TCAS-aided multilateration for terminal surveillance with improved accuracy

In this paper, we propose a new Time Lag of Arrival (TLOA) aided position estimation algorithm for enhancing the existing Time Difference of Arrival (TDOA) based aircraft multilateration (MALT) concept. This method will yield better estimation accuracy in a passive manner with minimum cost increase, leveraging ambient Traffic Collision Avoidance System (TCAS) interrogation and reply messages. Conventional MLAT system is modified to receive on both 1030 MHz TCAS interrogation links as well as 1090 MHz transponder reply links to support the new algorithm. The results of a simulation study suggests that the proposed algorithm can significantly improve position estimation accuracy, and this performance can be achieved without adding new multilateration sensors.