• Title/Summary/Keyword: KOREASAT 1

Search Result 44, Processing Time 0.029 seconds

A Study on the Design and Fabrication of Diplexer Using H-plane T-junction for KOREASAT-III Transponder (자계면 T-접합을 이용한 무궁화 III호 위성체용 다이플렉서의 설계 및 제작에 관한 연구)

  • 이용민;홍완표;신철재;강준길;나극환
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.10 no.4
    • /
    • pp.582-593
    • /
    • 1999
  • This paper presents the design and fabrication of the diplexer for a KOREASAT-III Ka-band satellite transponder. The transmission characteristics of the diplexer is analyzed by calculating the generalized scattering matrix using mode matching method. It is composed of 2 bandpass filters, coupled with H-plane T-junction having symmetrical inductive iris and E-plane metal insert structures. Compared with the size and weight of the Rx and Tx filter loaded with a transponders respectively, those of the diplexer can be effectively reduced. In a high power transmission, the variation of the filter characteristics is minimized by the scheme that irises are extended to the exterior of H-plane of the waveguide. This scheme needs no extra heat sinks for dissipating high power. The diplexer is designed to improve the simplification, durability and reliability by eliminating tuning screws, which have been used to compensate for the characteristics of fabricated filters. The bandpass filters of the diplexer show the insertion loss of less than 1.2 dB and the return loss in excess of 15 dB. The isolations of more than 65 dB have been achieved between Rx and Tx filter.

  • PDF

Attitude Controller Design for a Bias Momentum Satellite with Double Gimbal (더블김벌을 장착한 바이어스 모멘텀 위성의 자세제어기 설계)

  • Park, Young-Woong;Bang, Hyo-Choong
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.32 no.4
    • /
    • pp.34-42
    • /
    • 2004
  • In this paper, a double gimbal is used for roll/yaw attitude control of spacecraft and two feedback controllers are designed. One is a PD controller of no phase difference between roll and yaw control input. The other is a PD controller with a phase lag compensator about the yaw control input. The phase lag compensator is designed a first order system and a lag parameter is designed for the control of yaw angle. There are two case simulations for each of controllers; constant disturbance torques and initial errors of nutation. We obtain the results through simulations that a steady-state error and a rising time of yaw angle are developed by the compensator. In this paper, simulation parameters use the values of KOREASAT 1.

The Study of De-orbit Time Prediction Using Temperature Change of Geostationary Satellite Propellant System (정지궤도위성 추진시스템의 온도변화를 이용한 위성폐기시점 추정연구)

  • Park Eung Sik;Park Bong Kyu;Han Cho Young;Kim Yong Min
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • v.y2005m4
    • /
    • pp.5-10
    • /
    • 2005
  • The geostationary satellite propulsion system has thermistors which can measure liquid propellant temperature at tanks, pipes and etc. In the satellite propulsion system with several tanks, the propellant in the tanks is moved by temperature change and this temperature pattern is constant. In this paper, the temperature change pattern of KOREASAT 1 propulsion system is compared and the prediction study of pressurant inflow using temperature change of geostationary satellite propulsion system is described.

  • PDF

Fault Tolerance Design of Uplink Command Processor (상향링크 명령 처리기의 결함 허용 설계)

  • Gu, Cheol Hoe
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.31 no.3
    • /
    • pp.95-100
    • /
    • 2003
  • Electronic equipment used in satellites are demanding extremely high reliability, so they should be designed to have immunity for some critical faults by using redundancy component. Generally, Communication satellites are assigned to meet the 15 years mission lifetime, of the analysis about faults must be performed to electronic equipments of satellite. This paper is a summary of the fault tolerance design research of command processor, the improvement of reliability and trade-off study of fault tolerance design result. The reliability prediction value of the satellite component used in this research was taken from Koreasat 3 and Kompsat 1. It is important to perform many trade-off studies for fault tolerance design, especially to choose the most proper fault tolerance method for the specified fault scenario.

NORTH/SOUTH STATION KEEPING OF GEOSTATIONARY SATELLITE USING MFT (MFT 기법을 이용한 정지위성의 남/북 위치보존)

  • 안웅영;김천휘;박봉규
    • Journal of Astronomy and Space Sciences
    • /
    • v.14 no.1
    • /
    • pp.150-157
    • /
    • 1997
  • A precise determination of the fuel efficiency is important because North/South station keeping, which controls the inclination of the geostationary orbit, consumes most of the satellie fuel. We estimate the amount of fuel required during the lifetime of the KOREASAT when MFT(Minimum Fuel Target) technique is adopted, and the result is compared to those when MCT(Maximum Compensation Target) and TBCT(Track-Back Chord Target) technique are applied. From this computation, we find that if MFT technique is adopted, the lifetime of the satellite can be extended at least 45 and 15 days, respectively, compared to those consumed with MCT and TBCT technique.

