Dead-Reckoning Position

Advance an initial position by a course and speed for a given elapsed time - the basic DR calculation.

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

d\text{Lat} = D \cdot \cos C, \quad \text{Dep} = D \cdot \sin C, \quad d\text{Lon} = \tfrac{\text{Dep}}{\cos L_m}

Symbol	Meaning	Unit
$C$	True course	°T
$D$	Distance	nm
$L_m$	Mid-latitude	°
$Dep$	Departure (east-west distance in nm)	nm

Source: Bowditch - American Practical Navigator

Advance an initial position by a course and speed for a given elapsed time - the basic DR calculation.