PERIMETER
PERIMETER (ПЕРИМЕТР) is the integrated national air-defence network of Arvor. It consists of a combination of hardened ground-based and mobile, tactical radar sites supplemented by airbourne early warning and control aircraft and naval vessels, all interconnected by the secure ELEKTRON (ЭЛЕКТРОН) military telecommunications satellite network, which allows both digital data and voice communications to be sent using an encrypted military grade version of the Grid (Сетка, Setka) e-terminal network and processed by the AURORA (АВРОРА) computer system. The system today includes operates 16 monitoring stations using the P-53 Crystal (Кристалл) long-range radar system, which is designed to be resistant to jamming.