M-TAV: Multi-tiered ADS-B Validation (passive)

Sagetech Avionics is a privately funded, SBA-certified HUBzone small business incorporated under Delaware statutes. Sagetech Avionics’ headquarters, engineering design office, technical support, and production facilities are located at 317 W. Steuben St., Bingen, WA 98605. Onsite production includes final assembly, test, and validation of all avionics products.  Traditional collision avoidance systems utilize active surveillance to validate ADS-B position reports received from nearby aircraft. The FAA requires ADS-B position data to be validated when used as an input to a collision avoidance system. This ensures the data is accurate and mitigates some of the vulnerabilities of ADS-B, such as spoofing.  Without validation the spoofed or faulty ADS-B messages could cause an aircraft to change course when responding to an undesired advisory and result in unnecessary and even dangerous maneuvers.?? Commercially, the need to validate ADS-B has been met with either an active surveillance solution or a radar. The active surveillance solution interrogates the transponder providing the ADS-B message and based on time to receive a reply the system calculates the slant range to validate the ADS-B data. The radar transmits a signal and then listens for the reflected radar return to measure slant range to validate the ADS-B data.   Active surveillance and a radar are not appropriate for EMCON (Emissions Control) operations as they require high power RF transmissions. Sagetech has developed a concept for a Multi-Tiered ADS-B Validation (M-TAV) approach that can meet the passive reception needs of the Navy. The M-TAV system functionality uses one or more of the following techniques to validate ADS-B messages:? RSS - Received Signal Strength (Power) on Arrival Difference Diversity Antennas Azimuth Estimation Using Time, Phase and/or Amplitude Differences Between Antennas Doppler Effect Sagetech plans to partially implement the M-TAV system and perform a series of experiments to demonstrate passive validation of “ADS-B In” by correlating changes in reported separation (range) with changes in received signal strength. This testing will be performed first using a ground-based system then through flight tests with the system installed on an aircraft contracted by Sagetech.? The system will include the Sagetech MX and ACAS X prototype units with software modifications.  Sagetech’s MXS ADS-B receivers are TSO certified and are utilized commercially by many customers including DoD, so are TRL 9.  The ACAS X prototypes have been successfully utilized in numerous labs, aircraft flight trials and in commercial flight operations and are TRL-8.  The high TRL of the complete prototype solution will ensure the demonstration will not be affected by underlying system issues.