# Constant Gamma Clutter

Constant gamma clutter simulation

**Library:**Radar Toolbox

## Description

The Constant Gamma Clutter block generates constant gamma clutter reflected from homogeneous terrain for a monostatic radar transmitting a narrowband signal into free space. The radar is assumed to be at constant altitude moving at constant speed.

## Ports

### Input

`PRFIdx`

— PRF Index

positive integer

Index to select the pulse repetition frequency (PRF), specified as a
positive integer. The index selects the PRF from the predefined vector
of values specified by the **Pulse repetition frequency
(Hz)** parameter.

**Example: **
`4`

#### Dependencies

To enable this port, select **Enable PRF selection
input**.

**Data Types: **`double`

`W`

— Element weights

length-*N* complex-valued vector

Weights applied to each element in array, specified as a
length-*N* complex-valued vector.
*N* is the number of elements in the array selected
in the **Sensor array** panel.

#### Dependencies

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

**Data Types: **`double`

**Complex Number Support: **Yes

`WS`

— Subarray element weights

*N*_{E}-by-*N*_{S}
complex-valued matrix

Weights applied to each element in a subarray, specified as an
*N*_{E}-by-*N*_{S}
complex-valued matrix.

When you set

**Specify sensor array**to`Replicated Subarray`

, all subarrays have the same dimensions. Then, you can specify the subarray element weights as a complex-valued*N*_{E}-by-*N*_{S}matrix.*N*is the number of elements in each subarray and_{E}*N*_{S}is the number of subarrays. Each column of`WS`

specifies the weights for the corresponding subarray.When you set

**Specify sensor array**to`Partitioned array`

, subarrays are not required to have identical dimensions and sizes. You can specify subarray element weights as a complex-valued*N*_{E}-by-*N*_{S}matrix, where*N*_{E}now is the number of elements in the largest subarray. The first*K*entries in each column are the element weights for the corresponding subarray where*K*is the number of elements in the subarray.

#### Dependencies

To enable this port, set **Specify sensor array**
to `Partitioned array`

or
`Replicated Subarray`

. Then, set
**Subarray steering method** to
`Custom`

.

**Data Types: **`double`

**Complex Number Support: **Yes

`Steer`

— Steering angle input

scalar | 2-by-1 real-valued vector

Steering angle, specified as a scalar or a 2-by-1 real-valued vector.
As a vector, the steering angle takes the form of
`[AzimuthAngle; ElevationAngle]`

. As a scalar, the
steering angle represents the azimuth angle only. Then the elevation
angle is assumed to be zero degrees. Units are in degrees

#### Dependencies

To enable this port, set **Specify sensor array**
to `Partitioned array`

or
`Replicated Subarray`

. Then, set
**Subarray steering method** to
`Phase`

or
`Time`

.

**Data Types: **`double`

### Output

`Out`

— Simulated clutter

*N*-by-*M* complex-valued
matrix

Simulated clutter, returned as an
*N*-by-*M* complex-valued
matrix.

*N* is the number of samples output from the block.
When you set the **Output signal format** parameter to
`Samples`

, specify *N*
using the **Number of samples in output** parameter.
When you set the **Output signal format** parameter to
`Pulses`

, *N* is the total
number of samples in the next *P* pulses where
*P* is specified in the **Number of pulse
in output** parameter.

*M* is either

the number of subarrays in the sensor array if sensor array contains subarrays.

the number of radiating or collecting elements if the sensor array does not contain subarrays.

**Data Types: **`double`

## Parameters

### Main Tab

`Terrain gamma value (dB)`

— Clutter model parameter

`0`

(default) | scalar

Clutter model parameter, specified as a scalar. This parameter contains the $$\gamma $$ value used in the constant $$\gamma $$ clutter model. The $$\gamma $$ value depends on both terrain type and the operating frequency. Units are in dB.

**Example: **`-5.0`

**Data Types: **`double`

`Earth model`

— Earth shape

`Flat`

(default) | `Curved`

Specify the earth model used in clutter simulation as
`Flat`

or
`Curved`

. When you set this parameter to
`Flat`

, the earth is assumed to be a plane.
When you set this parameter to `Curved`

, the
earth is assumed to be spherical.

`Minimum range of clutter region (m)`

— Minimum range of clutter region

`0`

| nonnegative scalar

Specify the minimum range for the clutter simulation as a positive scalar. The minimum range must be nonnegative. Units are in meters.

