• Title/Summary/Keyword: space coordinate system

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Multi-beam Antenna Analysis

  • Lee, Jeom-Hun;Oh, Seung-Hyeub
    • International Journal of Aeronautical and Space Sciences
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    • v.5 no.2
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    • pp.71-76
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    • 2004
  • This paper describes the antenna analysis of the multi-beam for communicationsatellite. The design core parameters of the antenna system are optimal antennadiameter, feed horn type and hom size, F/D, and the coordinate of offset horns. Thepaper deals with the method to determine design core parameters of optimal antennadiameter, feed horn type and horn size. F/D, and the coordinate of offset horns, andthe performances of design result.

KA-BAND ANTENNA PERFORMANCE ANALYSIS OF COMS SATELLITE

  • Lee Jeom-Hun;Choi Jang-Sup;Lee Seong Pal
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.316-320
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    • 2004
  • This paper describes Ka-band antenna performance analysis of COMS satellite. The key parameters of the antenna system are optimal antenna diameter, feed horn type and horn size, F/D, and the coordinate of offset horns. The paper deals with the method to determine design core parameters of optimal antenna diameter, feed horn type and horn size, F/D, and the coordinate of offset horns, and the performances of design result.

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A study on the rectangular coordinate system via comparing the interrelated influence between mathematical knowledge evolution and historical development of Cartography in Europe (서양의 역사적인 지도제작법의 발달 과정과 수학적 지식의 상호 영향 관계를 통해 본 직교좌표계)

  • Lee, Dong Won
    • Journal for History of Mathematics
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    • v.25 no.4
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    • pp.37-51
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    • 2012
  • By comparing the development history of rectangular coordinate system in Cartography and Mathematics, we assert in this manuscript that the rectangular coordinate system is not so much related to analytic geometry but comes from the space perceiving ability inherent in human beings. We arrived at this conclusion by the followings: First, although the Cartography have much influenced to various area of Mathematics such as trigonometry, logarithm, Geometry, Calculus, Statistics, and so on, which were developed or progressed around the advent of analytic geometry, the mathematical coordinate system itself had not been completely developed in using the origin or negative axis until 100 years and more had passed since Descartes' publication. Second, almost mathematicians who contributed to the invention of rectangular coordinate system had not focused their studying on rectangular coordinate system instead they used it freely on solving mathematical problem.

Development of a Data Reduction algorithm for Optical Wide Field Patrol

  • Park, Sun-Youp;Keum, Kang-Hoon;Lee, Seong-Whan;Jin, Ho;Park, Yung-Sik;Yim, Hong-Suh;Jo, Jung Hyun;Moon, Hong-Kyu;Bae, Young-Ho;Choi, Jin;Choi, Young-Jun;Park, Jang-Hyun;Lee, Jung-Ho
    • Journal of Astronomy and Space Sciences
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    • v.30 no.3
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    • pp.193-206
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    • 2013
  • The detector subsystem of the Optical Wide-field Patrol (OWL) network efficiently acquires the position and time information of moving objects such as artificial satellites through its chopper system, which consists of 4 blades in front of the CCD camera. Using this system, it is possible to get more position data with the same exposure time by changing the streaks of the moving objects into many pieces with the fast rotating blades during sidereal tracking. At the same time, the time data from the rotating chopper can be acquired by the time tagger connected to the photo diode. To analyze the orbits of the targets detected in the image data of such a system, a sequential procedure of determining the positions of separated streak lines was developed that involved calculating the World Coordinate System (WCS) solution to transform the positions into equatorial coordinate systems, and finally combining the time log records from the time tagger with the transformed position data. We introduce this procedure and the preliminary results of the application of this procedure to the test observation images.

Implementation of GPS/Galileo Integrated Navigation Algorithm and Analysis of Different Time-Coordinate Effect (GPS/Galileo 통합항법알고리즘 구현 및 시각 및 좌표계차이에 따른 영향분석)

  • Song, Jong-Hwa;Jee, Gyu-In;Jeong, Seong-Kyun;Lee, Sang-Uk;Kim, Jae-Hoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.2
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    • pp.171-178
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    • 2008
  • Galileo is the Europe's global navigation satellite system corresponding to the GPS. The GIOVE-A test experiment has been finished and the second test satellite GIOVE-B will be launched soon. The integration of GPS and Galileo lead an increase of visible satellite number. We can obtain an improved navigation performance in signal blocked area such as urban or forest. GPS and Galileo have each time-coordinate system and use the different error model to calculate the navigation solution. In this paper, we studied on GPS and Galileo channel error model and time-coordinate system. Using this result, we implement the integrated navigation algorithm. In simulation, we analyzed the navigation error caused by time and coordinate disagreement and verified performance of integrated navigation algorithm in terms of visible satellite number, DOP(Dilution of Pression) and position error.

