• Title/Summary/Keyword: Geo-Pointing

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Enhancement of Geo-pointing Performance for Electro-Optical Systems by Compensating Transmission Time Delay of Navigation Data (항법정보 전송지연 보상을 통한 전자광학장비 좌표지향성능 향상)

  • Kim, Sung-Su;Moon, Seong-Man;Kwon, Kang-Hun;Yun, Chang-Ryul
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.2
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    • pp.191-198
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    • 2013
  • Geo-pointing is a function that maintains LOS(Line of Sight) to a stationary ground target by controlling azimuth and elevation angles of a EOS(Electro-Optical System) which are calculated from aircraft navigation data and target coordinates. In design and implementation of the geo-pointing, a transmission time delay between GPS/INS and EOS is a major degradation factor of the geo-pointing performance when the aircraft is rapidly maneuvered especially. In this paper, a kalman filter is designed to compensate the transmission time delay of aircraft navigation data. Simulation and test results show that the geo-pointing performance is enhanced by the proposed compensation technique.

Development of a Geo-Pointing System of Helicopter-Mounted FLIR (헬기 장착 전방관측적외선장비 좌표지향시스템 개발)

  • Kim, Sung-Su;Shin, Yong-San;Kim, Sung-Soo;Kwon, Kang-Hun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.6
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    • pp.750-759
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    • 2009
  • FLIR(Forward Looking Infrared) geo-pointing is a function that helps pilots to see a target within the field of view under all coordinates and attitudes of helicopter. Geo-pointing controls FLIR LOS(line of sight) toward known target coordinates by using azimuth and elevation angles calculated from several information such as helicopter coordinates and attitudes, a FLIR position from a GPS antenna, and target coordinates. Geo-pointing performance has been tested and evaluated on the ground to save flight test costs and ensure flight safety. In this paper, design and implementation of a geo-pointing system is described with the results of performance test conducted on the ground test system.

Compensation of Geo-Pointing Error due to Information Transport Delay for Electro-Optical Tracking System (전자광학 추적장비의 정보 전송지연에 따른 좌표지향 오차보상)

  • Yim, Jong-Bin;Moon, Seong-Man;Lyou, Joon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.48 no.5
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    • pp.1-7
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    • 2011
  • EOTS(Electro-Optical Tracking System) provides stabilized images while tracking a moving target. The key of geo-pointing is the function that fixes EOTS's sight to a specific position(geo-point) throughout aircraft maneuvers. In this paper, a major error source for the geo-pointing is identified as the transport delay of navigation information, and an augmented Kalman filter is designed to estimate the present attitude of aircraft using delayed navigation information. Simulation results including the presented scheme shows that the error due to the information transport delay reduces under half.

The optimum design of optical transmitting antenna versus elevation angle on the optical satellite communication up-link for B-ISDN (B-ISDN용 광위성 통신 업링크의 앙각에 따른 송신안테나 최적설계에 관한 연구)

  • 한종석;이준구;정진호;김영권
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.10
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    • pp.64-72
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    • 1995
  • In this paper, atmospheric turbulence and absorption under clear weather condition, which affect the optical satellite up-link communication between geo-satellites and earth station, were studied. In case of the up-link communication, the received optical power is weakened by pointing loss caused by beam tilt which is the main effect of turbulent atmosphere. This pointing loss directly has relation to the diameter of optical transmitting antenna. From the inverse proportion of the pointing and spaced loss, it is the regions where the diameter of transmitting antenna increases abruptly and the efficient design of transmitting antenna is impossible. In case of using channel coding, it was shown that the peak value of diameter moved to the lower regions of elevation angle with increasing the coding gain and its width was also decreased. In case of considering both coding gain and transmission rate on the design of transmitting antenna, it was known that more coding gain was necessary as transmission rate was increased.

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IRES Support Structure Design in a GEO Multi-Functional Satellite (정지궤도 복합위성의 적외선 지구센서 지지구조물 설계)

  • Park, Jong-Seok;Jeon, Hyung-Yoll;Kim, Chang-Ho
    • Aerospace Engineering and Technology
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    • v.8 no.2
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    • pp.68-74
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    • 2009
  • Infra-red earth sensors(IRES) are accommodated in a geostationary multi-functional satellite, which includes optical payloads for observing the earth, to provide pointing reference for the payloads. Even the slight pointing difference between the IRES and the payloads is so critical from the geostationary orbit that can degrade their imaging performance. Therefore, a dedicated support structure is required to guarantee the stability during the flight operation. This paper shows the design justification for the IRES support structure employed in the Communication, Ocean and Meteorological Satellite(COMS). It intends to give an overall design presentation and to justify that this design is compatible with all the requirements in terms of stiffness and strength as well as the stability.

