In the context of navigation integrity, which statement best describes RAIM status and protection levels?

• A. RAIM status indicates satellite redundancy and consistency, while protection levels quantify bounds.
• B. RAIM status alone guarantees integrity.
• C. Protection levels replace RAIM status.
• D. RAIM cannot indicate integrity.

Answer: (C)

Navigation integrity today is expressed through protection levels, which give a quantitative bound on how large the true navigation error could be for a given probability. This bound is what you use to decide whether the current solution meets the required safety and performance standards. RAIM status, on the other hand, was a diagnostic that assessed satellite redundancy and consistency, but it doesn’t provide a numeric bound on the error itself. Because protection levels directly define the safe limits and are tied to the integrity requirements, they effectively replace relying on RAIM status alone as the basis for trusting the navigation solution. So, the statement that protection levels replace RAIM status best captures how integrity is assessed in modern navigation.