Magnetic tracking system
First Claim
1. An electromagnetic tracking system comprisinga magnetic field generating unit driven by a drive signal, a field sensing unit having a sensing signal responsive to a changing magnetic field, the generating and sensing units being arranged to generate and to sense, respectively, an electromagnetic field in an arena of interest, and wherein at least one of said units is movable, signal measurement and conditioning circuitry connected to said units to (i) detect the drive signal and the sensing signal, (ii) ratiometrically combine said signals to form a mutual inductance matrix, and a processor operative with the mutual inductance matrix to determine coordinates of the movable unit.
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Abstract
The present invention provides an electromagnetic tracking system that includes a field generator and a field sensor arranged to generate and detect, respectively, an electromagnetic field. Both the transmitter and receiver coils are connected to signal conditioning and processing circuitry to provide outputs indicative of the coil signals. A processor operates on the signals to determine the coordinates of the sensing assembly relative to the generator assembly. The signal processor produces ratiometric outputs, and applies a mutual inductance model to solve for position/orientation coordinates. In some embodiments, a disturber in the form of a conductive ring or a sheath is disposed about an interfering piece of equipment to moderate and standardize disturbances due to eddy currents.
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Citations
8 Claims
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1. An electromagnetic tracking system comprising
a magnetic field generating unit driven by a drive signal, a field sensing unit having a sensing signal responsive to a changing magnetic field, the generating and sensing units being arranged to generate and to sense, respectively, an electromagnetic field in an arena of interest, and wherein at least one of said units is movable, signal measurement and conditioning circuitry connected to said units to (i) detect the drive signal and the sensing signal, (ii) ratiometrically combine said signals to form a mutual inductance matrix, and a processor operative with the mutual inductance matrix to determine coordinates of the movable unit.
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7. An electromagnetic tracking system comprising:
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a magnetic field generating unit configured to generate a magnetic field signal;
a magnetic field sensor responsive to a changing magnetic field, wherein at least one of said magnetic field generating unit and said magnetic field sensor is movable;
signal measurement and control circuitry connected to said magnetic field generating unit and said magnetic field sensor, said signal measurement and control circuitry being adapted to (i) detect the generated magnetic field signal, (ii) detect a magnetic field sensor response signal output by said magnetic field sensor, and (iii) ratiometrically combine the generated magnetic field signal and the magnetic field response signal to form a mutual inductance matrix; and
a processor adapted to determine a position of at least one of said magnetic field generating unit and said magnetic field sensor through the mutual inductance matrix.
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8. An electromagnetic tracking system comprising
a movable magnetic field generating unit driven by a first signal, a movable field sensing unit outputting a second signal responsive to a changing magnetic field; -
signal measurement and conditioning circuitry connected to said units to (i) detect the first and second signals, (ii) ratiometrically combine said signals to form a mutual inductance matrix, and a processor operative with the mutual inductance matrix to determine coordinates of said units.
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Specification