# surfclutterrcs

Surface clutter radar cross section (RCS)

Since R2021a

## Syntax

``RCS = surfclutterrcs(NRCS,R,az,el,graz,tau)``
``RCS = surfclutterrcs(NRCS,R,az,el,graz,tau,c)``

## Description

example

````RCS = surfclutterrcs(NRCS,R,az,el,graz,tau)` returns the radar cross section (RCS) of a clutter patch that is of range `R` meters away from the radar system. `az` and `el` are the radar system azimuth and elevation beamwidths, respectively, corresponding to the clutter patch. `graz` is the grazing angle of the clutter patch relative to the radar. `tau` is the pulse width of the transmitted signal. The calculation automatically determines whether the surface clutter area is beam limited or pulse limited, based on the values of the input arguments.```
````RCS = surfclutterrcs(NRCS,R,az,el,graz,tau,c)` specifies the propagation speed in meters per second.```

## Examples

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Calculate the RCS of a clutter patch and estimate the clutter-to-noise ratio (CNR) at the receiver. Assume that the patch has a normalized radar cross section (NRCS) of 1 m²/m² and is 1.0 km away from the radar system. The azimuth and elevation beamwidths are 1° and 3°, respectively. The grazing angle is 10°. The pulse width is 10μs. The radar operates at a wavelength of 1 cm with a peak power of 5 kW.

```nrcs = 1; rng = 1.0e3; az = 1; el = 3; graz = 10; tau = 10e-6; lambda = 0.01; ppow = 5000; rcs = surfclutterrcs(nrcs,rng,az,el,graz,tau)```
```rcs = 5.2627e+03 ```
`cnr = radareqsnr(lambda,rng,ppow,tau,'rcs',rcs)`
```cnr = 75.2006 ```

## Input Arguments

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Normalized radar cross section of clutter patch in units of square meters/square meters, specified as a scalar.

Data Types: `double`

Range of clutter patch from radar system in meters, specified as a scalar.

Data Types: `double`

Azimuth beamwidth of radar system corresponding to clutter patch in degrees, specified as a nonnegative scalar.

Data Types: `double`

Elevation beamwidth of radar system corresponding to clutter patch in degrees, specified as a nonnegative scalar.

Data Types: `double`

Grazing angle of clutter patch relative to radar system in degrees, specified as a nonnegative scalar.

Data Types: `double`

Pulse width of transmitted signal in seconds, specified as a nonnegative scalar.

Data Types: `double`

Propagation speed in meters per second, specified as a positive scalar.

Example: `343` meters per second approximates the speed of sound at sea level and at a temperature of 20 °C under normal atmospheric conditions.

Data Types: `double`

## Output Arguments

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Radar cross section of clutter patch, returned as a scalar.

## Tips

• You can calculate the clutter-to-noise ratio using the output of this function as the `RCS` input argument value in `radareqsnr`.

## Algorithms

See .

 Richards, M. A. Fundamentals of Radar Signal Processing. New York: McGraw-Hill, 2005, pp. 57–63.