ARTS  2.2.66
sensor.cc File Reference

Functions related to sensor modelling. More...

#include <cmath>
#include <list>
#include <stdexcept>
#include "arts.h"
#include "logic.h"
#include "make_vector.h"
#include "matpackI.h"
#include "matpackII.h"
#include "messages.h"
#include "sorting.h"
#include "sensor.h"
Include dependency graph for sensor.cc:

Go to the source code of this file.

Functions

void antenna1d_matrix (Sparse &H, const Index &antenna_dim, ConstMatrixView antenna_los, const GriddedField4 &antenna_response, ConstVectorView za_grid, ConstVectorView f_grid, const Index n_pol, const Index do_norm)
 antenna1d_matrix More...
 
void antenna2d_simplified (Sparse &H, const Index &antenna_dim, ConstMatrixView antenna_los, const GriddedField4 &antenna_response, ConstVectorView za_grid, ConstVectorView aa_grid, ConstVectorView f_grid, const Index n_pol, const Index do_norm)
 antenna2d_simplified More...
 
void gaussian_response_autogrid (Vector &x, Vector &y, const Numeric &x0, const Numeric &fwhm, const Numeric &xwidth_si, const Numeric &dx_si)
 gaussian_response_autogrid More...
 
void gaussian_response (Vector &y, const Vector &x, const Numeric &x0, const Numeric &fwhm)
 gaussian_response More...
 
void mixer_matrix (Sparse &H, Vector &f_mixer, const Numeric &lo, const GriddedField1 &filter, ConstVectorView f_grid, const Index &n_pol, const Index &n_sp, const Index &do_norm)
 mixer_matrix More...
 
void sensor_aux_vectors (Vector &sensor_response_f, ArrayOfIndex &sensor_response_pol, Vector &sensor_response_za, Vector &sensor_response_aa, ConstVectorView sensor_response_f_grid, const ArrayOfIndex &sensor_response_pol_grid, ConstVectorView sensor_response_za_grid, ConstVectorView sensor_response_aa_grid, const Index za_aa_independent)
 sensor_aux_vectors More...
 
void sensor_integration_vector (VectorView h, ConstVectorView f, ConstVectorView x_f_in, ConstVectorView x_g_in)
 sensor_integration_vector More...
 
void sensor_integration_vector2 (VectorView h, ConstVectorView f, ConstVectorView x_f, ConstVectorView x_g_in)
 sensor_integration_vector More...
 
void sensor_summation_vector (VectorView h, ConstVectorView f, ConstVectorView x_f, ConstVectorView x_g, const Numeric x1, const Numeric x2)
 sensor_summation_vector More...
 
void spectrometer_matrix (Sparse &H, ConstVectorView ch_f, const ArrayOfGriddedField1 &ch_response, ConstVectorView sensor_f, const Index &n_pol, const Index &n_sp, const Index &do_norm)
 spectrometer_matrix More...
 
void stokes2pol (ArrayOfVector &s2p, const Numeric &nv)
 stokes2pol More...
 
bool test_and_merge_two_channels (Vector &fmin, Vector &fmax, Index i, Index j)
 Test if two instrument channels overlap, and if so, merge them. More...
 
void find_effective_channel_boundaries (Vector &fmin, Vector &fmax, const Vector &f_backend, const ArrayOfGriddedField1 &backend_channel_response, const Numeric &delta, const Verbosity &verbosity)
 Calculate channel boundaries from instrument response functions. More...
 

Variables

const Numeric PI
 
const Numeric NAT_LOG_2
 
const Index GFIELD1_F_GRID
 
const Index GFIELD4_FIELD_NAMES
 
const Index GFIELD4_F_GRID
 
const Index GFIELD4_ZA_GRID
 
const Index GFIELD4_AA_GRID
 

Detailed Description

Functions related to sensor modelling.

Author
Mattias Ekström ekstr.nosp@m.om@r.nosp@m.ss.ch.nosp@m.alme.nosp@m.rs.se
Date
2003-02-27

Functions to model sensor behaviour and integration calculated as vector multiplication.

Definition in file sensor.cc.

Function Documentation

◆ antenna1d_matrix()

void antenna1d_matrix ( Sparse H,
const Index antenna_dim,
ConstMatrixView  antenna_los,
const GriddedField4 antenna_response,
ConstVectorView  za_grid,
ConstVectorView  f_grid,
const Index  n_pol,
const Index  do_norm 
)

antenna1d_matrix

Core function for setting up the response matrix for 1D antenna cases.

