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EUSAR 2014; 10th European Conference on Synthetic Aperture Radar; Proceedings of

Date 3-5 June 2014

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Displaying Results 1 - 25 of 364
  • Sentinel-1 System

    Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    The paper provides an overview of the Copernicus Sentinel-1 system capabilities. In particular, the characteristics of the Sentinel-1 SAR imaging modes and their key performance parameters, as well as the specifics of related attitude and orbit control modes, i.e. roll steering mode and zero-Doppler steering mode are described. In addition, the Sentinel-1 SAR interferometry (InSAR) capabilities including TOPS InSAR and the strategy for maintaining the orbital baseline are discussed. View full abstract»

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  • Sentinel-1 Spacecraft

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1096 KB)  

    The Copernicus Sentinel-1 Earth Radar Observatory, a mission funded by the European Union and developed by ESA, is a constellation of two C-band radar satellites. The satellites have been conceived to be a continuous and reliable source of C-band SAR imagery for operational applications such as mapping of global landmasses, coastal zones and monitoring of shipping routes. The Sentinel-1 satellites are built by an industrial consortium led by Thales Alenia Space Italia as Prime Contractor and with AIRBUS Defence and Space as SAR Instrument Contractor. The first of the two satellites has finalized its environmental test campaign and is now ready for launch on 3 April 2014. The paper describes the general satellite architecture, its key performance as well as its environmental qualification. View full abstract»

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  • Sentinel-1A LEOP and Commissioning Results

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (127 KB)  

    Sentinel-1A, the first component of the Copernicus Space Segment developed by the European Space Agency, has been launched 3 April 2014. The LEOP Phase is expected to last three days where all subsystems and the SAR instrument will be checked. It will immediately be followed by the three-month Commissioning Phase that will include the in-orbit Calibration and Characterisation, and the verification of the satellite, in order to deliver a full functional and well performing satellite to the mission operations. This paper will present the LEOP and Commissioning activities already completed, and the status of Calibration, Characterisation and Verification activities of the Commissioning in place. View full abstract»

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  • SAR Architectures based on DBF for C- and X-band applications

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (402 KB)  

    This paper gives an overview on current activities at Astrium GmbH in Friedrichshafen in the field of technology development for future space-borne SAR systems based on Digital Beam Forming. The focus is put on both, C-band and X-band applications. The critical modules for future instruments are identified and their functionalities are briefly described. The effort aims, from an application point of view, at significant increase of the imaging capabilities of future SAR systems. View full abstract»

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  • An L- and S-band SAR Mission Concept for Earth Science and Applications

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (282 KB)  

    The National Aeronautics and Space Administration (NASA) in the United States and the Indian Space Research Organisation (ISRO) have embarked on a study of a future Earth-orbiting science and applications mission that exploits synthetic aperture radar to map Earth's surface every 12 days. To meet demanding coverage, sampling, and accuracy requirements, the system was designed to achieve over 240 km swath at fine resolution, and using full polarimetry where needed. To address the broad range of disciplines and scientific study areas of the mission, a dual-frequency system was conceived, at L-band (24 cm wavelength) and S-band (10 cm wavelength). To achieve these observational characteristics, a reflector-feed system is considered, whereby the feed aperture elements are individually sampled to allow a scan-on-receive ("SweepSAR") capability at both L-band and Sband. This paper describes the mission characteristics, current status of the joint study, and the technology development efforts in the United States that are reducing risk on the key radar technologies needed to ensure proper SweepSAR operations. View full abstract»

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  • Digital Beam Forming for Ka-band InSAR instruments

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (811 KB)  

