• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.218-223
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• 2020

There are communication methods that guarantees real-time and method of performing the simultaneous acquisition through the synchronized multi-channels to improve the reliability of the telemetry system. Such synchronized systems need to be verified to confirm the simultaneous measurement performance of channels. In this paper, we propose a method to measure the time difference between synchronized channels in a telemetry system through simultaneous acquisition performance test. The simulation signal is applied for measurement and the difference between the sampling period and the simulation signal period is defined as the concept of time resolution. The principle of checking the measurement time difference between channels through time resolution was explained. In addition, the proposed principle was verified through simulation in the situation when measurement time difference may occur. And a procedure for identifying a measurement time difference in an actual telemetry system is described.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.452-459
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• 2019

In this paper, we describe a PCM encoder structure that can update the telemetry system parameters in real time. In the PCM encoder, an analog signal control unit for FPGA, flash memory, and sensor data acquisition was constructed. UART communication, analog signal control, flash memory control, and frame generation are possible through logic inside FPGA of PCM encoder. UART communication allows the PC to transmit parameter data to the PCM encoder, and flash memory is controlled to update the parameter of the telemetry system in real time and finally the frame is formed. Simulation and verification were performed to confirm whether the parameter data is updated in real time, and the proposed structure was used to construct a telemetry system with enhanced flexibility and convenience.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.662-664
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• 1998

본 논문에서는 다목적 실용위성인 아리랑위성(KOMPSAT-I)에서 지상과의통신을 위해 사용하는 CCSDS(Consultative Committee for Space Data Systems)표준 Command/Telemetry(CMD/TLM)시스템과 KOMPSAT-I의 목적에 맞게 이를 적용한 CMD/TLM 시스템을 소개한다. 현재 한국항공우주 연구소는 Observer 회원 자격으로 CCSDS 에 가입되어 있으며 국내 위성 개발에서 CMD/TLM 시스템에 CCSDS프로토콜을 사용한 것은 처음이다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1248-1255
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• 2003

Pressure coefficient in a rotating discharge hole was measured to gain insight into the influence of rotation on the discharge characteristics of rotating discharge holes. Pressures inside the hole were measured by a telemetry system that had been developed by the authors. The telemetry system is characterized by the diversity of applicable sensor type. In the present study, the telemetry system was modified to measure static pressure using piezoresistive pressure sensors. The pressure sensor is affected by centrifugal force and change of orientation relative to the gravity. The orientation of sensor installation for minimum rotating effect and zero gravity effect was found out from the test. Pressure coefficients in a rotating discharge hole were measured in longitudinal direction as well as circumferential direction at various rotating speeds and three different pressure ratios. From the results, the behaviors of pressure coefficient that cannot be observed by a non-rotating setup were presented. It was also shown that the discharge characteristics of rotating discharge hole is much more influenced by the Rotation number irrespective of pressure ratio.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.2
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• pp.141-147
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• 2008

Acoustic telemetry technique is one of useful tools to get behavioral information of the free-swimming fish. In this study, we conducted acoustic telemetry using coded acoustic transmitters to compare behavior characteristics between wild and cultured black seabream Acanthopagrus schlegeli, one of target species to promote resource in the marine ranching area. Two wild fish and five cultured fish were released in the marine ranching area after tagging surgically. Three of cultured fish were domesticated using the remote acoustic conditioning system for 3 weeks before being released. Two wild fish stayed at the released point for 2 hours and 9 days, respectively. One of wild fish was found about 10.8km away from the released point after 5 months. Two cultured fish stayed at the released point for 6 days and 75 days, respectively. One of acoustic conditioned fish stayed at the released point for 131 days and then was found about 10.1km away from the released point after 25 days. Others stayed at the released point during this study period(159 days).

• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.285-290
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• 2020

This paper presents a time synchronization algorithm based on PLL for application to telemetry systems and implement FPGA logic. The large aircraft of the telemetry system acquires status information through each distributed acquisition devices and analyzes the flight status in real time. For this reason, time synchronization between systems is important to improve precision. This paper presents a PLL based time synchronization algorithm that is less complex than other time synchronization methods and takes less time to process data because there is minimized message transmission for synchronization. The validity of proposed algorithm is proved by simulation of Python. And the VHDL logic was implemented in FPGA to check the time synchronization performance.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.5
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• pp.1-11
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• 2015

This paper is focused on how the trajectory of launch vehicle could be optimally estimated by the quadratic regression of trajectory data mining for the operation of telemetry ground system in NARO space center during real-time. To receive the telemetry data, the telemetry ground system has to track the space launch vehicle without tracking loss, and it is possible by the well-designed algorithm to estimate a flight position in real-time. For this reason, the quadratic regression model instead of interpolation was considered to estimate the exact position data of launch vehicle and the improvement of antenna performance. For analysis, the real trajectory data which had been logged during NARO 1st launch mission were used, the estimation result of launcher current position was analyzed by the mathematical modeling. In conclusion, the algorithm using quadratic regression based on trajectory data mining showed the better performance than previous interpolation algorithm to estimate the next flight position and the antenna driving performance.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.441-447
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• 2022

In this paper, we propose a FLL-assisted-PLL based time synchronization algorithm for telemetry systems where frequency and phase errors exist in time synchronization pulse. The telemetry system may analyze the flight state by acquiring the state information in the distributed system. Therefor, in order to collect each state information without errors, precise time synchronization between the master and the slave is required. At this time, the master's time pulse have frequency and phase changes that can be caused by external and internal factors, so a method to maintain precision time synchronization is essential to provide telemetry data continuously. We propose the FLL-assisted-PLL based algorithm that is capable of high-speed synchronization and has high time synchronization accuracy. The proposed algorithm is verified through python simulation, and the VHDL Logic has been implemented in FPGA to check the performance according to the frequency errors and phase errors.

• Proceedings of the KSRS Conference
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• v.2
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• pp.824-826
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• 2006

The number of satellite under operation is being on the increase, however, because the number of operator is limited the reliable control system is necessary for stable mission operation. Especially it is necessary that error event indication such as colour or sound should be displayed with high reliability for intuitional monitoring. The limit range of KOBAS2 provides realistic value that is defined with in-orbit value and related document. It makes it possible for operator to monitor a number of telemetry data easily through single screen system instead of monitoring each mnemonics. The development and operation experience of KOBAS2 will contribute to the development of the evolved automatic telemetry monitoring system for future mission.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.2
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• pp.3-9
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• 1994

Telemetry system which is mounted on the scientific sounding rocket KSR-420S transmits the informations about the performance of flighting rocket - distribution of the strain and temperature, accleration, pressure, velocity,attitude etc. - , the status of onboard circuit operating and measured data for scientific research such as ozone, ionosphere, x-ray etc. In this paper, PCM / FM telemetry system which was mounted on the KSR-420S is described.