Navigation Needs for the Unpiloted Airspace

The paper discusses the challenges of providing resilient navigation services to Advanced Air Mobility (AAM) and Uncrewed Aeronautical Systems (UAS) in various types of environments in, around and above urban areas. The analysis shows that at least three different types of urban/suburban environments are relevant, and the paper proposes a criterion to distinguish them, based on how much surrounding buildings influence radio propagation in a particular volume. Finally, the paper also proposes pathways to solving the foreseeable problems with three concepts that will enable higher navigation accuracy in urban environments: a low-power terrestrial navigation aid based on multifunction communication systems, a GNSS augmentation service with reduced time-to-alert, and a landing system for AAM aircraft drones in urban environments.