EngeePhased.BackscatterRadarTarget
Radar backscatter target.
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| Block |
Description
System object EngeePhased.BackscatterRadarTarget simulates a backscatter pattern from the target.
Backscattering is a special case of scattering of a radar target when the angles of incidence and reflection coincide. This type of scattering is applicable to monostatic radar configurations. The radar backscatter pattern defines the directional pattern of the target on the incident signal in the form of a reflected signal.
This system object allows you to set an angle-dependent backscatter model that covers a range of angles of incidence.
One of the four Drilling models can be used to create random fluctuations in the EPR scattering matrix. Select the model using the Model property. Then use the SeedSource and Seed properties to control the fluctuations.
To perform a radar backscatter simulation, follow these steps:
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Create an object EngeePhased.BackscatterRadarTarget and set its properties.
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Call the object with arguments as if it were a function.
To learn more about how to work with system objects, see Engee System Objects.
Syntax
Creation
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target = EngeePhased.BackscatterRadarTarget()— creates a backscatter radar target object with default property values. -
target = EngeePhased.BackscatterRadarTarget(Name=Value)— creates a backscatter radar target object with specified properties in the form of a pairName=Value, whereName— the name of the property, andValue— the appropriate value. You can specify multiple pairs «name-value» the order of the pairs does not matter. Unspecified properties retain their default values.Example:
target = EngeePhased.BackscatterRadarTarget(Model="Swerling2")
Using
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refl_sig = target(sig,ang)— returns a reflected refl_sig signal from an incident unpolarized sig signal arriving at the target at the angle specified in the ang argument. This syntax applies if for a property Model the value is set"Nonfluctuating". In this case, the values specified in the RCSPattern property are used to calculate the effective scattering area (ESR) for the angles of incidence and reflection (argument ang). -
refl_sig = target(sig,ang,update)— uses the input argument update to control the update of EPR values. This syntax applies if for the property Model one of the EPR models is set:"Swerling1","Swerling2","Swerling3"or"Swerling41". If the value of the update argument istrue, a new EPR value is generated. If the value of update isfalse, the previous EPR value is used.
Arguments
Input arguments
sig — narrow-band signal
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the complex matrix of N by M
Details
A narrow-band unpolarized signal defined as a matrix or tuple, depending on whether the signal is polarized or unpolarized. Value — this is the number of samples of the signal, and — the number of signals reflected from the target. Each column corresponds to an independent signal incident at a different angle of reflection.
| Типы данных |
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| Support for complex numbers |
Yes |
ang — input signal direction
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A 2-by-1 column vector with positive real values | a 2 by M matrix with positive real values
Details
The direction of the incident signal, defined as a column vector on or matrices on with positive real values.
Each ang column defines the direction of the incident signal as a pair of angles. [AzimuthAngle;ElevationAngle].
The number of columns in ang must correspond to the number of independent signals in the sig argument.
The units of measurement are degrees.
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update — EPR update
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false (by default) | true
Details
Allow updating EPR values for fluctuation models, set as false or true.
If the property [Property:update] is set to true, then each time the function is called, a new EPR value is generated.
If the property [Property:update] is set to false, The EPR remains the same every time the function is called.
| Типы данных |
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Output arguments
refl_sig — narrow-band reflected signal
+
the complex matrix of N by M
Details
A narrow-band unpolarized signal returned as a complex matrix on . Each column contains an independent signal reflected from the target.
Value — this is the number of samples of the signal, and — the number of signals reflected from the target. Each column corresponds to the angle of reflection.
The output signal refl_sig contains the signal samples arriving at the signal destination during the current input time interval. If the propagation time from the source to the destination exceeds the duration of the current time frame, the output does not contain all contributions from the input of the current time frame. The remaining output appears the next time the function is called.
Features
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AzimuthAngles —
description missing
Array of real numbers
Details
Description missing
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Seed —
description missing
Real number
Details
Description missing
#
PropagationSpeed —
description missing
Real number
Details
Description missing
#
OperatingFrequency —
description missing
Real number
Details
Description missing
#
ElevationAngles —
description missing
Array of real numbers
Details
Description missing
#
RCSPattern —
description missing
Array of real numbers
Details
Description missing
#
Model —
description missing
String
Details
Description missing
#
SeedSource —
description missing
String
Details
Description missing
Additional Info
Backscattered radiation
Details
For a narrow-band unpolarized signal, the reflected signal equal to:
where
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— input signal;
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— target gain factor, a dimensionless value defined as follows:
where
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— effective scattering area (ESR) of the target;
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— the wavelength of the input signal.
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The signal incident on the target is scaled by the square root of the gain factor.
For narrow-band polarized waves, a single scalar signal replaced by a vector signal with horizontal and vertical components. The scattering matrix, , replaces the scalar section . With the help of a scattering matrix, horizontally and vertically polarized incident signals are converted into horizontally and vertically polarized reflected signals.