Communications and broadcasting engineering test satellite (COMETS): Experimental results

The results of Ka-band and millimeter-wave mobile satellite communications experiments and 21-GHz satellite broadcasting experiments using the Communications and Broadcasting Engineering Test Satellite (COMETS) is described. The launch of COMETS on 21 February 1998 failed due to premature shut down of the second-stage engine of the H-II launch vehicle. Communications and broadcasting experiments were nonetheless made possible by maneuvering COMETS into a highly inclined elliptic orbit. As mobile satellite communications experiments, propagation measurements for land-mobile and aeronautical satellite communication channels, the bit error performances measured in a land-vehicle and an aircraft using several types of modems, the performance of a COMETS on-board regenerative transponder, and rain attenuation measurements in Asia and Pacific countries were carried out. As satellite broadcasting experiments, high definition TV transmission experiments using a trellis coded 8-PSK modulation technique, multiple-channel HDTV transmission over ATM, and TCP/IP connection of workstations over ATM were carried out.