Modern air traffic management systems (ATMs) depend heavily on the positioning, navigation, and timing provided by the Global Navigation Satellite System (GNSS). Because the GNSS signals are susceptible to interference, an alternative navigation system is needed to maintain normal aircraft and ATM system operation in the event of GNSS failure. In this study, the frequency difference of arrival positioning (FDOA) of real-world automatic dependent surveillance broadcast signals transmitted from aircraft were used to perform alternative navigation based on a wide area multilateration testbed. According to the simulation results, the measurement quality and geometric distribution of ground stations considerably influence the positioning performance. Moreover, aircraft can be passively located with real-world FDOA measurements using the extended Kalman filter.