Patent ID: 9194978
Filing Date: 2015-11-24
Classification: G01V

Abstract:
1. A locator for determining a depth of a buried electromagnetic marker, the locator having a major axis and being configured to be used with the major axis substantially perpendicular to a ground surface, the locator comprising: a transmission antenna configured to generate an oscillatory magnetic field parallel to the major axis, a first reception antenna configured to couple with an oscillatory magnetic field parallel to the major axis emitted by the electromagnetic marker and to generate a first detected signal, a second reception antenna displaced along the major axis from the first antenna and configured to couple with an oscillatory magnetic field parallel to the major axis emitted by the electromagnetic marker and to generate a second detected signal, a first analogue to digital converter configured to generate a first digitised signal from the first detected signal, a second analogue to digital converter configured to generate a second digitised signal from the second detected signal, and a processor configured to calculate the depth of the electromagnetic marker from the first digitised signal and the second digitised signal, wherein the transmission antenna generates the oscillatory magnetic field having the target frequency for a first time interval and the first reception antenna is prevented from generating the first detected signal and the second reception antenna is prevented from generating the second detected signal for at least the first time interval.