L’Interferometria SAR Terrestre per il monitoraggio geotecnico e strutturale. Landslide monitoring by Terrestrial SAR Interferometry: critical analysis of different. Applied Remote SEnsing Training. interferometrıa diferencial SAR1 (DInSAR) se han establecido como la . Las técnicas de Interferometrıa SAR (InSAR) nacen con el objetivo de medir distancias.
|Country:||Saint Kitts and Nevis|
|Published (Last):||16 February 2004|
|PDF File Size:||3.87 Mb|
|ePub File Size:||14.83 Mb|
|Price:||Free* [*Free Regsitration Required]|
We think you have liked this presentation.
If you wish to download it, please recommend it to your intefrerometria in any social system. Share buttons are a little bit lower. Published by Jaeden Jelks Modified over 3 years ago. An instrument used to interfere waves is called an interferometer. Interferometry is an important investigative technique in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, quantum mechanics, nuclear and particle physics, plasma physics, remote sensing and biomolecular interactions.
We call interferogram the image of the pixel to pixel phase differences.
An interferogram is a complex inteeferometria with a interferometrria given by the product of the SAR amplitudes and b phase the InSAR phase given by the path length difference, as well as variations of the scattering properties and the medium conditions.
The two SAR antennas are along-track aligned and acquire the scattered electromagnetic field at slightly different times. This mode is exploited to estimate the sea surface spectrum. This mode is obviously operated in a single-pass. The two SAR antennas are aligned across-track.
This mode can be operated both in single-pass and multi-pass configurations. The interferogram is the map of the pixel-to-pixel phase differences between S1 and S2: After registration, the two complex SAR images are multiplied, and the interferometric phase is obtained.
The spacing between the fringes depends on the perpendicular baseline: A phase unwrapping method can be then applied to calculate the exact phase value in order to extract correct information about the scene the elevation. It is typically applied to the filtered interferograms. Critical areas, such as areas of very low coherence or residues, are identified and avoided in the phase unwrapping.
In case of stronger delays, the spatial phase variations might be so large that at higher frequencies phase unwrapping could fail because of more cycles being wrapped. The amplitude is the degree of coherence, the phase is the interferometric phase. Coherence is a measure of the phase noise or fringe visibility Corso presso Univ. A part remains if we have a volume forest, snow, city.
This is called volume decorrelation and interterometria with the spatial baseline. Interferomdtria temporal coherence can NOT be filtered out, it is a property of the image. This is also referred to as temporal decorrelation term and depends on the stability of the objects between the two acquisitions.
Nhazca S.r.l. | Natural Hazards Control and Assessments | Interferometria satellitare
The critical value of the baseline at which complete decorrelation occurs is given by: Spectrum1 Spectrum2 If the spectrum shif is equal to the critical one see the formula abovethey automatically loose part of the correlation they have spatial decorrelation. Spectral shift filtering removes the effect of spatial decorrelation for level surfaces.
There is a proportional loss of range resolution. The two SAR images are only partially correlated because of the temporal interval between the acquisitions. In general it is likely that the longer the time interval between acquisitions, the stronger the temporal decorrelation. Taking into account that typically temporally unstable scatterers have dimensions of the order of a few centimeters or less e. DInSAR is used in seismology, for instance, when an earthquake takes place.
Two SAR images, one pre-seismic and one post-seismic, are acquired. The interferometric phase is computed. Using a DEM, the topographic phase is canceled.
The residual phase contains also interferrometria eventual surface deformation effect differential interferogram. For C-Band sensors it is about 2. The interferometric phase is: The residual phase contains, besides atmosphere and Noise phase component, the displacement projected onto the LOS. Phase unwrapping not required for the simulated interferogram. High accuracy of DEM required. The combination of complex interferograms interferometfia be of interest to do a kind of differential interferometry without phase unwrapping and geocoding requirement to improve the sensitivity to topography.
Detection of weak optical signals D. Resolution Resolving power Measuring of the ability of a sensor to distinguish between signals that are spatially near or spectrally similar.
My presentations Profile Feedback Log out. Auth with social network: Registration Forgot your password?
Nhazca S.r.l. | Natural Hazards Control and Assessments | Home