Validation of a fast and accurate magnetic tracker operating in the environmental field

TL;DR

This paper evaluates a magnetoresistor array-based magnetic tracker capable of high-speed, high-precision tracking of a magnetic source in environmental fields, suitable for medical eye-tracking diagnostics.

Contribution

It introduces a fast, accurate magnetic tracking system with a nonlinear fitting method, optimized for medical eye-tracking applications in environmental magnetic conditions.

Findings

High-speed tracking (≥100 Sa/s) achieved with sub-millimetric accuracy.

System demonstrates reliable performance in static and dynamic conditions.

Provides design insights for similar magnetic tracking setups.

Abstract

We characterize the performance of a system based on a magnetoresistor array. This instrument is developed to map the magnetic field, and to track a dipolar magnetic source in the presence of a static homogeneous field. The position and orientation of the magnetic source with respect to the sensor frame is retrieved together with the orientation of the frame with respect to the environmental field. A nonlinear best-fit procedure is used, and its precision, time performance, and reliability are analyzed. This analysis is performed in view of the practical application for which the system is designed that is an eye-tracking diagnostics and rehabilitative tool for medical purposes, which require high speed ($\ge 100$~Sa/s) and sub-millimetric spatial resolution. A throughout investigation on the results makes it possible to list several observations, suggestions, and hints, which will be useful in the design of similar setups.