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Rott H.,ENVEO IT | Rott H.,University of Innsbruck | Nagler T.,ENVEO IT | Ripper E.,ENVEO IT | And 8 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2014

Spatial and temporal characteristics of Ku- and X-band backscatter signatures of Alpine snow are discussed and related to in situ snow observations. The radar data have been acquired with the airborne SnowSAR sensor over three test sites in the Austrian Alps during the AlpSAR campaign in winter 2012/13. An example for inversion of backscatter images in terms of sow water equivalent (SWE) is presented. The backscatter signatures of three test sites in different elevation zones show significant differences in terms of mean values and temporal trends during the winter season. These variations can be attributed to snow structure and to properties of the medium below the snow pack. © 2014 IEEE.

Mittermayer J.,German Aerospace Center | Younis M.,German Aerospace Center | Metzig R.,German Aerospace Center | Wollstadt S.,German Aerospace Center | And 2 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2010

This paper presents results from the synthetic aperture radar (SAR) system performance characterization, optimization, and verification as carried out during the TerraSAR-X commissioning phase. Starting from the acquisition geometry and instrument performance, fundamental acquisition parameters such as elevation beam definition, range timing, receiving gain, and block adaptive quantization setting are presented. The verification of the key performance parameters-ambiguities, impulse-response function, noise, and radiometric resolution-is discussed. ScanSAR and Spotlight particularities are described. © 2009 IEEE.

Tebaldini S.,Polytechnic of Milan | Rocca F.,Polytechnic of Milan | Meta A.,MetaSensing | Coccia A.,MetaSensing
2015 European Radar Conference, EuRAD 2015 - Proceedings | Year: 2015

The ESA field experiment AlpTomoSAR has been planned to investigate the capabilities and potential of L-Band Synthetic Aperture Radar Tomography (TomoSAR) for studying the internal structures of glaciers and ice sheets. The scientific interest in this activity is motivated by the need for improved observations of snow and ice, which are relevant to climate researches and water management. TomoSAR represents today a new potential tool to obtain significant improvements in the capability to characterize natural media from remotely sensed data, providing 3D resolution capabilities of the imaged media. In this paper we present a tomographic analysis of the Mittelbergferner glacier, illuminated during AlpTomoSAR by flying repeatedly along an oval-like racetrack. 3D Single Look Complex cubes were focused for two opposite views by jointly processing all passes in the 3D space, resulting in a spatial resolution cell of about 2 m in all directions. The 3D data cubes were used as a basis for further physical analyses, revealing the presence of scattering elements at few tens of meters below the ice/snow interface. © 2015 EuMA.

Tebaldini S.,Polytechnic of Milan | Rocca F.,Polytechnic of Milan | Meta A.,MetaSensing | Coccia A.,MetaSensing
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

In this paper we discuss 3D tomographic techniques for processing airborne SAR data acquired from largely irregular trajectories. The discussion is based on the L-Band data-set acquired over the Mittelbergferner glacier in 2014 in the frame of the ESA campaign AlpTomoSAR. Signal focusing is based on Time Domain Back Projection (TDBP), concerning the generation of both 2D SLC data stacks and 3D Tomographic data cubes, as this approach allows to correctly cope with random trajectory deviations, as well as with range and azimuth shifts depending on focusing height. Data Phase Calibration is also considered, in order to recover phase screens due to an imperfect knowledge of flight trajectories. © 2015 IEEE.

Prats P.,German Aerospace Center | Scheiber R.,German Aerospace Center | Mittermayer J.,German Aerospace Center | Meta A.,MetaSensing | Moreira A.,German Aerospace Center
IEEE Transactions on Geoscience and Remote Sensing | Year: 2010

This paper presents an efficient phase preserving processor for the focusing of data acquired in sliding spotlight and Terrain Observation by Progressive Scans (TOPS) imaging modes. They share in common a linear variation of the Doppler centroid along the azimuth dimension, which is due to a steering of the antenna (either mechanically or electronically) throughout the data take. Existing approaches for the azimuth processing can become inefficient due to the additional processing to overcome the folding in the focused domain. In this paper, a new azimuth scaling approach is presented to perform the azimuth processing, whose kernel is exactly the same for sliding spotlight and TOPS modes. The possibility to use the proposed approach to process data acquired in the ScanSAR mode, as well as a discussion concerning staring spotlight, is also included. Simulations with point targets and real data acquired by TerraSAR-X in sliding spotlight and TOPS modes are used to validate the developed algorithm. © 2009 IEEE.

