Abstract
Exact measurement of heaving, rolling and pitching of the ship is important in exact searching for seabed patterns by a sonar and also in suppressing the swing of hovercrafts. From these viewpoints, the authors previously developed an on-line automatic ship's attitude measurement system, which used accelerometers appropriately located on the ship. But, having assumed exact knowledge on the rolling axis, the measurement system causes degradation in the measurement accuracy in the case where the rolling axis changes depending on the change of the weight loaded and a wave caused by a big ship sailing nearby.
The paper proposes an on-line ship's attitude measurement system which overcomes the problem. For realizing it, two inclinometers and one accelerometer are effectively utilized, and in the use of the inclinometers the dynamics of the moving elements are taken into account.
