Kalman filter

Motion of high frequency and relatively low amplitude do not need to be compensated by the DP systems. Such motion is the result of first order wave loads. In order to remove those wave frequency components from the position and heading measurements and estimated velocities, we use Kalman filter. The signal is filtered and then passed to the controller.

Having the DP system trying to compensate those wave-frequency motions would result to unnecessarilly high power compasation and potential wear of accuators.

[Figure of filtered and unfilltered signal]