• Title, Summary, Keyword: Telecommand

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Telecommand Decryption Verification for Engineering Qualification Model of Command Telemetry Unit in Communications Satellite (통신위성 원격측정명령처리기 성능검증모델 원격명령 암호복호 검증)

  • Kim, Joong-Pyo;Koo, Cheol-Hea
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.7
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    • pp.98-105
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    • 2005
  • In this paper, the decryption function of CCSDS telecommand of CTU EQM for the security of communications satellite was verified. In order to intensify the security level of DES CFB decryption algorithm applied to CTU EM, 3DES CFB decryption algorithm using three keys is implemented in the CTU EQM. As the decryption keys increased due to the 3DES algorithm, the keys and IV are stored in PROM memory, and used for the telecommand decryption by taking the keys and IVs corresponding to the selected key and IV indexes from the memory. The operation of the 3DES CFB is validated through the timing simulation of 3DES CFB algorithm, and then the 3DES CFB core implemented on the A54SX32 FPGA. The test environment for the telecommand decryption verification of the CTU EQM was built up. Through sending and decrypting the encrypted command, monitoring the opcodes, and confirming LED on/off by executing the opcodes, the 3DES CFB telecommand decryption function of the CTU EQM is verified.

Implementation of CCSDS Telecommand Decryptor in Geostationary Communications Satellite (정지궤도 통신위성의 CCSDS 원격명령 암호복호기 구현)

  • Kim,Jung-Pyo;Gu,Cheol-Hoe;Choe,Jae-Dong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.10
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    • pp.89-96
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    • 2003
  • In this paper, a CCSDS(Consultative Committee for Space Data Systems) telecommand(TC) decryptor for the security of geostationary communications satellite was implemented. For the confidentiality of CCSDS TC datalink security, Option-A which implements the security services below the transfer sublayer was selected. Also CFB(Cipher Feedback) operation mode of DES(Data Encryption Standard) was used for the encryption of 56-bit data bits in 64-bit codeblock. To verify Decryptor function, the DES CFB logic implemented on A54SX32 FPGA(Field Programmable Gate Array) was integrated with interface and control logics in a PCB(Printed Circuit Board). Using a function test PC, the encrypted codeblocks were generated, transferred into the decryptor, decrypted, and the decrypted codeblocks were transmitted to the function test PC, and then compared with the source codeblocks. Through LED(Light Emitting Diode) ON operation by driving the relay related to Op-code decoded and the comparison between the codeblock output waveforms measured and those simulated, the telecommand decryptor function was verified.

Efficiency Tests Results and New Perspectives for Secure Telecommand Authentication in Space Missions: Case-Study of the European Space Agency

  • Chiaraluce, Franco;Gambi, Ennio;Spinsante, Susanna
    • ETRI Journal
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    • v.27 no.4
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    • pp.394-404
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    • 2005
  • We discuss some typical procedures to measure the efficiency of telecommand authentication systems in space missions. As a case-study, the Packet Telecommand Standard used by the European Space Agency is considered. It is shown that, although acceptable under well consolidated evaluation suites, the standard presents some flaws particularly in regard to the randomness level of the pre-signature. For this reason, some possible changes are proposed and evaluated that should be able to improve performance, even reducing the on-board elaboration time.

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TELEMETRY AND TELECOMMAND SYSTEM OF LOW-EARTH-ORBIT MICROSATELLITE, KITSAT-1 AND 2 (저궤도 소형위성 우리별 1, 2호의 원격검침 및 명령부)

  • 김성헌;성단근;김형명;최순달;네빌빈
    • Journal of Astronomy and Space Sciences
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    • v.13 no.2
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    • pp.30-40
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    • 1996
  • The telecommand system of KITSAT micorsatellite receives commands from ground stations or on-board computers. It decodes, validates and delivers commands to sub-system. The telemetry system is to collect, process and format satellite housekeeping and mission data for use by on-board computer and ground station. It is crucial for the telemetry and telecommand system to have high reliability since the spacecraft operation is mostly based on the function of this system. The telemetry and telecommand(TTC) systems for KITSAT-1 and 2 had been developed under the consideratin of the space environment of Low-Earth-Orbit and the limited mass, volume and power of micorsatellite. Since both satellites were launched in August 1992 and September 1993 respectively, the have shown to be working successfully as well as the TTC systems on-board both satellites.

