Coastal Navigation Practice Exam 2026 – Complete Prep Guide

The difference is about certainty and how the position is derived. An estimated position is your best guess of where you are based on the information you have at the moment—speed, course, recent radar returns, sightings, and often only one line of position. It carries uncertainty because you haven’t pinned your location with two independent measurements. A fix, by contrast, comes from intersecting two or more independent lines of position (or using a reliable celestial or range/bearing measurement). That intersection gives you a definite position on the chart with a known, smaller error. So an estimated position is a best available guess, while a fix is a determined position from crossing independent data.