Main task is to extract correct antenna pattern, including frequency interpolation. Actual weights are calculated in sensor_integration_vector.

Parameters
HThe antenna transfer matrix
antenna_dimAs the WSV with the same name
antenna_losAs the WSV with the same name
antenna_responseAs the WSV with the same name
za_gridZenith angle grid for pencil beam calculations
f_gridFrequency grid for monochromatic calculations
n_polNumber of polarisation states
do_normFlag whether response should be normalised
Author
Mattias Ekström / Patrick Eriksson
Date
2003-05-27 / 2008-06-17

Definition at line 79 of file sensor.cc.

References GriddedField4::data, DEBUG_ONLY, GriddedField::get_numeric_grid(), GriddedField::get_string_grid(), GFIELD4_AA_GRID, GFIELD4_F_GRID, GFIELD4_FIELD_NAMES, GFIELD4_ZA_GRID, gridpos(), Sparse::insert_row(), interp(), interpweights(), joker, Sparse::ncols(), Array< base >::nelem(), ConstVectorView::nelem(), Sparse::resize(), and sensor_integration_vector().

Referenced by antenna2d_simplified(), and sensor_responseAntenna().

◆ antenna2d_simplified()

void antenna2d_simplified ( Sparse H,
const Index antenna_dim,
ConstMatrixView  antenna_los,
const GriddedField4 antenna_response,
ConstVectorView  za_grid,
ConstVectorView  aa_grid,
ConstVectorView  f_grid,
const Index  n_pol,
const Index  do_norm 
)

antenna2d_simplified

A first function for setting up the response matrix for 2D antenna cases.

Following the ARTS definitions, a bi-linear variation (in za and aa dimensions) for both antenna pattern and pencil beam radiances should be assumed here. This function does not handle this. It performs instead a series of 1D antenna calculations and "sums up" the results. In this summation, both antenna pattern and radiances are assumed to constant in the azimuthal direction around each point in aa_grid (corresponding to mblock_aa_grid). That is, for azimuth, a step-wise function is used instead of a piecewise linear one.

Parameters
HThe antenna transfer matrix
antenna_dimAs the WSV with the same name
antenna_losAs the WSV with the same name
antenna_responseAs the WSV with the same name
za_gridZenith angle grid for pencil beam calculations
aa_gridAzimuth angle grid for pencil beam calculations
f_gridFrequency grid for monochromatic calculations
n_polNumber of polarisation states
do_normFlag whether response should be normalised
Author
Patrick Eriksson
Date
2009-09-16

Definition at line 247 of file sensor.cc.

References antenna1d_matrix(), GriddedField4::data, GriddedField::get_numeric_grid(), GFIELD4_AA_GRID, gridpos(), Sparse::insert_row(), last(), ConstTensor4View::nbooks(), ConstVectorView::nelem(), ConstTensor4View::npages(), ConstTensor4View::nrows(), Sparse::resize(), GriddedField4::resize(), and GriddedField::set_grid().

Referenced by sensor_responseAntenna().

◆ find_effective_channel_boundaries()

void find_effective_channel_boundaries ( Vector fmin,
Vector fmax,
const Vector f_backend,
const ArrayOfGriddedField1 backend_channel_response,
const Numeric delta,
const Verbosity verbosity 
)

Calculate channel boundaries from instrument response functions.

This function finds out the unique channel boundaries from f_backend and backend_channel_response. This is not a trivial task, since channels may overlap, or may be sorted in a strange way. The function tries to take care of all that. If channels overlap, they are combined to one continuous frequency region. therefore the number of elements in the output vectors fmin and fmax can be lower than the number of elements in f_backend and backend_channel_response.

The function also does consistency checking on the two input variables.

The output vectors fmin and fmax will be monotonically increasing.

Author
Stefan Buehler
Parameters
[out]fminVector of lower boundaries of instrument channels.
[out]fmaxVector of upper boundaries of instrument channels.
[in]f_backendNominal backend frequencies.
[in]backend_channel_responseChannel response, relative to nominal frequencies.
[in]deltaExtra margin on both sides of each band. Has a default value of 0.

delta;

Definition at line 1325 of file sensor.cc.

References CREATE_OUT2, get_sorted_indexes(), is_increasing(), last(), Array< base >::nelem(), ConstVectorView::nelem(), Vector::resize(), and test_and_merge_two_channels().

