Range Doppler Response

The Doppler range response.

blockType: RangeDopplerResponse

Path in the library:

/Phased Array Systems/Detection/Range Doppler Response

Description

The Range-Doppler Response block calculates a map of the Doppler range of the input signal. The output response is a matrix, the rows of which are range elements, and the columns are Doppler intervals.

Ports

Entrance

X — input signal
complex column vector K by 1 | complex matrix K by L | complex array K by N by L

The input signal.

The number of samples for the first dimension of the input matrix can be changed to simulate a change in the length of the signal. A change in size can occur, for example, in the case of a pulse waveform with a variable pulse repetition rate.

When using pulse signals, the length of the signal may vary. Then only the Matched filter option of the Range method processing parameter can be applied.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Support for complex numbers: Yes

XRef — pass reference signal:q[ ] complex column vector K by 1

A reference signal specified as a column vector with the same number of rows as X. This argument can be set with single or double precision.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Coeff — coefficients of the matched pass filter:q[ ] complex column vector

Coefficients of the matched filter, specified as a complex column vector. This argument can be set with single or double precision.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

PRF — pulse repetition rate
positive scalar

The pulse repetition rate, set as a positive scalar. The PRF must be less than or equal to the sampling frequency specified in the SampleRate property divided by the length of the first measurement of the input signal X. This argument can be set with single or double precision.

Dependencies

To use this argument, set the PRFSource property to Input port.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Output

Resp — response of the Doppler range
complex matrix M by N | array M by N by P

The response of the Doppler range in X, returned as a complex-valued matrix of M to P or an array of M to N to P. The values of P and M depend on the syntax. N has the same value as for the input argument X.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Range — range values according to the grid of pass ranges:q[ ] the valid column vector is M by 1

Values of the range at which the Doppler response range is estimated. Here `rnggrid' is a column vector of length M.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Dop — Doppler sampling
the valid column vector is M by 1

Doppler samples or velocity samples, at which the response of the Doppler range is estimated. Here dopgrid' is a column vector of length P. Whether the `dopgrid contains Doppler or velocity samples depends on the DopplerOutput property.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Parameters

Range processing method — pass range processing method:q[ ] Matched filter (default) | FFT

The range processing method specified as Matched filter or `FFT'.

Matched filter — the block applies a matched filter to the incoming signal. This approach is usually used for pulsed signals, when the matched filter is a temporary feedback characteristic of the transmitted signal.
The 'FFT' block applies the FFT to the input signal. This approach is commonly used for FMCW and linear FM pulse signals.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Signal propagation speed — signal propagation speed, m/s
3e8 (default) | positive scalar

The propagation velocity of the signal in the form of a real positive scalar. The default value for the speed of light is `3e8 m/s'.

The units of measurement are meters per second.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Source of pulse repetition frequency — pulse repetition frequency source
Auto | Property | Input port

The pulse repetition rate source is set as:

Auto — automatic pulse repetition rate (PRF) calculation. The PRF is the sampling frequency of the signal divided by the number of lines in the input port signal, X.
Property — set the pulse repetition rate using the PRF parameter.
`Input port' — specify the PRF using the PRF input port.

Use the Property or Input port parameter if the pulse repetition rate cannot be determined by the duration of the signal, as is the case with range capture data.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Pulse repetition frequency of the input signal — pulse repetition frequency of the input signal, Hz
positive scalar

The pulse repetition rate of the input signal, set as a positive scalar. The PRF must be less than or equal to the sampling frequency divided by the number of input lines. If the length of the signal is variable, then the maximum possible number of input lines should be used instead.

Dependencies

To use this parameter, set the Source of pulse repetition frequency parameter to Property.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Inherit sample rate — inherit the sample rate of
enabled (by default) | disabled

Check the box to inherit the sampling rate from higher-level blocks. Otherwise, set the sampling rate using the Sample rate (Hz) parameter.

