WinChirpRgCompPow.h File Reference

Chirp and range compress related helper functionalities. More...

#include <complex>
#include <tuple>
#include <vector>
#include <isce3/core/EMatrix.h>
#include "WinChirpRgCompPow.icc"

Go to the source code of this file.

Namespaces
namespace	isce3
	base interpolator is an abstract base class

Typedefs
using	isce3::antenna::detail::RowMatrixXcf = isce3::core::EMatrix2D<std::complex<float>>

Functions
template<typename T = float>
std::vector< T >	isce3::antenna::detail::genRaisedCosineWin (int size, double ped)
	Generate a raised-cosine window function with a desired pedestal.
std::vector< std::complex< float > >	isce3::antenna::detail::genRcosWinChirp (double sample_freq, double chirp_slope, double chirp_dur, double win_ped=0.0, bool norm=true)
	Generate a unit-energy raised-cosine-windowed baseband complex analytical chirp.
Eigen::ArrayXd	isce3::antenna::detail::meanRgCompEchoPower (const Eigen::Ref< const RowMatrixXcf > &echo_mat, const std::vector< std::complex< float > > &chirp_ref)
	Averaged Power of range compressed complex raw echo over multiple range lines as a function of true valid range bins.
std::tuple< Eigen::ArrayXd, Eigen::ArrayXd >	isce3::antenna::detail::rangeCalibAvgEchoPower (const Eigen::Ref< const Eigen::ArrayXd > &echo_pow, double rg_start, double rg_spacing, int size_avg=1)
	Path-loss corrected/calibrated averaged/decimated uniformly-sampled echo power as a function of slant ranges.

Detailed Description

Chirp and range compress related helper functionalities.

Function Documentation

genRaisedCosineWin()

template<typename T = float>

std::vector< T > isce3::antenna::detail::genRaisedCosineWin	(	int	size,
		double	ped )

Generate a raised-cosine window function with a desired pedestal.

Window is symmetric and has a peak equal to 1.0 at the center only for odd window size. The end points are equal to pedestal value.

Parameters

[in]	size	a positive integer for size of the window > 1.
[in]	ped	pedestal of the widnow. A value within [0.0, 1.0] where 1.0 is rectangular window while 0.0 is Hann window. Ped=0.08 is a Hamming window.

Returns

a floating-point vector of window function.

Exceptions

InvalidArgument

Note

Given pedestal value "p" and size "L", the window function is \(\frac{1+p}{2} - \frac{1-p}{2} \times \cos(\frac{2\pi}{L-1}n)\) where \(n = 0, 1, 2, \cdots, L-1\).

genRcosWinChirp()

std::vector< std::complex< float > > isce3::antenna::detail::genRcosWinChirp ( double sample_freq, double chirp_slope, double chirp_dur, double win_ped = 0.0, bool norm = true )

inline

Generate a unit-energy raised-cosine-windowed baseband complex analytical chirp.

That is a basebanded linear FM with a symmetric rectangular or raised-cosine envelope.

Parameters

[in]	sample_freq	sampling frequency in (Hz) or (MHz)
[in]	chirp_slope	chirp slope in (Hz/sec) or (MHz/usec) depending on unit of "sample_freq".
[in]	chirp_dur	chirp duration in (sec) or (usec) depending on the inverse unit of "sample_freq".
[in]	win_ped	raised-cosine window pedestal, a value within [0.0, 1.0]. Default is "Hann" window.
[in]	norm	a bool, whether or not normalize output to be unit-energy.

Returns

a vector of time-series complex floating-point chirp samples.

Exceptions

InvalidArgument

See also

isce3::focus::formLinearChirp(), genRaisedCosineWin()

meanRgCompEchoPower()

Eigen::ArrayXd isce3::antenna::detail::meanRgCompEchoPower ( const Eigen::Ref< const RowMatrixXcf > & echo_mat, const std::vector< std::complex< float > > & chirp_ref )

inline

Averaged Power of range compressed complex raw echo over multiple range lines as a function of true valid range bins.

Only valid part of range compressed data will be returned!

Parameters

[in]	echo_mat	raw echo matrix, a row-major Eigen matrix of type complex float. The rows represent range lines. The matrix shape is pulses (azimuth bins) by range bins.
[in]	chirp_ref	Basebanded Chirp reference complex float vector used in range compresssion. Its size shall not be larger than number of range bins or columns of "echo_mat", otherwise, it throws LengthError.

Returns

An eigen vector of real-value double precision representing averaged power over range lines of range compressed echo as a function of true and valid range bins after pulse extension deconvolution. The number of range bins will be smaller than that of raw echo (its columns) due to pulse extension.

Exceptions

LengthError

rangeCalibAvgEchoPower()

std::tuple< Eigen::ArrayXd, Eigen::ArrayXd > isce3::antenna::detail::rangeCalibAvgEchoPower ( const Eigen::Ref< const Eigen::ArrayXd > & echo_pow, double rg_start, double rg_spacing, int size_avg = 1 )

inline

Path-loss corrected/calibrated averaged/decimated uniformly-sampled echo power as a function of slant ranges.

Note that the last few samples might be thrown out depending on averaging block size.

Parameters

[in]	echo_pow	a vector of echo power uniformly-sampled in range.
[in]	rg_start	starting range in (meters)
[in]	rg_spacing	range spacing in (meters)
[in]	size_avg	block size for averaing. That is the number of range bins to be averaged. This also deteremines the final range spacing which is "size_avg * rg_space". Note that size_avg shall be within [1,echo_pow.size].

Returns

power array

slant-range array

Exceptions

InvalidArgument,LengthError