    Ka-Band interferometry offers new opportunities in Earth observation for science and civil security applications due to the unique characteristics of this higher frequency band. Several Ka-Band satellite missions and instruments are currently under development. The first Ka-band instrument, Altika Altimeter [1], is in orbit and has shown remarkable performance confirming the feasibility to use this frequency for EO application despite higher atmospheric losses. However for Ka-band interferometric SAR operating from a single platform the link budget is critical and requires signal recovery techniques. Scan-on-receive combined with digital beam forming overcomes these restrictions and offers additional features leading to high performance systems. This paper discusses possibilities to apply digital beam forming techniques to Ka-band instruments enhancing the performance. View full abstract»

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  • Calibration of Multi-Channel Spaceborne SAR - Challenges and Strategies

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (214 KB)  

    Instrument calibration has ever been essential to synthetic aperture radar. This paper reviews the calibration functionality of current state-of-the-art spaceborne SAR and then proceeds to suggest calibration strategies for future SAR systems. These systems will incorporatemulti-channel digital beamforming capabilities which offer new opportunities but also challenges for digital calibration. At the same time, the increased complexity of instrument calibration can not be extrapolated to future systems. This requires a reconsideration of the calibration strategy for spaceborne SAR. The paper is seen as a step in this direction. View full abstract»

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  • Comparison of Digital Beamforming Techniques for Enhanced Ice Sounding Radar Data Processing

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1090 KB)  

    Ice sounding radar from high altitudes is compromised by off-nadir ice surface reflections (clutter), which overlays the nadir signal of interest originating from the bedrock and/or internal ice layers. Multi-aperture antenna radar systems were developed to mitigate the impact of surface clutter allowing spatially variant digital beamforming (DBF) processing of the data received from the individual spatially separated apertures. This paper investigates four different beamforming algorithms: conventional beamsteering, nulling of clutter angles, optimum beamformer and the MVDR beamformer. Comparisons are performed based on simulations for an airborne ice sounding scenarios. In addition, real echograms are computed from data acquired by the P-band POLARIS sensor. Relevant conclusions are drawn with respect to the implementation of a future space-based ice sounding mission. View full abstract»

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  • Biomass Estimation of Boreal Forests Using Single-Pass Polarimetric SAR Tomography at L-band

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1182 KB)  

    This paper addresses forest heights and biomass estimation by applying single-pass polarimetric SAR tomography to PolInSAR data acquired by Intermap's L-Band SAR system. For the purpose of biomass estimation, the feasibility of this special single-pass tomographic configuration is demonstrated over boreal forests at the test site of Edson in Alberta, Canada. The estimated ground topography and tree top heights have been validated against LiDAR data[1]. The corresponding allometric model is calculated from the in-situ data provided by West Fraser Mills Ltd forest company and the biomass over our test sites is estimated via this allometic model. View full abstract»

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  • A Comparison of Multi-Baseline Polarimetric Inteferometry at La Amistad and La Selva, Costa Rica with a Modified PolSARProSim Scattering Tool

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2804 KB)  

    The increased number of polarimetric interferometric datasets collected over a range of biomes allows for more complete characterization of performance and an increased understanding of the underlying scattering mechanisms in multi-baseline polinsar determinations of vegetation structure. UAVSAR collected at La Amistad, Costa Rica in February of 2010 L-band radar data encompassing a range of physical and temporal baselines. To understand these datasets more fully we have modified the ESA PolSARProSim scattering tool to allow more flexible and accurate scattering simulations. This paper compares polinsar UAVSAR data collected at La Amistad and La Selva, Costa Rica to simulated data from PolSARProSim+. View full abstract»

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  • Tomographic imaging of tropical forests: perspectives for the BIOMASS Mission

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (522 KB)  

    The next ESA Earth Explorer Core Mission BIOMASS is envisaged to collect multiple baselines during the initial phase of its lifetime. Such data will allow a vertical resolution of about 20 m, sufficient to decompose the backscattered power from a tropical forest into two to three layers. A recent study on the site of Paracou, French Guiana, has shown that this information helps improve forest above ground biomass retrieval, final accuracy being assessed in about 10% at a resolution of 1.5-ha using airborne data from the TropiSAR campaign. In this paper we aim at making a first step towards a generalization of this result, by i) considering a new test-site (Nouragues, central French Guiana) and ii) taking into account the 6 MHz bandwidth limit imposed by ITU regulations. The results support the claim that BIOMASS tomography could be used to assess above ground biomass in tropical forests to within an accuracy of 11% at a resolution of 4-ha. View full abstract»