Referenced by f_gridFromSensorAMSU(), f_gridFromSensorAMSUgeneric(), and f_gridFromSensorHIRS().

◆ gaussian_response()

void gaussian_response ( Vector y,
const Vector x,
const Numeric x0,
const Numeric fwhm 
)

gaussian_response

Returns a 1D gaussian response

y is the gaussian function on grid x, with max at x0 and width following fwhm.

Parameters
yCalculated response.
xGrid.
x0The x-position of response centre/max.
fwhmThe full width at half-maximum of the response
Author
Patrick Eriksson
Date
2009-09-20

Definition at line 452 of file sensor.cc.

References NAT_LOG_2, ConstVectorView::nelem(), PI, and Vector::resize().

Referenced by antenna_responseVaryingGaussian(), and gaussian_response_autogrid().

◆ gaussian_response_autogrid()

void gaussian_response_autogrid ( Vector x,
Vector y,
const Numeric x0,
const Numeric fwhm,
const Numeric xwidth_si,
const Numeric dx_si 
)

gaussian_response_autogrid

Returns a 1D gaussian response with a suitable grid

First a grid is generated. The grid is si*[-xwidth_si:dx:xwidth_si], where si is the "standard deviation" corresponding to the FWHM, and dx is biggest possible value < dx_si, to enusre an symmetric grid wth end points exactly at xwidth_si. That is, width and spacing of the grid is specified in terms of number of standard deviations. If xwidth_si is set to 2, the response will cover about 95% the complete response. For xwidth_si=3, about 99% is covered.

y is the gaussian function on grid x, with max at x0 and width following fwhm.

Parameters
xGrid generated.
yCalculated response.
x0The x-position of response centre/max.
fwhmThe full width at half-maximum of the response
xwidth_siThe one-sided width of x. See above.
dx_siThe grid step size of x. See above.
Author
Patrick Eriksson
Date
2009-09-20

Definition at line 412 of file sensor.cc.

References gaussian_response(), NAT_LOG_2, and nlinspace().

Referenced by antenna_responseGaussian(), antenna_responseVaryingGaussian(), and backend_channel_responseGaussian().

◆ mixer_matrix()

void mixer_matrix ( Sparse H,
Vector f_mixer,
const Numeric lo,
const GriddedField1 filter,
ConstVectorView  f_grid,
const Index n_pol,
const Index n_sp,
const Index do_norm 
)

mixer_matrix

Sets up the sparse matrix that models the response from sideband filtering and the mixer.

The size of the transfer matrix is changed in the function as follows: nrows = f_mixer.nelem() ncols = f_grid.nelem()

The returned frequencies are given in IF, so both primary and mirror band is converted down.

Parameters
HThe mixer/sideband filter transfer matrix
f_mixerThe frequency grid of the mixer
loThe local oscillator frequency
filterThe sideband filter data. See sideband_response for format and constraints.
f_gridThe original frequency grid of the spectrum
n_polThe number of polarisations to consider
n_spThe number of spectra (viewing directions)
do_normFlag whether rows should be normalised
Author
Mattias Ekström / Patrick Eriksson
Date
2003-05-27 / 2008-06-17

Definition at line 496 of file sensor.cc.

References GriddedField1::data, DEBUG_ONLY, GriddedField::get_numeric_grid(), GFIELD1_F_GRID, Sparse::insert_row(), last(), ConstVectorView::nelem(), Sparse::resize(), Vector::resize(), and sensor_summation_vector().

Referenced by sensor_responseMixer().

◆ sensor_aux_vectors()

void sensor_aux_vectors ( Vector sensor_response_f,
ArrayOfIndex sensor_response_pol,
Vector sensor_response_za,
Vector sensor_response_aa,
ConstVectorView  sensor_response_f_grid,
const ArrayOfIndex sensor_response_pol_grid,
ConstVectorView  sensor_response_za_grid,
ConstVectorView  sensor_response_aa_grid,
const Index  za_aa_independent 
)

sensor_aux_vectors

Sets up the the auxiliary vectors for sensor_response.

The function assumes that all grids are common, and the aux vectors are just the grids repeated.

