable for understanding the Earth's energy budget balance. The geostationary OLR retrievals require angular and spectral integration using an empirical equation for irradiance flux-to-OLR from a regression analysis, which determines the accuracy of the narrowband satellite-based OLR. We selected homogeneous pixels which is satisfied less temporal-spatial variability of cloud, on three infrared channels (6.7, 10.8, $12.0{\mu}m$) of the first multipurpose geostationary satellite in Korea, namely the Communication, Ocean and Meteorological Satellite/Meteorological Imager (COMS/MI). Multiple regression analysis was performed to retrieve OLR with improved accuracy using selected parameters based on theoretical and physical significance. This algorithm yielded retrieval with higher accuracy than broadband-based OLR retrieval: RMSE of 10.54 to $3.81W\;m^{-2}$, and bias of -8.49 to $-0.07W\;m^{-2}$.

• Journal of Astronomy and Space Sciences
• /
• v.35 no.4
• /
• pp.227-233
• /
• 2018

This study presents the generation and accuracy assessment of predicted orbital ephemeris based on satellite laser ranging (SLR) for geostationary Earth orbit (GEO) satellites. Two GEO satellites are considered: GEO-Korea Multi-Purpose Satellite (KOMPSAT)-2B (GK-2B) for simulational validation and Compass-G1 for real-world quality assessment. SLR-based orbit determination (OD) is proactively performed to generate orbital ephemeris. The length and the gap of the predicted orbital ephemeris were set by considering the consolidated prediction format (CPF). The resultant predicted ephemeris of GK-2B is directly compared with a pre-specified true orbit to show 17.461 m and 23.978 m, in 3D root-mean-square (RMS) position error and maximum position error for one day, respectively. The predicted ephemeris of Compass-G1 is overlapped with the Global Navigation Satellite System (GNSS) final orbit from the GeoForschungsZentrum (GFZ) analysis center (AC) to yield 36.760 m in 3D RMS position differences. It is also compared with the CPF orbit from the International Laser Ranging Service (ILRS) to present 109.888 m in 3D RMS position differences. These results imply that SLR-based orbital ephemeris can be an alternative candidate for improving the accuracy of commonly used radar-based orbital ephemeris for GEO satellites.

• Journal of Satellite, Information and Communications
• /
• v.10 no.4
• /
• pp.95-100
• /
• 2015

These days, satellite core technologies are being developed as a way to provide various information by considering simultaneously sending, wide area covering, highly precide, and anti-disaster technologies. Not only global positioning, and image but also space launcher, satellite bus, satellite payload, earth station are being convergently developed in a different technological field. Especially, it is required a lot of initial investing expenditure to provide the Earth observational information service based on the space technologies. Such a trend and change of satellite technologies Korea has realized the necessity for the domestic independent development of next generation earth observation satellites, and are preparing the profound items such as a detailed implementation plan for the efficient development project. Like the satellite advanced countries, it should be transparently carried out that an efficient implementation of the developing target related to the geostationary earth observation satellite development, establishment of technological auditing function and quality assurance system, implementation plan, progressing courses and results of the satellite development program by way of planning, evaluation and management. For these things cited above, it is necessary to operate systematically and continuously the professional structural system by the governmental department in order to control the geostationary earth observation satellite development project. Therefore, this study proposes a development project management improvement method of the Korea next generation geostationary earth observation satellite based on the development project management system of the domestic geostationary satellite system.

• Journal of Satellite, Information and Communications
• /
• v.2 no.2
• /
• pp.29-35
• /
• 2007

COMS satellite is a multipurpose satellite in the geostationary orbit, which accommodates multiple payloads of the Ka band Satellite Communication Payload, Meteorological Imager, and Geostationary Ocean Color Imager into a single spacecraft platform. In this paper, Korea's first innovative geostationary Communication, Ocean and Meteorological Satellite (COMS) program is introduced which is fully funded by Korean Government. The satellite platform is based on the Astrium EUROSTAR 3000 communication satellite, but creatively combined with MARS Express satellite platform to accommodate three different payloads efficiently for COMS. The goals of the Ka band satellite communication mission are to in-orbit verify the performances of advanced communication technologies and to experiment wide-band multi-media communication service. The Meteorological Imager mission is to continuously extract meteorological products with high resolution and multi-spectral imager, to detect special weather such as storm, flood, yellow sand, and to extract data on long-term change of sea surface temperature and cloud. The Geostationary Ocean Color Imager mission aims at monitoring of marine environments around Korean peninsula, production of fishery information (Chlorophyll, etc.), and monitoring of long-term/short-term change of marine ecosystem. The system design difficulties are in the different kinds of payload mission requirements of communication and remote sensing purposes and how to combine them into one to meet the overall satellite requirements. In this paper, Ka band communication payload system is more highlighted.

• Korean Journal of Remote Sensing
• /
• v.26 no.2
• /
• pp.277-285
• /
• 2010

Geostationary Ocean Color Imager(GOCI-I), the world's first space-borne ocean color observation geostationary satellite, will be launched on June 2010. Development of GOCI-I took about 6 years, and its expected lifetime is about 7 years. The mission and user requirements of GOCI-II are required to be defined at this moment. Because baseline of the main mission of GOCI-II must be defined during the development time and early operational period of GOCI-I. The main difference between these missions is the global-monitoring capability of GOCI-II, which will meet the necessity of the monitoring and research on climate change in the long-term. The user requirements of GOCI-II will have higher spatial resolution, $250m{\times}250m$, and 12 spectral bands to fulfill GOCI-I's user request, which could not be implemented on GOCI-I for technical reasons. A dedicated panchromatic band will be added for the nighttime observation to obtain fishery information. GOCI-II will have a new capability, supporting user-definable observation requests such as clear sky area without clouds and special-event areas, etc. This will enable higher applicability of GOCI-II products. GOCI-II will perform observations 8 times daily, the same as GOCI-I's. Additionally, daily global observation once or twice daily is planned for GOCI-II. In this paper, we present an improved development and organization structure to solve the problems that have emerged so far. The hardware design of the GOCI-II will proceed in conjunction with domestic or foreign space agencies.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.702-702
• /
• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1991.10a
• /
• pp.366-371
• /
• 1991