`Maximum range of clutter region (m)`

— Maximum range of clutter region

`5000`

| nonnegative scalar

Specify the maximum range for the clutter simulation as a positive
scalar. The maximum range must be greater than the value specified in
the `Radar height`

parameter. Units are in
meters.

`Azimuth center of clutter region (deg)`

— Azimuth center of clutter region

`0`

| scalar

The azimuth angle in the ground plane about which clutter patches are generated. Patches are generated symmetrically about this angle. Units are in degrees.

`Azimuth span of clutter region (deg)`

— Azimuth span of clutter region

`60`

(default) | positive scalar

Specify the azimuth span of each clutter patch as a positive scalar. Units are in degrees. Units are in degrees.

`Azimuth span of clutter patches (deg)`

— Azimuth span of clutter patches

`1`

(default) | positive scalar

Azimuth span of each clutter patch, specified as a positive scalar. Units are in degrees.

**Data Types: **`double`

`Clutter coherence time (s)`

— Coherence time of clutter simulation

`Inf`

(default) | positive scalar

Coherence time for the clutter simulation, specified as a positive
scalar. After the coherence time elapses, the block updates the random
numbers it uses for the clutter simulation at the next pulse. When you
use the default value of `Inf`

, the random numbers are
never updated. Units are in seconds.

**Example: **`4`

**Data Types: **`double`

`Signal propagation speed (m/s)`

— Signal propagation speed

`physconst('LightSpeed')`

(default) | real-valued positive scalar

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`

`Sample rate (Hz)`

— Clutter sample rate

`1e6`

(default) | positive scalar

Clutter sample rate, specified as a positive scalar. Units are in Hertz.

**Example: **`10e6`

**Data Types: **`double`

`Pulse repetition frequency (Hz)`

— Pulse repetition frequency

`1e4`

(default) | positive scalar | row vector of positive values

Pulse repetition frequency, PRF, specified as a positive scalar or a row vector of positive values. Units are in Hertz.

**Example: **`[1e4,2e4]`

**Data Types: **`double`

`Enable PRF selection input`

— Select predefined PRF

off (default) | on

Select this parameter to enable the `PRFIdx`

port.

When enabled, pass in an index into a vector of predefined PRFs. Set predefined PRFs using the

**Pulse repetition frequency (Hz)**parameter.When not enabled, the block cycles through the vector of PRFs specified by the