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  • 3-D Structure Of Forests: First Analysis of Tomogram Changes Due to Weather and Seasonal Effects at L-Band

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (922 KB)  

    Due to its ecological importance, the monitoring of the vertical structure of forests is continuously raising the interest of the synthetic aperture radar (SAR) scientific community. SAR tomography allows reconstructing the 3-D distribution of the radar power backscattered by a volume by combining more than two SAR acquisitions with baseline diversity. Beyond specific estimation algorithms, the link between the estimated tomograms (depending in general on frequency, polarization and acquisition geometry) and physical forest structure is essential for establishing potential applications. In this work, we contribute to this topic by presenting first investigations aimed to characterize the changes on forest tomograms due to weather and seasonal effects, with the perspective of analysing potentials for monitoring forest ecosystem changes and discuss guidelines for an effective implementation of spaceborne forest structure sensing. View full abstract»

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  • Preliminary results of 3D SAR imaging using a sparse antenna array at K-band

    Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (354 KB)  

    3D radar imaging at K-band is performed by using a sparse linear antenna array for obtaining resolution in range, antenna array direction and in cross range, by moving the antenna array perpendicular to the antenna array direction. The sparse antenna array is designed as a patch antenna with 8 transmitting element on each end of 16 sparsely distributed receiving antenna elements. The data is thus registered in a bistatic geometry. Preliminary 3D-image result is shown of a private car and a reference corner reflector. The image result is close to expected quality in terms of resolution and side lobe levels. View full abstract»

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  • High-Rise Building Feature Extraction Using High Resolution Spotlight TanDEM-X Data

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (6561 KB)  

    The inherent spatial scales of buildings are determined by the typical floor height of three meter and the distance of adjacent windows. With meter-resolution images delivered by modern SAR satellites like TerraSAR-X and TanDEM-X, it is now possible to map urban areas from space in very high level of detail using many advanced interferometric techniques such as PSI and TomoSAR processing, whereas these multi-pass interferometric techniques are based on a great number of images. In the paper we propose a workflow, taking advantages of the single-pass high resolution InSAR data free of motion and temporal decorrelation, to extract features of high rise building. These features include building masks, orientations and especially, a new feature - the iso-height lines. Incorporating the extracted building features as prior knowledge into the TomoSAR inversion may reduce the required number of images. The proposed approach is validated using a high resolution spotlight TanDEM-X pair over a high rise area in Las Vegas. View full abstract»

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  • Detecting Building Layovers in a SAR Interferometric Processor Without External References

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1708 KB)  

    A novel technique for the derivation of building layovers is presented. It makes use of the behaviour of the geocoding processing stage embedded in an interferometric SAR processor for this particular case. It is shown how layover pixels create a regular pattern in the range mapping matrices, with a multiple mapping of a single SAR pixel for different DEM cells. The exploitation of these patterns yields a generation of a layover map without the use of external supports. The integration in an interferometric processor with a limited additional computational load and the capability to isolate building signatures are additional benefits. The algorithm is tested on a TanDEM-X spotlight acquisition over Berlin (Germany). View full abstract»

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  • Propagation mechanisms in urban canyons. Distorsions and entropy

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1097 KB)  

    A district in San Francisco Bay is misclassified when applying the H - alpha decomposition. It is actually classified as an high entropy area, whereas this is expected to be of low entropy as it is an urban area. Among the differences between this district and the neighboring ones, we can quote the orientation of the streets and the inner organization. We use a 3D commercial tool (FEKO) to simulate an urban canyon in ideal conditions first and then for two types of geometric distortion. The analysis shows that these distortions may explain this high entropy observed for this particular district. View full abstract»

