SAR raw data (<YYYYMMDD>.raw)
Raw data (eg. 20120304.raw) are supplied as complex samples as
bytes, ether as a single real byte per sample (offset video
format), or in IQ format as complex byte pairs, one byte real,
the other imaginary. Each record of the raw data usually has a
header of fixed size determined by the station doing the
transcription. The raw data file itself may have a header at the
beginning of the file that describes the file contents. In
addition, each radar echo may be padded with zeroes to achieve a
particular fixed length. These parameters are described in the
SAR sensor parameter file
documentation.
Range compressed data
(<YYYYMMDD>.rc)
The range compressed data are in complex floating point
representation, each complex sample consists of two 4 byte
floating point numbers, real and imaginary part. There is no file
header, or zero padding of the data. Each record corresponds to a
single range compressed echo. The number of samples/line is
entered in the processing parameter file MSP processing parameter file or can be
modified on the command line of the range compression programs
pre_rc, pre_rc_JERS, pre_rc_RSAT, rc_real. The the number of complex samples in
each range compressed line is stored in the MSP processing
parameter file in the range_pixels parameter.
Single-look complex SAR data
(<YYYYMMDD>.slc)
The SLC data are in complex floating point representation, each
complex sample consists of two 4 byte floating point numbers,
real and imaginary part. There is no file header, or zero padding
of the data. Each record corresponds to a single range line. The
number of samples/line is the range width of the final SLC as
determined by the range width after range-compression.
Multi-look intensity SAR data
(<YYYYMMDD>.mli)
The Multilook intensity images (MLI) consist of 4-byte floating
point numbers with the image width and height determined by the
number of range and azimuth looks selected either on the command
line calling the program multi_SLC.
Image width and height are written to the MSP processing
parameter file.
Azimuth power spectrum
(<YYYYMMDD>.azsp)
The <YYYYMMDD>.azsp file contains three
columns of values (ASCII format) corresponding to:
| 1 | Fraction of normalized PRF (0,1) |
| 2 | Normalized azimuth power spectrum |
| 3 | Ratio (power of lower half of spectrum)/(power of upper half of spectrum), is used to determine Doppler centroid |
Doppler centroid as function of range
(<YYYYMMDD>.dop)
The <YYYYMMDD>.dop file contains five
columns of values (ASCII format) corresponding to:
| 1 | Slant range [km] to center of raw data swath |
| 2 | Measured Doppler centroid centroid [Hz] |
| 3 | Polynomial fit to the range dependent Doppler centroid |
Power spectral density
(<YYYYMMDD>.psd)
The <orbit>.psd file is a binary file containing power
spectra used for radio interference (RFI) suppression in
processing of JERS data (done in program rspec_JERS). The first record of the file
contains a binary header that defines the number and size of the
range spectra used to detect RFI. RFI_filters.dat contains the
power spectral density of the range chirps used to compress the
JERS data. These chirps are modified to suppress RFI.
extract_psd reads the
<orbit>.psd file or RFI_filters.dat files and prints out a
selected spectrum as columns of a table (ASCII format) that can
be plotted using gnuplot.
The average level of the PSD is normalized with the median of the PSD values.