| 摘要 |
<p>A guidance system for a drill tool (60) comprising a primary navigation package (80) and a secondary navigation package (74). The primary navigation package contains a triaxial magnetometer and a triaxial accelerometer. The set of signals produced by the triaxial magnetometer and triaxial accelerometer are manipulated to determine the orientation of the drill tool and, by integration over the distance the drill tool has traveled, the approximate position of the drill tool during a directional drilling operation. The secondary navigation package contains a magnetic dipole antenna for emitting an electromagnetic dipole field. Using a locator (100), an operator can periodically determine the actual drill tool position by detecting the electromagnetic dipole field. The actual position of the drill tool as determined by the secondary navigation package is used to correct for an integration error that is introduced into the drill tool position by the navigation technique used by the primary navigation package.</p> |
