Magnetic anomaly detection is a technique used to identify variations in the Earth's magnetic field caused by the presence of objects, such as submarines or unexploded ordnance. By measuring these magnetic field changes, specialized sensors can detect anomalies that indicate the location of these hidden objects. This method is commonly employed in military and environmental applications. It relies on the principle that different materials, like metal, have distinct magnetic signatures. Magnetic sensors are often mounted on aircraft, ships, or ground vehicles to efficiently survey large areas for potential threats or hazards.