sarnoiserefl

Noise equivalent reflectivity of SAR

Syntax

``neq = sarnoiserefl(freq,freqref,imgsnr,sigmaref)``
``neq = sarnoiserefl(freq,freqref,imgsnr,sigmaref,n)``

Description

example

````neq = sarnoiserefl(freq,freqref,imgsnr,sigmaref)` computes the noise equivalent reflectivity.```
````neq = sarnoiserefl(freq,freqref,imgsnr,sigmaref,n)` specifies a frequency-dependent proportionality factor that depends upon the target characteristics.```

Examples

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Estimate the noise equivalent reflectivity of a side-looking SAR operating at a frequency of 16 GHz for a target reflectivity of –25 dB at the Ku band (nominally 16.7 GHz) and to form an image having an SNR of 30 dB.

```f = 16e9; sigmaref = -25; fref = 16.7e9; snr = 30;```

Convert the target reflectivity to linear units. Compute the noise equivalent reflectivity.

`neq = sarnoiserefl(f,fref,snr,db2pow(sigmaref))`
```neq = -55.1860 ```

Input Arguments

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Radar frequency in hertz, specified as a positive real scalar or a vector.

Data Types: `double`

Nominal reference frequency in hertz, specified as a positive real scalar.

Data Types: `double`

Image signal-to-noise ratio (SNR) of the SAR in decibels, specified as a real scalar or a vector.

Data Types: `double`

Reflectivity at nominal reference frequency in square meters per square meter, specified as a positive real scalar.

Data Types: `double`

Frequency-dependent proportionality factor, specified as a real scalar. For distributed targets, `n` varies between 0 and 1. For nondistributed targets, `n` is a positive real scalar.

Data Types: `double`

Output Arguments

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Noise equivalent reflectivity in decibels, returned as a matrix. The rows of `neq` correspond to the frequency values in `freq`. The columns of `neq` correspond to the image SNR values in `imgsnr`.

Version History

Introduced in R2021a