Chart Navigation & Plotting · Fixes & LOPs
An estimated position (EP) differs from a DR position because the EP:
- AIgnores current entirely
- BIncorporates the best available information such as a single LOP, set, and drift✓ Correct
- CIs always more accurate than a fix
- DRequires three bearings
Explanation
An EP refines the DR using whatever partial information is at hand — most commonly a single LOP (drop a perpendicular from the DR to the LOP) or an estimate of set and drift. It is better than a DR but less certain than a true fix.
Authority: Bowditch, Pub. No. 9 (estimated position)
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