An analysis of an experiment to determine the precision, the effects of varying amounts of environmental data, and the feasibility of the use of historical environmental data at the NAVTORPSTA, Keyport, Washington, Dabob Bay facility is presented. The analysis verifies and extends the results of a preliminary investigation of the experimental data. The experiment consisted of tracking a 75-kHz source at six depths at each of six horizontal ranges. The data were analyzed using an isogradient ray-tracing program. The results showed that the precision of the range position as determined by the ranging system is dependent only on the rise-time of the 75kHz signal that the use of less environmental data and historical data as the environmental input for position calculations have been shown to cause only a minor degradation in the accuracy of the ranging system.