Parameters
sensor_response_fAs the WSV with same name
sensor_response_polAs the WSV with same name
sensor_response_zaAs the WSV with same name
sensor_response_aaAs the WSV with same name
sensor_response_f_gridAs the WSV with same name
sensor_response_pol_gridAs the WSV with same name
sensor_response_za_gridAs the WSV with same name
sensor_response_aa_gridAs the WSV with same name
za_aa_independentFlag to indicate that za and aa dimensions are "perpendicular". This is only valid before the antenna response has been considered.
Author
Patrick Eriksson
Date
2008-06-09

Definition at line 627 of file sensor.cc.

References Array< base >::nelem(), ConstVectorView::nelem(), and Vector::resize().

Referenced by sensor_responseAntenna(), sensor_responseBackend(), sensor_responseBackendFrequencySwitching(), sensor_responseBeamSwitching(), sensor_responseFillFgrid(), sensor_responseFrequencySwitching(), sensor_responseGenericAMSU(), sensor_responseInit(), sensor_responseMixer(), sensor_responseMultiMixerBackend(), sensor_responsePolarisation(), and sensor_responseWMRF().

◆ sensor_integration_vector()

void sensor_integration_vector ( VectorView  h,
ConstVectorView  f,
ConstVectorView  x_f_in,
ConstVectorView  x_g_in 
)

sensor_integration_vector

Calculates the (row) vector that multiplied with an unknown (column) vector approximates the integral of the product between the functions represented by the two vectors: h*g = integral( f(x)*g(x) dx )

Basic principle follows Eriksson et al., Efficient forward modelling by matrix representation of sensor responses, Int. J. Remote Sensing, 27, 1793-1808, 2006. However, while in Eriksson et al. the product between f*g is assumed to vary linearly between the grid point, the expressions applied here are more advanced and are completly exact as long as f and g are piece-wise linear functions. The product f*g is then a quadratic funtion between the grid points.

Parameters
hThe multiplication (row) vector.
fThe values of function f(x).
x_f_inThe grid points of function f(x). Must be increasing.
x_g_inThe grid points of function g(x). Can be increasing or decreasing. Must cover a wider range than x_f (in both ends).
Author
Mattias Ekström and Patrick Eriksson
Date
2003-02-13 / 2008-06-12

Definition at line 723 of file sensor.cc.

References b0, dx, is_decreasing(), is_increasing(), min, and ConstVectorView::nelem().

Referenced by antenna1d_matrix(), spectrometer_matrix(), and Test().

◆ sensor_integration_vector2()

void sensor_integration_vector2 ( VectorView  h,
ConstVectorView  f,
ConstVectorView  x_f,
ConstVectorView  x_g_in 
)

sensor_integration_vector

Calculates the (row) vector that multiplied with an unknown (column) vector approximates the integral of the product between the functions represented by the two vectors.

E.g. h*g = integral( f(x)*g(x) dx )

See Eriksson et al., Efficient forward modelling by matrix representation of sensor responses, Int. J. Remote Sensing, 27, 1793-1808, 2006, for details.

Parameters
hThe multiplication (row) vector.
fThe values of function f(x).
x_f_inThe grid points of function f(x). Must be increasing.
x_g_inThe grid points of function g(x). Can be increasing or decreasing. Must cover a wider range than x_ft (in both ends).
Author
Mattias Ekström and Patrick Eriksson
Date
2003-02-13 / 2008-06-12

Definition at line 886 of file sensor.cc.

References dx, is_decreasing(), is_increasing(), and ConstVectorView::nelem().

Referenced by Test().

◆ sensor_summation_vector()

void sensor_summation_vector ( VectorView  h,
ConstVectorView  f,
ConstVectorView  x_f,
ConstVectorView  x_g,
const Numeric  x1,
const Numeric  x2 
)

sensor_summation_vector

Calculates the (row) vector that multiplied with an unknown (column) vector approximates the sum of the product between the functions at two points.

E.g. h*g = f(x1)*g(x1) + f(x2)*g(x2)

The typical application is to set up the combined response matrix for mixer and sideband filter.

See Eriksson et al., Efficient forward modelling by matrix representation of sensor responses, Int. J. Remote Sensing, 27, 1793-1808, 2006, for details.

No normalisation of the response is made.

Parameters
hThe summation (row) vector.
fSideband response.
x_fThe grid points of function f(x).
x_gThe grid for spectral values (normally equal to f_grid)
x1Point 1
x2Point 2
Author
Mattias Ekström / Patrick Eriksson
Date
2003-05-26 / 2008-06-17

Definition at line 1030 of file sensor.cc.

