Flight Test Results of Separation Assurance Methods for Joint Manned and Unmanned Aircraft Operations Using GNSS Measurement-Based ADS-L

This paper discusses a precise relative navigation and separation assurance system based on the exchange of Global Navigation Satellite (GNSS) measurements via new message types for Automatic Dependent Surveillance–Light (ADS-L). A measurement-based ADS-L implementation, which transmits raw measurements from the GNSS receiver rather than aircraft state vectors and performance parameters, is utilized to improve surveillance performance and add integrity to the surveillance solution. Furthermore, recent flight tests with one manned aircraft and two UASs are discussed, and the benefits of using GNSS measurement-based ADS-L data for separation assurance as opposed to traditional methods are reviewed.