Method and apparatus for electromagnetic position and orientation tracking with distortion compensation employing modulated signal
US6624626B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 2002 |
| Grant date | Sep 23, 2003 |
| Priority date | — |
| Expiry date | Jun 4, 2022 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A modulated signal (e.g., single tone FM or AM) and DSP spectral and phase analysis is used to enhance the performance of an AC magnetic tracker. The algorithm allows distinguishing between the direct source—sensor response and the response due to eddy currents, thus allowing elimination of effects of the electromagnetic distortion. This, in turn, eliminates the need for a calibration/mapping, which has proven to be the main obstacle for the wide application of AC electromagnetic tracking systems. The new method and system disclosed do not require witness sensors (but may be used in a combination with them), works in a narrow frequency band that ensures noise stability, may have high operation frequencies (e.g., about 50 kHz) that gives high quality of the signal and increased operation range, as well as high solution update rate, performs real time (each frame) distortion compensation without any prior knowledge about physical properties of distorters. At the same time the new system preserves all known advantages of the AC trackers. The approach finds applicability in head tracking systems and helmet-mounted displays for fighter aircraft, head trackers for armored vehicles,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.