Hee-Seob Kim

Space-Based Earth Observation Activities in South Korea [Space Agencies]

This paper describes space-based Earth observation activities in South Korea. Korean satellite development has been accomplished in three categories in accordance with the national space development program: science and technology satellites (STSAT-series), low Earth orbit satellites (KOMPSAT-series), and geostationary satellites (COMS). To achieve success, the Korea Aerospace Research Institute plays a leading role in satellite development, operations, and applications.

SATELLITE OPERATION DESIGN FOR ASSESSING MTF PERFORMANCE OF EARTH OBSERVATION SATELLITE USING STELLAR SOURCES

Modulation Transfer Function (MTF) of satellite image is an important performance index in satellite image applications. Therefore MTF performance is assessed using satellite image for the ground target during LEOP phase after launch. But the MTF performance assessment using the ground target can be affected by imaging conditions such as cloud and weather. In this paper system requirements and satellite operation for assessing MTF performance of satellite image using stellar sources are proposed. Satellite capability in collecting stellar sources using the satellite which is designed for earth observation and satellite image usefulness for assessing MTF performances were analyzed. The proposed approach will be useful to assess MTF performance of earth observation satellite in lower earth orbit.

Absolute misalignment estimation with respect to a scanning image sensor

This letter proposes a simple but effective method for in-flight estimation of absolute misalignment, which is defined as the orientation offset error between attitude sensors and an imaging payload. The method was developed for high-resolution spaceborne/airborne imaging systems, which use a scanning image sensor in their payload. This type of image sensor operates in the pushbroom mode, so that previously existing methods are not easily applicable. The proposed method utilizes the pre-existing attitude-determination algorithms originally used to estimate the attitude of a star tracker equipped with a planar image sensor. We converted the geo-referencing relation between the GCP (Ground Control Point) directions and their image vectors into a new expression which enables the application of the attitude-determination algorithms to identify the absolute misalignment. Pointing knowledge analysis, using actual in-flight data, is presented to verify the developed method.

Conceptual Design Procedure of Satellites

Design sketch of electrical power system, mass, and cost of a new satellite is an inevitable step preceding the full-scale development of the satellite. In this paper, major features of recently developed conceptual design tools of satellites are investigated. And, based on the surveying results, we summarize the conceptual design procedure of satellites. The required electrical power to support the operation of the payload mission determines the size of solar panel and battery. The mass of the integrated system and subsystems is then estimated based on the database of the previously developed satellites. Cost can also be roughly estimated using the database without consideration of complex calculations. ࠀȀ耀Ѐ

Spatial Resolution Improvement Using Over Sampling and High Agile Maneuver in Remote Sensing Satellite

Spatial resolution is an important parameter in the field of remote sensing. Therefore most of the commercial satellites are designed to obtain high resolution images. But satellite image resolution is limited by satellite design and imaging conditions. In this paper spatial resolution improvement method using over sampling and high agile maneuver is proposed. Satellite collects informations on the target in the satellite flight path along direction and cross direction. Target information is extracted from the collected informations, which are degraded by satellite modulation transfer function. By numerical simulation, we show that over sampling and high agile maneuver can be used to obtain high resolution images at sub pixel level.

MTF Analysis for the Image Performance Prediction of Observation Satellites

The prediction of image performance of an observation satellite necessitates analysis of the performance of a satellite payload and the static/dynamic characteristics of a spacecraft in the space environment. This paper introduces essential performance indices and their systematic relationships required to estimate and analyze image performance of an observation satellite. It also presents techniques and methods of integrated modeling for efficient evaluation of image performance. And the results of a system MTF (modulation transfer function) prediction are given with a consideration of each subsystem MTF of an observation satellite