Aircraft–Receiver Distance Estimation Using ADS-B Signal Strength for Position Verification Application

Estimation of aircraft–receiver distance based on the received signal strength (RSS) of a civil aviation system called the Automatic Dependent Surveillance—Broadcast (ADS-B) was investigated. The estimated distance was intended to be used for position verification, which is a countermeasure against spoofing. A two-step method was proposed in order to mitigate the uncertainty issue regarding the aircraft’s equivalent isotropically radiated power (EIRP), leveraging the regularity of flight schedule. The first step is calibration, where the bias of the EIRP from a nominal value is obtained under the assumption that the ADS-B position is true. The obtained value is stored to be used in the second step, where the distance is estimated when the same aircraft reappears. The proposed method was evaluated with measurement data. As a result, distance errors with a mean of 0.8 km and a standard deviation of 18.6 km were obtained. Also, the resulting error distribution was approximated by a normal distribution.