Methods to Provide System-Wide ADS-B Back-Up, Validation and Security

A major part of the business case for automatic dependent surveillance-broadcast (ADS-B) is attributed to the savings generated by decommissioning or reducing reliance on conventional radar systems. In order to maintain some form of redundancy, a networked, system-wide back-up and validation approach is required. During the transition to end-state surveillance architectures, there are likely be a mixture of various types of surveillance sources including primary surveillance radar, secondary surveillance radar, multilateration, and ADS-B. This paper describes an integrated approach to the surveillance architecture and one means for facilitating the application of multiple surveillance sources. Surveillance sensor performance is based on the categories defined in ADS-B standards. The relevant parameters are navigation accuracy category (NAC), navigation integrity category (NIC), and surveillance integrity level (SIL). These standards have been adapted to create a generic surveillance performance categorization method. This method would enable air traffic service providers to develop criteria for combining information from multiple surveillance sensors. The categorization also enables a method for defining the associated aircraft separation requirements