Passive system for navigational aids performance monitoring

A novel approach for independent performance measuring of ground-based navigational aids network is presented. A passive system includes three software defined radios and processing equipment. System is grounded on synchronous receiving of interrogation signals from on-board equipment of airplane and reply signals from navigational aids for performance analysis. Also, system includes one-channel radio for receiving air traffic data obtained from decoded messages of Automatic Dependent Surveillance-Broadcast. System supports measurements of interrogation rate, reply efficiency, and other parameters of navigational signals. A demonstration shows that proposed system can be used for measuring an interrogation rate and reply efficiency of distance measuring equipment within the ground network that helps to estimate workload of the navigational aids network.