Release Notes GAMMA Software, Linux Distribution Windows Distribution Mac OSX GAMMA Software Training Courses

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1 Release Notes GAMMA Software, (Urs Wegmüller, Charles Werner, Andreas Wiesmann, Othmar Frey 1-Dec-2014) Gamma Remote Sensing AG Worbstrasse 225, CH-3073 Gümligen This information is provided to users of the GAMMA software. Further distribution of this document is restricted. This release of the Gamma software includes new programs that provide new capability, additional features to existing programs and bug fixes. Linux Distribution This Linux Gamma software distribution is based on Ubuntu LTS 64-bits. Furthermore, a 64-bit Redhat RHEL 6 is provided as well in the same directory. Windows Distribution The Windows version of the Gamma software is fully 64-bits! The software has been compiled and tested under 64-bit Windows 7. The software does work with 64-bit Windows 8, but has not been fully tested on this platform. The build uses the MINGW64 GCC compilers. This release requires installation of a new GAMMA_LOCAL_w64_ zip file containing updated libraries and support for the updated compiler. Support for LAPACK and LAPACKe, gdal 1.10, and hdf has been included in GAMMA_LOCAL_w64_ Mac OSX The software in this version has been compiled again using Yosemite OSX On OSX there is no longer an OSX local file to install, rather, each user installs his own version of MacPorts to handle libraries such as FFTW, GTK2, GDAL, HDF5. GAMMA Software Training Courses GAMMA plans to organize in spring 2015 again training courses at GAMMA (near Bern, Switzerland) for SAR/INSAR (MSP/ISP/DIFF&GEO/LAT) and for PSI (IPTA). See also our web-site under 1

2 Significant Changes in the Gamma Software Modules since the Jul release Sensors In this period the support for SAR interferometry for the 3 new sensors was consolidated: - Sentinel-1 - ALOS PALSAR-2 - KOMPSAT-5 For Sentinel-1 the functionality necessary to do SAR interferometry using TOPS mode SLC data is now included. The main changes are modifications related to the burst mode SLC format with multiple bursts and sub-swaths, modifications related to the strong Doppler Centroid variation in azimuth direction present in each burst (e.g. requesting adaptations to the SLC resampling), and modifications related to the very high co-registration accuracy required to get a continuous interferometric phase without jumps at burst and sub-swath interfaces. The related steps could be implemented and tested on real Sentinel-1 data pairs. An example of a differential interferogram generated and of the corresponding RGB coherence product are shown in Figure 1. Figure 1 Geo-referenced S1 TOPS differential interferogram (top) and RGB composite (bottom, red: coherence, green: backscatter, blue: backscatter change). In the differential interferogram One color cycle corresponds to one phase cycle. No phase jumps are visible at the burst interfaces. The phase matches also well between adjacent sub-swaths. The area is about 250 km x 100 km. 2

3 The related changes to the software are only shortly discussed below in the software changes. For a more comprehensive discussion we refer to the new Sentinel-1 User Guide (file Sentinel-1_users_guide_v1_0.pdf in DIFF/html) that we wrote. It explains the new functionality and suited processing sequences. Furthermore, we generated a Sentinel-1 Interferometry DEMOCD that provides you with a real Sentinel-1 TOPS data pair (consisting of only 2 sub-swaths with only 2 burst each to reduce the data volume and speed up the testing with the data) together with the commands that can be used to generate a differential interferogram. The Sentinel-1 Interferometry DEMOCD can be downloaded by GAMMA Software users at: account: user: kf93duz password: CTgIMLOOo The size of the demo data is about 1.6 GByte. The resulting differential interferogram is shown in Figure 2. Figure 2 Geo-referenced S1 TOPS differential interferogram over Mexico City and Puebla, formed in the demo example using 2 Sentinel-1 IWS sub-swaths with 2 consecutive bursts each. For ALOS PALSAR-2 we could get access to real data, including an interferometric pair. The data readers (for CEOS format data) were updated. The PALSAR 1 data could be imported and analyzed, including the generation of a differential interferogram. More details on the ALOS-2 PALSAR-2 support in GAMMA Software are provided in a separate document provided with these release notes (see PALSAR2_Support_in_GAMMA_ pdf). For KOMPSAT-5 no further work was done since the last upgrade. As reported in July 2014 we wrote data readers and tested interferometry. The procedures used and results obtained were documented and provided in the upgrades information in July The software is already adapted for the use of KOMPSAT-5 data. 3

