Error Response of Distance Measuring Equipment with Trapezoidal Pulses in Case of Multipath Effects and Noise

摘要

The influence of multipath disturbances and noise on precision distance measuring equipment (PDME) for aviation, using trapezoidal pulses, was investigated. Usually DME pulses have curved edges, i.e., cosinus and cosinus squared functions. The PDME system with trapezoidal pulses combined with the delay and compare (DAC) trigger method allows for disturbed pulses to show, especially clearly, the dependence of the trigger error on pulse rise time, on the parameters of the triggering method, and on the disturbance. Since results are also valid for the cosinus-cosinus squared pulse, which is favored for PDME, the design of the PDME pulse and the DAC trigger circuit is affected.