Embodiments described herein relate to a device and method for detecting metal and other ferrous and non-ferrous objects, and, in particular, to a device and method for detection of objects using electromagnetic sensing as well as ambient magnetic field detection.
Various techniques have been developed for sensing ferrous and non-ferrous objects, such as unexploded ordnances (UXO), on or under the ground. One of these techniques involves the use of a magnetometer to detect the distortion of an ambient magnetic field caused by ferrous objects. Another technique involves the active use of an electromagnetic field transmitter and an induction sensor, using the transmitter as an electromagnetic pulse generator and reading the inductive response of nearby objects using the sensor. Each of these techniques has strengths and drawbacks: while a magnetometer is effective at a relatively great distance, a pulse induction sensor is more adept at sensing closer, smaller objects and at sensing non-ferrous objects.
As each of the two techniques have different advantages and disadvantages, it is desirable to use both techniques to survey an area.