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Playback Downlink and Telecommand Uplink Channel Design for Transportable KOMPSAT Ground Station (이동형 다목적실용위성 소형 관제국의 Playback 하향 링크 및 원격 명령 상향 링크 채널 설계)

  • Ahn, Sang-Il;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.4
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    • pp.396-405
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    • 2009
  • This paper describes playback downlink and telecommand uplink channel design performed for a transportable small-sized KOMPSAT(Korea Multi-Purpose Satellite) ground station. As a result of downlink channel design, required receiving performance was calculated from the threshold signal-to-noise ratio of playback signal and it was revealed that this performance can be guaranteed in 1.5 m ground station with 6.5 dB/K of G/T. For the uplink channel design, 40 dBW of EIRP was derived from the threshold signal-to-noise ratio of telecommand signal received at on-board receiver. The implemented small-sized ground station based on design was evaluated to be fully acceptable for KOMPSAT TT&C(Telemetry, Tracking and Command) system and playback downlink design without taking account of additional 3 dB system link margin was shown to be effective because it had provided constantly initial channel performance without any remarkable degradation over several years of tests with KOMPSAT and KOMPSAT-2, for both uplink and playback downlink in the elevation angle above $10^{\circ}$.

Design and fabrication of test equipment of RF Telecommand and Telemetry for satellite control (위성 제어용 RF Telecommand 및 Telemetry 시험 장비 설계 및 제작)

  • Chang, Lae-Kyu;Jo, Seong-Won;Lee, Hyung-Goo;Hong, Sung-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.2
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    • pp.187-192
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    • 2009
  • Telecommand & telemetry control equipment is needed for the testing of the transponders during the development of satellite. This equipment must have a loopback function to perform the self testing without satellite. The fabrication of the designed system is easier and cheaper than the conventional testing system using direct modulation method. The measured results of fabricated equipment are satisfied with required specifications. A overall path loss of uplink and downlink is 47.8 dB and 42.6 dB, respectively. Also, IMD3 of uplink has measured 60.68 dBc at an output of -50 dBm.

Automated command generation for satellite control

  • Mo, Hee-Sook;Kim, Jae-Hoon;Lee, Ho-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • pp.380-383
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    • 1995
  • Since the generation and transmission of telecommand in satellite monitoring and control system depend on the decisions of operators, it is possible that operators with different levels of knowledge may generate different telecommands in the same situation. Because of this reason, automation technology of satellite operation is being researched and developed to minimize the decision error due to the operator's lack of experience. This paper suggests a method of automated satellite control, which generates telecommands automatically using the knowledge of satellite subsystem engineers or specialists for the ground system. This method provides safe satellite operation and expansion of satellite life time by automatic generation of the telecommands, so that the operator's interrupt is minimized which provides the efficient satellite control.

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A Study on the Optimization of the Transmission Method for COMS Satellite Control Signal (통신해양기상위성의 위성 관제 신호 전송 방식의 최적화 연구)

  • Kim, Yeong-Wan;Yang, U-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.11
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    • pp.47-53
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    • 2006
  • The power losses due to modulation index for multi-modulation scheme were analyzed under various transmission mode of satellite control and the necessary satellite link margin for transmission mode were proposed in this paper On the basis of the analyses for interference between the transmission signals and threshold of satellite control signal receiver, the optimal subcarrier signals were proposed for satellite range measurement methods, respectively. The subcarrier signal of 12 kHz or 14 kHz is proper for telecommand using the ESA method, and 16 kHz for telecommand signal using the GSTDN method. On the other hand, the telemetry subcarrier of 65.536 kHz is a proper in the viewpoint of receiver threshold value.

Engineering Model Design and Implementation of Telemetry-Command Unit for STSAT-2 (과학기술위성 2호 원격검침-명령 유닛 시험모델 설계 및 구현)

  • Oh, Dae-Soo;Ryu, Chang-Wan;Nam, Myeong-Ryong;Hwang, Dong-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.5
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    • pp.93-98
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    • 2005
  • An Engineering Model(EM) of the Telemetry-Command Unit(TCU) for STSAT-2 was developed. The TCU of STSAT-2 has some improved features compared with that of STSAT-1. To reduce weight and size of TCU all logics are implemented in FPGA without CPU. EM I&T(Integration and Test) was successfully performed with no errors.

COMS System Bus Design and Analysis using MIL-STD-1553B (MIL-STD-1553B 버스를 이용한 통신해양기상위성의 시스템 버스 설계 및 분석)

  • Cho, Young-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.7
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    • pp.1285-1289
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    • 2008
  • In this paper, we design COMS system bus that the 1553 Data Bus is able to link all the units of the satellite managed by the SCU using one Prime Data Bus and on Redundant Data Bus. Also we analyze MIL-STD-1553B bus load and relevant exchange memory budgets in system bus of the COMS satellite. This data is used in the satellite mission and software design by system engineer.