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phased.AngleDopplerResponse System object

Package: phased

Angle-Doppler response

Description

The AngleDopplerResponse object calculates the angle-Doppler response of input data.

To compute the angle-Doppler response:

  1. Define and set up your angle-Doppler response calculator. See Construction.

  2. Call step to compute the angle-Doppler response of the input signal according to the properties of phased.AngleDopplerResponse. The behavior of step is specific to each object in the toolbox.

    Note:   Starting in R2016b, instead of using the step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

Construction

H = phased.AngleDopplerResponse creates an angle-Doppler response System object, H. This object calculates the angle-Doppler response of the input data.

H = phased.AngleDopplerResponse(Name,Value) creates angle-Doppler object, H, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

Properties

SensorArray

Sensor array

Sensor array specified as an array System object belonging to the phased package. A sensor array can contain subarrays.

Default: phased.ULA with default property values

PropagationSpeed

Signal propagation speed

Specify the propagation speed of the signal, in meters per second, as a positive scalar.

Default: Speed of light

OperatingFrequency

System operating frequency

Specify the operating frequency of the system in hertz as a positive scalar. The default value corresponds to 300 MHz.

Default: 3e8

PRF

Pulse repetition frequency

Specify the pulse repetition frequency (PRF) in hertz of the input signal as a positive scalar.

Default: 1

ElevationAngleSource

Source of elevation angle

Specify whether the elevation angle comes from the ElevationAngle property of this object or from an input argument in step. Values of this property are:

'Property'The ElevationAngle property of this object specifies the elevation angle.
'Input port'An input argument in each invocation of step specifies the elevation angle.

Default: 'Property'

ElevationAngle

Elevation angle

Specify the elevation angle in degrees used to calculate the angle-Doppler response as a scalar. The angle must be between –90 and 90. This property applies when you set the ElevationAngleSource property to 'Property'.

Default: 0

NumAngleSamples

Number of samples in angular domain

Specify the number of samples in the angular domain used to calculate the angle-Doppler response as a positive integer. This value must be greater than 2.

Default: 256

NumDopplerSamples

Number of samples in Doppler domain

Specify the number of samples in the Doppler domain used to calculate the angle-Doppler response as a positive integer. This value must be greater than 2.

Default: 256

Methods

cloneCreate angle-Doppler response object with same property values
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs from step method
isLockedLocked status for input attributes and nontunable properties
plotResponsePlot angle-Doppler response
releaseAllow property value and input characteristics changes
stepCalculate angle-Doppler response

Examples

expand all

Calculate the angle-Doppler response of the 190th cell of a collected data cube.

Load data cube and construct a phased.AngleDopplerResponse System object™.

load STAPExampleData;
x = shiftdim(STAPEx_ReceivePulse(190,:,:));
response = phased.AngleDopplerResponse(...
    'SensorArray',STAPEx_HArray,...
    'OperatingFrequency',STAPEx_OperatingFrequency,...
    'PropagationSpeed',STAPEx_PropagationSpeed,...
    'PRF',STAPEx_PRF);

Plot angle-Doppler response.

[resp,ang_grid,dop_grid] = response(x);
contour(ang_grid,dop_grid,abs(resp))
xlabel('Angle')
ylabel('Doppler')

Algorithms

phased.AngleDopplerResponse generates the response using a conventional beamformer and an FFT-based Doppler filter. For further details, see [1].

References

[1] Guerci, J. R. Space-Time Adaptive Processing for Radar. Boston: Artech House, 2003.

Introduced in R2012a

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