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objectives: (a) antenna pattern measurement: propagation measurement to verify the antenna pattern of the MBA Chubu beam; (b) antenna tracking characteristics: the ight experiment includes gure-of-eight and banked ight to investigate the tracking characteristics of the antenna; (c) data transmission: investigation of the eect of ight on the rate of data transmission; and (d) transmission of a large-volume le, in which image data les acquired by Pi-SAR [8] are used to test le transmission performance.4Experimental results(a)Antenna pattern measurementFigure 7 shows the level of received power from the MBA’s Chubu beam as measured along the ight route indicated. e aircra ew straight through the center of the beam at an altitude of 5,300 m. Time variation of re-ceived power during the ight is shown in Fig. 8. e maximum received power was at the beam center and communication ceased at a point more than 172 km from the center of beam. Figure 9 shows a characteristic an-tenna pattern as plotted against the distance from the center of the beam. e red plot in the gure indicates the pattern obtained at the initial check-out. In the initial check-out, antenna beam measurements were conducted by FiF5　Network configurationWINDSaeronauticalearthstationWINDSfixedgroundearthstationWINDSFiF6　Areas irradiated by WINDS multi-beam antennaBeijingShanghaiSeoulChubu beam TokyoNagoyaFiF7　Received power map during a straight flightLongitude LatitudeReceived power [dBm]FiF4　The earth station and measurement devices on board the planeModem (IDU)PC(data transmission test)Spectrum analyzer1413-8 Aeronautical Satellite Communications using WINDS