SBIR-STTR Award

This proposal supports F20 A3.01 - Advanced Air Traffic Management Systems Concepts; Technology Area TA15 : Aeronautics - specifically, independent verification and validation of Aircraft ADS-B transmissions. Safely achieving full autonomy and higher density in the NAS requires that the position of every aircraft in a given airspace be known to all participants in that airspace with a very high level of integrity. GNSS (including GPS) and ADS-B can provide sufficient aircraft-to-aircraft accuracy, but the inherent vulnerabilities of GNSS and ADS-B to interference, jamming and spoofing require that GNSS and ADS-B systems be independently validated for accuracy. The ATCRBS (Air Traffic Control Radar Beacon System), based on ground-based radar interrogation of transponders, provides redundant position information in many situations. Where position information from both ADS-B and ATCRBS exists, it can be compared for purposes of verification and validation.) Valid position information needs to be available real time for an autonomous system to provide safe navigation, particularly for collision avoidance. . This proposal will develop a flexible, multi-lateration system that easily integrates the ATCRBS capability of position information into modern avionics designed for ADS-B as well as transponders. This allows redundant independent verification of the location all equipped aircraft in all airspace. The proposed approach can effectively provide high integrity aircraft location information that can be used for navigation and T-CAS safety functions based on aircraft-to-aircraft ADS-B data, significantly reducing usage of the transponder spectrum. Potential NASA Applications Independent Validation of GPS and ADS-B will enable trusted use of ADS-B and allow much higher density use of all airspace for UAS and air transport vehicles. The same techniques can be applied to ground based and space based vehicles for other applications. Potential Non-NASA Applications Virtually all air vehicles worldwide can make use of this approach to validation of an aircraft position. It is a needed capability for the military and DHS for validation that vehicles in the airspace are where they say they are. Important for police and all emergency vehicles in the airspace as well.

For safe navigation and collision avoidance during autonomous UAS operations, where UASs are directed by onboard flight management systems, valid/trusted position data must be available and processed in real-time for safety of flight and mission effectiveness. The desired result from this SBIR project is a multi-functional avionic system that is small and lightweight enough to be used on small UASs (sUASs), and capable of functioning with both the traditional ATCRBS/transponder position reporting system and the GPS-based ADS-B position reporting system. It will have to transmit and receive on both ADS-B frequencies and be capable of responding with standard 1090 MHz Mode A/C information to interrogations from ATCRBS and TCAS. A highly desirable feature will be the ability to interrogate cooperative (transponder equipped) aircraft in “blind airspaces” where ATCRBS cannot reach. This interrogation would primarily be intended for avoidance of collisions and could be relatively low power and short range while providing information to a pilot (onboard or remote) in time to avoid a midair collision. Finally, because this system will mostly be used on sUASs and small GA aircraft, a low-cost design is highly desired. This SBIR demonstrates that advanced development of software defined radios (SDRs) has produced highly capable, multifunctional, miniature avionics suitable for all aircraft, including small UAS, and addressing the concerns and weaknesses of both ATCRBS and ADS-B position reporting systems. A side-benefit attributed to this micro-avionic system is reduced usage of the transponder spectrum, responding to the concerns of overcrowding 1090 MHz spectrum. Potential NASA Applications (Limit 1500 characters, approximately 150 words) The validation of aircraft ADS-B signals (and the position information derived from on-board GPS systems) for both manned and unmanned aircraft is critical to maintain the safety of the airspace. All NASA vehicles in or entering the airspace need to be assured that the position of all platforms is known with a very high integrity. This system can be used both on platform, or from a local ground station to assure the position of all platforms is correct. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) The validation of aircraft ADS-B signals (and the position derived from on-board GPS systems) for both manned and unmanned aircraft is critical to maintain the safety of the airspace. All vehicles need to be assured that the position of all platforms is known with a very high integrity. This approach enables fully autonomous operation in those situations it is required.