Passive Localization and Synchronization Using Arbitrary Signals

Time-of-arrival (TOA) localization is tightly coupled with sensor time synchronization. Synchronization can be obtained by GPS, atomic clocks, or message exchange protocols. All methods affect the energy sources and the synchronization protocols use valuable bandwidth. We present self-synchronized localization algorithms that rely exclusively on TOA measurements performed by the sensor network on passing sources rendering it completely passive. The same methods can be applied to time-difference-of-arrival (TDOA) measurements allowing the use of a larger family of signals. Localization performance is close to that provided by a perfectly synchronized network. Such algorithms can also be used for sensor network synchronization and communication networks in general.