Which statement correctly describes maintaining position after GPS fix during navigation?

• A. GPS alone is always perfect with no need for cross-checks.
• B. Landmarks or dead reckoning should be ignored.
• C. Radar data should replace GPS entirely.
• D. Position should be fixed by GPS and confirmed by landmarks or dead reckoning as needed.

Answer: (D)

After you get a GPS fix, keep your navigation position under cross-check with other references. GPS provides a precise read, but it isn’t flawless—satellite geometry, signal reflections, obstructions, or equipment glitches can introduce errors or temporary outages. By comparing the GPS position with known landmarks or charted features and by applying dead reckoning (using your speed, course, and time to project your position), you verify accuracy and catch any discrepancies early. If the GPS reading doesn’t align with your dead-reckoned position or with radar bearings and ranges, you reassess and adjust as needed. Radar data is valuable for confirming proximity to shore or other objects, but it shouldn’t replace GPS entirely; it serves as a corroborating tool. The best practice is to fix position with GPS and confirm it with landmarks or dead reckoning as needed, maintaining reliable situational awareness throughout the voyage.