• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.97-107
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• 2009

Experiments using real guided weapons for the development of the LADAR(Laser radar) are not practical. Therefore, we need computing environment that can simulate the 3D detections by LADAR. Such simulations require dealing with large sized data representing buildings and terrain over large area. And they also need the information of 3D target objects, for example, material and echo rate of building walls. However, currently used 3D models are mostly focused on visualization maintained as file-based formats and do not contain such semantic information. In this study, as a solution to these problems, a method to use a spatial DBMS and a 3D model suitable for LADAR simulation is suggested. The 3D models found in previous studies are developed to serve different purposes, thus, it is not easy to choose one among them which is optimized for LADAR simulation. In this study, 4 representative 3D models are first defined, each of which are tested for different performance scenarios. As a result, one model, "Body-Face", is selected as being the most suitable model for the simulation. Using this model, a test simulation is carried out.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.219-220
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• 2009

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

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.497-500
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• 2008

3차원 오브젝트의 위치 및 정보 획득을 위한 레이저레이더 시뮬레이션의 성능을 향상시키기 위해서는 시뮬레이션의 결과로 획득되는 공간의 범위와 해당 사물의 정보를 정확하고 빠르게 획득해야 한다. 본 연구에서는 이러한 레이더 시뮬레이션의 성능을 향상시키기 위해서 3차원 공간 데이터를 공간DB에 저장하고, 질의를 수행하여 해당 3차원 오브젝트의 정보를 효과적으로 추출해내는 방법론을 제시하였다. 이를 위해 본 연구에서는 시뮬레이션에서 사용되는 3차원 지형지물(지형, 건물 사물 등) 모델의 정보를 데이터모델링을 통해 토폴로지 형태를 갖도록 하였으며, 이를 공간DB에 저장하고, 레이저 신호와의 연산 쿼리를 시행하는 과정을 예시하였다. 이러한 과정을 구현하기 위하여 OGC 기반의 공간 데이터 타입, 함수, 인덱스들을 제공하는 PostgreSQL과 PostGIS를 사용하였다. 지형, 건물, 탱크 등 이렇게 세 가지의 범주의 사물로 나누어 각각을 공간DB로 구현, 쿼리를 실시하였다. 지형정보는 TIN을 사용하였고, 건물의 좌표 값들은 도화원도에서 추출하였으며, 탱크와 같은 사물은 VRML 모델의 좌표 값을 사용하였다.

• Korean Journal of Optics and Photonics
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• v.27 no.4
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• pp.133-142
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• 2016

This paper presents the design and simulation of a three-dimensional pixel-by-pixel scanning light detection and ranging (LIDAR) system with a microelectromechanical system (MEMS) scanning mirror and direct sequence optical code division multiple access (DS-OCDMA) techniques. It measures a frame with $848{\times}480$ pixels at a refresh rate of 60 fps. The emitted laser pulse waves of each pixel are coded with DS-OCDMA techniques. The coded laser pulse waves include the pixel's position in the frame, and a checksum. The LIDAR emits the coded laser pulse waves periodically, without idle listening time to receive returning light at the receiver. The MEMS scanning mirror is used to deflect and steer the coded laser pulse waves to a specific target point. When all the pixels in a frame have been processed, the travel time is used by the pixel-by-pixel scanning LIDAR to generate point cloud data as the measured result.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.387-390
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• 2017

With the advent of high-resolution sensors in the embedded field, the demand for heterogeneous computing continues to increase. Logic Module is an embedded system for controlling LADAR system components and for real-time 3D imaging of laser radar image data. In this paper, we discuss the design of Logic Module and the signal processing using CPU-GPU heterogeneous computing.