How are DME pulse trains made unique to each aircraft?

The distinction of DME (Distance Measuring Equipment) pulse trains for each aircraft is primarily achieved through the use of random pulse recurrence frequency. This approach ensures that each aircraft transmits its unique signal pattern, which helps in reducing the potential for interference with signals from other aircraft.

DME systems rely on pulse modulation techniques, where specific frequencies are used to transmit distance information to the aircraft. By employing a random recurrence frequency, each aircraft is able to generate a unique signature in its pulse train, making it easily distinguishable from signals of other aircraft in the vicinity. This uniqueness is critical for accurate distance measurement and air traffic management, ensuring that each aircraft can precisely determine its position relative to the DME ground stations without confusion or signal overlap.

Other methods, while relevant in different contexts, do not provide the same level of unique identification for DME communications. For instance, varying frequencies could potentially lead to confusion between aircraft if not handled correctly, and changing pulse intervals might not consistently produce distinct pulse trains. Specific aircraft identifiers can be used for identification but are typically not the means by which DME pulse trains are made unique.