What is a common ARPA limitation in rough seas?

• A. Target motion causing unstable track.
• B. ARPA has unlimited range and resolution in rough seas.
• C. ARPA requires no operator training.
• D. ARPA functions identically in all weather.

Answer: (A)

In rough seas, the motion of targets becomes highly erratic due to wind and waves. ARPA tracks are built on a predictive model of target motion and regular radar measurements. When a target doesn’t follow the assumed motion because of maneuvers or sea-state-induced accelerations, the tracking algorithm struggles to stay on the correct path. The result is an unstable track where the plot may jump, drift, or momentarily lose the target. This instability is a common limitation because the system’s predictive fitting relies on smooth, predictable motion, which rough seas disrupt.

The other statements aren’t correct because ARPA performance is not unlimited in range or resolution under rough conditions, operator training is still required, and ARPA does not operate identically in all weather—the radar’s clutter, sea state, and target maneuvers all affect tracking.