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.