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Rh = horizonrange(H)
Rh = horizonrange(H,Re)
Rh = horizonrange(___,'SurfaceHeight',surfht)


Rh = horizonrange(H) returns the horizon range, Rh, of a radar system H meters above the surface. The computation uses an effective earth radius of approximately 4/3 times the actual earth radius.

Rh = horizonrange(H,Re) specifies the effective earth radius, Re.

Rh = horizonrange(___,'SurfaceHeight',surfht) also specifies the surface height, surfht.

Input Arguments


Height of radar system above surface, specified as a scalar or a length-M vector. Units are in meters.


Effective earth radius, specified as a positive scalar. Units are in meters

Default: effearthradius, which is approximately 4/3 times the actual earth radius


Height of earth surface at the horizon, specified as a scalar or length-M vector. This input can also be interpreted as the height of significant ground clutter at the horizon. If H and surfht are vectors, their lengths must be equal. Defaults to 0 m.

Output Arguments


Horizon range in meters of radar system at altitude H.


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Find the range to the horizon from an antenna that is 30 m high.

R = horizonrange(30)

More About

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Horizon Range

The horizon range of a radar system is the distance from the radar system to the earth along a tangent. Beyond the horizon range, the radar system detects no return from the surface through a direct path.

The value of the horizon range is:


where Re is the effective earth radius and H is the altitude of the radar system.


[1] Long, Maurice W. Radar Reflectivity of Land and Sea, 3rd Ed. Boston: Artech House, 2001.

[2] Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill, 2001.

Extended Capabilities

Introduced in R2021a