Dual path distance measurement system - uses supplementary measurement signals with slightly different carrier frequencies for high accuracy

摘要

A dual path distance measurement system has an interrogation station transmitting twin-pulse signals with carrier wave having a first h.f. and a responder station transmitting twin pulse response signals with a carrier having second h.f. The difference between transmission time and response reception time at the interrogation station is measured and used for coarse distance derivation. Very high accuracy measurements are obtained. For fine measurements further interrogation and response signals are used with carrier frequencies slightly differing from the main carriers. The difference frequencies bear a harmonic proportionality.