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  • Detection of Coherent Scatterers in SAR Data: Application for Urban Environments

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1555 KB)  

    Potentials and limitations of using coherent scatterers (CSs) to monitor urban subsidences by means of differential SAR interferometry (D-InSAR) techniques are investigated in this paper. Recently, a new CS detector based on the generalized likelihood ratio test (GLRTA) has been proposed, and a complete performance analysis together with an extensive experimentation on real data have already been presented, showing its good behavior. Thus, CSs revealed by means of this detector are chosen as reference points for the generation of deformation maps in the framework of an experimental D-InSAR processor developed at the Microwaves and Radar Institute (HR) of the German Aerospace Center (DLR). The obtained results are compared with the ones achieved by using permanent scatterers (PSs). Finally, some conclusions about the choice of CSs in D-InSAR applications are given. View full abstract»

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  • Urban Regularity in PS point clouds

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (702 KB)  

    Man-made structures like urban areas are often characterized by geometrically simple and repeated forms. This leads to a preferred rectangular and regular alignment of objects like windows or balconies at facades of the majority of buildings in modern cities. In this paper we show how this regularity can be exploited for the challenging task of Synthetic Aperture Radar (SAR) scene description and demonstrate the applicability in a case study. We present a virtually parameter free method to segment a Persistent Scatterer point cloud which is based on spectral clustering theory. In a consecutive step we fit optimal lattices into the clustered PS sets to describe separate facades. This leads to an object based representation of the SAR data which allows for many new applications in the field of building monitoring and change detection in urban areas. View full abstract»

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  • Fast processing of very high resolution and/or very long range airborne SAR images

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1316 KB)  

    Beyond autofocus and motion compensation issues, airborne SAR imaging at very high resolution, at very long range, or on wide swath raises severe computational difficulties due to the large raw signal data block involved, as well as huge resulting image handling issues. With the exception of a technical detail with azimuth resampling in the sliding spotlight geometry required by very high azimuth resolution (namely, consequences of an integration angle possibly wider than the Doppler ambiguous angle), the image synthesis can be performed with a conventional stripmap processor, but the processing must be divided in sub-parts due to the limited memory available on one computer node. This processing by part may also decrease processing duration by processing sub-parts simultaneously in parallel on distinct computing nodes. The global computation time can also be limited by using massively parallel processor nodes such as graphic processing units (GPU), but as graphic memory on these devices are even more limited (though much faster) than that available on conventional CPU based nodes, expedients such as swapping with concurrent transfers & computations and multi-GPU pipelining are required. Acceleration of autofocus and image registration, which are the two next heavier computations after image synthesis, will be also addressed. View full abstract»

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  • Range Cell Migration Correction for Phase Error Compensation of Highly Squinted SAR

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (173 KB)  

    Phase error compensation within motion compensation techniques requires range cell migration corrected SAR data. The main contribution of this paper is providing a non-approximated range cell migration correction (RCMC) for processing highly squinted SAR data. Embedded in the conventional Omega-K processing, the approach consists of two coordinate transformations carried out in the 2D frequency domain and a modification made to the 2D matched filter. The first coordinate transformation is a rotation that removes the effect of the squint angle, the second one is an azimuth wavenumber dependent shift of the range wavenumber. It is shown that the proposed approach works for squint angles up to 60deg. View full abstract»

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  • Processing of MIRANDA35 FMCW-SAR Data using a Time-Domain Algorithm

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1087 KB)  

    Results from an airborne SAR campaign in July 2013 using the FMCW SAR system MIRANDA35 developed by FHR are presented. This system offers a high flexibility regarding the possible swath-widths, flight altitudes and operating band-widths. The platform is an optionally piloted aircraft operated by the Swiss Procurement and technology Center armasuisse. The navigational data is a combined product from INS / GPS and dGPS data. The data were focused and geocoded with a Time-Domain Algorithm dedicated to the processing of FMCW SAR systems. Examples of resulting high-resolution SAR images are shown. The focusing quality is assessed using corner reflectors. View full abstract»

