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traveled in gure-eight patterns to understand the satellite tracking characteristics of the WINDS-compatible marine-based earth station.e ship’s gure-eight course is shown in Fig. 6. e xed object on the ship deck shown in Fig. 7 sometimes blocked transmission between the onboard earth station and the satellite, causing communication loss and interrup-tion, when the ship was oriented in a certain direction. e relationship between the azimuth (AZ) of the antenna and the C/N0 level of beacon signals from the satellite was analyzed (Fig. 8) to determine the AZ range within which the onboard object interrupts communication. Antenna AZ to the right and le with respect to the ship’s bow direction (0°) are represented by positive and negative values, respec-tively. Communication was interrupted when the ship was oriented in a northwestly direction and the satellite was positioned almost due south (i.e., when the antenna AZ was between -120° and -147°) (Fig. 8).e movement of the satellite tracking antenna in terms of AZ and elevation (EL) is shown in Figs. 9 and 10, re-spectively, in relation to the ship traveling in gure-eight patterns. In addition, the C/N0 levels of beacon signals from the satellite are shown in Fig. 11.e antenna accurately tracked the satellite during radical ship movements. We conrmed normal antenna movement (Figs. 9 and 10) and stable beacon signal recep-tion (Fig. 11). e antenna continuously tracked the satel-lite except when the xed object on the ship deck (Fig. 7) interrupted communications. e margin of error for the FiF9The angle of azimuth motion situation of the antenna at cruise of figure eight AZ [degree] Time [sec] FiF8　Verification of communication blocking area AZ [degree] Beacon C/N0 [dB-Hz] Beacon C/N0 AZ 27°Time [sec] Blocking Blocking FiF10The angle of elevation motion situation of the antenna at cruise of figure eight EL [degree] Time [sec] FiF6　Trajectory of figure eight cruise Latitude [degree] Longitude [degree] Suruga Bay FiF7　Something to block on research vessel3 Ultra-High-Speed Satellite Communication Technology154　　　Journal of the National Institute of Information and Communications Technology Vol. 64 No. 2 (2017)