1
Ernest B Blood: Device for quantitatively measuring the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields. Ascension Technology Corporation, Davis Bujold & Streck, July 31, 1990: US04945305 (472 worldwide citation)

A device for measuring the position (location and orientation), in the six degrees of freedom of receiving antennae (3) with respect to transmitting antennae (2) utilizing pulsed DC magnetic signals. The transmitting and receiving components consist of two or more transmitting antennae of known loca ...


2
Ernest B Blood: Device for quantitatively measuring the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields. Ascension Technology Corporation, Anthony G M Davis, Michael J Bujold, John J Welch Jr, July 18, 1989: US04849692 (330 worldwide citation)

A device for quantitatively measuring the relative position and orientation of two bodies in the presence of metals via measuring the position and orientation of receiving antennae with respect to transmitting antennae utilizing direct current electromagnetic field signals is hereby disclosed. The t ...