PURPOSE: To stably measure the position of a marine vessel with high accuracy by expressing heaving, rolling, and pitching in a dynamics model expressing state variables as a linear system and combining the observation equations obtained by means of servo type inclined-angle sensors and a servo type acceleration sensor.
CONSTITUTION: Three sensors of two servo type inclined-angle sensors S1 and S2 one servo type accelerometer S3 are positioned to point J on the deck 3 of a marine vessel immediately above the intersection 0 of the rolling axis X-X and pitching axis Y-Y of the vessel so that the measuring axis and sensitive axes of the sensors can intersect each other at right angles. Even when the sensors S1, S2, and S3 are collectively positioned to the T-point, each linear observation equation holds when the centrifugal force is contained in the term corresponding to noise. The dynamics models of heaving, rolling and pitching are prepared by introducing state variables composed of resultant waves of short-period waves and long-period waves to the equations and the outputs of the models are passed through a Kalman filter. Therefore, the attitude of the marine vessel can be detected with high accuracy regardless of the size of the vessel.
KAMAIKE KAORU
TANAKA SHOGO
