Method and apparatus for precisely locating a buried utility conveyance
US5644237A · kind A · utility
134Cited by
17References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1995 |
| Grant date | Jul 1, 1997 |
| Priority date | — |
| Expiry date | Sep 27, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An underground utility conveyance (10) may be precisely located by impressing both a locating tone and a confirmation tone on the conveyance. The locating tone is an RF signal that produces a first field that radiates above the earth that is sensed by a first, above-ground signal detector (22) to establish the general location of the conveyance. The confirmation tone is a near-DC signal that produces a second, field having a relatively limited radiation path. A second detector (24) is inserted into the earth at successive places in the region where the conveyance is located to establish its precise location.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.