Analysis of the Effectiveness of Counterpoise on DME Signal Coverage

Associated VOR and DME systems (VOR/DME) is an international recognized standard civil navigation aid system, as component of VOR station, the purpose of implement counterpoise is to reduce vertical terrain radiation attenuation below the counterpoise horizon. In case of associated VOR/DME station operation, whether the counterpoise is making influence on DME signal coverage performance is of concern. In this paper, equivalent modeling and simulation are established to analyze the shielding performance of counterpoise in the frequency range of 100MHz~1200MHz. By setting parameters of counterpoise as variable, its corresponding shielding performance relative to frequency is studied, and for common sized counterpoise, the shielding performance corresponding to VOR and DME frequency band is discussed in particular. A case study is further introduced by analyzing the DME signal coverage performance when DME antenna relocation is involved, and whether the counterpoise is contributing to signal coverage performance is discussed.