Novel current control for PWM AC-DC converter using internal principle of PI controller (PI 제어기의 내부원리를 이용한 PWM AC-DC 컨버터의 새로운 전류제어)

  • Heo, T.W.;Hwang, Y.M.;Kim, Y.B.;Lee, H.W.;Woo, J.I.
    • Proceedings of the KIEE Conference
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    • 1998.07f
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    • pp.1944-1946
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    • 1998
  • This paper presents a novel current control system to eliminate the steady state control error for PWM AC-DC converter. A general mathematical model of the converter which is represented as a state-space model is established. The state-space model is used for the simulation of converter with the proposed tracking control system of sinusoidal current. In this system, a novel current control which do not require coordinate transformations using internal principle of PI controller is described. It is proved that the steady state deviation reduce to zero through a transfer function of source current control system. Finally, simulations show good source current control characteristics by means of a simplified control system which do not require coordinate transformations.

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Nonlinear control of a double-effect evaporator by riemannian geometric approach

  • Izawa, Yoshiaki;Hakomori, Kyojiro
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.405-410
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    • 1994
  • The purpose of this paper is to present the details of design procedure of a nonlinear regulator by Riemannian geometric approach and to applied it to the case of a double-effect evaporator. A nonlinear geometric model is proposed on a direct sum space of a state vector and a control vector as well as in the previous parers by the authors. The geometric model is derived by replacing the orthogonal straight coordinate axes of a linear system on the direct sum space with the curvilinear coordinate axes. The integral manifold of the geometric model becomes homeomorphic to that of fictitious linear system. For the geometric model a nonlinear regulator with a performance index is designed renewedly by the procedure of optimization. The construction method of the curvilinear coordinate axes on which the nonlinear system behaves as a linear system is discussed. To apply the above regulator theory to double-effect evaporators especially to the pilot plant at the University of Alberta, a suitable nonlinear model is determined by the plant dynamics. The optimal control law is derived through the calculation of the homeomorphism. As a result it is confirmed that the regulator is effective and superior to that of the conventional control.

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Robot motion planning for time-varying obstacle avoidance using distance function (거리 함수를 이용한 로보트의 시변 장애물 회피 동작계획)

  • 전흥주;고낙용;남윤석;이범희;고명삼
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.1034-1039
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    • 1991
  • A robot motion planning algorithm for time-varying obstacle avoidance is proposed. The robot motion planning problem is replaced with the optimization problem by using the distance function with the divided configuration space. To divide the configuration space, the polar coordinate system is used. For each divided configuration space, the admissible region where the robot can reach without collisions is obtained using the distance function. For an object moving in a plane, the admissible region is described by linear constraints on the polar coordinate system. A numerical algorithm that solves the optimization problem is shown and the computer simulation is carried out.

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The 3-Dimensional Localization System Based on Beacon Expansion and Coordinate-Space Disassembly (비컨노드 확장과 좌표공간 분해 기반 3차원 위치인식시스템)

  • Lee, Ho Chul;Lee, Dong Myung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.1
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    • pp.80-86
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    • 2013
  • The 3-Dimensional(3D) localization system based on beacon expansion and coordinate-space disassembly for the design of the 3D localization system in indoor environment is proposed and the performance of the proposed system is analyzed in this paper. The localization ratio of the 3D localization system adapts the proposed algorithm is analyzed by the calculation of errors occurred in the coordinates that the mobile node locates. It is indicated that the average error distance of the 3D localization system adapts the proposed algorithm is less than that of the 3D localization system not adapts the proposed algorithm as 0.47m. The localization average distance error in 12 coordinates is indicated that the 1.5m case is less than 2.5m case as 0.38m by some experimentations under the condition that the distances between the ceiling and the mobile node are 1.5m and 2.5m measured from the ceiling respectively. It is seen that the 3D localization system based on beacon expansion and coordinate-space disassembly can improved the degradation of the quality of service that is caused by some conditions and performance differences in sensors.

A method for image processing by use of inertial data of camera

  • Kaba, K.;Kashiwagi, H.
    • 제어로봇시스템학회:학술대회논문집
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    • 1998.10a
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    • pp.221-225
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    • 1998
  • This paper is to present a method for recognizing an image of a tracking object by processing the image from a camera, whose attitude is controlled in inertial space with inertial co-ordinate system. In order to recognize an object, a pseudo-random M-array is attached on the object and it is observed by the camera which is controlled on inertial coordinate basis by inertial stabilization unit. When the attitude of the camera is changed, the observed image of M-array is transformed by use of affine transformation to the image in inertial coordinate system. Taking the cross-correlation function between the affine-transformed image and the original image, we can recognize the object. As parameters of the attitude of the camera, we used the azimuth angle of camera, which is de-fected by gyroscope of an inertial sensor, and elevation an91e of camera which is calculated from the gravitational acceleration detected by servo accelerometer.

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