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Release Notes GAMMA Software, 20150630 (Urs Wegmüller, Charles Werner, Andreas Wiesmann, Othmar Frey 30-Jun-2015)

Gamma Remote Sensing AG

Worbstrasse 225, CH-3073 Gümligen

http://www.gamma-rs.ch

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 14.04 LTS 64-bits.

Furthermore, 64-bit Redhat RHEL 5 and RHEL 6 versions based on Centos 5 and 6 are

provided in the same directory.

Windows Distribution

The Windows7,8 version of the Gamma software is fully 64-bits and multi-threaded

The software has been compiled under Win8 and will also work on Win7. The build uses the

MINGW64 GCC compilers.

The installation instructions for the binary distributions has been updated for the 64-bit

release. See INSTALL_WIN64.TXT.

This software release requires installation of a new GAMMA_LOCAL_w64_20150227.zip

file containing updated libraries and support for the updated compiler. Support for LAPACK

and LAPACKe, gdal 1.10, and hdf 1.8.11 has been included in

GAMMA_LOCAL_w64_20150227. Using any previous versions of GAMMA_LOCAL will

not work with this release.

Mac OSX

The software in this version has been compiled using Yosemite 10.10.3. You will need to

install libraries such as GDAL using MacPorts.

Instructions are in the INSTALL_OSX.txt file.

GAMMA Software Training Courses

GAMMA plans to organize in fall 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 http://www.gamma-rs.ch/courses/training-courses.html.

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Significant Changes in the Gamma Software Modules since the Dec. - 2014 release

Sensors

In this period further adaptations and optimizations to support Sentinel-1 and ALOS

PALSAR-2 could be realized.

For Sentinel-1 new functionality was added:

- a program to concatenate subsequent IWS SLCs into one large burst SLC

- a program to extract a section of an IWS burst SLC consisting of several bursts in one,

two or three sub-swaths

- a program to read OPOD precision state vectors and write those to an SLC parameter

file

- a program to support a spectral diversity method for the overlap region between

neighboring sub-swaths was added

functionality was improved:

- for GRD products the image geometry is now directly changed to slant range

geometry when reading the data which permits geocoding, co-registration, and offset

tracking at very high accuracy and which also assures full compatibility with SLC data

based images; the geometry was cross-validated against the SLC geometry

- IWS SLC data can now be read in as FCOMPLEX or SCOMPLEX burst SLC;

programs used for the burst SLC data were adapted to support both formats

- The radiometric calibration done when importing the S1 SLC or GRD data products

was updated to consider also the noise data files and the calibration was cross-

validated between SLC and GRD products

processing S1 data was made more comfortable and more efficient:

- a program to automate the co-registration sequence of IWS SLC data was added

- the efficiency of programs was increased

the user guide was updated:

- more information on using S1 data for PSI

- providing more information on using S1 data for offset tracking

- providing more information on using S1 data for split-beam interferometry

- providing new information on ionospheric effects observed

The related changes to the software are only shortly discussed below in the software changes.

For a more comprehensive discussion we refer to the updated Sentinel-1 User Guide (file

Sentinel-1_users_guide_v1_0.pdf in DIFF/html) that we wrote. It explains the functionality

and suited processing sequences.

Furthermore, we updated the 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. Furthermore, an example for an

offset tracking sequence and for split-beam interferometry will be added shortly.

The Sentinel-1 Interferometry DEMOCD can be downloaded by GAMMA Software users at:

account: http://www.gamma-rs.ch/userdata/Gamma_demo_S1_Mexico_INSAR

user: kf93duz

password: SITcbRDHZ

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For ALOS PALSAR-2 we could confirm that ScanSAR interferometry is supported. 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_150630.pdf).

For PALSAR-2 ScanSAR mode data SAR interferometry is supported when starting from the

following ALOS-2 Scansar data SLC data product:

Processing level: Level 1.1 (=SLC)

Format: CEOS

Processing method: Full-Aperture

In this data format one SLC per sub-swath is provided. The data can be read using the

GAMMA Software and interferometry is supported. Interferometry is done for the individual

sub-swath SLC in slant range geometry. Using the orbit based phase model (phase_sim_orb

program) assures that the differential interferogram will be without steps between sub-swaths.

