How do PSR and SSR differ in terms of target information?

• A. PSR detects targets passively without cooperative transponders; SSR uses transponder replies to provide identity, altitude, and precise position.
• B. PSR detects targets passively; SSR uses transponder replies to provide identity, altitude, and precise position.
• C. Both PSR and SSR rely on transponder replies for all information.
• D. PSR provides weather data; SSR provides navigation data.

Answer: (A)

Primary radar and secondary radar differ in what information they provide about a target. Primary Surveillance Radar (PSR) sends out a pulse and listens for reflections from objects. Because there’s no transponder involved, PSR can only show where a target is in space (range and bearing) and that there’s something there; it cannotIdentify the aircraft or its altitude. Secondary Surveillance Radar (SSR) instead interrogates the aircraft’s transponder, which replies with encoded data such as an identity (flight ID or squawk code) and an altitude. This cooperative data makes the target information richer and more actionable, effectively giving you who the aircraft is and how high it’s flying, in addition to positional information. Weather data and navigation data aren’t the primary outputs of PSR or SSR, which further clarifies why relying on transponder replies for identity and altitude is the defining difference.