DPCA Canceller

Displaced phase center array (DPCA) pulse canceller for a uniform linear array

  • Library:
  • Phased Array System Toolbox / Space-Time Adaptive Processing

Description

The DPCA Canceller block filters clutter impinging on a uniform linear array using a displaced phase center array pulse canceller.

Ports

Input

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Input signal, specified as an M-by-N-by-P complex-valued array. M is the number of range samples, N is the number of channels, and P is the number of pulses.

The size of the first dimension of the input matrix can vary to simulate a changing signal length. A size change can occur, for example, in the case of a pulse waveform with variable pulse repetition frequency.

Data Types: double
Complex Number Support: Yes

Index of range cells to compute processing weights.

Example: 1

Data Types: double

Pulse repetition frequency of current pulse, specified as a positive scalar.

Dependencies

To enable this port, set the Specify PRF as parameter to Input port.

Data Types: double

Targeting direction, specified as a 2-by-1 real-valued vector. The vector takes the form of [AzimuthAngle;ElevationAngle]. Angle units are in degrees. The azimuth angle must lie between –180° and 180°, inclusive, and the elevation angle must lie between –90° and 90°, inclusive. Angles are defined with respect to the local coordinate system of the array.

Dependencies

To enable this port, set the Specify direction as parameter to Input port.

Data Types: double

Targeting Doppler frequency of current pulse, specified as a scalar.

Dependencies

This port appears when the Output pre-Doppler result check box is cleared and the Specify targeting Doppler as parameter is set to Input port.

Data Types: double

Output

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Processing output, returned as an M-by-1 complex-valued vector. The quantity M is the number of range samples in the input port X.

Data Types: double
Complex Number Support: Yes

Processing weights, returned as Length N*P complex-valued vector. The quantity N is the number of channels and P is the number of pulses. When the Specify sensor array as parameter is set to Partitioned array or Replicated subarray, N represents the number of subarrays. L is the number of desired beamforming directions specified in the Ang input port or by the Beamforming direction (deg) parameter. There is one set of weights for each beamforming direction.

Dependencies

To enable this port, select the Enable weights output check box.

Data Types: double
Complex Number Support: Yes

Parameters

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Main Tab

Signal propagation speed, specified as a real-valued positive scalar. The default value of the speed of light is the value returned by physconst('LightSpeed'). Units are in meters per second.

Example: 3e8

Data Types: double

System operating frequency, specified as a positive scalar. Units are in Hz.

Source of PRF value, specified as Property or Input port. When set to Property, the Pulse repetition frequency (Hz) parameter sets the PRF. When set to Input port, pass in the PRF using the PRF input port.

Pulse repetition frequency, PRF, specified as a positive scalar. Units are in Hertz. Set this parameter to the same value set in any Waveform library block used in the simulation.

Dependencies

To enable this parameter, set the Specify PRF as parameter to Property.

Specify whether the targeting direction for the STAP processor block comes from a block parameter or from the ANG input port. Values of this parameter are

Property

  • For the ADPCA Canceller and DPCA Canceller blocks, targeting direction is specified using Receiving mainlobe direction (deg).

  • For the SMI Beamformer block, targeting direction is specified using Targeting direction.

These parameters appear only when the Specify direction as parameter is set to Property.

Input port

Enter the targeting directions using the Ang input port. This port appears only when Specify direction as is set to Input port.

Specify the direction of the main lobe of the receiving sensor array as a real-valued 2-by-1 vector. The direction is specified in the format of [AzimuthAngle; ElevationAngle]. The azimuth angle should be between –180° and 180° and the elevation angle should be between –90° and 90°.

Example: [100;-45]

Dependencies

To enable this parameter, set Specify direction as to Property.

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.

Specify whether targeting Doppler values for the STAP processor comes from the Targeting Doppler (Hz) parameter of this block or using the DOP input port. For the ADPCA Canceller and DPCA Canceller blocks, the Specify targeting Doppler as parameter appears only when the Output pre-Doppler result check box is cleared. Values of this parameter are

PropertySpecify targeting Doppler values using the Targeting Doppler parameter of the block. The Targeting Doppler parameter appears only when Specify targeting Doppler as is set to Property.
Input portSpecify targeting Doppler values using the Dop input port. This port appears only when Specify targeting Doppler as is set to Input port.

