Flux plane locating in an underground drilling system

摘要

A portable locator and method are described for tracking the position of a boring tool and/or one or more buried lines within a region. In tracking a boring tool, a flux plane may be used to establish a flux vector as at least an intermediate step in guiding an operator of the portable locator to one or both locate points seen in the boring tool dipole locating field. The horizontal flux vector is used in determining a predicted locate point position. Locating of a locate line in the dipole locating field is performed by determining a predicted locate line angular orientation that is based upon horizontal flux vector determinations. The predicted locate line angular orientation, at least to an approximation, limits the possible directions to and orientations of a predicted locate line relative to the particular orientation of the portable locator at the above ground point. Cable line locating is performed by measuring a local flux intensity of the locating signal at a first above ground point within the region using a portable locator in a particular orientation. A cable line angular orientation is established which limits the possible directions to the cable line relative to the particular orientation of the portable locator. The portable locator display is configured for periodic updates such that displayed positional relationships are essentially continuous, including accommodation of positional and/or orientation changes seen by the portable locator in dipole or cable line tracking.