Device for quantitatively measuring the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields

A device for quantitatively measuring the relative location and orientation of receiving antennae with respect to transmitting antennae in the presence of metals utilizing direct current magnetic fields, comprising:

• (a) Transmitting means for transmitting direct current magnetic fields sequentially on three orthogonal axes no more than two at a time;
• (b) Receiving means for receiving said transmitted direct current magnetic fields;
• (c) Means for supplying direct current electrical signal pulses to said transmitting means for creating said transmitted direct current magnetic fields;
• (d) Means for controlling circuit elements of said transmitting and receiving means, measuring received signals, and converting output signals from said receiving means into location in three coordinate directions and orientation about three coordinate axes measurements.

A system for quantitatively measuring the position of magnetic field sensor means with respect to magnetic field transmitter means, comprising:

• transmitter means consisting of at least two magnetic field transmitter elements to generate a corresponding number of aparallel DC magnetic field vectors;
• drive means for sequentially supplying said transmitter elements with DC pulses to generate said aparallel DC magnetic field vectors;
• magnetic field sensor means consisting of at least two magnetic field sensor elements differentially responsive to said magnetic field vectors generated by the said transmitter elements;
• the arithmetic product of the number of transmitter elements and the number of sensor elements being not less than the number of degrees of freedom to be measured;
• means for compensating for the effects of the earth's magnetic field;
• means operable to effect executive control of the said drive means and of the said compensating means and to compute from signals derived as a result of such executive control the relative position of the magnetic field sensor means with respect to the said magnetic field transmitter means.