**Pulse repetition frequency (Hz)**parameter. If**Pulse repetition frequency (Hz)**is a scalar, the PRF is constant.

`Source of simulation sample time`

— Source of simulation sample time

`Derive from waveform parameters`

(default) | `Inherit from Simulink engine`

Source of simulation sample time, specified as ```
Derive from waveform
parameters
```

or `Inherit from Simulink engine`

.
When set to `Derive from waveform parameters`

, the block runs
at a variable rate determined by the PRF of the selected waveform. The elapsed time is
variable. When set to `Inherit from Simulink engine`

, the
block runs at a fixed rate so the elapsed time is a constant.

#### Dependencies

To enable this parameter, select the **Enable PRF selection
input** parameter.

`Output signal format`

— Format of the output signal

`Pulses`

(default) | `Samples`

The format of the output signal, specified as `Pulses`

or `Samples`

.

If you set this parameter to `Samples`

, the output of the block consists of multiple samples. The number of samples is the value of the **Number of samples in output** parameter.

If you set this parameter to `Pulses`

, the output of the block consists of multiple pulses. The number of pulses is the value of the **Number of pulses in output** parameter.

`Number of samples in output`

— Number of samples in output

`100`

(default) | positive integer

Number of samples in the block output, specified as a positive integer.

**Example: **`1000`

#### Dependencies

To enable this parameter, set the **Output signal format**
parameter to `Samples`

.

**Data Types: **`double`

`Number of pulses in output`

— Number of pulses in output

`1`

(default) | positive integer

Number of pulses in the block output, specified as a positive integer.

**Example: **`2`

#### Dependencies

To enable this parameter, set the **Output signal
format** parameter to
`Pulses`

.

**Data Types: **`double`

`Simulate using`

— Block simulation method

`Interpreted Execution`

(default) | `Code Generation`

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 Simulation | Simulation Behavior | ||

`Normal` | `Accelerator` | `Rapid Accelerator` | |

`Interpreted Execution` | The block executes using the MATLAB interpreter. | The block executes using the MATLAB interpreter. | Creates a standalone executable from the model. |

`Code Generation` | The block is compiled. | All blocks in the model are compiled. |

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

**Radar Tab**

`Operating frequency (Hz)`

— System operating frequency

`3.0e8`

(default) | positive real scalar

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

`Effective transmitted power (W)`

— radar system effective transmitted power

`5000`

(default) | positive scalar

Effective radiated power (ERP) of the radar system, specified as a positive scalar. Units are in watts.

**Example: **`3500`

**Data Types: **`double`

`Radar height (m)`

— Height of radar above surface

`0`

(default) | nonnegative scalar

Height of radar above surface, specified as a nonnegative scalar. Units are in meters.

**Example: **`50`

**Data Types: **`double`

`Radar speed (m/s)`

— Radar platform speed

`0`

(default) | nonnegative scalar

Radar platform speed, specified as a nonnegative scalar. Units are in meters per second.

**Example: **`5`

**Data Types: **`double`

`Radar motion direction (deg)`

— Direction of motion of radar platform

`[90;0]`

(default) | 2-by-1 real vector

Specify the direction of radar platform motion as a 2-by-1 real vector
in the form `[AzimuthAngle;ElevationAngle]`

. Units are
in degrees. Both azimuth and elevation angle are measured in the local
coordinate system of the radar antenna or antenna array. Azimuth angle
must be between –180° and 180°. Elevation angle must be
between –90° and 90°.

The default value of this parameter indicates that the radar platform is moving perpendicular to the radar antenna array broadside direction.

**Example: **`[25;30]`

**Data Types: **`double`

`Sensor mounting angles sensor (deg)`

— Sensor mounting angles

`[0 0 0]`

(default) | length-3 vector of positive values

Specify a 3-element vector that gives the intrinsic yaw, pitch, and roll of the sensor frame from the inertial frame. The 3 elements define the rotations around the z, y, and x axes respectively, in that order. The first rotation, rotates the body axes around the z-axis. Because these angles define intrinsic rotations, the second rotation is performed around the y-axis in its new position resulting from the previous rotation. The final rotation around the x-axis is performed around the x-axis as rotated by the first two rotations in the intrinsic system.

**Example: **`[0,-10,4]`

**Data Types: **`double`

`Enable weights input`

— Enable antenna element weights input port

unchecked (default) | checked

Check box to enable antenna element weights input port,
`W`

.

### Sensor Array Tab

`Specify sensor array as`

— Method to specify array

`Array (no subarrays)`

(default) | `Partitioned array`

| `Replicated subarray`

| `MATLAB expression`

Method to specify array, specified as ```
Array (no
subarrays)
```

or `MATLAB expression`

.

`Array (no subarrays)`

— use the block parameters to specify the array.`Partitioned array`

— use the block parameters to specify the array.`Replicated subarray`

— use the block parameters to specify the array.`MATLAB expression`

— create the array using a MATLAB expression.