The differential interferograms are then geocoded and mosaiced into one large differential

interferogram. Examples processed for the first and second strong Nepal Earthquakes in 2015

are shown in Figure 1 and Figure 2. The LOS displacement is displayed (after unwrapping the

phase and after removing an overall phase ramp) using a cyclic color scale with 10cm per

color cycle. For these pairs the pairs are well synchronized. We also processed other pairs

where the ScanSAR data were not synchronized so that no coherence result could be obtained.

Figure 1: Co-seismic displacement map for the Nepal

Earthquake on 25-Apr-2015 using PALSAR-2 ScanSAR

data acquired on 5-Apr-2015 and 3-May-2015. The line-

of-sight (LOS) displacement component is shown using

a cyclic color scale with 10cm per color cycle.

Figure 2: Co-seismic displacement map for the Nepal

Earthquake on 12-May-2015 using PALSAR-2

ScanSAR data acquired on 3-May-2015 and 17-May-

2015. The line-of-sight (LOS) displacement component

is shown using a cyclic color scale with 10cm per color

cycle

Radargammetry

As an ouptlook we like to inform you that we started implementing a Radargrammetry

module for the GAMMA Software. If you are interested in related information please let us

know.

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MSP

azsp_IQ.c doppler.c ptarg.c rspec_IQ.c: Changed default gnuplot terminal for Linux to qt and

changed default gnuplot terminal for OSX and WIN to wxt (wxWidgets).

ISP

par_TX_SLC: Added functionality to calculate Doppler centroid rate for Spotlight mode data.

As a consequence TX Spotlight mode InSAR is now supported.

par_S1_SLC: Added capability to output SCOMPLEX SLC format. Added test for NaN

values and set to 0.0 if this is the case. Check for complex data that are (0,0) and represent as

float data with real part = 1.18e-38 (to prevents holes with "no data"). Parallelized code with

OpenMP. Adapted radiometric calibration and subtraction of thermal noise. Modified to

detect the number of state vectors in the data set rather than relying on a fixed number.

SLC_cat_S1_TOPS: Added program to concatenate S1 TOPS SLC data producing a new

multi-scene burst SLC.

SLC_deramp, SLC_interp_S1_TOPS, SLC_cat_S1_TOPS, SLC_copy_S1_TOPS,

SLC_mosaic_S1_TOPS, multi_S1_TOPS: all these programs were adapted to support S1 IWS

burst SLC data in both FCOMPLEX and SCOMPLEX format.

par_S1_GRD: The program was changed to convert the GRD products to slant range

geometry when reading the data (this because of the complexity of the geometry of the GRD

product geometry). Added algorithm to detect start and end of valid data (to avoid bands of

samples in the near and far range that are non-zero but not valid image samples); setting these

values to zero ensures clean geocoded images. Parallelized code with OpenMP. Adapted

radiometric calibration and subtraction of thermal noise. Modified to allow higher order

polynomial for coordinate conversion, slant-range to ground-range and ground-range to slant-

range (ESA increased in March 2015 the number of parameters from 6 to 9. Added option to

extrapolate the SR-GR polynomials to cover the entire image, rather than restricting GR to SR

conversion to the start and stop times of the polynomials (without this extrapolation the lines

after the last polynomial are lost which results in gaps when mosaicing subsequent GRD

products).

multi_S1_TOPS: Corrected an error in calculation of the start time of the multilook image

(that occurred if sub-swath 2 or 3 started earlier than sub-swath 1). All sub-swaths are now

checked to determine the earliest burst.

S1_OPOD_vec: Added program to read OPOD precision state vectors made available by ESA

at https://qc.sentinel1.eo.esa.int/aux_poeorb/ . Uses Julian dates to detect if state vectors cover

the duration of an SLC image. Program detects if the state vectors end before the start of the

SLC or begin only after the end of the SLC. When nstate is entered, then state vectors begin 1

min before SLC image start and end after nstate state vectors have been read if available.

offset_pwr, offset_pwr_tracking: Added routines peak_snr() and peak7() to SWAP_io.c.

These routines are used in offset_pwr.c and offset_pwr_tracking.c to separately estimate SNR

and peak location.SNR estimate is based on using the entire 2D correlation function to

estimate the pedestal height relative to the peak of the correlation. Added option to specify

number of parallel threads for processing via the OMP_NUM_THREADS environment

variable.

