What is a key requirement for SSR and MLAT technologies?

The key requirement for SSR (Secondary Surveillance Radar) and MLAT (Multilateration) technologies is that they need equipment that can respond to ground-based signals. SSR relies on transponders installed in aircraft that respond to interrogation signals sent from ground radar systems, enabling the tracking and identification of aircraft. This interaction is essential for the operational functionality of SSR systems.

Similarly, MLAT technology uses multiple ground-based receivers to determine the position of an aircraft based on the time of arrival of signals emitted from the aircraft. This also necessitates that the aircraft have transponders to broadcast their locations, which are then triangulated by the ground-based receivers. Therefore, the operational effectiveness of both SSR and MLAT fundamentally depends on equipment that can respond appropriately to signals originating from ground systems. This establishes a clear link between the aircraft and the ground infrastructure, ensuring accurate tracking and data exchange essential for air traffic management.