Gamma MSP: Reference Manual

cat_raw

ANSI-C program: cat_raw.c

NAME
cat_raw - concatenate SAR raw data files and generate the related MSP SAR sensor and MSP processing parameter files for the concatenated data set

SYNOPSIS cat_raw <RAW_list> <SAR_par> <PROC_par> <RAW_out> [fill] [loff] [nl]

<RAW_list>	(input) 3 column list of input raw data and MSP parameter files (text): 1. SAR raw data file 2. MSP SAR sensor parameter file 3. MSP processing parameter file
<SAR_par>	(output) MSP sensor parameter file for concatenated raw data set
<PROC_par>	(output) MSP processing parameter file for concatenated raw data set
<RAW_out>	(output) output concatenated raw data file
[fill]	fill gaps between raw data files (default=0: no 1:yes)
[loff]	number of lines offset from start of input file to begin data extraction (enter - for default: 0)
[nl]	number of lines to extract (enter - for default: to end of data)

EXAMPLE
cat_raw raw_list 20040629.ASAR.par p20040629.slc.par20040629.raw

where the raw_list input file is as follows for an example with 3 scenes:

20040629_192048.raw 20040629_192048.ASAR.par p20040629_192048.slc.par 20040629_192103.raw 20040629_192103.ASAR.par p20040629_192103.slc.par 20040629_192118.raw 20040629_192118.ASAR.par p20040629_192118.slc.par

DESCRIPTION
cat_raw is used to concatenate a set of overlapping raw data files acquired on a single satellite track. Each of the input raw data files must have an associated MSP sensor parameter file and processing parameter file. The program uses the range and azimuth timing information in the parameter files to determine the overlap. Using this information the cat_raw compares the sample values to confirm that the files actually match.In the case where there are different time-delays to the first data sample for the raw data files (normally the case), the program extends the range swath width and updates the parameter file values. In the following table are listed the different programs for generating MSP compatible raw data sets and parameter files for different sensors:

`Sensor`	`Programs`
`ERS-1,ERS-2`	`ERS_proc_* generate MSP processing parameter file, (PAF dependent) ERS_fix correct missing lines, and concatenates raw data files`
`Radarsat-1`	`RSAT_raw generate MSP processing parameter file and sensor parameter file concatenates raw data files`
`JERS-1`	`JERS_proc generate MSP processing parameter file JERS_fix correct missing lines and concatenates raw data files`
`ASAR`	`ASAR_IM_proc generate MSP sensor parameter and processing parameter files cat_raw concatenates MSP format raw data files and adjusts MSP sensor parameter and processing parameter files`
PALSAR	PALSAR_proc generate MSP sensor parameter and procesing parameter files `cat_raw concatenates MSP format raw data files and adjusts MSP sensor parameter and processing parameter files`

ERS, Radarsat-1, and JERS-1 use the CEOS format for the frame data and metadata, while ASAR uses a format specific to all ENVISAT data.
The input to cat_raw is the RAW_list text file containing the filenames of the data and parameter files of the input data frames.
The frames must be listed in increasing time order with the raw data listed in column 1, the MSP sensor parameter file in column 2, and the MSP processing parameter file in column 3.

The user can also specify if any gaps between raw data sets will be filled with blank lines. By default, gaps between non-overlapping raw data files are flagged as an error and the program will exit with an error message. Processing an image with a significant gap relative to the length of the synthetic aperture results in a loss of resolution and the appearance of a dark band in the image. None the less, if the gap is correctly filled the full data set can be used.