ANSI-C program: rspec_JERS.c
NAME
rspec_JERS - Range spectra estimation for
JERS-1 stripmap raw data
SYNOPSIS
rspec_JERS <SAR_par> <PROC_par>
<signal_data> <range_spec> [nr_samp] [nl_spec] [loff]
[nlines] [nr_ext] [fr_ext]
| <SAR_par> | MSP SAR sensor parameter file |
| <PROC_par> | MSP Processing Parameter File |
| <signal_data> | raw SAR data (IQ format) |
| <range_spec> | range spectra data file for RFI suppression |
| [nr_samp] | number of range samples (enter - for default from PROC_par) |
| [nl_spec] | number of lines used to estimate spectrum (enter - for default=1024) |
| [loff] | offset in echos for first line to process (enter - for default from PROC_par) |
| [nlines] | number of lines to process (enter - for default from PROC_par) |
| [nr_ext]; | near range swath extension in samples (default from PROC_par) |
| [fr_ext] | near range swath extension in samples (default from PROC_par) |
EXAMPLE
rspec_JERS JERS-1.par p19961116.slc.par 19961116.raw
19961116.psd
DESCRIPTION
rspec_JERS estimates the
range power spectrum for suppression of radio frequency
interference (RFI) for both JERS-1 and PALSAR stripmap raw
SAR data.The range power spectrum is calculated every
nl_spec (nominal value: nl_spec = 1000, about
every .6 seconds) lines for the SAR raw data. The FFT
size and number of lines to include in the estimation are defined
by the user. rspec_JERS generates range spectra used to
identify Radio Frequency Interference (RFI). The range
compression program pre_rc_JERS
uses this information to notch the range chirp matched
filter thereby suppressing the RFI.
rspec_JERS has the capability to provide spectra with additional data points for extending the processed image swath beyond the region of full resolution. The nominal number of samples in the range compressed data is the number of echo samples processed minus the number of samples in the range chirp. Outside of the nominal full resolution swath are two bands, one in the near range and the other in the far range. Both of these bands are as wide as the range chirp width in samples. Across these bands the resolution degrades linearly starting at the full resolution and going to zero. These regions also fade in intensity proportional to the loss in resolution due to the decreasing number of echo samples for these image pixels. The user can specify the swath extension for both the near and far range in the processing parameter file or via the command line parameters nr_ext and fr_ext .
The individual range power spectra may be extracted from the *.psd files with extract_psd and and plotted usinggnuplot. The format of the text file produced by extract_psd is pairs of numbers (sample number, spectrum value).
Notice: The values of the nr_samp, nr_ext, and fr_ext values must be identical when running rspec_JERS and pre_rc_JERS; otherwise the RFI range spectra will not have the same size and the pre_rc_JERS will exit.
SEE ALSO
Users Guide, typedef_MSP.h, pre_rc_JERS, MSP
Processing Parameter File, extract_psd.