`Expression`

— MATLAB expression used to create an array

Phased Array System Toolbox™ array System object

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**

`Element type`

— Array element types

`Isotropic Antenna`

(default) | `Cosine Antenna`

| `Custom Antenna`

| `Omni Microphone`

| `Custom Microphone`

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

`Isotropic Antenna`

`Cosine Antenna`

`Custom Antenna`

`Omni Microphone`

`Custom Microphone`

`Operating frequency range (Hz)`

— Operating frequency range of the antenna or microphone element

`[0,1.0e20]`

(default) | real-valued 1-by-2 row vector

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
```

.

`Operating frequency vector (Hz)`

— Operating frequency range of custom antenna or microphone elements

`[0,1.0e20]`

(default) | real-valued row vector

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.

`Baffle the back of the element`

— Set back response of an `Isotropic Antenna`

element or an `Omni Microphone`

element to zero

off (default) | on

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`

.

`Exponent of cosine pattern`

— Exponents of azimuth and elevation cosine patterns

`[1.5 1.5]`

(default) | nonnegative scalar | real-valued 1-by-2 matrix of nonnegative values

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 responses (dB)`

— Antenna and microphone frequency response

`[0,0]`

(default) | real-valued row vector

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`

.

`Input Pattern Coordinate System`

— Coordinate system of custom antenna pattern

`az-el`

(default) | `phi-theta`

Coordinate system of custom antenna pattern, specified `az-el`

or `phi-theta`

. When you specify `az-el`

, use the **Azimuth angles (deg)** and **Elevations angles (deg)** parameters to specify the coordinates of the pattern points. When you specify `phi-theta`

, use the **Phi angles (deg)** and **Theta angles (deg)** parameters to specify the coordinates of the pattern points.

#### Dependencies

To enable this parameter, set **Element type** to `Custom Antenna`

.

`Azimuth angles (deg)`

— Azimuth angles of antenna radiation pattern

`[-180:180]`

(default) | real-valued row vector

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 the **Element type** parameter to
`Custom Antenna`

and the **Input Pattern Coordinate
System** parameter to `az-el`

.

`Elevation angles (deg)`

— Elevation angles of antenna radiation pattern

`[-90:90]`

(default) | real-valued row vector

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 the **Element type** parameter to
`Custom Antenna`

and the **Input Pattern Coordinate
System** parameter to `az-el`

.

`Phi Angles (deg)`

— Phi angle coordinates of custom antenna radiation pattern

`0:360`

| real-valued 1-by-*P* row vector

Phi angles of points at which to specify the antenna radiation pattern, specify as a real-valued 1-by-*P* row vector. *P* must be greater than 2. Angle units are in degrees. Phi angles must lie between 0° and 360° and be in strictly increasing order.

#### Dependencies

To enable this parameter, set the **Element type** parameter to `Custom Antenna`

and the **Input Pattern Coordinate System** parameter to `phi-theta`

.

`Theta Angles (deg)`

— Theta angle coordinates of custom antenna radiation pattern

`0:180`

| real-valued 1-by-*Q* row vector

Theta angles of points at which to specify the antenna radiation pattern, specify as a real-valued 1-by-*Q* row vector. *Q* must be greater than 2. Angle units are in degrees. Theta angles must lie between 0° and 360° and be in strictly increasing order.

#### Dependencies

To enable this parameter, set the **Element type** parameter to `Custom Antenna`

and the **Input Pattern Coordinate System** parameter to `phi-theta`

.

`Magnitude pattern (dB)`

— Magnitude of combined antenna radiation pattern

`zeros(181,361)`

(default) | real-valued *Q*-by-*P* matrix | real-valued *Q*-by-*P*-by-*L* array

Magnitude of the combined antenna radiation pattern, specified as a
*Q*-by-*P* matrix or a
*Q*-by-*P*-by-*L* array.

When the

**Input Pattern Coordinate System**parameter is set to`az-el`

,*Q*equals the length of the vector specified by the**Elevation angles (deg)**parameter and*P*equals the length of the vector specified by the**Azimuth angles (deg)**parameter.When the

**Input Pattern Coordinate System**parameter is set to`phi-theta`

,*Q*equals the length of the vector specified by the**Theta Angles (deg)**parameter and*P*equals the length of the vector specified by the**Phi Angles (deg)**parameter.

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 pattern (deg)`

— Custom antenna radiation phase pattern

`zeros(181,361)`

(default) | real-valued *Q*-by-*P* matrix | real-valued *Q*-by-*P*-by-*L* array

Phase of the combined antenna radiation pattern, specified as a
*Q*-by-*P* matrix or a
*Q*-by-*P*-by-*L* array.

When the

**Input Pattern Coordinate System**parameter is set to`az-el`

,*Q*equals the length of the vector specified by the**Elevation angles (deg)**parameter and*P*equals the length of the vector specified by the**Azimuth angles (deg)**parameter.When the

**Input Pattern Coordinate System**parameter is set to`phi-theta`

,*Q*equals the length of the vector specified by the**Theta Angles (deg)**parameter and*P*equals the length of the vector specified by the**Phi Angles (deg)**parameter.

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 (**

#### Dependencies

To enable this parameter, set **Element type** to
`Custom Antenna`

.

`MatchArrayNormal`

— Rotate antenna element to array normal

`on`

(default) | `off`

Select this check box to rotate the antenna element pattern to align with the array normal. When not selected, the element pattern is not rotated.

When the antenna is used in an antenna array and the **Input Pattern Coordinate System** parameter is `az-el`

, selecting this check box rotates the pattern so that the *x*-axis of the element coordinate system points along the array normal. Not selecting uses the element pattern without the rotation.

When the antenna is used in an antenna array and **Input Pattern Coordinate System** is set to `phi-theta`

, selecting this check box rotates the pattern so that the *z*-axis of the element coordinate system points along the array normal.

Use the parameter in conjunction with the **Array normal** parameter of the `URA`

and `UCA`

arrays.

#### Dependencies

To enable this parameter, set **Element type** to `Custom Antenna`

.

`Polar pattern frequencies (Hz)`

— Polar pattern microphone response frequencies

1e3 (default) | real scalar | real-valued 1-by-*L* row vector

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`

.

`Polar pattern angles (deg)`

— Polar pattern response angles

`[-180:180]`

(default) | real-valued -by-*P* row vector

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
```

.

