Electronic marker locator system and method
US6617856B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 2002 |
| Grant date | Sep 9, 2003 |
| Priority date | — |
| Expiry date | Feb 15, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/081
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system and method to locate electronic marker balls includes receiving a signal representative of a detected marker ball. The signal includes the resolved in-phase and quadrature-phase (I and Q) components, each centered about a first frequency. The I and Q components are filtered in order to shift the first frequency to a second frequency and match the second frequency I and Q components to exponential decay characteristics associated with the marker balls. The second frequency I and Q components phase integrated in order to distinguish the components from noise. The integrating is based upon predetermined gain coefficients and produces integrated I and Q components in accordance with the predetermined gain coefficients. Next, a magnitude of the integrated I and Q components is determined to produce an I and Q magnitude vector and a noise variance associated with the magnitude vector is determined. Finally, the recursive coefficients are adjusted in accordance with the determined noise variance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.