Journal of Navigation and Port Research (한국항해항만학회지)

Korean Institute of Navigation and Port Research (한국항해항만학회)
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A generation method of ASF mapping by the predicted ASF with the measured one in the Yeongil Bay

ASF 예측모델과 실측치를 이용한 영일만 해상 ASF 맵 생성기법

  • Hwang, Sang-Wook (Department of Electronics Engineering, Chungnam National University) ;
  • Shin, Mi Young (Maritime Safety Research Division, Korea Institute of Ocean Science & Technology) ;
  • Choi, Yun Sub (Department of Electronics Engineering, Chungnam National University) ;
  • Yu, Donghui (Department of Multimedia Engineering, Catholic University of Pusan) ;
  • Park, Chansik (Department of Electronics Engineering, Chungbuk National University) ;
  • Yang, Sung-Hoon (Time and Frequency Group, Korea Research Institute of Standard and Science) ;
  • Lee, Chang-Bok (Time and Frequency Group, Korea Research Institute of Standard and Science) ;
  • Lee, Sang Jeong (Department of Electronics Engineering, Chungnam National University)
  • Received : 2013.07.01
  • Accepted : 2013.08.27
  • Published : 2013.08.31
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Abstract

In order to establish eLoran system it needs the betterment of a receiver and a transmitter, the add of data channel to loran pulse for loran system information and the differential Loran for compensating Loran-c signal. Precise ASF database map is essential if the Loran delivers the high absolute accuracy of navigation demanded at maritime harbor entrance. In this study we developed the ASF mapping method using predicted ASFs compensated by the measured ASFs for maritime in the harbor. Actual ASF is measured by the legacy Loran signal transmitted from Pohang station in the GRI 9930 chain. We measured absolute propagation delay between the Pohang transmitting station and the measurement points by comparing with the cesium clock for the calculation of the ASFs. Monteath model was used for the irregular terrain along the propagation path in the Yeongil Bay. We measured the actual ASFs at the 12 measurement points over the Yeongil Bay. In our ASF-mapping method we estimated that the each offsets between the predicted and the measured ASFs at the 12 spaced points in the Yeongil. We obtained the ASF map by adjusting the predicted ASF results to fit the measured ASFs over Yeungil bay.

eLoran 시스템의 구축을 위해서는 기존 LORAN-C 설비의 보완과 데이터채널, dLoran 기준국, ASF 데이터베이스 등의 추가가 필요하다. 특히 항만접근 시 eLoran을 이용한 정밀 위치측정을 위해서는 항만 해역에 대한 ASF 맵이 반드시 이용자에게 제공되어야 한다. 본 연구에서는 eLoran 시스템의 주요 오차 요인인 항만에서의 ASF를 효율적으로 생성 및 보완하기 위하여, ASF 예측모델과 실측치를 이용한 ASF 맵 생성기법에 대해 연구하였다. 포항 LORAN-C 주국(9930M)에서 송신신호와 LORAN-C 수신기의 수신신호를 각각 세슘원자시계를 기준으로 측정하는 전파지연 측정법을 적용하여 ASF 실측치를 얻었고, ASF 예측맵은 불규칙한 지형을 적용한 몬테스 모델로 구현하였다. 본 논문에서는 영일만 해상 12 개 측정점에서의 ASF 실측값과 ASF 모델링을 통해 획득한 예측값의 옵셋을 보정하여 영일만의 ASF 맵을 생성하였다.

Keywords

References

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