Radar & Optical Horizon

Horizon distance - how far a radar or an observer can see - as a function of antenna/eye height.

NavigationRadar

Antenna / eye height above sea levelm

Radar horizon: 11.2nm

Optical horizon: 10.4nm

Changing the inputs requires JavaScript. The calculator above shows its default inputs and result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

d_\text{radar} \approx 2.23 \sqrt{h}, \quad d_\text{optical} \approx 2.072 \sqrt{h}

Symbol	Meaning	Unit
$h$	Height above sea level	m
$d$	Horizon distance	nm

Source: IEC 62388 - Radar performance; Bowditch Ch.13

In short

Horizon distance - how far a radar or an observer can see - as a function of antenna/eye height.

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