`Polar pattern (dB)`

— Custom microphone polar response

`zeros(1,361)`

(default) | real-valued *L*-by-*P* matrix

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**

`Geometry`

— Array geometry

`ULA`

(default) | `URA`

| `UCA`

| `Conformal Array`

Array geometry, specified as one of

`ULA`

— Uniform linear array`URA`

— Uniform rectangular array`UCA`

— Uniform circular array`Conformal Array`

— arbitrary element positions

`Number of elements`

— Number of array elements

`2`

for ULA arrays and `5`

for
UCA arrays (default) | integer greater than or equal to 2

The number of array elements for ULA or UCA arrays, specified as an integer greater than or equal to 2.

When you set **Specify sensor array as** to ```
Replicated
subarray
```

, this parameter applies to each subarray.

#### Dependencies

To enable this parameter, set **Geometry** to `ULA`

or `UCA`

.

`Element spacing (m)`

— Spacing between array elements

`0.5`

for ULA arrays and `[0.5,0.5]`

for
URA arrays (default) | positive scalar for ULA or URA arrays | 2-element vector of positive values for URA arrays

Spacing between adjacent array elements:

ULA — specify the spacing between two adjacent elements in the array as a positive scalar.

URA — specify the spacing as a positive scalar or a 1-by-2 vector of positive values. If

**Element spacing (m)**is a scalar, the row and column spacings are equal. If**Element spacing (m)**is a vector, the vector has the form`[SpacingBetweenArrayRows,SpacingBetweenArrayColumns]`

.When you set

**Specify sensor array as**to`Replicated subarray`

, this parameter applies to each subarray.

#### Dependencies

To enable this parameter, set **Geometry** to `ULA`

or `URA`

.

`Array axis`

— Linear axis direction of ULA

`y`

(default) | `x`

| `z`

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.

`Array size`

— Dimensions of URA array

`[2,2]`

(default) | positive integer | 1-by-2 vector of positive integers

Dimensions of a URA array, specified as a positive integer or 1-by-2 vector of positive integers.

If

**Array size**is a 1-by-2 vector, the vector has the form`[NumberOfArrayRows,NumberOfArrayColumns]`

.If

**Array size**is an integer, the array has the same number of rows and columns.When you set

**Specify sensor array as**to`Replicated subarray`

, this parameter applies to each subarray.

For a URA, array elements are indexed from top to bottom along the
leftmost column, and then continue to the next columns from left to right. In this
figure, the **Array size** value of `[3,2]`

creates an
array having three rows and two columns.

#### Dependencies

To enable this parameter, set **Geometry** to `URA`

.

`Element lattice`

— Lattice of URA element positions

`Rectangular`

(default) | `Triangular`

Lattice of URA element positions, specified as `Rectangular`

or `Triangular`

.

`Rectangular`

— Aligns all the elements in row and column directions.`Triangular`

— Shifts the even-row elements of a rectangular lattice toward the positive row-axis direction. The displacement is one-half the element spacing along the row dimension.

#### Dependencies

To enable this parameter, set **Geometry** to `URA`

.

`Array normal`

— Array normal direction

`x`

for URA arrays
or `z`

for UCA arrays (default) | `y`

Array normal direction, specified as `x`

, `y`

,
or `z`

.

Elements of planar arrays lie in a plane orthogonal to the selected array normal direction. Element boresight directions point along the array normal direction.

Array Normal Parameter Value | Element Positions and Boresight Directions |
---|---|

`x` | Array elements lie in the yz-plane. All
element boresight vectors point along the x-axis. |

`y` | Array elements lie in the zx-plane. All
element boresight vectors point along the y-axis. |

`z` | Array elements lie in the xy-plane. All
element boresight vectors point along the z-axis. |

#### Dependencies

To enable this parameter, set **Geometry** to `URA`

or `UCA`

.

`Radius of UCA (m)`

— UCA array radius

0.5 (default) | positive scalar

Radius of UCA array, specified as a positive scalar.

#### Dependencies

To enable this parameter, set **Geometry** to `UCA`

.

`Element positions (m)`

— Positions of conformal array elements

`[0;0;0]`

(default) | 3-by-*N*matrix of real values

Positions of the elements in a conformal array, specified as
a 3-by-*N* matrix of real values, where *N* is
the number of elements in the conformal array. Each column of this
matrix represents the position `[x;y;z]`

of an array
element in the array local coordinate system. The origin of the local
coordinate system is *(0,0,0)*. Units are in meters.

**Specify sensor array as** to ```
Replicated
subarray
```

