Magnetic anomaly detector
From Free net encyclopedia
A magnetic anomaly detector (MAD) is a piece of equipment that is used to detect minute variations in the Earth's magnetic field. Image:RNZAF Orion.jpg
The term refers specifically to magnetometers used either by military forces to detect submarines—such a mass of ferromagnetic material disturbs the magnetic field and can be detected—or to a geomagnetic survey instrument used to search for minerals by the disturbance of the normal earth-field.
To reduce interference from electrical equipment aboard anti-submarine aircraft the 'MAD head' is placed out from the aircraft on a boom or is a towed aerodynamic device. Even so the submarine must be very near the aircraft's position (and close to the sea surface) to detect the change or anomaly. The detection range is normally related to the distance between the sensor and the submarine. The size of the submarine and its hull material composition also determines the detection range. Image:SH-60B Seahawk.jpg MAD devices are usually mounted on aircraft.
For geomagnetic survey work the detector can be mounted on a long probe in front of the aircraft or be a towed device. A chart is produced that geologists can study to determine the location and extent of mineral deposits.
Another, similar use was by the original AC-130A Spectre gunships, which employed the "Pave Mace"/"Black Crow" magnetic anomaly detection system to detect truck ignition coils (hidden in heavy overhead jungles) during the Vietnam War.
See also: Antisubmarine warfarees:Detector de anomalías magnéticas