horizonrange

Horizon range

Since R2021a

Syntax

Rh = horizonrange(H)

Rh = horizonrange(H,Re)

Rh = horizonrange(___,SurfaceHeight=surfht)

Description

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.

Examples

Compute Range to Horizon

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

R = horizonrange(30)

Input Arguments

H — Height of the radar system above the surface

scalar | vector

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

Data Types: double

Re — Effective earth radius

effearthradius (default) | positive scalar

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

surfht — Height of earth surface at the horizon

0 (default) | scalar | vector

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

Rh — Horizon range

scalar | vector

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

More About

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:

$$\sqrt{2R_{e}H+H^2}$$

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

References

[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

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

Does not support variable-size inputs.

Version History

Introduced in R2021a