2,135 research outputs found
SAR monitoring of progressive and seasonal ground deformation using the permanent scatterers technique
No full text
Moving from PS to Slowly Decorrelating Targets: A Prospective View
Get PDFDuring the last 8 years Permanent Scatterer interferometry (PSInSAR) has been widely used as a powerful tool for
surface deformation monitoring both for scientific and commercial projects. A few years after the introduction of this
technology, it was highlighted how the constraints on the stability of the radar signature of the targets used as opportunistic
measurement points could be too tight. Forcing the PS to be coherent in all interferometric pairs used in the analysis
could cause the loss of information coming from scatterers exhibiting PS behavior only in a subset of SAR images.
Another concern was related to the estimation of the DEM reconstruction: the problem here is to take advantage of the PS
framework trying to extend the set of image pixels where an estimation of the elevation is possible. Apart from geometrical
decorrelation and variations of the Doppler centroid values of the acquisitions, temporal decorrelation phenomena strongly
limit the coherence values of many scatterers within the area of interest. The question arising is whether the presence of
radar scatterers exhibiting high or moderate coherence levels at low temporal baselines (typically one month) can be useful
for real life applications and, in case of positive answer, which algorithms are most suited to extract useful information
from slowly decorrelating scatterers. Although this topic is still the subject of extensive research activities, this paper
summarizes some facts that, in the authors’ opinion, will be the base of any future algorithm. In particular, the analysis
of the coherence matrix computed on a pixel-by-pixel basis is shown to be a key-element of any study of decorrelating
targets. Its modeling can be extremely useful to extract feature parameters for image segmentatio
Postal de Claudio Vivas a Maruja Vieira, junio 23 de 1955
No full textPostal de Claudio Vivas a Maruja Vieira, felicitándola por el reconocimiento que le fue otorgado a la autora de poemasPostcard from Claudio Vivas to Maruja Vieira, congratulating her for the recognition given to the author of poems.Publicación, fondo Maruja Vieira, carpeta 1, folio
Exploitation of Coherence Matrices in Multi-temporal SAR Datasets: the SqueeSAR approach
No full text
High resolution CSK data for emergency response
No full textOn January 13, 2012, the Italian vessel Costa Concordia wrecked offshore the Giglio Island, along the coast of
Tuscany (Italy). The ship partially sunk, lying on the starboard side on a steep rocky seabed, creating also pernicious
conditions for divers involved in the search and rescue operations. Starting from January 19, the Italian
COSMO-SkyMed (CSK) constellation of was tasked to acquire high resolution images of the wreck. Thanks to
CSK’s short response and revisiting time and its capability to acquire high resolution images in spotlight mode,
satellite data were integrated within the real time, ground-based monitoring system already installed, in order to
provide the Civil Protection authorities with a regular update on the ship stability
Study of GPS and InSAR time series for detecting and understanding crustal deformation and atmospheric signals
No full textNowadays a wealth of information is available from different space geodetic techniques to address different study areas in the fields of geodesy and geophysics. The GNSS and InSAR techniques play a key role in the determination of crustal deformation with high precision and resolution which is a fundamental contribution towards the interpretation of geodynamic processes at different spatial and temporal scales. Dense GNSS networks allow determining the total water vapor content of the atmosphere thus contributing to short-term weather forecast. InSAR determined atmospheric artifacts can be compared with the GNSS estimates aiming at a higher coherence between the two techniques. The integration of GNSS and INSAR into a multi-technique approach for monitoring the Earth system will significantly contribute to the detection and understanding of both natural and anthropogenic fingerprints in climate variability and changes. GNSS coordinate time series often suffer from undesired signals of different nature which may impair the reliable estimation of the long-period trend and that should be therefore corrected in the original data series. We have adapted the STARS methodology, first proposed by Rodionov (2004), to the detection of discontinuities in the GPS time series of EUREF stations located in and around the city of Bologna in Italy. Jumps were identified due to changes in the reference system, to the magnitude 5.9 earthquake that on May 20th 2012 struck a vast area of the Po Plain, to increasing multipath effects in conjunction with the year 2000 solar maximum, to local water table variations and to instrumentation maintenance/changes. After correcting the GPS time series for the identified jumps, over the time period 2010-2011, comparisons were performed for the up and east coordinates with the results derived from a PS-InSAR analysis of COSMO SkyMed images made available by the Italian Space Agency (ASI). Differential tropospheric delays derived by both the GPS and PS-InSAR analysis were also compared
- …
