Signal-to-noise ratio of SAR image

Since R2021a

Syntax

``imgsnr = radareqsarsnr(r,lambda,pt,tau,rnggain,azgain)``
``imgsnr = radareqsarsnr(r,lambda,pt,tau,rnggain,azgain,Name,Value)``

Description

example

````imgsnr = radareqsarsnr(r,lambda,pt,tau,rnggain,azgain)` returns the SAR image signal-to-noise ratio (SNR).```

example

````imgsnr = radareqsarsnr(r,lambda,pt,tau,rnggain,azgain,Name,Value)` specifies additional options using name-value arguments.```

Examples

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Estimate the image SNR for a SAR operating in broadside at a frequency of 5.3 GHz and 5 kW peak power to form an image of a target at 50 km. Assume an RCS of 1 m${}^{2}$ and rectangular waveform with a bandwidth of 0.05 microseconds. The range processing gain is 29.8 dB and the azimuth processing gain is 42.7 dB. Assume no losses.

```lambda = freq2wavelen(5.3e9); pt = 5e3; r = 50e3; tau = 0.05e-6; rnggain = 29.8; azgain = 42.7;```

Compute the image SNR.

`snr = radareqsarsnr(r,lambda,pt,tau,rnggain,azgain)`
```snr = 34.5704 ```

Input Arguments

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Range to target in meters, specified as a scalar, a column vector, a 1-by-2 row vector, or a 2-column matrix.

• Specify this argument as a scalar or a column vector for a monostatic radar.

• Specify this argument as a 1-by-2 row vector or as a 2-column matrix for a bistatic radar.

• The first element or column corresponds to the range from the transmitter to the target.

• The second element or column corresponds to the range from the target to the receiver.

Data Types: `double`

Wavelength of radar operating frequency in meters, specified as a positive real scalar.

Data Types: `double`

Transmitter peak signal power in watts, specified as a positive real scalar or a vector.

Data Types: `double`

Pulse width at the antenna port in seconds, specified as a positive real scalar.

Data Types: `double`

SNR gain due to range processing in decibels, specified as a real scalar.

Data Types: `double`

SNR gain due to azimuth processing in decibels, specified as a real scalar.

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: `'Ts',293,'Gain',12`

Target radar cross-section in square meters, specified as a scalar or a vector. `radareqsarsnr` assumes a nonfluctuating target (Swerling case 0).

Data Types: `double`

System noise temperature in kelvins, specified as a positive scalar.

Data Types: `double`

Antenna gain in decibels, specified as a scalar or 1-by-2 row vector.

• If you specify this argument as a two-element vector, the first element represents antenna transmit gain and the second element represents the antenna receive gain.

• If you specify this argument as a scalar, `radareqsarsnr` assumes the antenna has equal transmit and receive gains.

Data Types: `double`

System loss in decibels, specified as a scalar or a vector.

Data Types: `double`

Atmospheric absorption loss in decibels, specified as a scalar, a column vector, a 1-by-2 row vector, or a 2-column matrix.

• Specify this argument as a scalar or a column vector to represent the atmospheric absorption loss for a one-way path.

• Specify this argument as a 1-by-2 row vector or as a 2-column matrix to represent a transmit path and a receive path.

• The first element or column corresponds to the atmospheric absorption loss for the transmit path.

• The second element or column corresponds to the atmospheric absorption loss for the receive path.

Data Types: `double`

Propagation factor in decibels, specified as a scalar, a column vector, a 1-by-2 row vector, or a 2-column matrix.

• Specify this argument as a scalar or a column vector to represent the propagation factor loss for a one-way path.

• Specify this argument as a 1-by-2 row vector or as a 2-column matrix to represent a transmit path and a receive path.

• The first element or column corresponds to the propagation factor for the transmit path.

• The second element or column corresponds to the propagation factor for the receive path.

Data Types: `double`

Custom factor in decibels, specified as a scalar or a vector. This argument contributes to the received signal energy and can include other factors.

Data Types: `double`

Output Arguments

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SAR image signal-to-noise ratio in decibels, returned as a column vector.

Version History

Introduced in R2021a