Gamma DIFF&GEO: Reference Manual

S1_deramp_TOPS_slave

NAME
S1_deramp_TOPS_slave - Script to deramp a Sentinel-1 TOPS mode burst SLC slave with the same phase ramps as used to deramp the corresponding reference.

SYNOPSIS
S1_deramp_TOPS_slave <SLC_tab_slave> <SLC_ID_slave> <SLC_tab_ref> [RLK] [AZLK] [cleaning]

<SLC_tab_slave>	(input) SLC_tab of S1 TOPS burst SLC slave (that is co-registered to reference) (e.g. 20141126.RSLC_tab)
<SLC_ID_slave>	(input) ID for the S1 TOPS burst SLC slave files (e.g. 20141126)
<SLC_tab_ref>	(input) SLC_tab of S1 TOPS burst SLC reference (e.g. 20141015.SLC_tab)
[RLK]	number of range looks in the output MLI image (default=10)
[AZLK]	number of azimuth looks in the output MLI image (default=2)
[cleaning]	flag to indicate if deramped sub-swath SLCs (*.IW1.slc.deramp etc.) shall be deleted (default = 1 --> deleted, 0: not deleted)

EXAMPLE
S1_deramp_TOPS_slave 20141126.RSLC_tab 20141126 20141015.SLC_tab 10 2 1

Conducts a deramping of the slave burst SLC data with the same azimuth phase ramps as used to deramp the corresponding reference scene. The filenames for the deramped data are generated based on SLC_tab.

DESCRIPTION
S1_deramp_TOPS_slave is used to deramp the burst SLC data of a S1 TOPS slave scene that has already been co-registered to a refernce burst SLC. For each burst the deramp phase used for the reference scene is subtracted. The deramped data (as burst SLC, i.e. with the individual files for each sub-swath) and the phase ramps subtracted (in the same format, but using float values) are generated, as well as the SLC mosaic (considering the indicated number of range and azimuth looks in the decision where to set the interface between the subsequent bursts and adjecent subswaths.

The filenames for the output files are automatically generated based on the filenames of the input data. The output SLC_tab for the deramped burst SLC consists of the SLC_tab name with ".deramp". Similarly, the burst SLC file names of the deramped data are generated:
20141126.RSLC_tab --> 20141126.RSLC_tab.deramp
20141126.IW1.rslc --> 20141126.IW1.rslc.deramp
20141126.IW1.rslc.par --> 20141126.IW1.rslc.deramp.par
20141126.IW1.rslc.TOPS_par --> 20141126.IW1.rslc.deramp.TOPS_par

The name of the output SLC mosaic and the related SLC parameter file are generated based on the indicated SLC_ID_slave: "SLC_ID_slave.rslc.deramp" and "SLC_ID_slave.rslc.deramp.par".

S1_deramp_TOPS_slave checks if the required deramping phases (output from S1_deramp_TOPS_reference) already exists. If this is the case then it is used, otherwise the deramping phases are calculated. In this case the corresponding file names for the deramp phases subtracted are:
20141015.IW1.rslc.deramp.dph, 20141015.IW2.rslc.deramp.dph, and 20141015.IW3.rslc.deramp.dph.

The azimuth spectra of the deramped data should be in the base band and centered and should not vary in azimuth direction. To check the spectra you can use the program dismph_fft.

Deramping of the S1 TOPS data may be used to apply oversampling in offset tracking, apply common band filtering in azimuth direction or to apply split-beam interferometry, or to use the spectral diversity criteria in the IPTA for the point target candidate identification (program sp_stat). For differential interferoemtry, on the other hand, deramping of the S1 IWS data is not necessary.

Subtracting the same phase ramp for the reference scene and slave scenes that have been co-registered to the reference scene is strongly recommended to avoid phase effects from subtracting different azimuth phase ramps.

OPTIONS
To deramp a refernce burst SLC the program S1_deramp_TOPS_slave can be used.