, this parameter applies to each subarray.

#### Dependencies

To enable this parameter set **Geometry** to ```
Conformal
Array
```

.

`Element normals (deg)`

— Direction of conformal array element normal vectors

`[0;0]`

| 2-by-1 column vector | 2-by-*N* matrix

Direction of element normal vectors in a conformal array, specified as a 2-by-1 column vector
or a 2-by-*N* matrix. *N* indicates the number of
elements in the array. For a matrix, each column specifies the normal direction of the
corresponding element in the form `[azimuth;elevation]`

with respect to
the local coordinate system. The local coordinate system aligns the positive
*x*-axis with the direction normal to the conformal array. If the
parameter value is a 2-by-1 column vector, the same pointing direction is used for all
array elements.

**Specify sensor array as** to ```
Replicated
subarray
```

, this parameter applies to each subarray.

You can use the **Element positions (m)** and **Element
normals (deg)** parameters to represent any arrangement in
which pairs of elements differ by certain transformations. The transformations
can combine translation, azimuth rotation, and elevation rotation.
However, you cannot use transformations that require rotation about
the normal direction.

#### Dependencies

To enable this parameter, set **Geometry** to ```
Conformal
Array
```

.

`Taper`

— Array element tapers

1 (default) | complex-valued scalar | complex-valued row vector

Element tapering, specified 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.

Also known as *element weights*, tapers multiply the array element
responses. Tapers modify both amplitude and phase of the response to reduce side lobes
or steer the main response axis.

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.
The number of weights must match the number of elements of the array.

**Specify sensor array as** to ```
Replicated
subarray
```

, this parameter applies to each subarray.

`Subarray definition matrix`

— Define elements belonging to subarrays

logical matrix

Specify the subarray selection as an *M*-by-*N*
matrix. *M* is the number of subarrays and *N* is the
total number of elements in the array. Each row of the matrix represents a subarray and
each entry in the row indicates when an element belongs to the subarray. When the entry
is zero, the element does not belong the subarray. A nonzero entry represents a
complex-valued weight applied to the corresponding element. Each row must contain at
least one nonzero entry.

The phase center of each subarray lies at the subarray geometric center. The subarray
geometric center depends on the **Subarray definition matrix** and
**Geometry** parameters.

#### Dependencies

To enable this parameter, set **Specify sensor array as** to
`Partitioned array`

.

`Subarray steering method`

— Specify subarray steering method

`None`

(default) | `Phase`

| `Time`

Subarray steering method, specified as one of

`None`

`Phase`

`Time`

`Custom`

Selecting `Phase`

or `Time`

opens the
`Steer`

input port on the Narrowband Receive Array,
Narrowband Transmit Array, Wideband Receive Array,
Wideband Transmit Array blocks, Constant Gamma
Clutter, and GPU Constant Gamma Clutter blocks.

Selecting `Custom`

opens the `WS`

input port on the
Narrowband Receive Array, Narrowband Transmit Array,
Wideband Receive Array, Wideband Transmit Array
blocks, Constant Gamma Clutter, and GPU Constant Gamma
Clutter blocks.

#### Dependencies

To enable this parameter, set **Specify sensor array as** to
`Partitioned array`

or ```
Replicated
subarray
```

.

`Phase shifter frequency (Hz)`

— Subarray phase shifting frequency

`3.0e8`

(default) | positive real-valued scalar

Operating frequency of subarray steering phase shifters, specified as a positive real-valued scalar. Units are Hz.

#### Dependencies

To enable this parameter, set **Sensor array** to ```
Partitioned
array
```

or `Replicated subarray`

and set **Subarray
steering method** to `Phase`

.

