What type of feature is Mode 5 in the radar system?

Mode 5 in radar systems is primarily a positive identification feature that enhances the ability to distinguish between friendly and potentially hostile aircraft. This feature leverages advanced encryption and transmission protocols to ensure that only verified and authorized aircraft can be identified as friendlies. By requiring specific identification codes and responses from transponders on aircraft, it prevents misidentification in complex airspace scenarios, significantly aiding in decision-making for air defense operations.

In the context of air defense, this capability is crucial since differentiating between friend and foe can directly affect the safety of personnel and the effectiveness of defense systems. Other options like video enhancement, surveillance capabilities, or operational range do not specifically address the requirement for verifying the identity of aircraft, which is fundamentally the purpose of Mode 5. Therefore, focusing on positive identification is what sets this feature apart and makes it essential for air defense operations.