Range Doppler Response
Range-Doppler response
Libraries:
Phased Array System Toolbox /
Detection
Description
The Range-Doppler Response block computes the range-Doppler map of an input signal. The output response is a matrix whose rows represent range gates and whose columns represent Doppler bins.
Ports
Input
X — Input
complex-valued K-by-L
matrix | K-by-N-by-L
array
Input data, specified as a complex-valued K-by-L matrix or K-by-N-by-L array where
K denotes the number of fast-time samples.
N denotes the number of channels such as beams or sensors. When N is one, only a single data channel is present.
L denotes the number of pulses for matched-filter processing and the number of sweeps for FFT processing.
Data Types: single
| double
Coeff — Matched filter coefficients
column vector
Matched filter coefficients, specified as a column vector.
Dependencies
To enable this port, set the Range processing
method to Matched filter
.
Data Types: single
| double
XRef — Reference signal
vector
Reference signal, specified as a
Dependencies
To enable this port, set the Range processing
method to FFT
and then select the
Dechirp input signal check box.
Data Types: double
PRF — Pulse repetition frequency
positive scalar
Pulse repetition frequency, specified as a positive scalar.
prf
must be less than or equal to the sample
rate specified in the SampleRate
property divided
by the length of the first dimension of the input signal,
x
. You can specify this argument as single or
double precision.
Dependencies
To enable this port, set the Source of pulse repetition
frequency drop down menu to Input
port
.
Data Types: double
Output
Resp — Range-Doppler response
complex
Range-Doppler, returned as a complex-valued M-by-P matrix or an M-by-N-by-P array.
Range — Range samples
vector
Range samples at which the range-Doppler response is evaluated. The output is a column vector of length M.
Data Types: double
Dop — Doppler or speed samples
vector
Doppler samples or speed samples at which the range-Doppler response is evaluated.
returned as a column vector of length P. Whether
Dop
contains Doppler or speed samples depends
on the Doppler output parameter.
Data Types: double
Parameters
Range processing method — Range processing method
Matched filter
(default) | FFT
Specify the method of range processing as Matched
filter
or FFT
Matched filter
| Applies a matched filter to the incoming signal. This
technique is commonly used for pulsed signals, where the
matched filter is the time reverse of the transmitted
signal. Choosing this option creates the
Coeff input port. |
FFT
| Performs range processing by applying an FFT to the input signal. This approach is commonly used with FMCW and linear FM pulsed signals. |
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
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
Reference range (m) — Reference range
0
(default)
Specify the reference range of the range grid as a nonnegative scalar.
If you set the Range processing method parameter to
Matched filter
, the reference range is set to the start of the range grid.If you set the Range processing method property to
FFT
, the reference range depends on the Set reference range at center check box.When you select the Set reference range at center check box, the reference range is set to the center of the range grid.
If you do not select the Set reference range at center check box, the reference range is set to the start of the range grid.
Units are in meters.
Source of pulse repetition frequency — Source of pulse repetition frequency
Auto
(default) | Property
| Input port
Specify the source of pulse repetition frequency as
Auto
— automatically compute the pulse repetition frequency (PRF). The PRF is the sample rate of the signal divided by the number of rows in the input port signal,X
.Property
— specify the pulse repetition frequency using thePRF
parameter.Input port
— specify the PRF using thePRF
input port.
Use the Property
or
Input port
option when the pulse repetition
frequency cannot be determined by the signal duration, as is the case with
range-gated data.
Pulse repetition frequency of the input signal (Hz) — Pulse repetition frequency of the input signal
10e3
(default)
Specify the pulse repetition frequency of the input signal as a positive
scalar. PRF
must be less than or equal to the sample
rate divided by the number of rows of the input signal. When the signal
length is variable, use the maximum possible number of rows of the input
signal instead.
Dependencies
To enable this parameter, set the Source of pulse repetition
frequency parameter to
Property
.
Source of FFT length in Doppler processing — Source of FFT length in Doppler processing
Auto
(default) | Property
Specify how the block determines the length of the FFT used in Doppler processing. Values of this parameter are
Auto
| The FFT length equals the number of rows of the input signal. |
Property
| The FFT length in Doppler processing parameter of this block specifies the FFT length. |
FFT length in Doppler processing — FFT length in Doppler processing
1024
Specify the length of the FFT used in Doppler processing as a positive integer.
Dependencies
This parameter appears only when you set Source of FFT
length in Doppler processing to
Property
.
Doppler processing window — Doppler processing window
None
(default) | Hamming
| Chebyshev
| Hann
| Kaiser
| Taylor
Specify the window used for Doppler processing using one of
None |
Hamming |
Chebyshev |
Hann |
Kaiser |
Taylor |
If you set this parameter to
Taylor
, the generated Taylor window has four
nearly-constant sidelobes adjacent to the mainlobe.
Doppler sidelobe attenuation level — Doppler sidelobe attenuation level
30
(default)
Specify the sidelobe attenuation level as a positive scalar, in decibels.
Dependencies
This parameter appears only when Doppler processing
window is set to Kaiser
,
Chebyshev
, or
Taylor
.
Doppler output — Doppler output
Frequency
(default) | Speed
Specify the Doppler domain output as Frequency
or Speed
Frequency
| Doppler shift, in hertz. |
Speed
| Radial speed corresponding to Doppler shift, in meters per second. |
Signal carrier frequency (Hz) — Signal carrier frequency
3e8
(default) | positive scalar
Signal carrier frequency, specified as a positive scalar. Units are in Hz.
Data Types: double
FM sweep slope (Hz/s) — FM sweep slope
1e9
(default)
Specify the slope of the linear FM sweeping, in hertz per second, as a scalar.
Dependencies
This parameter appears only when you set Range processing
method to FFT
.
Dechirp input signal — Dechirp input signal
off (default) | on
Select this check box to make the block perform the dechirp operation on the input signal. Clear this check box to indicate that the input signal is already dechirped and no dechirp operation is necessary.
Dependencies
This check box appears only when you set Range processing
method to FFT
.
Source of FFT length in range processing — Source of FFT length in range processing
Auto
(default) | Property
Specify how the block determines the FFT length in range processing. Values of this parameter are
Auto
| The FFT length equals the number of rows of the input signal. |
Property
| The FFT length is specified by FFT length in range processing . |
Dependencies
This parameter appears only when you set Range processing
method to FFT
.
FFT length in range processing — FFT length in range processing
1024
(default)
Specify the FFT length in the range domain as a positive integer.
Dependencies
This parameter appears only when you set Range processing
method to FFT
and
Source of FFT length in range processing to
Property
.
Range processing window — Range processing window
None
(default) | Hamming
| Chebyshev
| Hann
| Kaiser
| Taylor
Specify the window used for range processing using one of
None |
Hamming |
Chebyshev |
Hann |
Kaiser |
Taylor |
If you set this parameter to
Taylor
, the generated Taylor window has four
nearly-constant sidelobes adjacent to the mainlobe.
Dependencies
This parameter appears only when you set Range processing
method to FFT
.
Set reference range at center — Set reference range at center
on (default) | off
Set reference range at the center of range grid, specified as
on
or off
. Selecting this check
box, enables you to set the reference range at the center of the range grid.
Otherwise, the reference range is set to the beginning of the range
grid.
Range sidelobe attenuation level — Range sidelobe attenuation level
30
(default)
Specify the sidelobe attenuation level as a positive scalar, in decibels.
Dependencies
This parameter appears only when you set Range processing
method to FFT
and
Range processing window to
Kaiser
,
Chebyshev
, or
Taylor
.
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 R2014b
See Also
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