ANSI-C program: SLC_deramp.c
NAME
SLC_deramp - Calculate and subtract Doppler phase from an SLC
SYNOPSIS
SLC_deramp <SLC1_tab> <SLC2_tab>
<s1> <bn1> <s2> <bn2>
| <SLC-1> | (input) SLC data file (fcomplex or scomplex format) |
| <SLC_par1> | (input) SLC parameter file with Doppler information |
| <SLC-2> | (output) SLC with Doppler phase removed (or added) |
| <SLC_par2> | (output) SLC parameter file with Doppler information |
| <mode > | mode of operation: 0: subtract Doppler phase (deramp) 1: add Doppler phase ramp (reramp) |
| <dopph> | (output) Doppler phase (FLOAT) |
EXAMPLE
Apply azimuth deramp to a single burst from a Sentinel-1 TOPS acquisition, and save the deramp phase:
SLC_deramp 20140809_iw1_vv_4.slc
20140809_iw1_vv_4.slc.par 20140809_iw1_vv_4_deramp.slc
20140809_iw1_vv_4_deramp.slc.par 0
20140809_iw1_vv_4_deramp.dph
Output is written into
20140809_iw1_vv_4_deramp.slc. The deramp phase
function to 20140809_iw1_vv_4_deramp.dph.
DESCRIPTION
SLC_deramp calculates the Doppler phase by
integration of the Doppler function in the SLC_par. In the
case of TOPS mode data from Sentinel-1, this doppler polynomial
is calculated by SLC_burst_copy.
For Spotlight Mode from TerraSAR-X, the along-track change in Doppler rate polynomial can be calculated from the raw data doppler polynomial and the FM rate provided with the SLC annotation.
The Doppler phase that is applied to the data is calculated by simple integration of the Doppler function with respect to azimuth time. The Doppler phase function is set to 0.0 at the azimuth center line of the SLC.
An example of running SLC_deramp is shown below:
$ SLC_deramp 20140809_iw1_vv_4.slc
20140809_iw1_vv_4.slc.par 20140809_iw1_vv_4_deramp.slc
20140809_iw1_vv_4_deramp.slc.par 0
*** Calculate and subtract Doppler phase from an SLC image
***
*** Copyright 2014, Gamma Remote Sensing, v1.2 24-Oct-2014 clw
***
SLC-1
file:
20140809_iw1_vv_4.slc
SLC parameter file 1: 20140809_iw1_vv_4.slc.par
SLC-1 title:
s1a-iw1-slc-vv-20140809t165546-20140809t165611-001866-001c20-004.tiff
SLC-1 radar sensor: S1A IW IW1 VV
SLC format: FCOMPLEX
mode: subtract Doppler phase ramp (deramp)
number of bytes/input SLC image line: 170024
number SLC image lines in the
file: 1629
number of
samples/line:
21253
radar center frequency: 5.405000e+09
Doppler poly. coeff.:
-103.51893 -4.54061e-04 2.50805e-09
Doppler rate poly. coeff.: 1.73851e+03 -1.68100e-03
index range (m)
fd (Hz) fddot (Hz/s)
***********************************************
0
800420.5701 -92.2791 1781.0891
2000 805079.6941
-94.3947 1772.9291
4000 809738.8181
-96.5102 1764.8360
6000 814397.9421
-98.6257 1756.8105
8000 819057.0661
-100.7412 1748.8532
10000 823716.1901
-102.8568 1740.9648
12000 828375.3141
-104.9723 1733.1459
14000 833034.4381
-107.0878 1725.3971
16000 837693.5621
-109.2033 1717.7192
18000 842352.6861
-111.3189 1710.1126
20000 847011.8101
-113.4344 1702.5782
line time (s)
range (m) phase (rad)
***********************************************
0 60954.8193
825174.496 16379.271
200 60955.2304
825174.496 9520.982
400 60955.6415
825174.496 4508.881
600 60956.0526
825174.496 1342.967
800 60956.4637
825174.496 23.241
1000 60956.8748
825174.496 549.703
1200 60957.2859
825174.496 2922.351
1400 60957.6971
825174.496 7141.188
1600 60958.1082
825174.496 13206.211
lines: 1629 width: 21253
output SLC: 20140809_iw1_vv_4_deramp.slc
output SLC parameter file: 20140809_iw1_vv_4_deramp.slc.par
user time (s):
2.690
system time (s): 0.100
elapsed time (s): 2.830
SEE ALSO
SLC_par, typedef_ISP.h, SLC_burst_copy