Airborne DInSAR time series at X-Band.
ABSTRACT Differential SAR Interferometry (DInSAR) is a remote sensing technique which allows monitoring ground deformation with accuracy of the order of the transmitted wavelength by exploiting the phase difference (interferogram) of two temporally separated SAR images relevant to the same area. In addition, when more than two multi-pass acquisitions relevant to the same area are available, they can be properly combined by means of recent multitemporal DInSAR algorithms, in order to detect and follow the temporal evolution of ground deformation via the generation of spatially dense time series. Such a multitemporal DInSAR technique is nowadays developed and operative with space-borne SAR data, whereas specific problems may limit its application to airborne data. In this work, starting from the results already shown in previous works and relevant to an X-Band airborne DInSAR experiment carried out over the Perugia area (center of Italy) by using the OrbiSAR system, we carry out a DInSAR multitemporal analysis of data relevant to a 16 km (in azimuth) by 4 km (in range) region.
- SourceAvailable from: Alberto Moreira[show abstract] [hide abstract]
ABSTRACT: Proposes a new approach for high-resolution airborne SAR data processing, which uses a modified chirp scaling algorithm to accommodate the correction of motion errors, as well as the variations of the Doppler centroid in range and azimuth. By introducing a cubic phase term in the chirp scaling phase, data acquired with a squint angle up to 30° can be processed with no degradation of the impulse response function. The proposed approach is computationally very efficient, since it accommodates the variations of Doppler centroid without using block processing. Furthermore, a motion error extraction algorithm can be incorporated into the proposed approach by means of subaperture processing in azimuth. The new approach, denoted as extended chirp scaling, is considered to be a generalized algorithm suitable for the high-resolution processing of most airborne SAR systemsIEEE Transactions on Geoscience and Remote Sensing 10/1994; · 3.47 Impact Factor
Conference Proceeding: Airborne D-InSAR at X-band: Results with the Complete Repeat-pass Processing Methodology.[show abstract] [hide abstract]
ABSTRACT: This paper presents the interferometric airborne repeat-pass mode results at X-band after applying a complete residual motion compensation (MoCo) strategy. The data were acquired, over the Perugia area, Italy, by the OrbiSAR sensor from OrbiSat, Brazil, and the first X-Band D-InSAR results were published, where a space-invariant topography-dependent MoCo was applied after focusing with smoothed elevation model. Now, in this paper, we apply to the same X-band data the precise topography- and aperture-dependent (PTA) MoCo and the weighted phase curvature autofocus (WPCA) to account for high-order residual motion errors. We compare the differential interferograms and coherence map obtained after PTA-WPCA to the formerly results. The results show improvement in the interferometric accuracy after PTA-WPCA processing. The need of such complete processing chain for narrowband systems is discussed.IEEE International Geoscience & Remote Sensing Symposium, IGARSS 2009, July 12-17, 2009, University of Cape Town, Cape Town, South Africa, Proceedings; 01/2009
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ABSTRACT: Temporal and geometrical decorrelation often prevents SAR interferometry from being an operational tool for surface deformation monitoring and topographic profile reconstruction. Moreover, atmospheric disturbances can strongly compromise the accuracy of the results. The authors present a complete procedure for the identification and exploitation of stable natural reflectors or permanent scatterers (PSs) starting from long temporal series of interferometric SAR images. When, as it often happens, the dimension of the PS is smaller than the resolution cell, the coherence is good even for interferograms with baselines larger than the decorrelation one, and all the available images of the ESA ERS data set can be successfully exploited. On these pixels, submeter DEM accuracy and millimetric terrain motion detection can be achieved, since atmospheric phase screen (APS) contributions can be estimated and removed. Examples are then shown of small motion measurements, DEM refinement, and APS estimation and removal in the case of a sliding area in Ancona, Italy. ERS data have been usedIEEE Transactions on Geoscience and Remote Sensing 02/2001; · 3.47 Impact Factor