AbstractThe effect of the geometricalrelationship between course‐line and ground stations on area navigation errors is analyzed. The analysis is applied to both the RHO/THETA and the RHO/RHO systems. Graphs for determining the along‐course and cross‐course error standard deviations for both systems are presented. The concepts of trading off along‐course precision for cross‐course precision and the selection of geometrically optimal ground station configurations are discussed and illustrated. The results of this paper are of operational value since they can be used to sequence ground station selections and determine the feasibility of existing ground stations to provide area navigation for the traffic patterns of a given geographic