HELICOPTER SATELLITE COMMUNICATION SYSTEM, HELICOPTER-MOUNTED COMMUNICATION APPARATUS, TERRESTRIAL STATION COMMUNICATION APPARATUS, COMMUNICATION METHOD, AND COMPUTER PROGRAM

摘要

A helicopter-mounted communication apparatus (200) of a helicopter satellite communication system (1) encodes video data at a compression rate based on a ratio of a time for which a transmitted beam is interrupted by the rotary wings. When the number of video packets is less than a predetermined number, the helicopter-mounted communication apparatus (200) inserts null packets to keep the packet rate constant. The helicopter-mounted communication apparatus (200) then deletes the null packets and adds, to another packet, additional information indicating the number of the deleted null packets. After buffering, the helicopter-mounted communication apparatus (200) modulates and transmits the signal toward a communication satellite (300) at timing when the transmission is possible. A terrestrial communication apparatus (100) receives the signal, which was transmitted from the helicopter-mounted communication apparatus (200), via the communication satellite (300) and demodulates the received signal, thereby generating a packet sequence. The terrestrial communication apparatus (100) inserts, on the basis of the additional information included in the generated packet sequence, the null packets to the packet sequence and buffers the packet sequence, thereby keeping the packet rate constant. The terrestrial communication apparatus (100) then separates the video packets from the packet sequence and decodes the separated video packets.