Wideband Backscatter Radar Target
Backscatter wideband signals from radar target
Libraries:
Phased Array System Toolbox /
Environment and Target
Description
The Wideband Backscatter Radar Target block models the monostatic reflection of nonpolarized wideband electromagnetic signals from a radar target. The target radar cross-section (RCS) model includes four Swerling target fluctuation models and a nonfluctuating model. You can model several targets simultaneously by specifying multiple radar cross-section RCS matrices.
Ports
Input
X — Wideband incident nonpolarized signal
N-by-1 complex-valued
vector | N-by-M complex-valued
matrix
Wideband incident nonpolarized signal, specified as an N-by-1 complex-valued vector or an N-by-M complex-valued matrix. The quantity N is the number of signal samples, and M is the number of independent signals reflecting off the target. Each column contains an independent signal to be reflected from the target.
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
Ang — Incident signal direction
2-by-1 real-valued column vector | 2-by-M real-valued column matrix
Incident signal direction, specified as a 2-by-1 real-valued column
vector or a 2-by-M real-valued column matrix.
M is the number of signals reflecting from the
target. Each column of Ang
specifies the incident
direction of the corresponding signal in the form of an
[AzimuthAngle;ElevationAngle]
pair. Units are
degrees. The number of columns in Ang
must match
the number of independent signals in X
.
Example: [30;45]
Data Types: double
Update — Switch to update RCS
false
| true
Switch to update RCS fluctuation model values, specified as
false
or true
. When
Update
is true
, the RCS
value is updated. If Update
is
false
, the RCS remains unchanged.
Dependencies
To enable this port, set the Fluctuation
model drop-down menu to
Swerling1
,
Swerling2
,
Swerling3
, or
Swerling4
.
Output
Port_1 — Narrowband reflected signal
1-by-M complex-valued vector | N-by-M complex-valued
matrix
Wideband nonpolarized signal, specified as an 1-by-M complex-valued vector or a N-by-M complex-valued matrix. Each column contains an independent signal reflected from the target.
The quantity N is the number of signal samples and M is the number of signals reflecting off the target. Each column corresponds to a different reflecting angle.
The output port contains signal samples arriving at the signal destination within the current input time frame. When the propagation time from source to destination exceeds the current time frame duration, the output does not contain all contributions from the input of the current time frame.
Parameters
Backscatter pattern frequency vector (Hz) — Wideband backscatter pattern frequencies
[0,1e20]
(default) | real-valued row vector of positive values in strictly increasing
order
Specify the frequencies used in the RCS matrix. The elements of this vector must be in strictly increasing order. The target has no response outside this frequency range. Frequencies are defined with respect to the physical frequency band, not the baseband. Frequency units are in Hz.
Data Types: double
Azimuth angles (deg) — Azimuth angles
[-180:180]
(default) | 1-by-P real-valued row vector | P-by-1 real-valued column vector
Azimuth angles used to define the angular coordinates of each column of the matrices specified by the RCS pattern (m^2) parameter. Specify the azimuth angles as a length P vector. P must be greater than two. Angle units are in degrees.
Example: [-45:0.1:45]
Data Types: double
Elevation angles (deg) — Elevation angles
[-90:90]
(default) | 1-by-Q real-valued row vector | Q-by-1 real-valued column vector
Elevation angles used to define the angular coordinates of each row of the matrices specified by the RCS pattern (m^2) parameter. Specify the elevation angles as a length Q vector. Q must be greater than two. Angle units are in degrees.
Example: [-30:0.1:30]
Data Types: double
RCS pattern (m^2) — Radar cross-section pattern
ones(181,361)
(default) | Q-by-P real-valued matrix | Q-by-P-by-K
real-valued array | 1-by-P-by-K real-valued
array | K-by-P real-valued matrix
Radar cross-section pattern, specified as a real-valued matrix or array.
Dimensions | Application |
---|---|
Q-by-P matrix | Specifies a matrix of RCS values as a function of Q elevation angles and P azimuth angles. The same RCS matrix is used for all frequencies. |
Q-by-P-by-K array | Specifies an array of RCS patterns as a function of Q elevation angles, P azimuth angles, and K frequencies. If K = 1, the RCS pattern is equivalent to a Q-by-P matrix. |
1-by-P-by-K array | Specifies a matrix of RCS values as a function of P azimuth angles and K frequencies. These dimension formats apply when there is only one elevation angle. |
K-by-P matrix |
Q is the length of the vector specified by the Elevation angles (deg) parameter.
P is the length of the vector specified by the Azimuth angles (deg) parameter.
K is the number of frequencies specified by the Backscatter pattern frequency vector (Hz) parameter.
You can specify patterns for L targets by putting L patterns into a cell array. All patterns must have the same dimensions. The value of L must match the column dimensions of the signals passed as input into the block. You can, however, use one pattern to model L multiple targets.
RCS units are in square meters.
Example: [1,2;2,1]
Data Types: double
Fluctuation model — Target fluctuation model
Nonfluctuating
(default) | Swerling1
| Swerling2
| Swerling3
| Swerling4
Target fluctuation model, specified as
Nonfluctuating
,
Swerling1
,
Swerling2
,
Swerling3
, or
Swerling4
. If you set this parameter to a
value other than Nonfluctuating
, you must pass
either true
or false
into the
Update
Update
port.
Propagation speed (m/s) — Signal propagation speed
physconst('LightSpeed')
(default) | 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')
.
Data Types: double
Operating frequency (Hz) — Signal carrier frequency
300.0e6
(default) | positive real-valued scalar
Signal carrier frequency, specified as a positive real-valued scalar. Units are in hertz.
Inherit sample rate — Inherit sample rate from upstream blocks
on (default) | off
Select this parameter to inherit the sample rate from upstream blocks. Otherwise, specify the sample rate using the Sample rate (Hz) parameter.
Data Types: Boolean
Sample rate (Hz) — Sampling rate of signal
1e6
(default) | positive real-valued scalar
Specify the signal sampling rate as a positive scalar. Units are in Hz.
Dependencies
To enable this parameter, clear the Inherit sample rate check box.
Data Types: double
Number of subbands — Number of processing subbands
64
(default) | positive integer
Number of processing subbands, specified as a positive integer.
Example: 128
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).
Programmatic Use
Block
Parameter:SimulateUsing |
Type:enum |
Values:Interpreted
Execution , Code Generation |
Default:Interpreted
Execution |
Version History
Introduced in R2016b
See Also
Objects
Blocks
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