ADS-B is a public interface, an easy target for attack. The US Air Force is actively studying how to add security to ADS-B to ensure that attempts to disrupt military missions are identified and counter attacked. In particular the Air Force is concerned that enemies could add ghost aircraft to congested airspace for the purpose of disrupting C17, C130 and C5 flights that supply troops overseas. The GPS Location Based Authentication (GBLA) technology presented in this document can solve that concern. In addition the Differential Co-Processing techniques to calculate relative position between aircraft can act as a backup to the air-to-air radars currently deployed for operations such as formation flying. The largest military application of GBLA may not be in aviation. GBLA provides military quality GPS authentication without needing a reference copy of the secret military GPS codes. GBLA embedded into a handheld GPS receiver allows that receiver to be built entirely with civilian hardware, drastically reducing the cost of the receivers.
Traffic Flow Management (TFM), Separation Assurance (SA), Super Dense Operations (SDO) and Unmanned Aerial Vehicles (UAV) in the National Airspace all make heavy use of Automatic Dependent Surveillance Broadcast (ADS-B). This proposal presents technology that brings extra capability to ADS-B in the form of unspoofable authentication and a method called differential co-processing that can calculate the relative position between aircraft more accurately than any civilian method today. The potential impact of these capabilities on NASA's NextGen requirements ranges from ADS-B authentication, detection and identification of attacks; to using better relative positions to determine more accurate wind-shear models and enabling precise trajectory modeling during Very Closely Spaced Parallel Approaches (VCSPA). In short, the GPS Based Location Authentication and Differential Co-Processing could change and accelerate the course of NextGen development.