Measurement of linear acceleration for inertial navigation - uses polarisation interferometer with ultra-sensitive ellipsometer to determine direction and magnitude of acceleration

摘要

Precise measurement of linear acceleration is required for inertial navigation. These measurements are obtained by combining a polarisation interferometer with an ultra sensitive ellipsometer. Variations of ellipticity are translated into movement of a mirror and then into acceleration. A separating cube (2) and two mirrors (3, 4) comprise an interferometer. The cube and one mirror (3) are attached to the housing (5) in turn attached to the housing (5) inturn attached to the accelerating mass (c). A test mass (6) is attached to the housing by a thin thread (7). A laser source (1) provides light for the interferometer whose output is directed to the ellipsometer (17). This laser source is common to three accelerometers to give direction of acceleration.