References gridpos(), interp(), interpweights(), last(), and ConstVectorView::nelem().

Referenced by mixer_matrix().

◆ spectrometer_matrix()

void spectrometer_matrix ( Sparse H,
ConstVectorView  ch_f,
const ArrayOfGriddedField1 ch_response,
ConstVectorView  sensor_f,
const Index n_pol,
const Index n_sp,
const Index do_norm 
)

spectrometer_matrix

Constructs the sparse matrix that multiplied with the spectral values gives the spectra from the spectrometer.

The input to the function corresponds mainly to WSVs. See f_backend and backend_channel_response for how the backend response is specified.

Parameters
HThe response matrix.
ch_fCorresponds directly to WSV f_backend.
ch_responseCorresponds directly to WSV backend_channel_response.
sensor_fCorresponds directly to WSV sensor_response_f_grid.
n_polThe number of polarisations.
n_spThe number of spectra (viewing directions).
do_normCorresponds directly to WSV sensor_norm.
Author
Mattias Ekström and Patrick Eriksson
Date
2003-08-26 / 2008-06-10

Definition at line 1096 of file sensor.cc.

References GFIELD1_F_GRID, Sparse::insert_row(), Array< base >::nelem(), ConstVectorView::nelem(), Sparse::resize(), sensor_integration_vector(), and ConstVectorView::sum().

Referenced by sensor_responseBackend().

◆ stokes2pol()

void stokes2pol ( ArrayOfVector s2p,
const Numeric nv 
)

stokes2pol

Sets up an array of vectors to convert the Stokes vector to different polarsiations.

The measured value is the sum of the element product of the conversion vector and the Stokes vector. Schematically:

y[iout] = sum( s2p[i].*iy(iin,joker)

The order of the vectors follow the coding described for sensor_pol, but zero-based indexing is used here. That is, the first vector (s2p[0]) corresponds to I.

Trailing zeros are not stored, to indicate the required value of stokes_dim*.

Vectors for I, Q, U and V are always normalised to have unit length (one value is 1, the remaining ones zero). The first element of remaining vectors is set to nv (and other values normalised accordingly), to allow that calibartion and other normalisation effects can be incorporated.

Parameters
s2pArray of conversion vectors.
nvNorm value for polarisations beside I, Q, U and V.
Author
Patrick Eriksson
Date
2011-11-01

Definition at line 1196 of file sensor.cc.

Referenced by iy_transmitterMultiplePol(), iy_transmitterSinglePol(), sensor_responsePolarisation(), and yCloudRadar().

◆ test_and_merge_two_channels()

bool test_and_merge_two_channels ( Vector fmin,
Vector fmax,
Index  i,
Index  j 
)

Test if two instrument channels overlap, and if so, merge them.

The channels boundaries are specified in two separate vectors, fmin and fmax. These vectors are both input and output. If merging has happened, they will each be one element shorter.

The positions of the channels to compare is given by the input parameters i and j. It is assumed that the minimum frequency of i is lower than or equal to that of j.

Furthermore, it is assumed that i itself is lower than j.

The range of the first channel (i) will have been extended to accomodate the second channel (j). The second channel will have been removed.

The function also handles the updating of index j: If the two channels do not overlap, j is increased by one.

Function returns true if merging has happened.

Author
Stefan Buehler
Returns
True if channels were merged, otherwise false.
Return values
fminLower channel boundaries.
fmaxUpper channel boundaries.
Parameters
iIndex of first channel.
jIndex of second channel.

Definition at line 1249 of file sensor.cc.

References ConstVectorView::nelem(), and Vector::resize().

Referenced by find_effective_channel_boundaries().

Variable Documentation

◆ GFIELD1_F_GRID

const Index GFIELD1_F_GRID

◆ GFIELD4_AA_GRID

const Index GFIELD4_AA_GRID

◆ GFIELD4_F_GRID

const Index GFIELD4_F_GRID

Referenced by antenna1d_matrix().

◆ GFIELD4_FIELD_NAMES

const Index GFIELD4_FIELD_NAMES

Referenced by antenna1d_matrix().

◆ GFIELD4_ZA_GRID

const Index GFIELD4_ZA_GRID

Referenced by antenna1d_matrix().

◆ NAT_LOG_2

const Numeric NAT_LOG_2

◆ PI

const Numeric PI

Referenced by gaussian_response().