A Satellite Broadcasting Reception System for Ship Using a Two-Axis Antenna Rotating Mechanism

Abstract

For developing a low-cost and simple reception system of satellite-broadcasting on board, an antenna tracking mechanism using a two-axis rotator is desired. On board of the Training Ship "Hokutomaru" (of Institute for Sea Training of Japan) cruising around Honshu and to Ishigaki Island, some receiving tests were carried out and the results are shown as follows. a) Around Ishigaki Island, good television pictures were received by a parabolic antenna of 75cm in diameter on condition of no precipitation, while it has been said that a larger size antenna is required. b) Around Honshu and near-by Okinawa Islands, the present tracking system worked successfully on moderate sea conditions up to rough sea. The results suggest following parameters to design low-cost reception systems. a) A parabolic antenna of 75cm in diameter is recommended practically for ships cruising around Japan proper. b) Two-axis tracking mechanism may be applied, which is able to rotate the antenna faster than 10deg/s. c) On the worse sea conditions than rough sea, hybrid tracking algorithm should be studied, combining informations given by a simple rolling-and-pitching sensor and AGC level of a receiver.