• 14:40 DIFF-TOMO OPPORTUNITIES FOR LONG WAVELENGTH SATELLITE SYSTEMS

  Lombardini, Fabrizio (1,2); Viviani, Federico (1,2) 1: University of Pisa, Italy; 2: CNIT/RaSS Nat. Lab. , Italy

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  Many SAR missions, both operational or experimental, have been conducted in the last few years exploiting interferometric processing techniques and more recently advanced coherent data combination methods, in particular Pol-InSAR and 3D SAR Tomography [1,2]. Concerning developments in coherent radar imaging and parameter retrieval algorithms, a new multidimensional imaging methodology bridging the gap between D-InSAR and 3D Tomography has been originated by University of Pisa (UniPi), termed Differential Tomography (Diff-Tomo) or 4D (“3D+Time”) imaging [3]. Diff-Tomo allows “opening” the SAR cell in complex non-stationary scenes, exploiting proper space-time spectral analysis operating typically on very sparse baseline-time data, to jointly resolve multiple elevation and deformation velocity components of the scatterers mapped in a SAR cell. This emerging methodology has been experimented and validated in the last few years, in particular for subsidence monitoring of dense layover urban areas with ERS, TerraSAR-X, and COSMO-SkyMed satellite data [4,5]. In this work, possible opportunities coming from the use of Diff-Tomo, with intended application to future advanced satellite missions operating at low carrier frequency like BIOMASS, are highlited and discussed. Diff-Tomo capabilities has been already proven with systems with monostatic acquisition patterns (one track per pass); it can be thus interesting to consider exploiting the synergy between the new algorithms potentials and the advanced BIOMASS system configuration, to deeply exploit the system, targeting extraction of enhanced or new information in a wide range of applications, including both forest, ice, and arid zones scenarios. In this framework, an ensemble of research developments carried out at UniPi and CNIT/RaSS Nat. Lab. and latest advances are presented of Diff-Tomo techniques, for the analysis of complex layover or volumetric scatterers and non-stationary deformating or decorrelating scenarios. Specifically, Diff-Tomo application over urban areas to estimate heights and deformation velocities of multiple scatterers with new generation high resolution SAR systems is recalled. Concerning natural scenarios, the Diff-Tomo enabled functionalities are shown of 3D forest Tomography robust to temporal decorrelation through higher-dimensional (4D+) processing [6], and separation in the height dimension of different temporal coherence levels, that are mixed (undiscriminated) in the classical (overall) coherence analysis. Both these unique functionalities exploit the Diff-Tomo identifiability of temporal harmonics from decorrelation. Robust Tomography may overcome a possible hindrance to operational development of spaceborne forest tomography, including the BIOMASS mission. Temporal coherence separation allows new phenomenological investigations to characterize the effect of decorrelation in Pol-InSAR and Tomo-SAR applications, and possibly new dynamic 3D forest features. Possible subcanopy subsidence monitoring is also discussed. It is worth noting that all these forest functionalities allow a large scale analysis with no special or dedicated hardware, differently from TropiScat. Finally, regarding the secondary goals of BIOMASS mission, possible advanced stratigraphy of dynamic processes inside ice volumes is tackled, together with concept of 4D subsurface water table level monitoring in arid zones [7,8]. Simulated results and real P-band BIOSAR-1 data experiments of these functionalities are shown. It is planned to report at the conference first results of a dedicated ground-based experiment for volumetric scenarios dynamic stratigraphy. The described methodologies may be fruitfully applied through dedicated work to the BIOMASS mission for refining or expanding data processing/science objectives. [1] A. Reigber, A. Moreira, “First Demonstration of Airborne SAR Tomography using Multibaseline L-band Data,” IEEE TGARS, 38(5), pp.2142-2152, 2000. [2] F. Lombardini, M. Montanari, F. Gini, “Reflectivity Estimation for Multibaseline Interferometric Radar Imaging of Layover Extended Sources,” IEEE Tr. SP, 51(6), pp.1508-1519, 2003. [3] F. Lombardini, “Differential Tomography: A New Framework for SAR Interferometry”, IEEE TGARS, 43(1), pp.37-44, 2005. [4] D. Reale, G. Fornaro, A. Pauciullo, X. Zhu, R. Bamler, “Tomographic Imaging and Monitoring of Buildings with Very High Resolution SAR Data,” IEEE GRSL, 8(4), pp.661-665, 2011. [5] F. Lombardini, M. Pardini, “Superresolution Differential Tomography: Experiments on Identification of Multiple Scatterers in Spaceborne SAR Data,” IEEE TGARS, 50(4), pp.1117-1129, 2012. [6] F. Lombardini, F. Cai, "Temporal Decorrelation-Robust SAR Tomography," IEEE TGARS, available in early access, 52(9), pp.5412-5421, 2014. [7] F. Lombardini, “Potentials of Volumetric Differential Interferometry and Robust Tomography,” ESA Fringe’07 Wrkshp. [8] F. Lombardini, F. Cai, “Evolutions of Diff-Tomo for Sensing Subcanopy Deformations and Height-varying Temporal Coherence,” Proc. ESA Fringe’11 Wrkshp.

  
   

• 15:00 Exploring Vegetation Profiles from TanDEM-X Phase, Lidar, and Field Measurements in Tropical Forests

  Treuhaft, Robert (1); Goncalves, Fabio (2); Keller, Michael (3); dos Santos, Joao Roberto (4) 1: Jet Propulsion Lab, United States of America; 2: Woods Hole Research Center; 3: USDA; 4: INPE

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  This paper explores the hypothesis that few-look phases from TanDEM-X have information about the vegetation profile over 50 x 50 m stands in tropical moist forests in Brazil. The formalism for modeling the interferometric phase of interferometric SAR (InSAR) is examined before taking the look, or ensemble average. It is suggested that it is the look averaging that produces the Fourier transform of the radar power profile in InSAR. Before the look averaging, a histogram of InSAR phases seems related to the radar power profile, which, in turn, is related to vegetation density. After a qualitative argument about the information in the few-look phases, 2-look phase histograms are shown along with lidar waveform profiles and modeled field profiles. A regression of field biomass versus Fourier transforms of the look-height distribution (LHD) shows about 15% improvement over using traditional single-baseline coherence and phase.

  
   

• 15:20 Round Table Discussion

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  Round Table Discussion

  
   

Highlights

In May 2013, the Biomass mission concept was selected to become the next in the series of satellites developed to further our understanding of Earth.

Released: 21/06/2013

REPLAY EARTH EXPLORER 7 USER CONSULTATION MEETING (PART 1)

Released: 11/03/2013

POLinSAR 2013 Workshop

Released: 22/02/2013