Lower bounds of accuracy for enhanced mode-S distributed sensor networks

The aim of this study is to analyse the accuracy of passive location systems by using the CraméŕRao lower bound (CRLB). The study is focused on sensor networks derived from the well-known Multilateration (MLAT) systems, used for aircraft and vehicle surveillance. The measurement used in the standard MLAT configuration is the Time Difference Of Arrival, but it can be improved by using other types of measurement like angle of arrival, round trip delay or time integration. Here, the CRLB is used to model the system accuracy performance using different measurements and related to the target kinematics, to evaluate a possible system evolution. In this frame, the CRLB analysis is useful to define the basic limitations and the advantages of different system architectures as well as to optimise existing architectures by adding new measurement capabilities to some receiving stations.