Detecting malicious ADS-B broadcasts using wide area multilateration

Automatic Dependent Surveillance Broadcast (ADS-B) is an emerging radio technology capable of extending or replacing current RADAR-based surveillance for air traffic management. However, due to its reliance on unencrypted radio transmissions, ADS-B is exploitable using relatively inexpensive and open source tools. This paper demonstrates how multilateration technique can be applied to detect some types of malicious ADS-B transmissions, based on known GPS errors (used by ADS-B transmitters) and clock precision inaccuracies (used by multilateration systems). As it requires the measurement of radio signal's time of arrival (TOA) at different sensors to calculate the transmitter's location, the placement of those sensors play an important role to determine the accuracy of the estimates. In this direction, this paper also presents a method based on genetic algorithms in order to determine the position of sensors that gives improved coverage and reduced error.