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Design and Implementation of a 3D Pointing Device using Inertial Navigation System (관성항법시스템을 이용한 3D 포인팅 디바이스의 설계 및 구현)

  • Kim, Hong-Sop;Yim, Geo-Su;Han, Man-Hyung;Lee, Keum-Suk
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.5
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    • pp.83-92
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    • 2007
  • In this paper, we present a design and implementation of three dimensional pointing device using Inertial Navigation System(INS) that acquires coordinates and location information without environmental dependancy. The INS measures coordinates based on the data from gyroscope and accelerometer and corrects the measured data from accelerometer using Kalman-Filter. In order to implement the idea of three dimensional pointing device, we choose a three dimensional Space-recognition mouse and use RFIC wireless communication to send a measured data to receiver for printing out the coordinate on display equipment. Based on INS and Kalman-Filter theoretical knowledge, we design and implement a three dimensional pointing device and verified the usability as an input device that can capture a human's move. also, we describe the applicability of this device in ubiquitous computing environment.

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ANTENNA POINTING TO THE GEO SATELLITE USING CONVERTED NORAD TLE FROM OSCULATING ORBITAL ELEMENTS (접촉궤도요소로부터 변환된 NORAD TLE를 이용한 정지위성의 안테나 포인팅)

  • Lee, Byoung-Sun;Kim, Hae-Yeon;Hwang, Yoo-La;Kim, Jae-Hoon
    • Journal of Astronomy and Space Sciences
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    • v.24 no.2
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    • pp.145-154
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    • 2007
  • Antenna pointing analysis for a geostationary satellite has been performed for using the NORAD Two-Line-Elements (TLE) converted from osculating Keplerian orbital elements. In order to check the possibility of the reception of the satellite signal, the antenna offset angles have been derived for the Communications, Ocean, and Meteorological Satellite (COMS) which carries out weekly East-West and North-South station-keeping maneuvers and twice a day thruster assisted momentum dumping. Throughout the analysis, it is shown that the use of converted NORAD TLE simplifies the antenna pointing related interfaces in satellite mission control system. For a highly eccentric transfer orbit cases, further analysis presents that the converted NORAD TLE from near apogee gives more favorable results.

Efficient Satellite Solar Array Drive Assembly Operation to Compensate Equation of Time (균시차 보상을 위한 효율적인 위성 태양전지판구동기 운용)

  • Park, Keun Joo;Park, Young-Woong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.12
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    • pp.890-896
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    • 2019
  • Due to the eccentricity of the Earth's orbit around the Sun and the obliquity of the Earth rotation axis against ecliptic frame, the apparent solar time differs from the mean solar time. Since the solar array of a GEO satellite makes a turn in mean solar day, the Sun pointing error of solar array is introduced over the year due to the equation of time. In this paper, efficient methods of compensating the equation of time to keep the solar array pointing the Sun are presented and verified with realistic simulation.

Seeking an Establishment of Structure in the Big-gut, Jaindanoje (자인단오제 큰굿의 구조 정립 모색)

  • Hong, Teahan
    • (The) Research of the performance art and culture
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    • no.19
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    • pp.35-60
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    • 2009
  • I insisted that the structure should be set newly, pointing out problems in a structure of the big gut, Jain dano je in this paper. Although, the big gut is playing now in Jain dano je, the features of gut geo-ri are vague ; that's why gut geo-ri and performances are entangled. Therefore, the gut geori showing strange structures not fitted with korean shamanist custom is playing these days like Pawangbyeolhui and Eoudong geori. The detailed procedure is also awkward. It is mixed with aspects of shaman custom in each region, instead showing features of regions. What's more, it became a dance drama, not gut geo-ri with several shamans dancing in a gut. Overcoming these problems, the big gut will be a cultural asset. Therefore, when considering the structure of korean gut, we will fit the order of gut geo-ri into the system of divine spirits keeping a plot-opening, developing and closing. It should be a gut geori-oriented play with only gut geo-ri things. Gut should be gone forward main shaman-oriented gut, setting up a main shaman who takes charge of each gut geo-ri. We should find out a new shaman who knows gut of Gyeong sang province well, if shaman who now takes charge of it has a problem. The big gut of Jain dano je became a part of intangible cultural assets. The performance is not a subject of curiosity and people's interests any more as it was in a past. It should be a traditional performance of representing our traditional culture. We should reorganize an epochal gut geo-ri after reexamining gut geo-ri which has played so far.

Analysis of Data Rate on Optical Communication Links between Geo-Satellite and Earth Station (정지궤도 위성과 지구국간 광통신 링크의 전송속도 해석)

  • Han, Jong-Seok;Jung, Jin-Ho;Kim, Yung-Kwon
    • Journal of IKEEE
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    • v.1 no.1 s.1
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    • pp.120-137
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    • 1997
  • Han's model, which is able to analyze optical communication between earth station and geo-satellite as a function of atmospheric conditions and elevation angles. is presented. In Han's model, atmospheric conditions are roughly classified into six basic types; clear sky, cloud, haze, fog, rain and snow. Data rate satisfying for the BER below $10^{-7}$ is analyzed by Han's model in case of up-link and down-link, respectively. Data rate is more limited by up-link than by down-link because the pointing loss caused by atmosphere on the up-link is greater than the spatial coherence degradation caused by atmosphere on the down-link.

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