ANSI-C programs: par_RISAT_GRD.c
NAME
par_RISAT_GRD - reads RISAT-1 data as provided by ISRO and
creates the ISP image parameter and GRD or MLI file in the
format used by GAMMA software
SYNOPSIS
par_RISAT_MLI <CEOS_leader> <BAND_META>
<GRD_par> <CEOS_image> [GRD] [line_dir] [pix_dir]
[cal_flg] [KdB]
| <CEOS_leader> | (input) CEOS SAR leader file (example: lea_01.001) |
| <BAND_META> | (input) BAND_META.txt, additional RISAT system parameters for the scene (format keywork=value) |
| <GRD_par> | (output) ISP GRD parameter file (example: yyyymmdd.slc.par) |
| <CEOS_image> | ((input) CEOS GRD or MLI image file (example: dat_01.001) |
| [GRD] | (output) GRD data with file and line headers removed (enter - for none: example: YYYYMMDD.slc) |
| <line_dir> |
set output image line
direction (enter - for default) 0: used value derived from CEOS leader file (default) 1: retain input data line direction -1: reverse input data line direction |
| <pix_dir> |
set output pixel direction
(enter - for default) 0: used value derived from CEOS leader file (default) 1: retain input data pixel direction -1: reverse input data pixel direction |
| [cal_flg] | calibration flag (enter - for default): 0: do not apply radiometric calibration 1: apply radiometric calibration including KdB and incidence angle correction (default) |
| [KdB] |
calibration constant (dB)
(enter - to use value in the CEOS leader) |
EXAMPLES
par_RISAT_GRD lea_01.001 BAND_META.txt 20120722_RH.grd.par
dat_01.001 20120722_RH.grd
Reads the CEOS leader file lea_01.001, BAND_META.txt, and
dat_01.001 files and
generates the 20120722_RH.grd.par and
20120722_RH.grd files.
Each polarization that is available for a particular scene has a
separate CEOS product. The program applies the calibration
constant contained in the BAND_META.txt file to produce
radiometrically calibrated output data.
DESCRIPTION
The RISAT-1 radar satellite was launched in April 2012 by ISRO
the Indian Space Research Organization http://www.isro.org/satellites/RISAT-1.aspx
and produces data in the CEOS format similar to that produced by
RADARSAT-1, see http://wgiss.ceos.org/archive/archive.pdf/sardata.pdf
and http://gs.mdacorporation.com/includes/documents/R1_PROD_SPEC.pdf.
The CEOS product contains a leader file that contains metadata
for the image including time, image dimensions, instrument
parameters and state vectors. For the RISAT CEOS products this
file has the name lea_01.001 The CEOS product also contains
the image data file dat_01.001. The image data file contains a
single header record that is 16252 bytes long containing
information on the data image type and image dimensions. Each
line of the image has a 192 byte record header with information
on the time and slant range parameters for that line. The
data are pairs of short integers (16 bits) that are the real and
imaginary parts of a complex number. These data are in
little-endian byte order. Each image line has a fixed number of
range samples.
The program par_RISAT_GRD generates the GAMMA format MLI/GRD parameter file and reformats the data to big-endian byte order. The user should not have to change the line_dir and pix_dir command line parameters from their default values. Data are produced in natural radar order such that the line direction and pixel direction are both increasing.
SEE ALSO