Abstract: A terminal to be installed in a machine having rotor blades in a communication system in which the terminal and a base station transmit and receive data via a relay station to and from each other, includes a rotor blade state monitoring unit that monitors a rotor blade state by measuring the timing at which the rotor blades block a communication path in midair between the relay station and the terminal, and a transceiver that transmits the rotor blade state to the base station and transmit the data using radio resources allocated by the base station.

Abstract: An antenna apparatus 100 includes: antenna units 30A and 30B arranged in a row and including: antennas 1A and 1B for receiving a radio wave from a satellite and generating received signals, and antenna drives 3A and 3B for changing an orientation direction, which is a direction in which the antennas 1A and 1B are directed; a direction command value generator 5 for generating a direction command value, which is a command value transmitted to the antenna drives 3A and 3B, so that the orientation direction matches a direction in which the satellite exists; a phase difference calculator 4 for calculating a phase difference, which is a difference between phases of the received signals generated by the antennas 1A and 1B; and a signal combiner 40 for combining the received signals on the basis of the phase difference.

Abstract: An axial-discrepancy amount calculating section 21 calculates discrepancy amounts between an azimuth angle and an elevation angle of a satellite 9 in the mobile object-fixed coordinate system computed by a satellite direction computing section 19 and an azimuth angle and an elevation angle of an antenna in the gimbal coordinate system detected after the antenna is directed by a peak direction drive controlling section 12 to a direction in which a peak received signal is given, and then commands an axial-discrepancy amount correcting section 20 to change the axial discrepancy amount.

Abstract: An axial-discrepancy amount calculating section 21 calculates discrepancy amounts between an azimuth angle and an elevation angle of a satellite 9 in the mobile object-fixed coordinate system computed by a satellite direction computing section 19 and an azimuth angle and an elevation angle of an antenna in the gimbal coordinate system detected after the antenna is directed by a peak direction drive controlling section 12 to a direction in which a peak received signal is given, and then commands an axial-discrepancy amount correcting section 20 to change the axial discrepancy amount.