US Patent 7222433 Electromagnetic inclinometer

An angle sensor comprising a housing (1) having horizontal and vertical axes, which housing is adapted to receive a magnetic core (5) such that the core remains in substantially the same plane, e.g. by floating on a liquid (4). The core is provided with two orthogonal windings (8,18). In use, an electric field is applied across the vertical axis of the housing, which electric field induces a voltage in the windings, wherein the magnitude of the induced field is dependent on the angle of the magnetic core to the horizontal winding.