Multilateration system for aircraft location

摘要

A multilateration system 1 is disclosed comprising a plurality of receiver stations 2 to 6 for receiving a transmitted signal including a code from a transponder mounted on an aircraft 7. A controller is provided to apply a multilateration process to the outputs of the receivers stations 2 to 6 to derive a position of the aircraft 7. The controller determines the number of active stations receiving the code, determines the type of code, and performs a multilateration process in accordance with the determination to provide a position of the aircraft 7. The code may be a Secondary Surveillance Radar code which may be a mode A, mode S, mode C or an unknown mode of code. The multilateration process may be performed using outputs of the receiver stations and the height of the aircraft. The multilateration process applied may be chosen with reference to the determined height of the aircraft. The multilateration process may be a three dimensional, a two dimensional or a two dimensional assisted by height data process.