• Title/Summary/Keyword: Satellite Attitude Control

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Qualification Test of ROCSAT -2 Image Processing System

  • Liu, Cynthia;Lin, Po-Ting;Chen, Hong-Yu;Lee, Yong-Yao;Kao, Ricky;Wu, An-Ming
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1197-1199
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    • 2003
  • ROCSAT-2 mission is to daily image over Taiwan and the surrounding area for disaster monitoring, land use, and ocean surveillance during the 5-year mission lifetime. The satellite will be launched in December 2003 into its mission orbit, which is selected as a 14 rev/day repetitive Sun-synchronous orbit descending over (120 deg E, 24 deg N) and 9:45 a.m. over the equator with the minimum eccentricity. National Space Program Office (NSPO) is developing a ROCSAT-2 Image Processing System (IPS), which aims to provide real-time high quality image data for ROCSAT-2 mission. A simulated ROCSAT-2 image, based on Level 1B QuickBird Data, is generated for IPS verification. The test image is comprised of one panchromatic data and four multispectral data. The qualification process consists of four procedures: (a) QuickBird image processing, (b) generation of simulated ROCSAT-2 image in Generic Raw Level Data (GERALD) format, (c) ROCSAT-2 image processing, and (d) geometric error analysis. QuickBird standard photogrammetric parameters of a camera that models the imaging and optical system is used to calculate the latitude and longitude of each line and sample. The backward (inverse model) approach is applied to find the relationship between geodetic coordinate system (latitude, longitude) and image coordinate system (line, sample). The bilinear resampling method is used to generate the test image. Ground control points are used to evaluate the error for data processing. The data processing contains various coordinate system transformations using attitude quaternion and orbit elements. Through the qualification test process, it is verified that the IPS is capable of handling high-resolution image data with the accuracy of Level 2 processing within 500 m.

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A Study on the Geomagnetic Reference Field Modeling from the Triaxial Magnetometer Data Onboard KOMPSAT-II (아리랑위성 2호의 삼축자력계로부터 관측된 지구자기장 모델 연구)

  • Kim, Hyung-Rae;Hwang, Jong-Sun;Kim, Jeong-Woo;Lee, Seon-Ho
    • Economic and Environmental Geology
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    • v.45 no.4
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    • pp.377-384
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    • 2012
  • The main field component of the Earth's magnetic field was modeled from the tri-axial magnetometer onboard KOrean MultiPurpose SATellite-II (KOMPSAT-II) for the purpose of satellite attitude control. The model computed by the KOMPSAT-II magnetometer measurement data is compared with the International Geomagnetic Reference Field (IGRF) model of a degree of up to 13 in spherical harmonic coefficients. The previous study with KOMPSAT-I (Kim et al. 2004) indicated a good correlation of power spectrum of spherical harmonic coefficients with respect to the degree up to 5. This study, however, showed an agreement of the degree up to 8-9 of the coefficient power spectrum and a discrepancy between degrees 10 and 13. We have concluded that relevant data selection process, removal of the external field from the data in the high latitude region, an accuracy of the magnetometer all play an important role in finding a coherence with the IGRF model. This study will be extended to the secular variation model of geomagnetism if longer-period data become available.

Discussion of Preliminary Design Review for MIRIS, the Main Payload of STSAT-3

  • Han, Won-Yong;Jin, Ho;Park, Jang-Hyun;Nam, Uk-Won;Yuk, In-Soo;Lee, Sung-Ho;Park, Young-Sik;Park, Sung-Jun;Lee, Dae-Hee;Ree, Chang-H.;Jeong, Woong-Seob;Moon, Bong-Kon;Cha, Sang-Mok;Cho, Seoung-Hyun;Rhee, Seung-Woo;Park, Jong-Oh;Lee, Seung-Heon;Lee, Hyung-Mok;Matsumoto, Toshio
    • Bulletin of the Korean Space Science Society
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    • 2008.10a
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    • pp.27.1-27.1
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    • 2008
  • KASI (Korea Astronomy and Space Science Institute) is developing a compact wide-field survey space telescope system, MIRIS (The Multi-purpose IR Imaging System) to be launched in 2010 as the main payload of the Korea Science and Technology Satellite 3. Through recent System Design Review (SDR) and Preliminary Design Review (PDR), most of the system design concept was reviewed and confirmed. The near IR imaging system adopted short F/2 optics for wide field low resolution observation at wavelength band 0.9~2.0 um minimizing the effect of attitude control system. The mechanical system is composed of a cover, baffle, optics, and detector system using a $256\times256$ Teledyne PICNIC FPA providing a $3.67\times3.67$ degree field of view with a pixel scale of 51.6 arcsec. We designed a support system to minimize heat transfer with Muti-Layer Insulation. The electronics of the MIRIS system is composed of 7 boards including DSP, control, SCIF. Particular attention is being paid to develop mission operation scenario for space observation to minimize IR background radiation from the Earth and Sun. The scientific purpose of MIRIS is to survey the Galactic plane in the emission line of Pa$\alpha$ ($1.88{\mu}m$) and to detect the cosmic infrared background (CIB) radiation. The CIB is being suspected to be originated from the first generation stars of the Universe and we will test this hypothesis by comparing the fluctuations in I (0.9~1.2 um) and H (1.2~2.0 um) bands to search the red shifted Lyman cutoff signature.

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