Three-axis angle sensor

Claim 1

A three axis sensor for sensing the angular position of a remote body in combination with a transceiver transmitting and receiving light beam signals and a target unit, the whole comprising: (a) a target device adapted to be aligned with said transceiver for attachment to said remote body for receiving and reflecting a light beam from and to said transceiver; (b) said target device including a reflective surface for receiving and reflecting said light beam to and from said autocollimator, an uncoated surface to permit a portion of said light beam transmitted from said autocollimator to pass therethrough, and a polarized surface polarized in a single plane; (c) prism means within said target device for receiving the portion of said light beam passing through said uncoated surface and transmitting it to said polarized surface to produce a polarized light beam for transmission to said polarimeter; (d) pitch and yaw detection means in said transceiver for receiving and examining the light beam reflected from said reflective surface to detect pitch and yaw variations in said target device; (e) roll detection means in said transceiver for receiving and examining said polarized light beam from said polarized surface to detect roll variations in said target device; (f) said roll detection means including a bifurcated analyzing element disposed in the path of said polarized light, said bifurcated analyzing element having contiguous first and second halves whose surfaces have polarization axes tilted with respect to each other whereby equal amounts of light pass through said surfaces when said bifurcated analyzing element is in a null position and different amounts of light pass through said surfaces when a roll movement of said target device with respect to said polarimeter is present; and (g) null adjustment means for rotating said bifurcated analyzing element to a null position to detect the magnitude of roll of said target device with respect to said transceiver.