Non-contacting angular encoder for determination of relative orientation of two reference frames attached compliantly

Abstract

A method within an electromagnetic sensing system including transmitting first, second and third reference signals from first, second and third transmitter coils, the coils having different dipole moment directions and forming a first transmitter coil set; reading the reference signals at each of a plurality of spaced sensors within a sensor chassis, where the sensor chassis moves independently from the first transmitter coil set, the reference signals having sinusoidal time variation and being harmonics of a base frequency with a period being an epoch, an origin of which is a time at which the reference signals are all at zero phase; synchronously stacking signals read by each sensor, creating a stacked signal for each of the sensors; processing the stacked signal for each sensor to create a matrix of complex coupling coefficients; and using the matrix to determine a relative orientation of the sensor chassis to the transmitter coil set.