Abstract
Exact measurement of heaving, rolling and pitching of ship is important in exact searching for the seabed patterns by a sonar. From this point of view, the authors developed before an automatic measurement system which measures the ship attitude by using three servo-type accelerometers appropriately located on the ship. It generally required, however, much computational time in getting the optimal estimate. This is because the ship attitude signals appear in the accelerometers in a strongly nonlinear form.
The present paper proposes a new automatic ship-attitude measurement system which promises a stable, easy and higher accurate measurement of the ship attitude by using four servo-type accelerometers appropriately located on the ship. For realizing it, adequate linear combinations of the four sensor outputs are considered to separate the three attitude signals from each other.
