In ARPA, which data source besides radar can be used to maintain tracks?

• A. AIS data.
• B. Weather data.
• C. Submarine sonar data.
• D. GPS coordinates of all vessels.

Answer: (A)

ARPA enhances track maintenance by merging radar with external data sources that provide independent position and identity information. AIS data is the best fit because ships broadcast their identity and motion data—position, speed, and course—making it possible for ARPA to refresh and confirm tracks even when radar returns are weak or cluttered. This fusion helps prevent misidentification and improves future position predictions, boosting overall situational awareness.

Weather data influences radar performance but doesn’t supply vessel positions to feed into ARPA tracks. Submarine sonar data comes from a different domain and isn’t used to maintain surface vessel tracks in ARPA. A universal feed of GPS coordinates for all vessels doesn’t exist in practice, so AIS provides the practical, reliable source for supplementing radar in track maintenance.