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6DOF electromagnetic tracker construction (edit)
Revision as of 02:30, 27 February 2025
, 27 Februaryno edit summary
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* [[6DOF_Electromagnetic_Tracker_Signal_to_Noise_Requirements_Calculation]] details calculating signal-to-noise ratio (SNR) from accuracy requirements.
* [[6DOF_Electromagnetic_Tracker_Signal_to_Noise_Requirements_Calculation]] details calculating signal-to-noise ratio (SNR) from accuracy requirements.
+==Hemisphere ambiguity==
* There is an inherent hemisphere ambiguity, since receiver at position = (Xo,Yo,Zo) and receiver at position = (-Xo,-Yo,-Zo) show identical HFluxPerIMeasured for identical orientations. This ambiguity can be resolved by using additional transmitter or receiver coils spaced away from the colocated transmitter or receiver coils.
* There is an inherent hemisphere ambiguity, since receiver at position = (Xo,Yo,Zo) and receiver at position = (-Xo,-Yo,-Zo) show identical HFluxPerIMeasured for identical orientations. This ambiguity can be resolved by using additional transmitter or receiver coils spaced away from the colocated transmitter or receiver coils.
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* The transmitter field on the unused side of the transmitter, can be eliminated by using a magnetic mirror: Reference expired [[U.S. patent 5,640,170]], which references many older expired EM-tracker patents.
* The transmitter field on the unused side of the transmitter, can be eliminated by using a magnetic mirror: Reference expired [[U.S. patent 5,640,170]], which references many older expired EM-tracker patents.
+==Accuracy==
* Accuracy is poor for lined-up pose: receiver positioned on a transmitter-coil axis, with receiver oriented to make receiver-coil axes parallel with transmitter-coil axes. Some of the first-order partial derivatives go to zero in these cases, causing the position-and-orientation solution to separate into four separate partial solutions.
* Accuracy is poor for lined-up pose: receiver positioned on a transmitter-coil axis, with receiver oriented to make receiver-coil axes parallel with transmitter-coil axes. Some of the first-order partial derivatives go to zero in these cases, causing the position-and-orientation solution to separate into four separate partial solutions.