Sample rate is the sampling frequency of the signal, Hz
positive scalar

Set the sampling frequency of the signal (in hertz) as a positive scalar. This parameter appears only if the Inherit sample rate option is not selected.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

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. The values of this parameter are:

Auto

The length of the FFT is equal to the number of input lines.

Property

The FFT length in Doppler processing parameter of this block sets the length of the FFT.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Set the window used for Doppler processing using one of the following values: No', `Hamming, Chebyshev, Hann, Kaiser, `Taylor'.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Doppler sidelobe attenuation level — Doppler processing window
Kaiser | Chebyshev | Taylor | positive scalar

This parameter appears only if the Doppler window is set to Kaiser, `Chebyshev' or `Taylor'. Set the attenuation level of the side lobes as a positive scalar in decibels.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Doppler output — output signal of the Doppler range
Frequency | Speed

Specify the Doppler area output signal as Frequency or `Speed'.

Frequency

Doppler shift, in hertz.

Speed

The radial velocity corresponding to the Doppler shift, in meters per second.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Signal carrier frequency — the carrier frequency of the signal, Hz
scalar

This parameter appears only if the Doppler output parameter is set to Speed. Set the carrier frequency in hertz as a scalar.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

FM sweep slope — the slope of the FM band sweep, Hz/c
scalar

This parameter appears only when the Range processing method is set to FFT. Set the slope of the FM band scan in hertz per second as a scalar.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Dechirp input signal — enabling decryption of input signals
enabled (by default) | disabled

Select this option so that the block performs the decryption operation of the input signal. Uncheck this box to indicate that the input signal has already been decrypted and no decryption operation is required.

Dependencies

To use this parameter, set the Range processing method parameter to FFT.

Source of FFT length in range — FFT length source
Auto (default) | Property

The source of the FFT length used to process decrypted signals in the range is set as Auto or Property.

Auto — The length of the FFT is equal to the length of the fast time measurement of the input data cube.
Property — Specify the length of the FFT using the FFT length in range processing parameter.

Dependencies

To use this parameter, set the Range processing method parameter to FFT.

FFT length in range processing — processing of the FFT length range
a positive integer

This parameter appears only if the Range processing method parameter is set to FFT, and the Source of FFT length in range processing parameter is set to Property. Set the length of the FFT in the range area as a positive integer.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Specify the window used for range processing using one of the following values: None', `Hamming, Chebyshev, Hann, Kaiser, `Taylor'.

If you set this parameter to Taylor, the generated Taylor window will have four almost permanent side lobes adjacent to the main lobe.

Dependencies

To use this parameter, set the Range processing method parameter to FFT.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Set reference range at center — sets the range of values in the center of the grid of pass ranges:q[ ] enabled (by default) | disabled

Set the range of values in the center of the range grid, set as on or off. By checking this box, you can set a range of values in the center of the range grid. Otherwise, the range of values is set to the beginning of the range grid.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Range sidelobe attenuation level — attenuation level of the side lobes of the
30 (default) | scalar

The attenuation level of the side lobes in the form of a positive scalar.

This attenuation applies only to Chebyshev, Kaiser, or Taylor windows. The units of measurement are dB.

Dependencies

To use this parameter, set the Range processing method parameter to FFT, and the Range processing window parameter to Chebyshev, Kaiser, or `Taylor'.

Reference range — range of values of the range grid, m
non-negative scalar

The range of values of the range grid, specified as a non-negative scalar.

If the Range processing method parameter is set to Matched filter, then the range of values is set to the beginning of the range grid.
If you set the Range processing method parameter to FFT, the range of values depends on the Set reference range at center checkbox.
- If the Set reference range at center checkbox is selected, the range of values will be set in the center of the range grid.
- If the Set reference range at center checkbox is not checked, the reference range is set to the beginning of the range grid.

The units of measurement are meters.

Example: 1000.0

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Examples

System model of bistatic radar with two targets