Asynchronous wide area multilateration system

A new method for a location service in the wide area multilateration (WAM) system is outlined. This method, which is called asynchronous WAM (AWAM), enables calculation of the geographical position of an aircraft without knowledge of relative time differences (RTDs) between measuring ground stations (sensors). The AWAM method is based on the measurement of round trip times (RTTs) between the aircraft and the serving ground station, and the solution of a nonlinear system of equations with ten variables. The elimination of the RTD parameters significantly simplifies the localization process in real-life WAM system. The proposed asynchronous method could be an alternative solution for the synchronous one as a backup method during the system's failure or as an independent method. The paper concentrates on the description of the method, solving the nonlinear system of equations with ten variables and simulation results.