GPS/ロランCシステムによる巨大架橋付近の電磁波じょう乱の検出

抄録

We have reported that the main towers of the large suspension-bridge have been considered macroscopically as a couple of the vertical electric dipoles from studying in Minami-Bisan Seto-Oohashi Bridge. In this paper, from experiments and theoretical considerations for 100kHz band waves near the Akashi-kaikyou-Ohhashi Bridge, it was confirmed that the sources of the secondary wave in the vicinity of the bridge is the metallic materials, "like main cable". Then, electric fields of the primary wave as well as the secondary waves re-radiated from both the two vertical towers and the metallic materials are derived theoretically. Furthermore, in the summer of 1997, a series of phase errors measurement of 8930 Loran-C chain was made, using both rho-rho Loran-C receivers and RTK-GPS/OTF. Taking notice of the phase errors within about ±200m from the bridge, the experimental values for Niijima station show the advances of about 0.5μ sec. Finally, it is shown that some aspects of the experimental results are reasonably interpreted by using the models of considering both a couple of vertical towers and the metallic materials to be vertical electric dipole antennas.