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Horizon range

Since R2021a



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.


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

R = horizonrange(30)

Input Arguments

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Height of the radar system above the surface in meters, specified as a scalar or a vector.

Data Types: double

Effective earth radius in meters, specified as a positive scalar. You can use effearthradius to compute the effective radius. The function provides a default value approximately 4/3 times the actual earth radius

Example: 6.4e6

Data Types: double

Height of earth surface at the horizon in meters, specified as a scalar or 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.

Data Types: double

Output Arguments

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Horizon range in meters of radar system at altitude H, returned as a scalar or a vector.

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

Version History

Introduced in R2021a