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  • Title/Summary/Keyword: Satellite sensor

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Accuracy Assessment of 3D Geopositioning of KOMPSAT-2 Images Using Orbit-Attitude Model (KOMPSAT-2 영상의 정밀궤도기반모델을 이용한 3차원 위치결정 정확도 평가)

  • Lee, Sang-Jin;Kim, Jung-Uk;Choi, Yun-Soo;Jung, Seung-Kyoon
    • Journal of Korean Society for Geospatial Information Science
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    • v.18 no.4
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    • pp.3-10
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    • 2010
  • In this study, the orbit-based sensor modeling is applied to the digital plotting and the accuracy of digital plotting is analyzed. The KOMPSAT-2 satellite image with orbit-attitude model is used for the analysis. The precise sensor modeling with various combination of parameters is performed for the stereo satellite image. In addition, we analyze the error range of ground control points by applying the result of stereo modeling to digital survey system. According to the result, it is possible to produce digital map using stereo image with a small number of GCPs when the orbit-based sensor modeling for KOMPSAT-2 is applied. This means that it is suitable for the generation of digital map on a scale of 1/5,000 to 1/25,000 considering the resolution of KOMPSAT-2 image.

Implementation and Validation of Earth Acquisition Algorithm for Communication, Ocean and Meteorological Satellite

  • Park, Sang-Wook;Lee, Young-Ran;Lee, Byoung-Sun;Hwang, Yoo-La;Lee, Un-Seob
    • Journal of Astronomy and Space Sciences
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    • v.28 no.4
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    • pp.345-354
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    • 2011
  • Earth acquisition is to solve when earth can be visible from satellite after Sun acquisition during launch and early operation period or on-station satellite anomaly. In this paper, the algorithm and test result of the Communication, Ocean and Meteorological Satellite (COMS) Earth acquisition are presented in case of on-station satellite anomaly status. The algorithms for the calculation of Earth-pointing attitude control parameters including those attitude direction vector, rotation matrix, and maneuver time and duration are based on COMS configuration (Eurostar 3000 bus). The coordinate system uses the reference initial frame. The constraint calculating available time-slot to perform the earth acquisition considers eclipse, angular separation, solar local time, and infra-red earth sensor blinding conditions. The results of Electronics and Telecommunications Research Institute (ETRI) are compared with that of the Astrium software to validate the implemented ETRI software.

BIDIRECTIONAL FACTOR OF WATER LEAVING RADIANCE FOR GOCI

  • Han, Hee-Jeong;Ahn, Yu-Hwan;Ryu, Joo-Hyung
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.79-81
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    • 2006
  • Geostationary ocean satellite, unlike other sun-synchronous polar-orbit satellites, will be able to take a picture of a large region several times a day (almost with every one hour interval). For geostationary satellite, the target region is fixed though the location of sun is changed always. Thus, the ocean signal of a given target point is largely dependent on time. In other words, the ocean signal detected by geostationary satellite sensor must translate to the signal of target when both sun and satellite are located in nadir, using another correction model. This correction is performed with a standardization of signal throughout relative geometric relationship among satellite - sun - target points. One signal value of a selected pixel point of the target region of Geostationary Ocean Colour Imager (GOCI) would be set up as a standard, and the ratio of all remained pixel point can be calculated. This relative ratio called bidirectional factor, the result of modelling of spatiotemporal variation of bidirectional factor is shown.

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Latent Heat Flux over the Global Ocean

  • Kubota, Masahisa
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.644-648
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    • 2002
  • Though it was difficult of globally monitor latent heat flux aver the ocean for many years, the situation is rapidly changing by the use of satellite data. Since a bulk formula is used to estimate turbulent heat flux using satellite data, we need wind speed, sea surface temperature and specific humidity data. However, it is not easy to accurately estimate specific humidity using satellite data. Now several algorithms for estimating specific humidity have been proposed and applied to construct latent heat flux data sets. Latent heat flux data sets derived from satellite data such as J-OFURO, HOAPS and GSSTF are available at present. Since the algorithm and used satellite data are not the same between them. the characteristics of each data set may be different. Therefore, it is important to clarify the difference between each data set and investigate the cause of the difference in latent heat flux estimates. In this paper we summarize the present state of the art with regard to the turbulent heat flux estimation by using satellite data. Also we present the comparison results of latent heat flux fields including not only satellite-derived flux fields but also analysis fields.

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Three Dimensional Positioning Accuracy of KOMPSAT-1 Stereo Imagery

  • Jeong, Soo;Kim, Yong-Soo
    • Korean Journal of Remote Sensing
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    • v.16 no.4
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    • pp.339-345
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    • 2000
  • KOMPSAT-1 was launched on 21 December, 1999 and the main mission of the satellite is the cartography to provide the imagery from a remote earth view for the production of maps of Korean territory. For this purpose, the satellite has capability to tilt the spacecraft utmost ±45 degrees to acquire stereo satellite imagery in different paths. This study aims to estimate the three dimensional positioning accuracy of stereo satellite imagery from EOC(electro-optical camera), a payload of KOMPSAT-1 satellite. For this purpose, the ground control points and check points were obtained by GPS surveying. The sensor modeling and the adjustment was performed by PCI software installed in KARI (Korea Aerospace Research Institute), which contained mathematical analysis module for KOMPSAT-1 EOC. The study areas were Taejon and Nonsan, placed in the middle part of Korea. As a result of this study, we found that the RMSE(root mean square error) value of three dimensional positioning KOMPST-1 stereo imagery can be less than 1 pixel (6.6 m) if we can use about 10 GCPs(ground control points). Then, a standarrd of FGDC (Federal Geographic Data Committee) of USA was applied to the result to estimate the three dimensional positioning accuracy of KOMPSAT-1 stereo imagery.

