• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.56-59
• /
• 2006

In this paper, Korea's first geostationary Communication, Ocean and Meteorological Satellte(COMS) program is introduced. COMS program is one of the Korea National Space Programs to develop and operate a pure civilian satellite of practical-use for the compound missions of meteorological observation and ocean monitoring, and space test of experimentally developed communication payload on the geostationary orbit. The target launch of COMS is scheduled at the end of 2008. COMS program is international cooperation program between KARI and ASTRIUM SAS and funded by Korean Government. COMS satellite is a hybrid satellite in the geostationary orbit, which accommodates multiple payloads of MI(Meteorological Imager), GOCI(Geostationary Ocean Color Imager), and the Ka band Satellite Communication Payload into a single spacecraft platform. The MI mission is to continuously extract meteorological products with high resolution and multi-spectral imager, to detect special weather such as storm, flood, yellow sand, and to extract data on long-term change of sea surface temperature and cloud. The GOCI mission aims at monitoring of marine environments around Korean peninsula, production of fishery information (Chlorophyll, etc.), and monitoring of long-term/short-term change of marine ecosystem. The goals of the Ka band satellite communication mission are to in-orbit verify the performances of advanced communication technologies and to experiment wide-band multi-media communication service mandatory.

• Journal of Biosystems Engineering
• /
• 제31권3호
• /
• pp.182-187
• /
• 2006

Aerial application using an unmanned agricultural helicopter can reduce labor and pollution. The development of an agricultural helicopter became urgent for both precise and timely spraying. In this study, a rotor system for unmanned helicopter capable of 20 $kg_f$ payload, was developed and lift capability was evaluated. A lift force over the dead weight of the helicopter was obtained at the pitch angle of $6^{\circ}$. As the pitch angle increased to $8^{\circ}\;and\;10^{\circ}$, the total lift increased to $74{\sim}81\;kg_f\;and\;86{\sim}93\;kg_f$, respectively. A range of engine speed at the rated flight condition, lifting mean payload of 23 $kg_f$ was determined. The data acquired from this study will be used for designing tail system and RF console in the next stage of the research. The rated lift capability was enough for loading 20 liters of spray material including spraying equipments.

• 천문학회보
• /
• 제37권2호
• /
• pp.228.1-228.1
• /
• 2012

Digital waveform generation technology for SAR payload can be divided into DDS(Direct Digital Synthesizer) method and Memory Mapped(M/M) method. DDS is the single chip which consists of the Sine Table, NCO(Numerically Controlled Oscillator), DAC, and so on. DDS method is a very simple method because the circuit configuration is not complex but has a disadvantage that can not control phase and amplitude easily by using NCO. M/M method has the complexity of the circuit configuration because it requires the memories which stores the waveforms, the control circuits, and DAC. And this method should apply the high interface technology for being compatible with the wide bandwidth of the digital signal and has the difficulty for PCB design because the number of the signal lines should be increased according to the number of the data bits for DAC. Although it has several disadvantages, this method has the capability of pre-distortion function which can compensate the phase and amplitude characteristics of the system and also has an excellent advantage to make any arbitrary waveform, so this method is considered as an important technology with DDS method. This research describes the technological trends of the waveform generator for the SAR payload and analyzes the characteristics of the technology.

• 항공우주기술
• /
• 제4권2호
• /
• pp.107-116
• /
• 2005

고도 685km에서 450mm~900mm 파장대역의 한 채널의 흑백영상과 4채널 칼라영상을 이미징하도록 개발된 MSC는 한반도의 정밀 지상관측 등 국가 영상정보 수요충족을 위해 운용예정인 저궤도용 다목적실용위성 2호의 유일한 탑재체로서 마지막 시험단계에 있다. MSC는 우주공간에서 운용되는 위성체 탑재체의 특성상 우주공간에서 경험하게 되는 직,간접의 태양광선, 그리고 극저온의 우주환경 등을 견뎌내도록 설계요구가 주어지는바 이를 위해서는 온도 제어가 불가피하고 또한 한정된 위성본체의 전원용량의 효율적인 사용도 고려되어서 설계되어야 한다. 특히 광학성능에 직접적인 영향을 미치게 되는 EOS의 효율적인 열제어는 MSC 설계요소의 가장 중요한 부분이기도 하다. 본 논문은 먼저 MSC의 전체적인 시스템구성과 열제어 시스템 개념을 소개한 다음, 실제 열제어를 수행하는 THTM(THermal and TeleMetry) 보드를 중심으로 열제어 시스템의 H/W와 S/W의 수행 내용들을 소개하였다.

