Using the future L-band communication system for navigation

In this paper, we propose to apply the future L-band digital aeronautical communication system not only for communications but also for navigation purposes. In particular, the future communication system might be used as alternative positioning, navigation, and timing means in case other navigation means, e.g. satellite based navigation, are temporally not available due to intentional or unintentional interference. The approach how navigation is achieved using the future communication system is described and first results about the feasibility of this approach are presented. The accuracy of the aircraft positioning estimates turns out to be in the order of 1 to 100 m, depending on the number and geographic distribution of the ground stations used for determining the underlying ranging estimates. Considering the horizontal aircraft position only, an even higher accuracy is achieved, since the ground stations are located at comparable altitude leading to a dominant position error in the vertical component. These promising first results lead to the conclusion that navigation with the future communication system is a very interesting approach for the alternative positioning, navigation, and timing system required as fallback solution for satellite-based navigation.