• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.884-887
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• 2006

This paper focuses on minimizing flood damage in the Yeongdeok basin of South Korea by establishing a flood prediction model based on a geographic information system (GIS), remote sensing, and geomorphoclimatic instantaneous unit hydrograph (GcIUH) techniques. The GIS database for flash flood prediction was created using data from digital elevation models (DEMs), soil maps, and Landsat satellite imagery. Flood prediction was based on the peak discharge calculated at the sub-basin scale using hydrogeomorphologic techniques and the threshold runoff value. Using the developed flash flood prediction model, rainfall conditions with the potential to cause flooding were determined based on the cumulative rainfall for 20 minutes, considering rainfall duration, peak discharge, and flooding in the Yeongdeok basin.

• Journal of Positioning, Navigation, and Timing
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• 제13권3호
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• pp.309-317
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• 2024

Satellite and receiver Inter-Frequency Biases (IFBs) should be estimated or calibrated by pre-defined values for generating precise navigation messages and augmentation data in satellite navigation systems or the augmentation system. In this paper, a Kalman filter is designed and implemented to estimate the ionospheric delay and satellite/receiver IFBs using a regional receiver network. First, an ionospheric model and its filter parameter is defined based on previous studies. Second, a measurement model for estimating the relative satellite/receiver IFBs without any constraints is proposed. Third, a procedure for ensuring the continuity of estimation is proposed in this paper. To verify the performance of the designed filter, six Continuously Operating Reference Stations (CORSs) are selected. Finally, the stability and accuracy of satellite/receiver IFB estimation are analyzed.

• 제어로봇시스템학회논문지
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• 제8권1호
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• pp.67-73
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• 2002

This paper presents the development of development of stabilization and tracking algorithms for a shipboard satellite antenna system. In order to stabilize the satellite antenna system designed in the previous work, a model for each control axis is derived and its parameters are estimated using a genetic algorithm, and the state feedback controller is designed based on the linearized model. Then a tracking algorithm is derived to overcome some drawbacks of the step tracking. The proposed algorithm searches for the best position using gradient-based formulae and signal intensities measured according to a search pattern. The effectiveness of both the stabilization and tracking algorithms is demonstrated through experiment using real-world data.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.75-80
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• 2002

The mainly used technique to rectify satellite images with distortion is to develop a mathematical relationship between the pixel coordinates on the image and the corresponding points on the ground. By defining the relationship between two coordinate systems, a polynomial model is designed and various linear transformations are used. These GCP based geometric correction has performed overall plane to plane mapping. In the overall plane mapping, overall structure of a scene is considered, but local variation is discarded. The highly variant height of region is resampled with distortion in the rectified image. To solve this problem this paper proposed the TIN-based rectification on a satellite image. The TIN based rectification is good to correct local distortion, but insufficient to reflect overall structure of one scene. So, this paper shows the experimental result and the analysis of each rectification model. It also describes the relationship GCP distribution and rectification model. We can choose a geometric correction model as the structural characteristic of a satellite image and the acquired GCP distribution.

• 한국측량학회지
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• 제23권2호
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• pp.137-145
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• 2005

이 논문에서는 선형 푸시브룸 방식으로 촬영한 위성영상에 대한 다양한 센서모델들의 정확도를 비교분석하고자 한다. 특히 이 논문에서는 센서모델의 정확도를 번들조정의 정확도와 외부표정요소추정의 정확도로 분리하여 고찰하려고 한다. 번들조정 정확도는 수립된 센서모델이 얼마나 기준점에 잘 부합하는 가를 알려주는 척도로 이제까지 대부분의 센서모델 정확도 분석에 사용되어온 기준이다. 이에 반하여 외부표정요소추정의 정확도는 센서모델이 얼마나 정확하게 촬영당시의 위성의 궤도 및 자세를 예측할 수 있는 지의 척도로서 매우 중요한 요소임에도 불구하고 기존의 연구에서 간과해온 부분이다. 이 논문에서는 여러 센서모델 중에서 사진측량분야에서 주로 사용하는 변형된 공선방정식기반 모델과 위성지상국 또는 자세제어분야에서 주로 사용하는 궤도좌표계 및 자세각에 기반한 모델의 정확도를 비교분석하고자 한다. 실험은 다목적실용위성 1호 EOC 영상과 GPS 수신기에서 취득한 기준점을 사용하였다. 실험결과 번들조정 정확도는 두 모델이 큰 차이를 보이지 않는 것으로 나타났으나 외부표정요소추정 정확도는 궤도좌표계 및 자세각에 기반한 모델이 더 나은 성능을 보였다.

