ABSTRACT: User at the Inland Sea requires high position accuracy which is 5 m (2drms) or less. Therefore the position accuracy of standalone GPS is insufficiency. Consequently it needs to use DGPS for navigator sailing the Inland Sea. We executed numerical simulation of the propagation characteristic on the extended line of bridge pier at opposite side from DGPS station, and already confirmed that bit error in DGPS correction data signal occurs, and that correction data could not form by bit error. Furthermore, we carried out numerical simulation of the propagation characteristic of DGPS correction data signal received at sailing through center of the bridge, and solved receiving condition of DGPS correction data signal before and after passing through the bridge. In this paper, we executed to inspect mutually results of electric field intensity simulation for oversea and overland propagation on some sea area of the Inland Sea and measuring results of electric field intensity for DGPS correction data signal, and evaluated the possibility of abnormal propagation comprehensively.

KEYWORDS: Differential GPS (DGPS), Global Maritime Distress and Safety System (GMDSS), Inland Sea, Propagation Characteristic, Radio Wave, LF Band Radio Wave, MF Band Radio Wave, DGPS Correction Data Signal

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