Virtual Target Overlay Technique by Matching 3D Satellite Image and Sensor Image (3차원 위성영상과 센서영상의 정합에 의한 가상표적 Overlay 기법)

  • Cha, Jeong-Hee;Jang, Hyo-Jong;Park, Yong-Woon;Kim, Gye-Young;Choi, Hyung-Il
    • The KIPS Transactions:PartD
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    • v.11D no.6
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    • pp.1259-1268
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    • 2004
  • To organize training in limited training area for an actuai combat, realistic training simulation plugged in by various battle conditions is essential. In this paper, we propose a virtual target overlay technique which does not use a virtual image, but Projects a virtual target on ground-based CCD image by appointed scenario for a realistic training simulation. In the proposed method, we create a realistic 3D model (for an instructor) by using high resolution Geographic Tag Image File Format(GeoTIFF) satellite image and Digital Terrain Elevation Data (DTED), and extract the road area from a given CCD image (for both an instructor and a trainee). Satellite images and ground-based sensor images have many differences in observation position, resolution, and scale, thus yielding many difficulties in feature-based matching. Hence, we propose a moving synchronization technique that projects the target on the sensor image according to the marked moving path on 3D satellite image by applying Thin-Plate Spline(TPS) interpolation function, which is an image warping function, on the two given sets of corresponding control point pair. To show the experimental result of the proposed method, we employed two Pentium4 1.8MHz personal computer systems equipped with 512MBs of RAM, and the satellite and sensor images of Daejoen area are also been utilized. The experimental result revealed the effective-ness of proposed algorithm.

A Study on the Design and Implementation of a Position Tracking System using Acceleration-Gyro Sensor Fusion

  • Jin-Gu, Kang
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.1
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    • pp.49-54
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    • 2023
  • The Global Positioning System (GPS) was developed for military purposes and developed as it is today by opening civilian signals (GPS L1 frequency C/A signals). The current satellite orbits the earth about twice a day to measure the position, and receives more than 3 satellite signals (initially, 4 to calculate even the time error). The three-dimensional position of the ground receiver is determined using the data from the radio wave departure time to the radio wave Time of Arrival(TOA) of the received satellite signal through trilateration. In the case of navigation using GPS in recent years, a location error of 5 to 10 m usually occurs, and quite a lot of areas, such as apartments, indoors, tunnels, factory areas, and mountainous areas, exist as blind spots or neutralized areas outside the error range of GPS. Therefore, in order to acquire one's own location information in an area where GPS satellite signal reception is impossible, another method should be proposed. In this study, IMU(Inertial Measurement Unit) combined with an acceleration and gyro sensor and a geomagnetic sensor were used to design a system to enable location recognition even in terrain where GPS signal reception is impossible. A method to track the current position by calculating the instantaneous velocity value using a 9-DOF IMU and a geomagnetic sensor was studied, and its feasibility was verified through production and experimentation.

DEM generation with other sensor images using digital photogrammetry techniques

  • Lee, Sung-Soon;Chi, Kwang-Hoon
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.182-182
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    • 2003
  • Generally, DEM (Digital Elevation Model) is generated by stereo-images acquired same conditions, sensor type, viewing angle, capturing elevation and etc. It is difficult to generate DEM with stereo images acquired different satellite. This study intends that it is DEM generation using pair-images with other sensor systems.

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Study on the Allocation Method of Sun Sensor Assembly for GEO-KOMPSAT2 (정지궤도복합위성 태양센서 장착방법에 관한 연구)

  • Park, Young-Woong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.7
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    • pp.551-556
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    • 2018
  • A lot of hardwares are allocated on the satellite to perform the attitude control. Sun sensor is very important hardware to acquire the initial attitude after separation from launcher and to maintain the safety attitude from the satellite anomaly operation. So the allocation of the sun sensor to acquire the field of view and the attitude control design using it, are critical work in the beginning of development. Number of Sun sensor for GEO-KOMPSAT2 is reduced with respect to COMS due to star tracker usage. The additional sun sensor using COMS heritage is considered. In this paper, it is described the analysis and the results on the method for the safety improvement which is to enlarge the field of view and to consider the harness connection of P/R-side of the sun sensor.

Generation of Land Surface Temperature Orthophoto and Temperature Accuracy Analysis by Land Covers Based on Thermal Infrared Sensor Mounted on Unmanned Aerial Vehicle (무인항공기에 탑재된 열적외선 센서 기반의 지표면 온도 정사영상 제작 및 피복별 온도 정확도 분석)

  • Park, Jin Hwan;Lee, Ki Rim;Lee, Won Hee;Han, You Kyung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.4
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    • pp.263-270
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    • 2018
  • Land surface temperature is known to be an important factor in understanding the interactions of the ground-atmosphere. However, because of the large spatio-temporal variability, regular observation is rarely made. The existing land surface temperature is observed using satellite images, but due to the nature of satellite, it has the limit of long revisit period and low accuracy. In this study, in order to confirm the possibility of replacing land surface temperature observation using satellite imagery, images acquired by TIR (Thermal Infrared) sensor mounted on UAV (Unmanned Aerial Vehicle) are used. The acquired images were transformed from JPEG (Joint Photographic Experts Group) to TIFF (Tagged Image File Format) format and orthophoto was then generated. The DN (Digital Number) value of orthophoto was used to calculate the actual land surface temperature. In order to evaluate the accuracy of the calculated land surface temperature, the land surface temperature was compared with the land surface temperature directly observed with an infrared thermometer at the same time. When comparing the observed land surface temperatures in two ways, the accuracy of all the land covers was below the measure accuracy of the TIR sensor. Therefore, the possibility of replacing the satellite image, which is a conventional land surface temperature observation method, is confirmed by using the TIR sensor mounted on UAV.