LOCATOR

摘要

A locator such as a ground penetration probe (24) has spaced antennae (21, 22, 23) therein which detect electromagnetic signals from an object (26) such as a buried cable. By analysing the electromagnetic signals using a suitable processor (25) it is possible to determine the separation of the locator and object (26), both in terms of the direction (X) corresponding to the spacing of the antennae (21, 22, 23) and the perpendicular direction (Y) to the object (26). This then permits a display to be generated showing visually the separation of the locator and the object (26). If the locator incorporates a tilt sensor, the processor (25) can then compensate for tilting of the locator, and determine the vertical and horizontal separation of the locator and the object (26). A confidence measurement may be obtained by measuring the separation of the locator and object (26) at one position, predicting the separation of the locator and object (26) at a second position, moving the locator to the second position, measuring the separation of the locator and object at the second position, and comparing the predicted and measured separations.