sarlen

Synthetic aperture length

Since R2021a

Syntax

``len = sarlen(v,t)``
``len = sarlen(r)``
``len = sarlen(r,Name,Value)``
``len = sarlen(r,lambda,daz)``
``len = sarlen(r,lambda,daz,Name,Value)``

Description

````len = sarlen(v,t)` returns the synthetic aperture length for a synthetic aperture radar given the sensor velocity and the synthetic aperture time.```
````len = sarlen(r)` returns the synthetic aperture length for the spotlight mode.```
````len = sarlen(r,Name,Value)` specifies additional options using the `ConeAngle` and `CoherentIntegrationAngle` name-value arguments.```

example

````len = sarlen(r,lambda,daz)` returns the synthetic aperture length for the strip-map mode.```

example

````len = sarlen(r,lambda,daz,Name,Value)` specifies additional options using the `ConeAngle` and `AzimuthBroadening` name-value arguments.```

Examples

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Estimate the synthetic aperture length of a side-looking airborne stripmap synthetic aperture radar (SAR) operating in broadside at a wavelength of 0.05 m for a target range of 10 km. The radar antenna has an aperture length of 3 m in the azimuth dimension and an azimuth impulse broadening factor of 1.3.

```lambda = 0.05; Daz = 3; R = 10e3; azb = 1.3;```

Compute the synthetic aperture length.

`synlen = sarlen(R,lambda,Daz,'AzimuthBroadening',azb)`
```synlen = 216.6667 ```

Input Arguments

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Sensor velocity in meters per second, specified as a positive real scalar or vector.

Data Types: `double`

Synthetic aperture time in seconds, specified as a positive real scalar or a vector.

Data Types: `double`

Range from target to antenna in meters, specified as a positive real scalar or a vector.

Data Types: `double`

Radar wavelength in meters, specified as a positive real scalar or a vector.

Data Types: `double`

Antenna width in the azimuth direction in meters, specified as a positive real scalar or a vector.

Data Types: `double`

Name-Value Arguments

Specify optional pairs of arguments as `Name1=Value1,...,NameN=ValueN`, where `Name` is the argument name and `Value` is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose `Name` in quotes.

Example: `'AzimuthBroadening',1.3,'ConeAngle',120`

Azimuth impulse broadening factor due to data weighting or windowing for sidelobe control, specified as a positive real scalar. This argument expresses the actual –3 dB mainlobe width with respect to the nominal width. Typical window functions like `hamming` and `hann` exhibit values in the range from 1 to 1.5.

Data Types: `double`

Coherent integration angle in degrees, specified as a scalar in the range [`0`, `180`]. This argument specifies the angle through which the target is viewed during the coherent processing aperture.

Data Types: `double`

Doppler cone angle in degrees, specified as a scalar in the range [`0`, `180`]. This argument identifies the direction toward the scene relative to the direction of motion of the array.

Data Types: `double`

Output Arguments

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Synthetic aperture length, returned as a matrix.

• If you specify `v` and `t` as input arguments, then `len` is a matrix with rows corresponding to the velocity values in `v` and columns corresponding to the aperture time values in `t`.

• If you specify `r` as input for the spotlight mode, then `len` has the same dimensions as `r`.

• If you specify `r`, `lambda`, and `daz` as input for the strip-map mode, then `len` is a matrix with rows corresponding to the radar range values in `r` and columns corresponding to the antenna azimuth dimension in `daz`.

Version History

Introduced in R2021a