4 MSP RAW_TO_SLC_CS & RAW_TO_SLC_CS_AF: The calibration was adjusted for SCOMPLEX case. ISP multi_s1_tops: New program to generate a MLI mosaic from a Sentinel-1 burst SLC file. The output is a standard MLI with a standard ISP MLI parameter file. Added capability to work with just 1 or 2 swaths of IW data. Calculating burst window parameters using the first and last valid sample to prevent gaps between swaths. The burst window parameters and the first and last valid pixel are written into the burst in the TOPS_PAR data structure. Added option to either use the existing burst window parameters calculated previously, or to recalculate them based on the geometry and the number of range and azimuth looks. SLC_mosaic_S1_TOPS: New program to generate a SLC mosaic from a Sentinel-1 burst SLC file. The output is one large standard SLC with a standard ISP SLC parameter file. Added capability to work with just 1 or 2 swaths of IW data. Calculating burst window parameters using the first and last valid sample to prevent gaps between swaths. The burst window parameters and the first and last valid pixel are written into the burst in the TOPS_PAR data structure. Added option to either use the existing burst window parameters calculated previously, or to recalculate them based on the geometry and the number of range and azimuth looks. par_s1_slc: Now using explicit azimuth line time interval parameter rather than calculating the azimuth line time interval from the start and end time of the scene. S1 annotation is not consistent. The azimuth time interval is correct based on geocoding results. SLC_interp_S1_TOPS: Added program for interpolation of Sentinel-1 TOPS patches using offset polynomial. ISP_lib: Added routines for Sentinel-1 geometry transformations between burst and mosaic. Added routines for calculation of azimuth FM rate and Doppler centroid across the swath. Updated dopc_2d() to use all terms in the Doppler polynomials to calculate Doppler centroid at a specific point. Added new routine dopc_ph_2d() to calculate Doppler phase to deramp SLC prior to interpolation. SLC_deramp: Added program to calculate and subtract Doppler phase (option to add phase). SLC_deramp_S1_TOPS: Added program to calculate and subtract Doppler phase for TOPS burst SLC data. SLC_burst_copy: Added to the program SLC_burst_copy that is used to extract a single burst into a normal SLC file with a normal SLC parameter file the functionality that it calculates the doppler polynomial parameters in the output SLC parameter file from Sentinel-1 TOPS annotation. Furthermore, the option to subtract the Doppler phase ramp from the extracted burst was added. SLC_copy_S1_TOPS: Added program to extract a set of bursts from a multi-swath S1 TOPS acquisition. The user can specify the swath and burst number of the first and last bursts. All bursts that start at the same time or later but also do not start later than the last burst are included in the set of output multi-burst images. par_eorc_palsar: Added in this pre-existing program (for PALSAR-1) the functionality to also read PALSAR-2 data. The chirp bandwidth is now read from the data. 4

5 offset_pwr, offset_pwr_tracking: Modified the SNR estimation to use the ratio of the peak of the correlation function to the average of the correlation function outside of the peak region. The peak region is defined to be with -3*osf -> +3*osf samples in the oversampled correlation function window. OSF is defined as SLC_oversampling_factor * the correlation oversampling factor. The nominal values of the SLC oversampling factor is 2 and the value of the correlation oversampling factor is four. image_stat: Added program to calculate image statistics in a rectangular data file region. Statistics calculated are mean, standard deviation, and the percentage of valid data. html files were written for the new programs. DIFF&GEO DIFF_lib.c, SLC_interp_lt.c MLI_interp_lt.c, WSS_interp_lt.c: Added routines SLC_coord(), lt_interp2(), and pm3() into the DIFF_lib. These routines are used for interpolation of SLC data using the lookup table removed SLC_coord from SLC_interp_lt.c MLI_interp_lt.c, WSS_interp_lt.c changed name of fpoly3() to pm3() and added to DIFF_lib.c to avoid conflicts with other programs with local copies of fpoly3 with different definition DIFF SLC_interp_lt_S1_TOPS: Added program to resample TOPS (IW mode) burst SLC using a lookup table and SLC offset polynomials for refinement. Generates both the resampled multi-burst SLC for the swath and the mosaicked SLC using the burst window parameters in the TOPS_PAR file. DIFF offset_pwrm,c offset_pwr_trackingm.c SWAP_io.c: Modified SNR estimation to use the ratio of the peak of the correlation function to the average of the correlation function outside of the peak region. The region around the peak is defined to be -3/8 rwin --> 3/8 rwin in range and -3/8 azwin --: 3/8 azwin. The nominal window size used for estimation of the correlation function is 64x64 section of the oversampled input image. The nominal oversampling factor is 2 and the correlation oversampling factor is 4. DIFF/scripts S1_coreg_overlap: Added Script to determine a co-registration offset of Sentinel-1 IW TOPS bursts based on the burst overlap double differential interferometric phases ( spectral diversity method ). html files were written for the new programs. Sentinel-1_users_guide_v1_0.pdf: An additional user guide in pdf format was added (in html directory) describing the processing of Sentinel-1 data and in particular Sentinel-1 SLC TOPS mode data co-registration and interferometry. DISP float_math: Added sqrt() function capability LAT No new program was added to the LAT in this period. IPTA 5

6 sp_stat: Now making sure the output data files (cc, msr, pwr) are set to 0.0 for all regions were the input data is 0.0. In the Sentinel-1 users guide (found in DIFF&GEO) it is discussed how Sentinel-1 IWS data can be used for PSI processing with the IPTA module. Following the co-registration procedure described co-registered burst SLCs can be derived. It is then recommended to deramp these (using the phase ramp of the master scene) and generate a stack of co-registered mosaic SLCs which can then be used in IPTA as normal SLCs. Appendices 1) PALSAR-2 support within GAMMA Software For further information considering Sentinel-1 see also the related users guide in the DIFF/html directory and the Sentinel-1 DEMOCD (see above for access information). 6