A detection system is provided for detecting entry of a target object into a protected area. The detection system includes a control unit and a search coil assembly comprising a plurality of search coil units in electronic communication with the control unit and extending continuously around a perimeter of the protected area to define a detection zone. The plurality of search coil units each comprise a transmitting coil and a receiving coil, wherein the transmitting coil is adapted to transmit an electromagnetic signal of a predetermined value, and the receiving coil is adapted to receive the electromagnetic signal, thereby generating an electromagnetic field. The control unit is configured to identify and initiate an emergency response condition in response to variations in the electromagnetic field corresponding to entry of the target object into the protected area via the detection zone.