Journal of Navigation and Port Research (한국항해항만학회지)

Korean Institute of Navigation and Port Research (한국항해항만학회)
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ASF Measurements on Maritime by the Signal of the Pohang Loran-C (9930M)

포항 로란-C (9930M) 신호를 이용한 ASF 해상측정

  • 이창복 (한국표준과학연구원 기반표준부) ;
  • 이종구 (한국표준과학연구원 기반표준부) ;
  • 김영재 (한국표준과학연구원 기반표준부) ;
  • 황상욱 (충남대학교 전기정보통신공학부) ;
  • 이상정 (충남대학교 전기정보통신공학부) ;
  • 양성훈 (한국표준과학연구원 기반표준부)
  • Received : 2011.07.20
  • Accepted : 2011.09.01
  • Published : 2011.10.31
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Abstract

A significant factor limiting the ranging accuracy of Loran (Long Range Navigation) signal is the additional secondary factor (ASF) in the time of arrival (TOA) measurements. Precise ASF values are essential if Loran deliver the high absolute accuracies demanded for aircraft approach, maritime harbour entrance. We measured the absolute propagation delay between Pohang Loran signal and Loran receiver output signal by comparing with Cesium atomic clock. In this study we measured ASFs between Pohang 9930M station and the 12 measurement points in the Yeongil Bay by using the measurement technique of absolute time delay. The measurement points were spaced at interval of 3 km by 3 km. An E-field antenna and an H-field antenna were used to improve the accuracy of ASF measurements and a DGPS (Differential GPS) receiver was used for accurate positions. We have gotten the result that the measured ASFs were compared with the predicted ASFs through this measurement technique.

Loran(LOang RAnge Navigation) 신호를 이용한 측위 시에 정확도에 가장 큰 영향을 미치는 오차요소는 TOA(Time of Arrival) 측정에서의 ASF(Additional Secondary Factor)이다. 따라서 공항접근이나 항만 접안 등의 측위 정확도를 만족시키려면 먼저 정확한 ASF측정이 선행되어야 하는데, 본 연구에서는 해상에서 ASF를 측정하는 기법을 연구하였다. 그 측정방법으로 포항 Loran-C 주국(9930M)에서 송신하는 로란 신호와 로란 수신기의 기준신호를 세슘원자시계를 기준으로 측정함으로써 해상에서의 ASF를 측정하였고 영일만 해상의 12 곳의 측정지점을 3 km 간격으로 설정하여 측정하였다. 해상측정에서 정확도를 높이기 위해서 전기장 안테나와 자기장 안테나를 동시에 사용하였으며 정확한 위치측정을 위해서 DGPS(Differential GPS)수신기를 이용하였다. 이런 방법을 이용하여 해상에서 ASF를 측정함으로써 ASF 예측값과 비교한 결과를 얻었다.

Keywords

References

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