• 대한원격탐사학회지
• /
• 제33권5_1호
• /
• pp.521-535
• /
• 2017

탑재체를 포함한 위성은 발사 이후 문제 발생시 조치할 수 있는 방법이 한정적이므로, 지상시험지원장비를 이용하여 그 기능을 충분히 검증하여야 한다. 또한 위성의 개발기간이 단축되고 있는 추세와 지상시험지원장비의 개발 완료시점이 전장품 엔지니어링 모델 개발완료보다 앞서야 한다는 점을 고려하면, 지상시험지원장비의 조기 확보는 위성 전체의 개발일정 준수를 위해서 반드시 필요하다고 할 수 있다. 본 논문에서는 지상시험지원장비의 일부인 탑재체 패킷 분석장치를 기능별 모듈화와 외부 파라메터화를 통해 시나리오 기반으로 동작할 수 있게 고안하여 고신뢰도의 지상시험지원장비 조기 확보방안을 제시하고, 구현한 장비를 실재 위성 개발사업에 적용한 결과를 보여준다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
• /
• pp.378-381
• /
• 2003

The Channel Coding Unit (CCU) is an integral component of Payload Data Transmission System (PDTS) for the Multi-Spectral Camera (MSC) data. The main function of the CCU is channel coding and encryption. CCU has two channels (I ＆ Q) for data processing. The input of CCU is the output of DCSU (Data Compression ＆ Storage Unit). The output of CCU is the input of QTX which modulate data for RF communication. In this paper, there are the overview, short H/W description and operation concept of CCU.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권3호
• /
• pp.1105-1118
• /
• 2014

In this paper, a new reversible data hiding method based on a dual binary tree of embedding levels is proposed. Four neighborhood pixels in the upper, below, left and right of each pixel are used as reference pixels to estimate local complexity for deciding embeddable and non-embeddable pixels. The proposed method does not need to record pixels that might cause underflow, overflow or unsuitable for embedment. This can reduce the size of location map and release more space for payload. Experimental results show that the proposed method is more effective in increasing payload and improving image quality than some recently proposed methods.

• International Journal of Computer Science & Network Security
• /
• 제23권3호
• /
• pp.94-100
• /
• 2023

The primary goal of any communication spacecraft is to provide communication in variety of frequency bands based on mission requirements within the Indian mainland. Some of the spacecrafts operating in S-band utilizes a 6m or larger aperture Unfurlable Antenna (UFA for S-band links and provides coverage through five or more S-band spot beams over Indian mainland area. The Unfurlable antenna is larger than the satellite and so the antenna is stowed during launch. Upon reaching the orbit, the antenna is deployed using motors. The deployment status of any deployment mechanism will be monitored and verified by the telemetered values of micro-switch position before the start of deployment, during the deployment and after the completion of the total mechanism. In addition to these micro switches, a camera onboard will be used for capturing still images during primary and secondary deployments of UFA. The proposed checkout system is realized for validating the performance of the onboard camera as part of Integrated Spacecraft Testing (IST) conducted during payload checkout operations. It is designed for acquiring the payload data of onboard camera in real-time, followed by archiving, processing and generation of images in near real-time. This paper presents the architecture, design and implementation features of the acquisition, processing and Image generation system for Camera onboard spacecraft. Subsequently this system can be deployed in missions wherever similar requirement is envisaged.

• 한국항공우주학회지
• /
• 제33권11호
• /
• pp.115-120
• /
• 2005

본 논문에서는 과학기술위성 2호 대용량 메모리 유닛(Mass Memory Unit, MMU)의 시험모델(Engineering Model, EM)을 개발하고 기능 및 성능 시험한 결과를 제시하였다. 성능 구현에 필요한 로직들을 별도의 전용 칩들을 사용하지 않고 하나의 FPGA에 구현함으로써 대용량 메모리 유닛을 소형화, 경량화하고 저전력으로 사용할 수 있도록 하였다. 대용량 메모리는 2Gbits SDRAM 모듈을 사용하였으며 파일 시스템을 운용하여 지상국에서의 데이터 관리가 용이 하도록 하였다. 대용량 메모리에서 발생하는 SEU(Single Event Upset)를 극복하기 위해서 RS(207,187) 코드가 소프트웨어로 구현되어 있어서 187바이트당 10바이트의 에러를 복구할 수 있다. 또한 탑재체 데이터의 수신 성능을 검증하기 위해서 시뮬레이터를 제작 하였다.

• 대한원격탐사학회지
• /
• 제18권1호
• /
• pp.53-59
• /
• 2002

The MSC is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a GSD(Ground Sample Distance) of 1 m over the entire FOV(Field Of View) at altitude 685 km. The instrument is designed to haute an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data compression/storage. The MSC instrument has one channel for panchromatic imaging and four channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI(Time Belayed Integration) CCD(Charge Coupled Device) FPA(Focal Plane Assembly). The MSC hardware consists of three subsystem, EOS(Electro Optic camera Subsystem), PMU(Payload Management Unit) and PDTS(Payload Data Transmission Subsystem) and each subsystems are currently under development and will be integrated and verified through functional and space environment tests. Final verified MSC will be delivered to spacecraft bus for AIT(Assembly, Integration and Test) and then COMSAT-2 satellite will be launched after verification process through IST(Integrated Satellite Test). In this paper, the introduction of MSC, the configuration of MSC electronics including electrical interlace and design of CEU(Camera Electronic Unit) in EOS are described. MSC Operation parameters induced from the operation concept are discussed and analyzed to find the influence of system for on-orbit operation in future.