Tracer: a voice-frequency relay system for radio navigation aids

A radio-navigation relay system has been developed to monitor and track the position of remote objects such as ships, buoys and balloons. R.f. signals received from a chain of radio-navigation transmitters are converted to an audio frequency and limited in amplitude in a simple low-cost converter unit. The audio output, which retains the position information contained in the initial navigation signals, may be telemetered over conventional voice-frequency radio-telephone or land line networks to a receiver/decoder station. The design principles are described and the results of field trials presented together with proposals for further applications such as marine collision avoidance, pilotage and radio navigation chain stability monitoring.