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offset_pwr, offset_pwr_tracking, ptarg_SLC, ptarg_cal_SLC, ptarg_cal_MLI: Changed

default gnuplot terminal for Linux to qt and changed default gnuplot terminal for OSX and

WIN to wxt (wxWidgets)

DIFF&GEO

typedef_DIFF.h DIFF_io.c: Added support for Sinsoidal projection

offset_pwrm, offset_pwr_trackingm: Added routines peak_snr() and peak7() to SWAP_io.c.

These routines are used in offset_pwrm.c and offset_pwr_trackingm.c to separately estimate

SNR and peak location.SNR estimate is based on using the entire 2D correlation function to

estimate the pedestal height relative to the peak of the correlation. Added option to specify

number of parallel threads for processing via the OMP_NUM_THREADS environment

variable.

quad_fit: Added range dependent phase models to be used in modeling range dependent phase

(e.g. for GPRI data, x->range, y -> azimuth):

0: a0 + a1*y + a2*x + a3*x*y + a4*x^2 + a5*y^2 (default)

1: a0 + a4*x^2 + a5*y^2

2: a0 + a1*y + a2*x + a3*x*y

3: a0 + a1*y + a2*x

4: a0 + a2*x + a4*x^2

5: a0 + a2*x

resamp_image: Added program to resample images of different formats by separate scale

factors applied across and down.

geocode_back, SWAP_io: Added option to interpolate using sqrt(dn) in interp_float(),

interp_double(), interp_short(). Bicubic spline interpolation of the sqrt(dn) may give more

accurate interpolation than bicubic spline interpolation or log(dn).

SLC_interp_lt_S1_TOPS: Modified to support both SCOMPLEX and FCOMPLEX format S1

TOPS data.

S1_coreg_overlap: Updated the 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”) – now threshold values can be indicated on the command line and now a

weighted averaging of the individual offset is done.

S1_coreg_subswath_overlap: Added script to determine azimuth refinement using spectral

diversity method based on phase of the sub-swath overlap double difference interferograms.

S1_coreg_TOPS: Added script to run an S1 IWS co-registration sequence using iterative

matching refinements and iterative spectral diversity refinements. The script also calculates

the resulting differential interferogram as well as detailed quality information.

S1_poly_overlap: Updated the Script to generates polygons for burst overlap areas (this script

is used in the script S1_coreg_TOPS).

S1_deramp_TOPS_reference: Added script to deramp a Sentinel-1 TOPS mode burst SLC

reference.

S1_deramp_TOPS_slave: Added script to deramp a Sentinel-1 TOPS mode burst SLC slave

(that is co-registered to the indicated reference). The script also generates the SLC mosaic for

deramped burst SLC slave.

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html files were written for the new programs and scripts.

Sentinel-1_users_guide_v1_0.pdf: Updated the Sentinel-1 users guide.

DISP

cpx_math: Added functionality to permit subtraction of phase of the average calculated from

the reference region for both data files.

cpd: cpd is program to copy a region of an image to an output file. Added capability to work

with scomplex data type

dispwr, dis2pwr: updated to accept absolute scale factors on the command line (as an option)

LAT

No new program was added to the LAT in this period.

IPTA

vu_disp. vu_disp2d, dis_data, dis_ipta, SWAP_io: Changed default gnuplot terminal for

Linux to qt and changed default gnuplot terminal for OSX to wxt (wxWidgets).

base_orbit_pt: Updated memory allocation to use calloc_1d. Now allocating sufficient

memory for all state vectors. Updated to generate baseline with 0.0 length when no state

vectors exist in the the SLC parameter files (as an update useful for IPTA analysis of GPRI

data).

disp_prt: date calculations are performed with fractional days for GPRI2 compatibility dh_err

can be optional, enter - for none

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.

Examples of S1 IPTA results are shown in Figure 3 (SBAS) and 4 (PSI). For further

information it is referred to the related Fringe 2015 paper [Wegmüller U., C. Werner, T.

Strozzi, A. Wiesmann, O. Frey, and M. Santoro, "Sentinel-1 support in the GAMMA

Software", Procs Fringe 2015 Conference, ESA ESRIN, Frascati, Italy, 23-27 Mar. 2015].

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Figure 3 Average vertical displacement rate derived

from a stack of 12 S1 IWS SLC over Mexico City using

an SBAS procesdure

Figure 4 Average vertical displacement rate derived

from a stack of 12 S1 IWS SLC over Mexico City using

a PSI procedure.

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).

-40cm/year 0 40cm/year

average vertical displacement rate