Meta A.,MetaSensing | Mittermayer J.,German Aerospace Center | Prats P.,German Aerospace Center | Scheiber R.,German Aerospace Center | Steinbrecher U.,German Aerospace Center
IEEE Transactions on Geoscience and Remote Sensing | Year: 2010

This paper reports about the performed investigations for the implementation of the wide-swath TOPS (Terrain Observation by Progressive Scan) imaging mode with TerraSAR-X (TSX). The TOPS mode overcomes the limitations imposed by the ScanSAR mode by steering the antenna along track during the acquisition of a burst. In this way, all targets are illuminated with the complete azimuth antenna pattern, and, thus, scalloping is circumvented, and an azimuth dependence of signal-to-noise ratio and distributed target ambiguity ratio (DTAR) is avoided. However, the use of electronically steered antennas leads to a quantization of the steering law and a nonideal pattern for squinted angles (grating lobes and main lobe reduction). The former provokes spurious peaks, while the latter introduces slight scalloping and DTAR deterioration. These effects are analyzed and quantified for TSX, and a TOPS system design approach is presented. Next, the requirements concerning interferometry are investigated. Finally, several results are shown with the TSX data, including a comparison between the TOPS and the ScanSAR modes and the reporting of the first TOPS interferometric results. © 2009 IEEE.

Alparone L.,University of Florence | Argenti F.,University of Florence | Bianchi T.,University of Florence | Abbate M.,University of Cassino and Southern Lazio | And 3 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2010

In this work, maximum a posteriori (MAP) despeckling, implemented in the multiresolution domain defined by the undecimated discrete wavelet transform (UDWT), will carried out on very high resolution (VHR) SAR images and compared with earlier multiresolution approaches developed by the authors. The MAP solution in UDWT domain has been specialized to SAR imagery. Every UDWT subband is segmented into statistically homogeneous segments and one generalized Gaussian (GG) PDF (variance and shape factor) is estimated for each segment. This solution allows to effectively handle scene heterogeneity as imaged by the VHR SAR system. Segmentation exploits a Tree Structured Markov Random Field (TSMRF), which is a low complexity MRF segmentation that allows the estimation of the number of segments and the segmentation itself to be carried out at same time. Experiments performed on a single-look VHR X-band SAR images demonstrate that the segmented approach is effective whenever the classical circular Gaussian model of complex reflectivity may no longer hold. © 2010 IEEE.

Coccia A.,University of Perugia | Lukic N.,MetaSensing | Meta A.,MetaSensing
GIM International | Year: 2013

The SnowSAR is a radar sensor which was commissioned to support the European Space Agency's (ESA) Cold Region Hydrology High-Resolution Observatory (CoReH2O) mission candidate Earth Explorer 7 satellite. Together with international partners, the idea of CoReH2O is to research the properties of snow and ice by employing a space-borne twin-frequency (X and Ku bands) polarimetric Synthetic Aperture Radar (SAR) instrument. The SnowSAR radar sensor has proven its snow and ice-monitoring capabilities both in three of the countries which have a share of the land in the Arctic Circle, namely Finland, Canada and US (Alaska), and outside of the Arctic Circle (in Austria). Snow pack structure and morphology can differ quite widely from region to region, depending on different terrain types and on the background composition. The first two SnowSAR measurement campaigns in the winters of 2011 and 2012 were conducted in collaboration with the Finnish Meteorological Institute in the Lappish region of Finland, which is an example of the typical Eurasian taiga belt.

Trampuz C.,MetaSensing | Coccia A.,MetaSensing | Meta A.,MetaSensing
GIM International | Year: 2011

Synthetic Aperture Radar (SAR) is becoming more and more requested in the commercial and scientific world, especially considering the latest developments toward compact, high-resolution and cost-effective sensors. Since 2008, MetaSensing has been commercially offering services and sensors allowing a larger group of users to benefit from the advantages of SAR technology.

Meta A.,MetaSensing | Trampuz C.,MetaSensing
European Microwave Week 2010, EuMW2010: Connecting the World, Conference Proceedings - European Radar Conference, EuRAD 2010 | Year: 2010

For the first time in the world airborne Frequency Modulated Continuous Wave (FMCW) Synthetic Aperture Radar (SAR) images have been acquired in interferometric mode. The paper reports on the X-band images collected by the new high resolution, compact MetaSensing interferometric SAR sensors in 2009. MetaSensing approach allows cost-effective SAR mapping by employing small, readily available Cessna 172/182 or similar in order to drastically cut the costs of current radar campaigns for scientific and commercial applications. MetaSensing X-band SAR sensor is able to transmit more than 1.4 GHz of bandwidth and its versatile two receiving channels allow along-track and cross-track interferometric acquisitions. A fully polarimetric L-band sensor is in the final test stage and is available from the third quarter of 2010. The new MetaSensing approach is an optimal solution for commercial and scientific application which requires SAR mapping on local areas. © 2010 EuMA.

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