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Workspace Method sensor_responseFillFgrid
Description
Polynomial frequency interpolation of spectra. z The sensor response methods treat the spectra to be piece-wise linear functions. This method is a workaround for making methods handling the spectra in a more elaborate way: it generates spectra on a more dense grid by polynomial interpolation. The interpolation is not done explicitly, it is incorporated into sensor_response. This method should in general increase the calculation accuracy for a given f_grid. However, the selection of (original) grid points becomes more sensitive when using this method. A poor choice of grid points can result in a decreased accuracy, or generation of negative radiances. Test calculations indicated that the error easily can increase with this method close the edge of f_grid, and it could be wise to make f_grid a bit wider than actually necessary to avoid this effect The method shall be inserted before the antenna stage. That is, this method shall normally be called directly after sensor_responseInit. Between each neighbouring points of f_grid, this method adds *nfill* grid points. The polynomial order of the interpolation is *polyorder*.
Authors: Patrick Eriksson
Synopsis
| sensor_responseFillFgrid( | sensor_response, sensor_response_f, sensor_response_pol, sensor_response_za, sensor_response_aa, sensor_response_f_grid, sensor_response_pol_grid, sensor_response_za_grid, sensor_response_aa_grid, polyorder, nfill ) |
Variables
| OUT | sensor_response | (Sparse) | The matrix modelling the total sensor response. |
| OUT | sensor_response_f | (Vector) | The frequencies associated with the output of sensor_response. |
| OUT | sensor_response_pol | (ArrayOfIndex) | The polarisation states associated with the output of sensor_response. |
| OUT | sensor_response_za | (Vector) | The relative zenith angles associated with the output of sensor_response. |
| OUT | sensor_response_aa | (Vector) | The relative azimuth angles associated with the output of sensor_response. |
| OUT | sensor_response_f_grid | (Vector) | The frequency grid associated with sensor_response. |
| IN | sensor_response | (Sparse) | The matrix modelling the total sensor response. |
| IN | sensor_response_f | (Vector) | The frequencies associated with the output of sensor_response. |
| IN | sensor_response_pol | (ArrayOfIndex) | The polarisation states associated with the output of sensor_response. |
| IN | sensor_response_za | (Vector) | The relative zenith angles associated with the output of sensor_response. |
| IN | sensor_response_aa | (Vector) | The relative azimuth angles associated with the output of sensor_response. |
| IN | sensor_response_f_grid | (Vector) | The frequency grid associated with sensor_response. |
| IN | sensor_response_pol_grid | (ArrayOfIndex) | The "polarisation grid" associated with sensor_response. |
| IN | sensor_response_za_grid | (Vector) | The zenith angle grid associated with sensor_response. |
| IN | sensor_response_aa_grid | (Vector) | The azimuth angle grid associated with sensor_response. |
| GIN | polyorder | (Index, Default: 3) | Polynomial order of interpolation |
| GIN | nfill | (Index, Default: 2) | Number of points to insert in each gap of f_grid |