Multipath tolerant ranging and data transfer techniques for air-to-ground and ground-to-air links

This work addresses data acquisition problems associated with an improved air traffic control system. A mathematical theory of scattering which describes the multipath process is developed. From this model, the optimum signal structure required for ranging and communicating data through the multipath propagation medium is derived. It is shown that the Reed-Solomon Codes have near optimum properties for ranging and data communications. A baseline data transmission system for air traffic control is designed which will accommodate 4000 aircraft per second at the rate of 100 bits per second in a 60 by 120 mile area. The baseline system combines coding with frequency hopping as the best means of combating severe multipath interference. Several coding systems are compared and curves relating error rate to Eb/N0(signal-to-noise energy per bit) for a channel characterized by Rayleigh fading are presented. This paper concludes that a ground-to-air and air-to-ground high capacity data link at a reasonable cost will be feasible for an improved air traffic control system.