Fix

Definition

A fix is a position established without reference to any previous position, obtained from the intersection of two or more simultaneous position lines. Three position lines are preferred because the resulting cocked hat reveals observational error; two lines give no check. The fix is plotted as a dot inside a small circle, labelled with the time in four-figure ship's time. Angles of cut between position lines should ideally approach 90 degrees, and cuts below about 30 degrees produce badly elongated error ellipses.