Importance

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Abstract

A system is disclosed which enables the measurement of the position and orientation of a permanent magnet within a three dimensional region in five degrees of freedom. In order to sense the position and orientation of the permanent magnet, three three-axis antennas are created with each antenna being composed of three mutually orthogonal Hall-effect devices. As is known, Hall-effect devices produce an output voltage proportional to the product of the input current, the magnet flux density and the sine of the angle between the magnet flux density and the plane of the Hall-effect device. The output voltages from the nine Hall-effect devices utilized in the system are inputted into a microprocessor device which first calculates an estimate of the position and orientation of the magnet utilizing a nonlinearized algorithm. Subsequently, the microprocessor uses a linearized algorithm to calculate the precise position and orientation of the permanent magnet. If desired, and in situations where operation is limited to a restricted area, the system may operate utilizing only six Hall-effect devices deployed as two 3-axis antennas. In one example of a system made in accordance with the present invention, operating in an area of approximately one cubic meter, the location of the permanent magnet was updated approximately 100 times per second and the location of the permanent magnet was determined with an accuracy of better than 0.5% in position and 0.5.degree. in orientation.

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First Claim