US 12,274,515 B2
Electromagnetic position measurement system with sensor parasitic loop compensation
Westley S. Ashe, Hinesburg, VT (US); and Georg Brunner, Constance (DE)
Assigned to Northern Digital Inc., Waterloo (CA)
Filed by Northern Digital Inc., Waterloo (CA)
Filed on Dec. 1, 2023, as Appl. No. 18/526,566.
Application 18/526,566 is a continuation of application No. 17/345,901, filed on Jun. 11, 2021, granted, now 11,883,115.
Claims priority of provisional application 63/037,868, filed on Jun. 11, 2020.
Prior Publication US 2024/0108418 A1, Apr. 4, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. A61B 5/00 (2006.01); A61B 5/06 (2006.01); A61B 34/20 (2016.01); G01V 3/10 (2006.01)
CPC A61B 34/20 (2016.02) [A61B 5/062 (2013.01); G01V 3/10 (2013.01); A61B 2034/2072 (2016.02)] 19 Claims
OG exemplary drawing
 
15. A method comprising:
receiving, at a processing device from a sensor configured to generate a sensor electromotive force (EMF) that measures a magnetic field that is generated by a magnetic field transmitter, a first measurement for a first operating mode in which the sensor generates the sensor EMF when receiving the magnetic field, the first measurement representing the sensor EMF and a parasitic EMF of an interconnecting circuit, wherein a switching device in parallel with the sensor is in a high impedance state in the first operating mode;
receiving, at the processing device from the sensor, a second measurement for a second operating mode in which the sensor generates a reduced sensor EMF when receiving the magnetic field, the second measurement representing the parasitic EMF and the reduced sensor EMF, wherein the switching device is in a low impedance state in the second operating mode, wherein the second operating mode comprises a direct current (DC) component having a value that exceeds a threshold value to saturate a core of the sensor;
comparing, by the processing device, the first measurement and the second measurement, wherein comparing the first measurement and the second measurement comprises determining a change an impedance of the interconnecting circuit in the second operating mode relative to the impedance of the interconnecting circuit in the first operating mode; and
based on comparing the first measurement and the second measurement, determine an approximate value of the sensor EMF.