Gamma ISP: Reference Manual

SLC_deramp_S1_TOPS

ANSI-C program: SLC_deramp_S1_TOPS.c

NAME
SLC_deramp_S1_TOPS - Calculate and subtract S1 TOPS Doppler phase from burst SLC data

SYNOPSIS
  SLC_deramp_S1_TOPS <SLC1_tab> <SLC2_tab> <s1> <bn1> <s2> <bn2>

<SLC1_tab> (input) 3 column list of TOPS SLC-1 swaths to be copied in row order IW1, IW2, IW3:
            SLC_tab line entries:   SLC    SLC_par   TOPS_par
<SLC2_tab> (input) 3 column list of the output copied SLC-1 TOPS swaths in the order IW1, IW2, IW3
<mode > mode of operation:
    0: subtract TOPS Doppler phase (deramp)
    1: add Doppler phase ramp (reramp)
<phflg> deramp phase flag:
    0: do not save TOPS Doppler phase (default)
    1: save TOPS Doppler phase, output filename is the same as the deramped SLC with extension .dph

EXAMPLES

Apply azimuth deramp phase to TOPS mode SLC bursts, save the deramp phase in a files named after the SLC swath files:

SLC_deramp_S1_TOPS SLC_20140809_tab SLC_20140809_deramp_tab 0 1

Output is written into the files listed in SLC_20140809_deramp_tab.

DESCRIPTION

 SLC_deramp_S1_TOPS deramps the bursts of an SLC. This means that the azimuth phase associated with the rapid change of the antenna pointing is removed. This facilitates operations on the such as filtering and interpolation.  Calculation of the azimuth chirp rate follows the approach described in the following ESA Application Note:

Definition of the TOPS SLC deramping function for products generated by the S-1 IPF

The deramp function is determined from the azimuth sweep rate, spacecraft along-track velocity, and the Azimuth FM rate that is a function of slant-range.

The SLC_tab file is a text file with one line for each SLC in the data set. Typically there are 3 images for Sentinel-1 Interferometric Wide Mode.  The three columns correspond to the SLC data file name, the SLC parameter file name and the TOPS_par file name. The TOPS_par contains information on each burst in the burst SLC.  The SLC_tab can contain fewer than 3 records, and in the case of Extended Wide mode, it can contain information for the five sub-swaths. The output SLC_tab can be produced simply with a text editor or written with a script.

Below are examples of the input SLC_tab: SLC_20140809_tab1

slc_TOPS/20140809_iw1_vv.slc  slc_TOPS/20140809_iw1_vv.slc.par  slc_TOPS/20140809_iw1_vv.tops_par
slc_TOPS/20140809_iw2_vv.slc  slc_TOPS/20140809_iw2_vv.slc.par  slc_TOPS/20140809_iw2_vv.tops_par
slc_TOPS/20140809_iw3_vv.slc  slc_TOPS/20140809_iw3_vv.slc.par  slc_TOPS/20140809_iw3_vv.tops_par

and the output SLC_tab 20140809_deramp_tab:

slc_TOPS_deramp/20140809_iw1_vv.slc  slc_TOPS_deramp/20140809_iw1_vv.slc.par  slc_TOPS_deramp/20140809_iw1_vv.tops_par
slc_TOPS_deramp/20140809_iw2_vv.slc  slc_TOPS_deramp/20140809_iw2_vv.slc.par  slc_TOPS_deramp/20140809_iw2_vv.tops_par
slc_TOPS_deramp/20140809_iw3_vv.slc  slc_TOPS_deramp/20140809_iw3_vv.slc.par  slc_TOPS_deramp/20140809_iw3_vv.tops_par

An example of running the SLC_deramp_S1_TOPS program is shown here for the first 2 bursts is shown below.

$ SLC_deramp_S1_TOPS SLC_20140809_tab SLC_20140809_deramp_tab 0 1
*** Calculate and subtract S1 TOPS Doppler phase from burst SLC data ***
*** Copyright 2014, Gamma Remote Sensing v1.2 30-Oct-2014 ***
OPENMP: number of physically available processors: 8
OPENMP: max. number of threads (program defined): 4
OPENMP: max. number of available threads, (environment variable OMP_NUM_THREADS): 8
OPENMP: number of threads that will be used: 4
TOPS SLC1_tab: SLC_20140809_tab
number of SLC swaths in SLC1_tab: 1
SLC-1 swath SLC: slc_TOPS/20140809_iw1_vv.slc
SLC-1 swath SLC parameter file: slc_TOPS/20140809_iw1_vv.slc.par
SLC-1 swath TOPS_PAR burst parameter file: slc_TOPS/20140809_iw1_vv.tops_par
r0 (m):      0.000  r2 (m):      0.000  nr:     0  rpix (m):  0.000000  t0 (s):     0.000000  t2 (s):     0.000000  nlines:      0  time_per_line (s): 0.000000e+00
SLC2_tab file for output deramped SLC swaths: SLC_20140809_deramp_tab

