A method of detecting an unknown signal and estimating a source location of the unknown signal using aircraft based on an automatic dependent surveillance-broadcast (ADS-B) system is provided. The method includes a first step (S100′) for obtaining from a plurality of airborne aircrafts provided with a network system, an aircraft signal transmitted to neighboring aircraft. The method further includes a second step (S200′) for detecting, by one of the plurality of aircraft, a presence of the unknown signal in the aircraft signal based on one of a time difference of arrival (TDOA) method, a time of arrival (TOA) method, and an angle of arrival (AOA) method. The method further includes a third step (S300′) for estimating the source location of the unknown signal and a fourth step (S400′) for transmitting unknown signal generation information and the source to neighboring aircraft and the ATC through a flight information services-broadcast (FIS-B).