ADS-B vulnerabilities and a security solution with a timestamp

Automatic Dependent Surveillance-Broadcast (ADS-B) is the foundation of NextGen Air Traffic Control (ATC) system, and all aircraft must be equipped with it by January 1, 2020. Despite the importance of ADS-B, it has been developed without security considerations and is subject to various types of attacks. A trustworthy ADS-B system will make the NextGen system more reliable and make air transportation safer. But current safety measures are inadequate and many research proposals are not yet practical or cost-effective. We developed a practical method that can reject virtually all spoofed ADS-B messages by monitoring the signal propagation time between senders and receivers. To measure the actual propagation time, the method uses a small timestamp value; hence, we call it "ADS-B with Timestamp" (ADS-BT). ADS-BT monitors the discrepancy between the time of flight based on the timestamp values and the time of flight based on the location data. In spoofed ADSB messages, the discrepancy between the two diverges over time, which allows us to identify spoofed ADS-B messages accurately.