mode: subtract Doppler phase ramp (deramp)
NOTE: saving TOPS mode Doppler phase
maximum number of bursts in an SLC swath: 9
TOPS SLC-2 swath SLC (output): slc_TOPS_deramp/20140809_iw1_vv.slc
TOPS Doppler phase (float): slc_TOPS_deramp/20140809_iw1_vv.slc.dph
TOPS SLC2 swath parameter file: slc_TOPS_deramp/20140809_iw1_vv.slc.par
TOPS SLC2 TOPS burst parameter file: slc_TOPS_deramp/20140809_iw1_vv.tops_par

SLC1: 1  TOPS file size (bytes): 2492721864
TOPS SLC1 number of records: 14661
TOPS number of records per burst: 1629
TOPS number of bursts: 9
S/C velocity vector (m/s) x: -4016.097  y: -2482.025    y: 5948.147
S/C velocity (m/s): 7594.072
wavelength (m): 0.055466
TOPS azimuth steering rate (deg/s): -1.590369
Doppler centroid rate due to antenna steering (Hz/s): 7.600724e+03
SLC-1 swath:1  burst: 1  window:  800420.5701   849921.4330    60946.53539    60949.57761       0   21250       0    1481
SLC-1 burst 1 date:            2014-08-09T16:55:46.535387
SLC-1 burst 1 Doppler date:    2014-08-09T16:55:47.908126
SLC-1 burst 1 az_FM_rate date: 2014-08-09T16:55:46.945386
SLC-1 burst 1 start time (s): 60946.5354  Doppler_poly_time: 60947.9081    az_FM_rate_time (s): 60946.9454

    pixel      range (m)     fd (Hz)     kr (Hz/s)     kt (Hz/s)  
******************************************************************
         0    800420.570    -126.489    -2326.3644     1781.1924
      2000    805079.694    -125.007    -2312.4669     1773.0338
      4000    809738.818    -123.608    -2298.7217     1764.9422
      6000    814397.942    -122.291    -2285.1288     1756.9180
      8000    819057.066    -121.056    -2271.6882     1748.9621
     10000    823716.190    -119.904    -2258.3999     1741.0750
     12000    828375.314    -118.835    -2245.2639     1733.2574
     14000    833034.438    -117.848    -2232.2803     1725.5099
     16000    837693.562    -116.944    -2219.4489     1717.8332
     18000    842352.686    -116.122    -2206.7699     1710.2278
     20000    847011.810    -115.383    -2194.2432     1702.6945

SLC-1 swath:1  burst: 2  window:  800420.5701   849921.4330    60949.57967    60952.35056       0   21250     132    1349
SLC-1 burst 2 date:            2014-08-09T16:55:49.308333
SLC-1 burst 2 Doppler date:    2014-08-09T16:55:50.666403
SLC-1 burst 2 az_FM_rate date: 2014-08-09T16:55:49.703663
SLC-1 burst 2 start time (s): 60949.3083  Doppler_poly_time: 60950.6664    az_FM_rate_time (s): 60949.7037

    pixel      range (m)     fd (Hz)     kr (Hz/s)     kt (Hz/s)  
******************************************************************
         0    800420.570     -69.985    -2326.2973     1781.1530
      2000    805079.694     -73.847    -2312.3991     1772.9940
      4000    809738.818     -77.555    -2298.6533     1764.9019
      6000    814397.942     -81.110    -2285.0598     1756.8773
      8000    819057.066     -84.512    -2271.6186     1748.9209
     10000    823716.190     -87.762    -2258.3298     1741.0333
     12000    828375.314     -90.858    -2245.1933     1733.2153
     14000    833034.438     -93.801    -2232.2091     1725.4674
     16000    837693.562     -96.592    -2219.3772     1717.7902
     18000    842352.686     -99.229    -2206.6977     1710.1845
     20000    847011.810    -101.714    -2194.1705     1702.6508

SEE ALSO

SLC_par,  typedef_ISP.h, TOPS_par

© Copyrights for Documentation, Users Guide and Reference Manual by Gamma Remote Sensing, 2014.
last change 10-Dec-2014