Journal of Advanced Navigation Technology (한국항행학회논문지)

The Korean Navigation Institute (한국항행학회)
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Phase Locked Loop based Time Synchronization Algorithm for Telemetry System

텔레메트리 시스템을 위한 PLL 기반의 시각동기 알고리즘

  • 김건희 (단암시스템즈 기술연구소) ;
  • 진미현 (단암시스템즈 기술연구소) ;
  • 김복기 (단암시스템즈 기술연구소)
  • Received : 2020.07.15
  • Accepted : 2020.08.25
  • Published : 2020.08.31
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Abstract

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.

본 논문에서는 텔레메트리 시스템에 적용하기 위한 PLL 기반의 시각동기 알고리즘을 제시하고 FPGA 로직을 구현하였다. 텔레메트리 시스템에서 대형 비행체의 경우 각각의 분산 획득 장치들을 통해 상태정보를 계측하여 실시간으로 비행 상태를 분석해야하므로 정밀도 향상을 위한 장치 및 시스템 간의 시각 동기의 중요성이 커지고 있다. 이 때문에 시각동기 기법으로 타 시각동기 방법보다 복잡도가 적고, 동기를 위한 추가적인 메시지 전송을 최소화하여 데이터 처리에 적은 시간이 소요되는 PLL 기반의 시각동기 알고리즘을 제안하였다. 타당성을 확인하기 위해 python 시뮬레이션을 수행하였으며 최종적으로 FPGA 내에 VHDL 로직을 구현하여 시각 동기 성능을 확인하였다.

Keywords

References

  1. A. Berdugo and J. Hildin, "A system approach to a network centric airborne data acquisition system," in Proceeding of the International Telemetry Conference, San Diego: CA, Vol.42, pp.198-206, Oct. 2006 .
  2. J. Hildin, and S. Arias, "Airborne Network Switch With IEEE-1588 Support", in Proceedings of the 42nd Annual International Telemetry Conference, San Diego: CA, Vol. 42, Oct. 2006.
  3. M. Mock, R. Frings, E. Nett and S. Trikaliotis, "Continuous clock synchronization in wireless real-time applications," in Proceeding of the 19th IEEE Symposium on Reliable Distributed Systems, Washington: WA, pp.125-133, Oct. 2000.
  4. F. Sivrikaya and B. Yener, "Time synchronization in sensor networks: a survey," IEEE Network, Vol. 18, No. 4, pp. 45-50, 2004. https://doi.org/10.1109/MNET.2004.1316761
  5. R. Michael, Digital Communications: A Discrete Time Approach, London, UK: Pearson, 2008.
  6. S. Buhr, M. Kreissig and F. Ellinger, "Low Power 16 Phase Ring Oscillator and PLL for Use in sub-ns Time Synchronization over Ethernet," in Proceeding of the IEEE International Conference on Electronic, Circuits and Systems, Bordeaux, pp.53-56, 2018.
  7. C. Andrich, J. Bauer, P. Grosse, A. Ihlow and G. D. Galdo, "A Fast and Stable Time Locked Loop for Network Time Synchronization with Parallel FLL and PLL," in Proceeding of the IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication, Geneva, pp.1-4, 2018
  8. F. Ring, T. Bigler and R. Exel, "Synchronization robustness using Kalman-based clock servos," in Proceeding of the IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication, Beijing:China, pp.64-69, 2015