• Title/Summary/Keyword: satellite communication system

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Design and Prototype Implementation of Hybrid App for Geo-Metadata Searching of Satellite Images (위성영상정보 공간 메타데이터 검색 하이브리드 앱 설계 및 시험 구현)

  • Kim, Kwang-Seob;Lee, Ki-Won
    • Korean Journal of Remote Sensing
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    • v.27 no.2
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    • pp.203-211
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    • 2011
  • Recently, information communication technologies such as smartphone or mobile app greatly affect various application fields including geo-spatial domain. And development scheme of mobile web app or hybrid app regards as the most important computing technology which is combined each advantage of mobile app and mobile web. Despite these trends, it is general case that satellite images are used for the background image for other contents services. With this motivation, hybrid app for geo-metadata as the base for dissemination and service is designed and implemented as the prototype, in this study. At the design stage, HTML5, which is the core technology on an international standardization process for hybrid app, is applied. In the implementation, PhoneGap and Sencha Touch as mobile SDK(Software Development Kit) supporting HTML5 on cross-platform in open sources are used. In prototype, some KOMPSAT-2 images covering small area and mandatory elements in geo-metafata standard are tested. As mobile industry applications and business service models based on satellite images on mobile platform are progressing and diversifying, it is expected that this approach and implemented prototype are considered as an important reference.

Development of a Driving Simulator for Telematics Human-Machine Interface Studies (텔레매틱스 HMI 연구를 위한 드라이빙 시뮬레이터의 개발)

  • Koo, Tae-Yun;Kim, Bae-Young;Shin, Hee-Jong;Son, Young-Tak;Suh, Myung-Won
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.4
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    • pp.16-23
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    • 2009
  • Driving simulators are useful tools not only to test the components of future cars but also to evaluate the telematics service and HMI (Human-Machine Interface). However driving simulators cannot be implemented to test and evaluate the telematics service system because the GPS (Global Positioning System) which contains basic functional support for the telematics module do not work in the VR (virtual reality) environment. This paper presents a method to implement telematics service to a driving simulator by developing the GPS simulator which is able to emulate GPS satellite signals consist of NMEA-0183 protocol and RS232C communication standards. It is expected that the driving simulator with the GPS simulator can be used to study HMI and human-factor evaluations of the commercial telematics system to realize the HiLES (Human-in-the-Loop Evaluation System).

A Study on the RRMC Implementation for the Efficient Resource Management in DBS System (DBS 시스템에서 효율적인 자원 관리를 위한 RRMC 구현에 관한 연구)

  • Shin, Cheon-Sig;Kim, Shin-Hong
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.12
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    • pp.3133-3138
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    • 1997
  • The Digital Broadcasting Satallite System consists of the Transmitter station, the Resource and Subscriber Management System, and the Receiver Test Unit. The RSMS consists or several modules such as Resource Main Module, Resource User Interface Module, Transmitter Station Interface Module, Receiver Test Unit Interface Module, Subscriber sales Outlets Module and Monitor & Control Module. In this paper we suppose the new RRMC Algorithms that is to manage efficiently the Resource and subscriber information in the Direct Broadcasting Satellite system based on client-sever features and demonstrates the implementation method of monitoring and control the system in real time. Also we explain the communication procedure between resource and subscriber managment and other equipment.

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PERFORMANCE OF COMS SNOW AND SEA ICE DETECTION ALGORITHM

  • Lee, Jung-Rim;Chung, Chu-Yong;Ahn, Myoung-Hwan;Ou, Mi-Lim
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.278-281
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    • 2007
  • The purpose of this study is to develop snow and sea ice detection algorithm in Communication, Ocean and Meteorological Satellite (COMS) meteorological data processing system. Since COMS has only five channels, it is not affordable to use microwave or shortwave infrared data which are effective and generally used for snow detection. In order to estimate snow and sea ice coverage, combinations between available channel data(mostly visible and 3.7 ${\mu}m$) are applied to the algorithm based on threshold method. As a result, the COMS snow and sea ice detection algorithm shows reliable performance compared to MODIS products with channel limitation. Specifically, there is partial underestimation over the complicated vegetation area and overestimation over the area of high level clouds such as cirrus. Some corrections are performed by using water vapor and infrared channels to remove cloud contamination and by applying NDVI to detect more snow pixels for the underestimated area.

