| 摘要 |
A runway collision avoidance system having warning devices is provided for the safety of aircraft taxiing, taking off, and landing. The system is capable of detecting ground traffic and obstacles including aircraft, maintenance vehicles and wildlife that may encroach upon an active runway during low visibility conditions or when visual observation is impaired. The system includes an electromagnetic transmitter positioned beyond one end of a runway which directs a continuous beam of high frequency radio signals, for example microwaves, longitudinally along the full length of the runway. A plurality of electromagnetic receivers positioned beyond the other end of the runway pick up the transmitted signals and apply them to a balance circuit and then to a comparator circuit. With a clear runway, the transmitted signals are received without interruption and the receiver outputs remain balanced or equal. However, should an obstruction occur on the runway, an attenuation is produced in one or more of the receivers and a warning output is generated by the comparator circuit. The comparator warning output is utilized to activate aural and visual indicators in the control tower as well as warning lights positioned at appropriate points near the runway.
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