Range Doppler Response

Doppler range response.

range doppler response

Description

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

Ports

Input

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

Input signal.

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

When pulse signals are used, the length of the signal may change. Then only the Matched filter option of the Range method processing parameters can be applied.

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

Support for complex numbers: Yes.

XRef - reference signal
`Complex vector-column K at 1

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

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

Coeff - coefficients of matched filter
complex column vector

The coefficients of the matched filter given as a complex vector-column. This argument can be specified with single or double precision.

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

PRF - pulse repetition frequency
positive scalar

The pulse repetition rate specified as a positive scalar. PRF must be less than or equal to the sampling rate specified in the SampleRate property divided by the length of the first measurement of the input signal X. This argument can be specified 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 - Doppler range response
complex matrix M by N | array M by N by P

Doppler range response by X, returned as a complex-valued matrix M on P or an array M on N on P. The values of P and M are syntax-dependent. N has the same meaning as for the input argument X.

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

Range - range values by range grid
actual vector-column M by 1

Range values over which the range of the Doppler response 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 samples
actual vector-column M by 1

Doppler or velocity samples on which the Doppler response is estimated. Here dopgrid is a column vector of length P. Whether 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 - range processing method
Matched filter (by default) | FFT

Range processing method specified as Matched filter or FFT.

Matched filter - The block applies a matched filter to the incoming signal. This approach is typically used for pulsed signals, where the matched filter is the temporal inverse of the transmitted signal.
FFT - the block applies an FFT to the input signal. This approach is typically 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/c
3e8 (by default) | positive scalar

Signal propagation speed as a real positive scalar. By default, the value of the speed of light is 3e8 m/c.

The unit of measurement is metres per second.

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

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

Source of pulse repetition frequency, set as:

Auto - automatic pulse repetition frequency (PRF) calculation. 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 frequency using the PRF parameters.
Input port - specify the PRF using the PRF input port.

Use the Property or Input port parameters if the pulse repetition rate cannot be determined from the signal duration, as in the case of 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 frequency of the input signal, specified as a positive scalar. PRF must be less than or equal to the sampling frequency divided by the number of lines of the input signal. If the signal length is variable, the maximum possible number of lines of the input signal 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 sample rate
On (By default) | Off

Select the checkbox to inherit sample rate from upstream blocks. Otherwise, set the sample rate using the Sample rate (Hz) parameters.

Sample rate - sampling frequency of the signal, Hz
`positive scalar

Set the sampling rate of the signal (in hertz) as a positive scalar. This parameter appears only if the Inherit sample rate parameter 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 (by default) | Property

Specify how the block determines the FFT length used in Doppler processing. The values of this parameters are:

Auto

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

Property

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

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

Specify 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 level of side lobe attenuation as a positive scalar in decibels.

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

Doppler output - Doppler output signal
Frequency | Speed

Specify the Doppler output signal as Frequency or Speed.

Frequency

Doppler shift, in hertz.

Speed

Radial velocity corresponding to the Doppler shift, in metres per second.

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

Signal carrier frequency - 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 - FM sweep slope, Hz/c
scalar

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

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

Dechirp input signal - enable input signal decryption
on (by default) | `off

Select this checkbox to make the unit perform the input signal decryption operation. Clear this check box to indicate that the input signal has already been decoded and no decoding 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 (By default) | Property.

The source of FFT length used for processing decrypted signals in range is specified as Auto or Property.

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

Dependencies

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

FFT length in range processing - FFT length range processing
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 FFT length in range processing as a positive integer.

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

Specify the window used to process the range 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 constant side petals adjacent to the main petal.

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 centre - setting the range of values at the centre of the range grid
On (by default) | Off

Set the range of values in the centre of the range grid, set as enabled or disabled. Checking this box sets the value range in the centre of the range grid. Otherwise, the value range 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 - sidelobe attenuation level
30 (By default) | scalar

Sidelobe attenuation level as a positive scalar.

This attenuation applies only to Chebyshev, Kaiser or Taylor windows. The unit of measurement is 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 range grid values, m
non-negative scalar

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

If the Range processing method parameters are set to Matched filter, the range of values is set to the beginning of the range grid.
If the Range processing method parameters are set to FFT, the range of values depends on the Set reference range at centre checkbox.
- If the Set reference range at centre checkbox is selected, the value range will be set to the centre of the range grid.
- If the Set reference range at centre checkbox is not selected, the reference range is set to the beginning of the range grid.

The units of measurement are metres.

*Example: 1000.0

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