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1IntroductionSatellite communication can provide eective alterna-tive tools to terrestrial communication systems for in-ight aircras and ships navigating o-shore, as well as, more importantly, in the case of large-scale disasters where ter-restrial-based mobile phone communications may become severely crippled. Large-volume data communication is in dire need in race-against-time disaster situations for shar-ing real-time information such as dynamic picture images and topographical data on site. e need for larger com-munication capacity shows no sign of abating even in normal times, for example, for in-ight entertainment purposes.NICT has been conducting research on the Wideband InterNetworking engineering test and Demonstration Satellite (WINDS)[1]. e project includes a variety of research related to mobile satellite communication such as the development and experimental operation of mobile earth stations mounted on a car [2] and on board a ship [3]. ey are equipped with an antenna system capable of au-tomatically detecting and tracking the WINDS satellite for uninterrupted communication during experiment/opera-tion. As a part of the WINDS project, an Aeronautical Earth Station (AES) was developed to research in-ight satellite communication. is report describes an overview of the AES, and the outcomes from ight experiments which were carried out with the earth station on board the aircra [4]–[6].2WINDS aeronautical earth station (AES)e specications of AES are listed in Table 1, and its conguration is shown in Fig. 1. e system has a 45-cm-diameter Cassegrain antenna as shown in Fig. 2. e transmission and receiving gain of the antenna are 38.7 dBi and 36.1 dBi, respectively. Other constituent elements in-clude a 200 W high power amplier (HPA), a low noise TabT1　Aeronautical earth station (AES) specificationsTx frequency27.5-28.6 GHzRx frequency17.7-18.8 GHz,18.9 GHz (for receiving beacon)Polarized waveLinearly-polarized wave (V/H)AntennaCassegrain antennaDiameter: 45 cmAntenna gain38.7 dBi (Tx)36.1 dBi (Rx)High power amplifier200 W TWTAG/T13.2 dB/KAntenna driving rangeEl: 25-65 degAz: endless rotationTracking accuracy<± 0.5 degData rateRegenerative modeTx: 1.5, 6, 24, 51 MbpsRx: 155 MbpsUser interfaceEthernet (1000 base-T)3-8 Aeronautical Satellite Communications using WINDSTomoshige KAN, Norihiko KATAYAMA, and Takashi TAKAHASHISatellite communication has caught the attention of researchers as an effective means of communication in the absence of mobile communication systems on ground systems such as during the takeoff and landing of aircraft. At the time of aircraft’s flight, a large-capacity communication is expecting for the use of entertainment for passengers on board. Its large capacity communication abilities will enable us to share detailed information, which is vital in times of disaster, such as movie images and ground data taken from synthetic aperture radar (SAR). In this study, we report the development of aeronautical earth station for WINDS and result of the flight experiment of satellite communication between developed aeronautical earth station and WINDS. We measured propagation characteristics that is pattern of the Multi-Beam Antenna (MBA) which was mounted on WINDS, variation of the Doppler shift for Ka-band aeronautical satellite communications, and the antenna tracking performance. In this experiment, we can success to transmit large capacity data in a few minutes on the fly.1393 Ultra-High-Speed Satellite Communication Technology