`Number of bits in phase shifters`

— Subarray steering phase shift quantization bits

`0`

(default) | non-negative integer

Subarray steering phase shift quantization bits, specified as a non-negative integer. A value of zero indicates that no quantization is performed.

#### Dependencies

To enable this parameter, set **Sensor array** to ```
Partitioned
array
```

or `Replicated subarray`

and set **Subarray
steering method** to `Phase`

.

`Subarrays layout`

— Subarray position specification

`Rectangular`

(default) | `Custom`

Specify the layout of replicated subarrays as `Rectangular`

or `Custom`

.

When you set this parameter to

`Rectangular`

, use the**Grid size**and**Grid spacing**parameters to place the subarrays.When you set this parameter to

`Custom`

, use the**Subarray positions (m)**and**Subarray normals**parameters to place the subarrays.

#### Dependencies

To enable this parameter, set **Sensor array** to ```
Replicated
subarray
```

`Grid size`

— Dimensions of rectangular subarray grid

`[1,2]`

(default)

Rectangular subarray grid size, specified as a single positive integer, or a 1-by-2 row vector of positive integers.

If **Grid size** is an integer scalar, the
array has an equal number of subarrays in each row and column. If **Grid
size** is a 1-by-2 vector of the form ```
[NumberOfRows,
NumberOfColumns]
```

, the first entry is the number of subarrays
along each column. The second entry is the number of subarrays in
each row. A row is along the local *y*-axis, and
a column is along the local *z*-axis. The figure
here shows how you can replicate a 3-by-2 URA subarray using a **Grid
size** of `[1,2]`

.

#### Dependencies

To enable this parameter, set **Sensor array** to ```
Replicated
subarray
```

and **Subarrays layout** to `Rectangular`

.

`Grid spacing (m)`

— Spacing between subarrays on rectangular grid

`Auto`

(default) | positive real-valued scalar | 1-by-2 vector of positive real-values

The rectangular grid spacing of subarrays, specified as a positive,
real-valued scalar, a 1-by-2 row vector of positive, real-values,
or `Auto`

. Units are in meters.

If

**Grid spacing**is a scalar, the spacing along the row and the spacing along the column is the same.If

**Grid spacing**is a 1-by-2 row vector, the vector has the form`[SpacingBetweenRows,SpacingBetweenColumn]`

. The first entry specifies the spacing between rows along a column. The second entry specifies the spacing between columns along a row.If

**Grid spacing**is set to`Auto`

, replication preserves the element spacing of the subarray for both rows and columns while building the full array. This option is available only when you specify**Geometry**as`ULA`

or`URA`

.

#### Dependencies

To enable this parameter, set **Sensor array** to ```
Replicated
subarray
```

and **Subarrays layout** to `Rectangular`

.

`Subarray positions (m)`

— Positions of subarrays

`[0,0;0.5,0.5;0,0]`

(default) | 3-by-*N* real-valued matrix

Positions of the subarrays in the custom grid, specified as
a real 3-by-*N* matrix, where *N* is
the number of subarrays in the array. Each column of the matrix represents
the position of a single subarray in the array local coordinate system.
The coordinates are expressed in the form `[x; y; z]`

.
Units are in meters.

#### Dependencies

To enable this parameter, set **Sensor array** to ```
Replicated
subarray
```

and **Subarrays layout** to `Custom`

.

`Subarray normals`

— Direction of subarray normal vectors

`[0,0;0,0]`

(default) | 2-by-*N* real matrix

Specify the normal directions of the subarrays in the array.
This parameter value is a 2-by-*N* matrix, where *N* is
the number of subarrays in the array. Each column of the matrix specifies
the normal direction of the corresponding subarray, in the form `[azimuth;elevation]`

.
Angle units are in degrees. Angles are defined with respect to the
local coordinate system.

You can use the **Subarray positions** and **Subarray
normals** parameters to represent any arrangement in which
pairs of subarrays differ by certain transformations. The transformations
can combine translation, azimuth rotation, and elevation rotation.
However, you cannot use transformations that require rotation about
the normal.

#### Dependencies

To enable this parameter, set the **Sensor array** parameter
to `Replicated subarray`

and the **Subarrays
layout** to `Custom`

.

## Extended Capabilities

### C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

## Version History

**Introduced in R2021a**

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