Pitch, roll or twist angle measurement for ship - using laser interferometry and polarisation measurement via devices mounted on ship

摘要

The pitch, roll or twist angle measurement for a ship uses interferometric measuring for the pitch and roll, each device utilising a laser beam (7) fed through a partially reflecting mirror (16) onto a fully reflecting mirror (17) with the reflected beams being compared, the twist angle measurement effected via a polarisation measurement. Pref. the frequency of the laser beam is determined by a modulator (24), the laser light being provided by a gas laser having a wise coherence length. USE - For compensating radar measurements etc for inherent movement of ship.