In coastal navigation (10-30 NM), after GPS, which fix source is used?

Master the Navigation, Seamanship, and Shiphandling (NSS) – Officer of the Deck (OOD) Phase 2 Exam with engaging flashcards and multiple choice questions, complete with hints and explanations. Prepare comprehensively for your test!

Multiple Choice

In coastal navigation (10-30 NM), after GPS, which fix source is used?

In coastal navigation, you want an independent check on your position to verify GPS. In the 10–30 NM range, the most practical post-GPS fix source is one drawn from visual references, radar observations, or a composite of both. Visual fixes come from bearings and ranges to charted landmarks or shore features, while radar fixes use ranges and bearings to known objects or to the coastline seen on radar. A composite fix blends these independent sources to improve accuracy and provide a reliable cross-check against GPS. Celestial navigation is generally not practical near shore due to horizon/visibility constraints and time requirements, and an INS alone drifts over time and isn’t a standalone fix. So the best answer is Visual/Radar/Composite.

In coastal navigation, you want an independent check on your position to verify GPS. In the 10–30 NM range, the most practical post-GPS fix source is one drawn from visual references, radar observations, or a composite of both. Visual fixes come from bearings and ranges to charted landmarks or shore features, while radar fixes use ranges and bearings to known objects or to the coastline seen on radar. A composite fix blends these independent sources to improve accuracy and provide a reliable cross-check against GPS. Celestial navigation is generally not practical near shore due to horizon/visibility constraints and time requirements, and an INS alone drifts over time and isn’t a standalone fix. So the best answer is Visual/Radar/Composite.

More practice questions