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Development of CanSat System for Collecting Weather Information With Autorotating Science Payload Ejection Function (자동회전 과학 탑재체 사출 기능을 갖춘 기상정보 수집용 캔위성 체계 개발)

  • Kim, Youngjun;Park, Junsoo;Nam, Jaeyoung;Lee, Junhyuck;Choi, Yunwon;Yoo, Seunghoon;Lee, Sanghyun;Lee, Younggun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.8
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    • pp.573-581
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    • 2022
  • This paper deals with the development of CanSat system, which ejects two maple seed-type autorotating science payloads and collects weather information. The CanSat consists of two autorotating science payloads and a container. The container is equipped with devices for launching science payloads and communication with the ground station, and launches science payloads one by one at different designated altitudes. The science payload consists of a space for loading and a large wing, and rotates to generate lift for slowing down the fall speed. Specifically, after being ejected, it descends at a speed of 20 m/s or less, measures the rotation rate, atmospheric pressure, and temperature, and transmits the measured value to the container at a rate of once per second. The communication system is a master-slave structure, and the science payload transmits all data to the master container, which aggregates both the received data and its own data, and transmits it to the ground station. All telemetry can be checked in real time using the ground station software developed in-house. A simulation was performed in the simulation environment, and the performance of the CanSat system that satisfies the mission requirements was confirmed.

System of Agricultural Land Monitoring Using UAV (무인항공기를 이용한 농경지 모니터링 시스템)

  • Kang, Byung-Jun;Cho, Hyun-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.6
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    • pp.372-378
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    • 2016
  • The purpose of this study is to develop a system configuration for gathering data and building a database for agriculture. Some foreign agriculture-related companies have already constructed such a database for scientific agriculture. The hardware of this system is composed of automatic capturing equipment based on aerial photography using a UAV. The software is composed of parts for stitching images, matching GPS data with captured images, and building a database of collected weather information, farm operation data, and aerial images. We suggest a method for building the database, which can include information about the amount of agricultural products, weather, farm operation, and agricultural land images. The images of this system are about 5 times better than satellite images. Factors such as farm working and environmental factors can be basic data for analyzing the full impact of agriculture land. This system is expected to contribute to the scientific analysis of Korea's agriculture.

Long-term and Real-time Monitoring System of the East/Japan Sea

  • Kim, Kuh;Kim, Yun-Bae;Park, Jong-Jin;Nam, Sung-Hyun;Park, Kyung-Ae;Chang, Kyung-Il
    • Ocean Science Journal
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    • v.40 no.1
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    • pp.25-44
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    • 2005
  • Long-term, continuous, and real-time ocean monitoring has been undertaken in order to evaluate various oceanographic phenomena and processes in the East/Japan Sea. Recent technical advances combined with our concerted efforts have allowed us to establish a real-time monitoring system and to accumulate considerable knowledge on what has been taking place in water properties, current systems, and circulation in the East Sea. We have obtained information on volume transport across the Korea Strait through cable voltage measurements and continuous temperature and salinity profile data from ARGO floats placed throughout entire East Sea since 1997. These ARGO float data have been utilized to estimate deep current, inertial kinetic energy, and changes in water mass, especially in the northern East Sea. We have also developed the East Sea Real-time Ocean Buoy (ESROB) in coastal regions and made continual improvements till it has evolved into the most up-to-date and effective monitoring system as a result of remarkable technical progress in data communication systems. Atmospheric and oceanic measurements by ESROB have contributed to the recognition of coastal wind variability, current fluctuations, and internal waves near and off the eastern coast of Korea. Long-tenn current meter moorings have been in operation since 1996 between Ulleungdo and Dokdo to monitor the interbasin deep water exchanges between the Japanese and Ulleung Basins. In addition, remotely sensed satellite data could facilitate the investigation of atmospheric and oceanic surface conditions such as sea surface temperature (SST), sea surface height, near-surface winds, oceanic color, surface roughness, and so on. These satellite data revealed surface frontal structures with a fairly good spatial resolution, seasonal cycle of SST, atmospheric wind forcing, geostrophic current anomalies, and biogeochemical processes associated with physical forcing and processes. Since the East Sea has been recognized as a natural laboratory for global oceanic changes and a clue to abrupt climate change, we aim at constructing a 4-D continuous real-time monitoring system, over a decade at least, using the most advanced techniques to understand a variety of oceanic processes in the East Sea.

