Method for decoupling interference due to bleedover in metallic pipe and cable locators
US7057383B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 2004 |
| Grant date | Jun 6, 2006 |
| Priority date | — |
| Expiry date | Nov 13, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/088
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
When cables run side by side over a longer distance, an alternating-current signal used for cable location can couple or ‘bleedover’ to neighboring cables. The coupled current flowing in the neighboring cable creates field distortion and makes position determination of the targeted cable difficult. The resulting magnetic field of both (or more) cables has a non-circular shape and is commonly known as a distorted field. Established methods for finding the position of the cable under investigation lead to inaccuracies or even wrong locates. The method described herein eliminates the field distortion that is due to the coupled cables by demodulating a phase reference signal placed on the cable by a transmitter into two signal strength constituents. The inphase signal represents the field strength of the targeted conductor and is substantially free of field distortion. The other quadrature signal contains the component of the field associated with distortion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.