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  • Real-Time Onboard Processing and Ground Based Monitoring of FMCW-SAR Videos

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    Airborne real-time SAR processing and ground based monitoring and observation of large areas by a remotely controlled radar sensor offers a variety of new and interesting applications. This is achieved through a compact and powerful radar system and a long-distance data link for the platform. In this paper we present the signal processing aspects for an efficient real-time SAR processing implementation. Further we describe the projection and transmission of the individual SAR images to a continuously flowing video signal and the used approximations in the millimeter wave domain. First results of the full operational system are demonstrated and compared to the post processed high resolution SAR images. Finally, an outlook is given on forthcoming expansions and possible scenarios. View full abstract»

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  • PALSAR-2 and Pi-SAR-L2 - Multi frequency Polarimetric Sensitivity on Disaster

    Page(s): 1 - 2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (262 KB)  

    We evaluated the polarimetric sensitivity of the multi frequency syhthetic aperture radars (SARs) for detecting the landslide areas in mountains using the polarimetric SARs. We found that three parameters - the coherence of HH and VV, the polarimetric entropy, and the power ratio of HH/HV - are very effective with L-band SARs, and that the land cover changes from the forest to the landslide can be effectively detected using these three parameters. We tested the X band sensitivity from spaceborne SARs, i.e., Terra SAR X and Cosmo SkyMed, at the same test site, the Totsukawamura area, Nara, Japan. Results showed that X-band SARs is less sensitive to the landslide events. This is because the X-band has less or no signal penetration through the forest while the Lband has larger signal penetration. We have L-C-X simultaneous data acquisitions on Sept. 11-13, 2013 at the Totsukawa-mura area and will describe the multi frequency sensitivity of the landslide disaster sensitivity. View full abstract»

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  • SAR analysis for the 2011 eruption of Shinmoe-dake, Japan

    Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1343 KB)  

    Concentrated SAR observation, especially by PALSAR, were carried out in the 2011 eruption of Shinmoe-dake eruption. We found pre-eruption inflation and co-eruption deflation in west-northwest of the crater, applying SAR interferometry to their images. Furthermore we investigated co-eruption deformation with higher temporal resolution using InSAR time-series analysis using multi-track SAR data. From SAR intensity images, lava effusion rate and amount were estimated. It was used in estimations of lava viscosity and of a relation between the amount of effusion and deflation of the deep source. ALOS-2 mission will enable us to provide more detailed information for an eruption activity. View full abstract»

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  • InSAR-based monitoring of mass movements in Southern Kyrgyzstan using ALOS/PALSAR

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    Southern Kyrgyzstan is an area of high landslide activity causing significant damage every year. Since large areas are affected there is a big need for efficient methods for landslide monitoring. We use L-band ALOS/PALSAR imagery to analyze surface deformation related to gravitational mass movements. A total of 26 L-band ALOS/PALSAR raw data sets were received from JAXA covering the study area in South-ern Kyrgyzstan during a time period between 2007 and 2010. We applied SAR interferometry (InSAR) technique to identify surface changes which are the result of hillslope processes. In this study we present the results for the Kainama test site which has been subject to high landslide activity. The interferograms obtained by SAR interferometry analysis show very good coherence even though temporal resolution is more than 2 years over mountainous and vegetated terrain. Our InSAR derived results have been validated by field observations. It could be shown that InSAR analysis is capable to resolve the mobilization of mass movements in a quantitative way and thus indicate areas which are especially prone to experiencing landslide failures in the near future. The obtained results show the big potential of radar interferometry for monitoring of slope instabilities in Southern Kyrgyzstan. View full abstract»

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