Targeting Doppler of STAP processor, specified as a scalar.

Dependencies

  • To enable this parameter for the SMI Beamformer block, set Specify targeting Doppler as to Property.

  • To enable this parameter for the ADPCA Canceller and DPCA Canceller blocks, first clear the Output pre-Doppler result check box. Then set the Specify targeting Doppler as parameter to Property.

Select this check box to obtain the beamformer weights from the output port, W.

Select this check box to output the results before Doppler filtering. Clear this check box to output the processing result after Doppler filtering. Selecting this check box will remove the Specify targeting Doppler as and Targeting Doppler (Hz) parameters.

Block simulation, specified as Interpreted Execution or Code Generation. If you want your block to use the MATLAB® interpreter, choose Interpreted Execution. If you want your block to run as compiled code, choose Code Generation. Compiled code requires time to compile but usually runs faster.

Interpreted execution is useful when you are developing and tuning a model. The block runs the underlying System object™ in MATLAB. You can change and execute your model quickly. When you are satisfied with your results, you can then run the block using Code Generation. Long simulations run faster with generated code than in interpreted execution. You can run repeated executions without recompiling, but if you change any block parameters, then the block automatically recompiles before execution.

This table shows how the Simulate using parameter affects the overall simulation behavior.

When the Simulink® model is in Accelerator mode, the block mode specified using Simulate using overrides the simulation mode.

Acceleration Modes

Block SimulationSimulation Behavior
NormalAcceleratorRapid Accelerator
Interpreted ExecutionThe block executes using the MATLAB interpreter.The block executes using the MATLAB interpreter.Creates a standalone executable from the model.
Code GenerationThe block is compiled.All blocks in the model are compiled.

For more information, see Choosing a Simulation Mode (Simulink).

Sensor Arrays Tab

Method to specify array, specified as Array (no subarrays) or MATLAB expression.

  • Array (no subarrays) — use the block parameters to specify the array.

  • MATLAB expression — create the array using a MATLAB expression.

MATLAB expression used to create an array, specified as a valid Phased Array System Toolbox array System object.

Example: phased.URA('Size',[5,3])

Dependencies

To enable this parameter, set Specify sensor array as to MATLAB expression.

Element Parameters

Antenna or microphone type, specified as one of the following:

  • Isotropic Antenna

  • Cosine Antenna

  • Custom Antenna

  • Omni Microphone

  • Custom Microphone

Specify the operating frequency range of the antenna or microphone element as a 1-by-2 row vector in the form [LowerBound,UpperBound]. The element has no response outside this frequency range. Frequency units are in Hz.

Dependencies

To enable this parameter, set Element type to Isotropic Antenna, Cosine Antenna, or Omni Microphone.

Specify the frequencies at which to set antenna and microphone frequency responses as a 1-by-L row vector of increasing real values. The antenna or microphone element has no response outside the frequency range specified by the minimum and maximum elements of this vector. Frequency units are in Hz.

Dependencies

To enable this parameter, set Element type to Custom Antenna or Custom Microphone. Use Frequency responses (dB) to set the responses at these frequencies.

Select this check box to baffle the back response of the element. When back baffled, the responses at all azimuth angles beyond ±90° from broadside are set to zero. The broadside direction is defined as 0° azimuth angle and 0° elevation angle.

Dependencies

To enable this check box, set Element type to Isotropic Antenna or Omni Microphone.

Specify the exponents of the cosine pattern as a nonnegative scalar or a real-valued 1-by-2 matrix of nonnegative values. When Exponent of cosine pattern is a 1-by-2 vector, the first element is the exponent in the azimuth direction and the second element is the exponent in the elevation direction. When you set this parameter to a scalar, both the azimuth direction and elevation direction cosine patterns are raised to the same power.

Dependencies

To enable this parameter, set Element type to Cosine Antenna.

Frequency response of a custom antenna or custom microphone for the frequencies defined by the Operating frequency vector (Hz) parameter. The dimensions of Frequency responses (dB) must match the dimensions of the vector specified by the Operating frequency vector (Hz) parameter.

Dependencies

To enable this parameter, set Element type to Custom Antenna or Custom Microphone.

Specify the azimuth angles at which to calculate the antenna radiation pattern as a 1-by-P row vector. P must be greater than 2. Azimuth angles must lie between –180° and 180°, inclusive, and be in strictly increasing order.

