phased.DPCACanceller

Displaced phase center array (DPCA) pulse canceller

Description

The DPCACanceller object implements a displaced phase center array pulse canceller for a uniform linear array (ULA).

To compute the output signal of the space time pulse canceller:

Define and set up your DPCA pulse canceller. See Construction.
Call step to execute the DPCA algorithm according to the properties of phased.DPCACanceller. 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.DPCACanceller creates a displaced phase center array (DPCA) canceller System object, H. The object performs two-pulse DPCA processing on the input data.

H = phased.DPCACanceller(Name,Value) creates a DPCA 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

Uniform linear array

Uniform linear array, specified as a phased.ULA System object.

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. You can specify this property as single or double precision.

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. You can specify this property as single or double precision.

Default: 3e8

PRFSource

Source of pulse repetition frequency

Source of the PRF values for the STAP processor, specified as 'Property' or 'Input port'. When you set this property to 'Property', the PRF is determined by the value of the PRF property. When you set this property to 'Input port', the PRF is determined by an input argument to the step method at execution time.

Default: 'Property'

PRF

Pulse repetition frequency

Pulse repetition frequency (PRF) of the received signal, specified as a positive scalar. Units are in Hertz. This property can be specified as single or double precision.

Dependencies

To enable this property, set the PRFSource property to 'Property'.

Default: 1

DirectionSource

Source of receiving mainlobe direction

Specify whether the targeting direction for the STAP processor comes from the Direction property of this object or from an input argument in step. Values of this property are:

`'Property'`	The `Direction` property of this object specifies the targeting direction.
`'Input port'`	An input argument in each invocation of `step` specifies the targeting direction.

Default: 'Property'

Direction

Receiving mainlobe direction

Specify the receiving mainlobe direction of the receiving sensor array as a column vector of length 2. The direction is specified in the format of [AzimuthAngle;ElevationAngle] (in degrees). The azimuth angle should be between –180° and 180°. The elevation angle should be between –90° and 90°. This property applies when you set the DirectionSource property to 'Property'. You can specify this argument as single or double precision.

Default: [0; 0]

NumPhaseShifterBits

Number of phase shifter quantization bits

The number of bits used to quantize the phase shift component of beamformer or steering vector weights. Specify the number of bits as a non-negative integer. A value of zero indicates that no quantization is performed. You can specify this property as single or double precision.

Default: 0

DopplerSource

Source of targeting Doppler

Specify whether the targeting Doppler for the STAP processor comes from the Doppler property of this object or from an input argument in step. Values of this property are:

`'Property'`	The `Doppler` property of this object specifies the Doppler.
`'Input port'`	An input argument in each invocation of `step` specifies the Doppler.

Default: 'Property'

Doppler

Targeting Doppler frequency (hertz)

Specify the targeting Doppler of the STAP processor as a scalar. This property applies when you set the DopplerSource property to 'Property'. You can specify this property as single or double precision.

Default: 0

WeightsOutputPort

Output processing weights

To obtain the weights used in the STAP processor, set this property to true and use the corresponding output argument when invoking step. If you do not want to obtain the weights, set this property to false.

Default: false

PreDopplerOutput

Output pre-Doppler result

Set this property to true to output the processing result before applying the Doppler filtering. Set this property to false to output the processing result after the Doppler filtering.

Default: false

Methods

step	Perform DPCA processing on input data

Common to All System Objects
`release`	Allow System object property value changes

Examples

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Process Data Cube Using DPCA

Open Live Script

Process a data cube using a DPCA processor. The weights are calculated for the 71st cell of the collected data cube. The look direction is (0,0) degrees and the Doppler shift is 12.980 kHz.

load STAPExampleData;
Hs = phased.DPCACanceller('SensorArray',STAPEx_HArray,...
    'PRF',STAPEx_PRF,...
    'PropagationSpeed',STAPEx_PropagationSpeed,...
    'OperatingFrequency',STAPEx_OperatingFrequency,...
    'WeightsOutputPort',true,...
    'DirectionSource','Input port',...
    'DopplerSource','Input port');
[y,w] = step(Hs,STAPEx_ReceivePulse,71,[0;0],12.980e3);

sAngDop = phased.AngleDopplerResponse(...
    'SensorArray',Hs.SensorArray,...
    'OperatingFrequency',Hs.OperatingFrequency,...
    'PRF',Hs.PRF,...
    'PropagationSpeed',Hs.PropagationSpeed);
plotResponse(sAngDop,w)

Figure contains an axes object. The axes object with title Angle-Doppler Response Pattern, xlabel Angle (degrees), ylabel Doppler Frequency (Hz) contains an object of type image.

Algorithms

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Single Precision

This System object supports single and double precision for input data, properties, and arguments. If the input data X is single precision, the output data is single precision. If the input data X is double precision, the output data is double precision. The precision of the output is independent of the precision of the properties and other arguments.

References

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

[2] Ward, J. “Space-Time Adaptive Processing for Airborne Radar Data Systems,” Technical Report 1015, MIT Lincoln Laboratory, December, 1994.

phased.DPCACanceller

Description

Construction