Evaluation of a new electromagnetic tracking system using a standardized assessment protocol

Phys Med Biol. 2006 May 21;51(10):N205-10. doi: 10.1088/0031-9155/51/10/N01. Epub 2006 Apr 26.


This note uses a published protocol to evaluate a newly released 6 degrees of freedom electromagnetic tracking system (Aurora, Northern Digital Inc.). A practice for performance monitoring over time is also proposed. The protocol uses a machined base plate to measure relative error in position and orientation as well as the influence of metallic objects in the operating volume. Positional jitter (E(RMS)) was found to be 0.17 mm +/- 0.19 mm. A relative positional error of 0.25 mm +/- 0.22 mm at 50 mm offsets and 0.97 mm +/- 1.01 mm at 300 mm offsets was found. The mean of the relative rotation error was found to be 0.20 degrees +/- 0.14 degrees with respect to the axial and 0.91 degrees +/- 0.68 degrees for the longitudinal rotation. The most significant distortion caused by metallic objects is caused by 400-series stainless steel. A 9.4 mm maximum error occurred when the rod was closest to the emitter, 10 mm away. The improvement compared to older generations of the Aurora with respect to accuracy is substantial.

Publication types

  • Evaluation Study

MeSH terms

  • Austria
  • Biomechanical Phenomena / instrumentation*
  • Biomechanical Phenomena / methods
  • Biomechanical Phenomena / standards
  • Calibration
  • Electromagnetic Phenomena / instrumentation*
  • Equipment Design
  • Equipment Failure Analysis / instrumentation*
  • Equipment Failure Analysis / methods
  • Equipment Failure Analysis / standards
  • Image Interpretation, Computer-Assisted / instrumentation*
  • Image Interpretation, Computer-Assisted / methods*
  • Image Interpretation, Computer-Assisted / standards
  • Physical Examination / instrumentation*
  • Physical Examination / methods
  • Physical Examination / standards
  • Quality Assurance, Health Care / methods
  • Quality Assurance, Health Care / standards
  • Reference Values