MLAT Impact Analysis / Part 2 - Simulation of Swiss Scenarios: Analysis of mutual interference od surveillance systems using 1030 / 1090 MHz signals

This study investigates the occupancy of the SSR frequencies 1030 and 1090 MHz due to interrogation of and replies from aircraft transponders caused by various sensors like SSR, Mode-S radar, MLAT system or ACAS systems. A special focus lies on the additional transponder load due to the introduction of a MLAT in addition to or as a replacement of one or more existing radar systems.
Additional to the prior assessment this follow up document introduces the simulation software TOPAS and evaluates the whole of Switzerland. This simulation is based on the real surveillance infrastructure and a real traffic scenario.
The results of the considered and simulated scenarios are all below the ICAO limits although the transponder occupancy due to MLAT systems (for the future case of both ground MLAT and WAM) is about 1 % which is half of the limit. If this poses a possible problem could be investigated by a more accurate emulation of the sensor environment and the traffic scenario. There are possibilities to reduce the influence of MLAT systems by using sector antennas and reducing the interrogation range.