Multilateration, or hyperbolic positioning, is the process of locating an object based in the Time Difference of Arrival (TDOA) of a signal emitted from that object to three or more sensors. When a signal is transmitted from an object, it will be received by two specially seperate sensors at different times. The time difference is then used to calculate the objects position. By using three or more sensors, a complete position analysis can be attained.

For ATC applications, multilateration provides the same level of fleet coverage as traditional SSR (i.e. all aircraft or vehicles equipped with an operational Mode A, Mode C or Mode S transponder). Multilateration will generally provide higher accuracy, greater update rate, better coverage and improved reliability when compared to traditional SSR, and will do so at a much lower initial cost and with lower annual maintenance costs.