DME Errors

Abstract

An analysis of the error components of standard distance measuring equipment (DME) is presented, with emphasis given to the dependence of noise and bias-type errors upon signal strength. The analysis is based upon lab measurements of equipment performance, static transponding experiments, and flight test data. An ARN-84 military TACAN set was used with F. A. A. maintained ground stations in the Northeastern U. S. The largest single error component in the system is found to be the variation from nominal of the average transponding delay in the ground station. This variation produces a mean ranging error which is dependent upon the strength of the interrogating signal; the nature of the dependence is in turn related to the type of equipment used at the ground station. The results of the error component analyses are assessed in terms of the design of accurate positioning systems which use DME.