Design and Analysis of 4D-8PSK-TCM System Considering the Nonlinear HPA Environment (비선형 HPA 환경을 고려한 4D-8PSK-TCM 시스템의 설계 및 분석)

  • An, Changyoung;Ryu, Sang-Burm;Lee, Sang-Gyu;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.4
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    • pp.299-307
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    • 2018
  • Considering a nonlinear high power amplifier(HPA) and a predistorter, we have designed a four-dimensional 8-ary phase shift keying trellis-coded modulation(4D-8PSK-TCM) system, which is recommended for X-band satellite communications. Subsequently, we have evaluated and analyzed the spectrum, constellation characteristics, and BER performance of the system. In satellite communications, owing to the limited power, nonlinear characteristics that determine the operating point of the HPA must be analyzed because the HPA consumes high power. We herein report the design of the 4D-8PSK-TCM system, with efficiencies of 2 and 2.25 bits/channel-symbol. The simulation results confirmed that a 0.35 roll-off value is effective, considering the low peak-to-average power ratio(PAPR) characteristic and the narrow occupation bandwidth of the spectrum. It also confirmed that approximately 15~20 dB of output backoff(OBO) value is required at the HPA when the predistorter is not used, and approximately 1 dB of the OBO value is required when the predistorter is used.

A Multi-sensor basedVery Short-term Rainfall Forecasting using Radar and Satellite Data - A Case Study of the Busan and Gyeongnam Extreme Rainfall in August, 2014- (레이더-위성자료 이용 다중센서 기반 초단기 강우예측 - 2014년 8월 부산·경남 폭우사례를 중심으로 -)

  • Jang, Sangmin;Park, Kyungwon;Yoon, Sunkwon
    • Korean Journal of Remote Sensing
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    • v.32 no.2
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    • pp.155-169
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    • 2016
  • In this study, we developed a multi-sensor blending short-term rainfall forecasting technique using radar and satellite data during extreme rainfall occurrences in Busan and Gyeongnam region in August 2014. The Tropical Z-R relationship ($Z=32R^{1.65}$) has applied as a optimal radar Z-R relation, which is confirmed that the accuracy is improved during 20mm/h heavy rainfall. In addition, the multi-sensor blending technique has applied using radar and COMS (Communication, Ocean and Meteorological Satellite) data for quantitative precipitation estimation. The very-short-term rainfall forecasting performance was improved in 60 mm/h or more of the strong heavy rainfall events by multi-sensor blending. AWS (Automatic Weather System) and MAPLE data were used for verification of rainfall prediction accuracy. The results have ensured about 50% or more in accuracy of heavy rainfall prediction for 1-hour before rainfall prediction, which are correlations of 10-minute lead time have 0.80 to 0.53, and root mean square errors have 3.99 mm/h to 6.43 mm/h. Through this study, utilizing of multi-sensor blending techniques using radar and satellite data are possible to provide that would be more reliable very-short-term rainfall forecasting data. Further we need ongoing case studies and prediction and estimation of quantitative precipitation by multi-sensor blending is required as well as improving the satellite rainfall estimation algorithm.

Circularly Polarized Microstrip Antenna Using I-Shape Ground Slot Perturbation and Perpendicular Feeding Network (I-모양 슬롯 섭동과 수직한 급전구조를 이용한 원형 편파 마이크로스트립 안테나)

  • Shin, Yooncheol;Noh, Yoonsang;Lee, Min-Jae;Pyo, Seongmin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.6
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    • pp.497-500
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    • 2017
  • This paper proposes a circularly polarized microstrip antenna using an I-shape ground slot perturbation and a perpendicular feeding network. The proposed antenna consists of the symmetrical and perpendicular feeding and the microstrip square radiator loaded with the I-shape ground slot perturbation. The left-handed circular polarization(LHCP) formed by a 90-degree phase difference can be radiated by the perpendicular feeding network and the ground slot perturbation. An implemented antenna is designed for the use in the satellite communication system operated in S-band of 2.2 GHz, and is to be the 91 MHz of -10 dB bandwidth. The measured results of the antenna gain, far-field radiation pattern, and axial ratio agree well with the simulation results.