  • PDF

Design and Operation of LAN Interconnection Service for Satellite Links (위성링크를 위한 LAN 접속 서비스 설계과 운영)

  • Kim, Jeong-Ho;Choe, Gyeong-Su
    • The Transactions of the Korea Information Processing Society
    • /
    • v.3 no.4
    • /
    • pp.961-968
    • /
    • 1996
  • In the frame of Koreasat Project, it has been identified the task to implement a pilot satellite network module to provide LAN-to-LAn in ground system for satellite links. The pilot network will support an experiment to verify the performances of the considered applications through a satellite.This paper proposes a satellite-LAN interconnecting architecture making full use of satellite benefits and counteracting satellite demerits. The architectureprovides high quality data transmission and high perfrmance for satellite bit errors by using a connection- oriented satellite protocol which can establish multiple logical links between two nodes. As a protocol conversion method, router-type interconnection was selected to guard against problems. Based on this architecture, a satellite LAN interconnecting system has been designed, which includes a 1.8 meter antenna with a 4 watt transceiver, a satellite modem and the developed satellite network interface. The system can support high speed transmission rates of up to 1.544 Mbs and superior network management as well.

  • PDF

A Study on the 8W High Power Amplifier for VSAT at Ku-band (Ku-band의 소형 지구국용을 위한 8W 고출력 증폭기에 관한 연구)

  • 조창환;이찬주;홍의석
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.7 no.1
    • /
    • pp.53-60
    • /
    • 1996
  • The 8W hybrid MIC SSPA has been developed in the frequency range from 14.0 GHz to 14.5 GHz for uplink of KOREASAT's earth station. The whole system was designed of two parts with driving amplifier and high power amplifier to simplify the fabrication process. we reduced weight and volum of power amplifier through arranging the bias circuits in the same housing. The realized SSPA has a small signal gain of $26\pm1dB$within 500 MHz bandwidith, and the input and output return losses are over 7dB and 12dB respectively. The output power of 39.0 ~ 39.2dBm is achieved at the 1dB gain compression point of 14 GHz, 14.25 GHz, and 14.5 GHz. That reveals higher power than 8W of design target. The proposed SSPA manufacture techni- ques in this paper can be applied to the implementation of power amplifiers for some radars and SCPC.

  • PDF

A study on the design for mobile satellite receiver antenna (이동체의 위성 수신용 안테나 설계에 관한 연구)

  • Ju, Sang-Ho;Ko, Jeong-Ho;Kim, Young-Goo;Choi, Ik-Guen
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.14 no.7
    • /
    • pp.1529-1536
    • /
    • 2010
  • In this paper, we propose a Axially displaced ellipse gregorian antenna with conical feed horn operating in Ku-band. For fast searching satellite position, it is designed the sub-reflector rotates about $1.5^{\circ}$ tilted by the central axis. the curvature and feed center of the main-reflector and sub-reflector are optimized to achieve maximum antenna efficiency. The designed reflector antenna shows the gain of 33dB and the cross polarization level of less than -21dB and the side-lobe level of less than -14 dB at 12.2 GHz. and C/N ratio of 19dB is proved by reception experiment of Koreasat with fabricated antenna.

Design and Performance Analysis of Satellite Terminal Management Protocol in KMILSATCOM (군 위성통신체계 위성단말관리 프로토콜 설계 및 성능분석)

  • Lee, Jong-Seong;Choe, Hyeong-Seok;Hwang, In-Gwan
    • Journal of Satellite, Information and Communications
    • /
    • v.2 no.1
    • /
    • pp.14-20
    • /
    • 2007
  • The Korean Military Satellite Communication System (KMILSATCOM) is composed of military payload of KOREASAT 5 and military satellite terminals. The military satellite terminals communicate with each other in satellite service area. The satellite terminal management system is developed for centralized management of satellite terminals and communications link. The satellite terminal management system dose not use terrestrial networks (i.e. Fiber optic, Microwave) for management because the KMILSATCOM is system for emergency (i.e. war time) and the satellite terminals has to move to operational area, so the management link must use satellite link. The management link is composed of 1 to N communication scheme for one manager and multiple terminals. This paper describes the satellite terminal management protocol architecture and the performance of the protocol of the KMILSATCOM system.

  • PDF

A study on the tracking antenna system for DBS receive on a ship (선박용 DBS수신 추적안테나 시스템의 구현)

  • 최조천;양규식;최병하
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.22 no.10
    • /
    • pp.2236-2245
    • /
    • 1997
  • The DBS system is being highlighted as actual area for the information societics. Specially, the DBS have been proposed very useful system to access the broading service in more widely sea. But the antenna tracking system for maritime DBS receiving is requried complicated control system because of the those complex motion represented pitching, rolling and yowing etc. Our resesrch target is a development of tracking system to the KOREASEA(MUGUNGWHA-1,2) for the applicated small size shipping. So our development focus was concentrated the two development direction. The first focus was represented low-cost system for popularization of small-size shipping around sea of the Korea peninsula. The second focus was an adaptive possibilities with domestic eqdupiment which was developed satellite receiving for KOREASAT. The anntenna mount is designed a compact size and easy operation use to the Az/El 2-axis type which is operated by step motor. And this mount type is very useful on a ship in the near sea of Korea peninsula. Basic tracking method is used th step-tracking algorithm, and the ship's moving compensation is adapted to the closed loop control method by ship's moving detection of gyro sensor. Control part is consists of converter, countertime, VCO, micro-computer and it's software. Testing the operation by the ship's moving simulator, and algorithm is designed tracking and moving compensation by receiving state.

  • PDF