Abstract: In a preferred embodiment, an apparatus for detecting the angular position, rotational speed, and/or acceleration of a rotatable member, including: an annular magnetic source circumferentially disposed on the rotatable member and rotatable therewith; a directional magnetometer having a toroidal core, disposed at a location in proximity to the magnetic source, with the rotatable member passing through the toroidal core, the directional magnetometer being oriented so as to detect the amplitude and/or change of amplitude of only a tangential magnetic flux field component of the magnetic source, and to provide outputs indicative thereof; and apparatus to receive the outputs and to determine therefrom the angular position, rotational speed, and/or acceleration of the rotatable member.

Abstract: A method of determining the angular position, rotational speed, and/or acceleration of a rotatable member, including: providing on the rotatable member an annular magnetic source generating tangential, radial, and axial magnetic flux field components; detecting, with a directional magnetometer having a toroidal core and two secondary output windings thereon, at a location radially spaced from the magnetic source, in proximity to the magnetic source, the amplitude(s) and/or change of amplitude(s) of one or more of the magnetic flux field components, and providing outputs indicative thereof; modifying the outputs, to equalize measured peak amplitudes of the magnetic flux field components and/or to compensate for environmental distortion thereof, by one or more methods selected from the group consisting of: (1) orienting the toroidal core such that the toroidal core lies in a plane at an angle between the plane of the annular magnetic source and a plane perpendicular to the plane of the annular magnetic source,