ADS-B space-oriented message set design

Abstract

This paper designs, simulates, and tests a potential Automatic Dependent Surveillance-Broadcast (ADS-B) space-oriented message set to improve situational awareness of commercial space vehicles inside the National Airspace System (NAS), and to minimize their impacts and potential hazards on the NAS. ADS-B is considered as the solution to integrate the future commercial space transportation system with the air transportation system. To accommodate future space flight operations in the NAS, a potential ADS-B space-oriented message set is proposed to be exclusively transmitted from space vehicles to other traffic and air traffic controllers. New data fields are defined in the message set to cover a space vehicle's entire flight profile. The formats of these new data fields are demonstrated in details. A simulation is created containing space vehicle and aircraft trajectories to test the functionality of the ADS-B space-oriented message set. The message set is encoded at the space vehicle site, transmitted from space vehicle to aircraft via the Universal Access Transceiver (UAT) datalink, and decoded at the aircraft site. The simulation eventually reaches a conflict scenario. By using the Closest Point of Approach (CPA) algorithm, the aircraft analyzes its own state vector and the space vehicle's state vector decoded from ADS-B messages to perform conflict detection. Sensitivity studies are conducted based on the CPA algorithm concentrating on three ADS-B system parameters, which are message update rate, data latency, and state vector accuracy.