Final answer:
The perimeter security fences of the airport, defined in the Aerodrome Security Regulation, are integral to airport security, designed to enclose and protect sensitive areas within airports from unauthorized access and security threats.
Step-by-step explanation:
The question refers to the perimeter security fences of the airport, which are crucial components of airport security infrastructure as defined in the Aerodrome Security Regulation. These fences are designed to protect the airport's sensitive areas, including runways, hangars, and passenger terminals, from unauthorized access and potential security threats. Within these perimeters, highly advanced security systems are utilized, such as security gates that are capable of detecting metals and determining their approximate height above the ground level.
Elaborating further, the effective air defense perimeter, with an estimated radius of 30 nautical miles, exemplifies the strategic implementation of security measures for protecting the airspace surrounding the airport from threats such as surface-to-air missile (SAM) sites. These perimeters ensure that both the airport's ground facilities and surrounding airspace are secured against unauthorized intrusions, providing a safe environment for airport operations and air travel.