• 대기
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• 제14권2호
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• pp.11-22
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• 2004

A technique on atmospheric correction algorithm to the multi-band reflectance of Landsat TM imagery has been developed using an atmospheric radiation transfer model for eliminating the atmospheric and surface diffusion effects. Despite the fact that the technique of satellite image processing has been continually developed, there is still a difference between the radiance value registered by satellite borne detector and the true value registered at the ground surface. Such difference is caused by atmospheric attenuations of radiance energy transfer process which is mostly associated with the presence of aerosol particles in atmospheric suspension and surface irradiance characteristics. The atmospheric reflectance depend on atmospheric optical depth and aerosol concentration, and closely related to geographical and environmental surface characteristics. Therefore, when the effects of surface diffuse and aerosol reflectance are eliminated from the satellite image, it is actually corrected from atmospheric optical conditions. The objective of this study is to develop an algorithm for making atmospheric correction in satellite image. The study is processed with the correction function which is developed for eliminating the effects of atmospheric path scattering and surface adjacent pixel spectral reflectance within an atmospheric radiation model. The diffused radiance of adjacent pixel in the image obtained from accounting the average reflectance in the $7{\times}7$ neighbourhood pixels and using the land cover classification. The atmospheric correction functions are provided by a radiation transfer model of LOWTRAN 7 based on the actual atmospheric soundings over the Korean atmospheric complexity. The model produce the upward radiances of satellite spectral image for a given surface reflectance and aerosol optical thickness.

• 대한원격탐사학회지
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• 제24권5호
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• pp.497-506
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• 2008

The needs for digital models of real environment such as 3D terrain or cyber city model are increasing. Most of applications related with modeling and simulation require virtual environment constructed from geospatial information of real world in order to guarantee reliability and accuracy of the simulation. The most fundamental data for building virtual environment, terrain elevation and orthogonal imagery is acquired from optical sensor of satellite or airplane. Providing interoperable and reusable digital model is important to promote practical application of high-resolution satellite imagery. This paper presents the new research regarding representation of geospatial information, especially for 3D shape and appearance of virtual terrain. and describe framework for constructing real-time 3D model of large terrain based on high-resolution satellite imagery. It provides infrastructure of 3D simulation with geographical context. Web architecture, XML language and open protocols to build a standard based 3D terrain are presented. Details of standard-based approach for providing infrastructure of real-time 3D simulation using high-resolution satellite imagery are also presented. This work would facilitate interchange and interoperability across diverse systems and be usable by governments, industry scientists and general public.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.342-348
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• 1998

The purpose of this paper is to extract fast DEM (Digital Elevation Model) using satellite images. DEM extraction consists of three parts. First part is the modeling of satellite position and attitude, second part is the matching of two images to find corresponding poults of them and third part is to calculate the elevation of each point by using the result of the first and second part. The position and attitude modeling of satellite is processed by using GCPs. A area based matching method is used to find corresponding points between the stereo satellite images. In the DEM generation system, this procedure holds most of a processing time, therefore a new fast matching algorithm is proposed to reduce the time for matching. The elevation of each point is calculated using the exterior orientation obtained from modeling and disparity from matching. In this paper, the SPOT satellite images, level IA 6000 $\times$6000 panchromatic images are used to extract DEM. The experiment result shows the possibility of fast DEM. extraction with the satellite images.

• 한국항행학회논문지
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• 제10권4호
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• pp.356-363
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• 2006

본 논문에서는 위성통신을 이용한 방송 및 디지털 멀티미디어 서비스의 요구증대를 앞두고 20 GHz 이상의 높은 주파수 대역의 강우에 의한 전파 손실 예측 모델을 제안하고 강우량에 따른 감쇠 정도를 기존의 모델과 비교 분석 하였다. 본 논문에서는 Ka 대역에서 강우 감쇠 특성에서 이론치와 실험치가 접근함을 보이고 강우감쇠에 효과적인 기법을 제안하여 적응변조 시스템의 성능을 분석하였다. 제안 예측모델에서는 강우 강도를 기준으로 위성링크 설계를 위한 안테나 크기, 시스템의 불작동율 등에 대한 기본 자료를 Ka 대역 위성통신 시스템의 원활한 운영을 위해 제공한다.

• 한국정보처리학회논문지
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• 제4권10호
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• pp.2501-2511
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• 1997

본 논문에서는 위성관제센터와 위성간의 명령어 및 텔레메트리 통신의 안정성을 위해 Shamir의 서명 방식을 변형한 인증 방식을 제안한다. 제안된 방식은 위성 고유 ID를 이용하며 재생 공격에 대한 보호를 위해 시간함수를 도입한 패스워드 개념의 인증 방식으로 위성의 실체 인증을 위해 사용한다. 또 사용중인 키와 알고리즘 내용을 포함한 명령어 카운터가 메시지 로딩과 명령어 실행 시 인증으로 이용되며 이를 기반으로 위성관제통신의 안정성을 위한 인증 모델을 제안하였다. 그밖에 위성관제센터와 위성간의 비밀 통신에 사용했던 비밀 키 교체와 확인을 위해 Two-way 키교체 방식을 제안하였다.