ONBOARD TRACKING BY LOW-SPEED AZ-EL MOUNT ROTATOR

Direct broadcast and meteorological satellites transmit many programs to a wide area, including the Japanese coastal seas. The authors have developed a tracking mechanism based on a low-speed two-axis rotator f or merchant ships and have established an algorithm for a low-speed tr acking mechanism. The required performance of a two-axis-type steering antenna is examined. The apparatus is composed of an inexpensive two- axis rotator, a clinometer, and a personal computer, and directs the a ntenna to the calculated satellite direction. The apparatus was instal led on the Hokuto Maru (5856 GT), which belongs to the Institute for S ea Training, Ministry of Transport, for testing during ocean cruises. It has been working almost perfectly for 3 years. The values measured by the apparatus show that the nominal radiation patterns of BS-3a, JC SAT-2, Superbird-B, and GMS are almost entirely consistent. (C) 1998 S cripta Technica.