MONITORING SYSTEMS

An aircraft threat monitoring system has several sensors responsive to a potential threat external to the aircraft such as a radar warning receiver, a radar sensor, a missile approach warning receiver, a forward-looking infrared detector and an electro-optic sensor. Each sensor has a respective inference processor the outputs of which are supplied to a groundspace map manager and an airspace map manager. The map managers collate the processor outputs to derive a threat output signal which is supplied to a planner programmed with tactical route information. The map managers also control operation of the sensors such as by modifying their sensitivity, scan or frequency in accordance with the output from other sensors.