Dependencies

To enable this parameter, set Element type to Custom Antenna.

Specify the elevation angles at which to compute the radiation pattern as a 1-by-Q vector. Q must be greater than 2. Angle units are in degrees. Elevation angles must lie between –90° and 90°, inclusive, and be in strictly increasing order.

Dependencies

To enable this parameter, set Element type to Custom Antenna.

Magnitude of the combined antenna radiation pattern, specified as a Q-by-P matrix or a Q-by-P-by-L array. The quantity Q equals the length of the vector specified by Elevation angles (deg). The quantity P equals length of the vector specified by Azimuth angles (deg). The quantity L equals the length of the Operating frequency vector (Hz).

  • If this parameter is a Q-by-P matrix, the same pattern is applied to all frequencies specified in the Operating frequency vector (Hz) parameter.

  • If the value is a Q-by-P-by-L array, each Q-by-P page of the array specifies a pattern for the corresponding frequency specified in the Operating frequency vector (Hz) parameter.

Dependencies

To enable this parameter, set Element type to Custom Antenna.

Phase of the combined antenna radiation pattern, specified as a Q-by-P matrix or a Q-by-P-by-L array. The quantity Q equals the length of the vector specified by Elevation angles (deg). The quantity P equals length of the vector specified by Azimuth angles (deg). The quantity L equals the length of the Operating frequency vector (Hz).

  • If this parameter is a Q-by-P matrix, the same pattern is applied to all frequencies specified in the Operating frequency vector (Hz) parameter.

  • If the value is a Q-by-P-by-L array, each Q-by-P page of the array specifies a pattern for the corresponding frequency specified in the Operating frequency vector (Hz) parameter.

Dependencies

To enable this parameter, set Element type to Custom Antenna.

Polar pattern microphone response frequencies, specified as a real scalar, or a real-valued, 1-by-L vector. The response frequencies lie within the frequency range specified by the Operating frequency vector (Hz) vector.

Dependencies

To enable this parameter, set Element type set to Custom Microphone.

Specify the polar pattern response angles, as a 1-by-P vector. The angles are measured from the central pickup axis of the microphone and must be between –180° and 180°, inclusive.

Dependencies

To enable this parameter, set Element type to Custom Microphone.

Specify the magnitude of the custom microphone element polar patterns as an L-by-P matrix. L is the number of frequencies specified in Polar pattern frequencies (Hz). P is the number of angles specified in Polar pattern angles (deg). Each row of the matrix represents the magnitude of the polar pattern measured at the corresponding frequency specified in Polar pattern frequencies (Hz) and all angles specified in Polar pattern angles (deg). The pattern is measured in the azimuth plane. In the azimuth plane, the elevation angle is 0° and the central pickup axis is 0° degrees azimuth and 0° degrees elevation. The polar pattern is symmetric around the central axis. You can construct the microphone response pattern in 3-D space from the polar pattern.

Dependencies

To enable this parameter, set Element type to Custom Microphone.

Array Parameters

Specify a ULA sensor array directly or by using a MATLAB expression.

Types

Array (no subarrays)
MATLAB expression

The number of array elements for ULA arrays, specified as an integer greater than or equal to two.

Example: 11

Data Types: double

Distance between adjacent ULA elements, specified as a positive scalar. Units are in meters.

Example: 1.5

Linear axis direction of ULA, specified as y, x, or z. All ULA array elements are uniformly spaced along this axis in the local array coordinate system.

Dependencies

  • To enable this parameter, set Geometry to ULA.

  • This parameter is also enabled when the block only supports ULA arrays.

Tapers, also known as element weights, are applied to sensor elements in the array. Tapers are used to modify both the amplitude and phase of the transmitted or received data.

Specify element tapering as a complex-valued scalar or a complex-valued 1-by-N row vector. In this vector, N represents the number of elements in the array. If Taper is a scalar, the same weight is applied to each element. If Taper is a vector, a weight from the vector is applied to the corresponding sensor element. A weight must be applied to each element in the sensor array.

Example: [0.5;1;0.5]

Data Types: double
Complex Number Support: Yes

MATLAB expression used to create a ULA array, specified as a valid Phased Array System Toolbox array System object.

Example: phased.ULA('NumElements',13)

Dependencies

To enable this parameter, set Specify sensor array as to MATLAB expression.

Introduced in R2014b