Victor Cazcarra-Bes

Capella Space was the first U.S. company to build, launch, and operate commercial synthetic aperture radar satellites capable of collecting very high resolution synthetic aperture radar data. In this article, we provide a brief overview of Capella Space and some of the capabilities we have developed in the first seven years.

Capella Space is the first American company to design, build and operate a constellation of small Synthetic Aperture Radar (SAR) satellites. Its first commercial satellite was launched in August 2020. The Capella Space constellation has been growing since then, as well as the technical capabilities of the system. Among others, a novel repeat taskin...

The present study addresses the development, implementation and validation of a forest height mapping scheme based on the combination of TanDEM-X interferometric coherence and GEDI waveform measurements. The very general case where only a single polarisation TanDEM-X interferogram, a set of spatially discrete GEDI waveform measurements and no DTM a...

Synthetic Aperture Radar (SAR) measurements are unique for mapping forest 3D structure and its changes in time. Tomographic SAR (TomoSAR) configurations exploit this potential by reconstructing the 3D radar reflectivity. The frequency of the SAR measurements is one of the main parameters determining the information content of the reconstructed refl...

Model-based forest height inversion from Pol-InSAR data relies on the realistic parameterization of the underlying (vertical) radar reflectivity function. In the context of interferometric TanDEM-X measurements - especially in the global single pol DEM mode - this is not possible due to the limited dimensionality of the observation space. In order...

With decreasing frequency synthetic aperture radar (SAR) pulses penetrate more and more into and through vegetation layers, and interact with vegetation elements located at different heights within the forest volume and with the underlying ground. This, combined with the ability of SAR tomographic (TomoSAR) techniques to reconstruct the 3D radar re...

The estimation and monitoring of 3D forest structure at large scales strongly relies on the use of remote sensing techniques. Today, two of them are capable to provide 3D forest structure estimates: lidar and Synthetic Aperture Radar (SAR) configurations. The differences in wavelength, imaging geometry, and technical implementation make the measure...

Synthetic aperture radar tomography (TomoSAR) at lower frequencies allows the reconstruction of the 3-D radar reflectivity of volume scatterers allowing access to their physical 3-D structure by means of multiangular SAR acquisitions. The performance of the reconstruction critically depends on the number and (spatial) distribution of the tomographi...

TanDEM-X experiments have shown that forest height can be estimated with single polarization X-band interferometric coherences. An external digital terrain model (DTM) not only allows to use both coherence magnitude and phase information, but also to overcome X-band penetration limitations. However, DTM information is not available for large areas....

Forest aboveground biomass is a key variable in remote sensing based forest monitoring. Active sensor systems, such as lidar, can generate detailed canopy height products. Relationships between canopy height and biomass are commonly established via regression analysis using information from ground-truth plots. In this way, many site-specific height...

The three dimensional (3-D) forest structure is a key parameter of the forest ecosystem useful for many applications like biomass estimation, plant biodiversity or forest management and productivity. Since decades, the most common way to characterize forest structure has been the use of single-tree information collected in situ. However, this type...

Forest structure is a key parameter for forest applications, but it is difficult to be estimated at the required spatial and temporal scales. In this context, synthetic aperture radar Tomography (TomoSAR) that allows, at lower frequencies, the 3-D imaging of natural volume scatterers with high spatial and temporal resolution may be a game changer....

The estimation and monitoring of 3D forest structure at large scales strongly rely on the use of remote sensing techniques. Today, two of them are able to provide 3D forest structure estimates: lidar and synthetic aperture radar (SAR) configurations. The differences in wavelength, imaging geometry, and technical implementation make the measurements...

The wavelength of synthetic aperture radar (SAR) waves affects the sensitivity to scatterers depending on their size and the penetration through forest volumes. Therefore, forest backscattering at different wavelengths (from P- up to X-band) contains different structural information about the geometry of vegetation elements and their distribution i...

There is a common agreement on the relevance of L-band wavelengths (around 20 cm) for forest observation. For instance, the larger backscatter dynamic range increases the sensitivity to larger biomass gradients with respect to C- and X-band. Furthermore, L-band allows the penetration into and through dense forest canopies in all forest ecosystems,...

Synthetic aperture radar (SAR) remote sensing configurations are able to provide continuous measurements on global scales sensitive to the vertical structure of forests with a high spatial and temporal resolution. Furthermore, the development of tomographic SAR techniques allows the reconstruction of the three-dimensional (3-D) radar reflectivity o...

The aim of this paper is to compare L- and P-band vertical backscattering profiles estimated by means of Synthetic Aperture Radar (SAR) Tomography (TomoSAR) and full LIght Detection And Ranging (lidar) waveforms in terms of their ability to distinguish different tropical forest structure types. The comparison relies on the unique DLR F-SAR and NASA...

Polarimetric SAR Interferometry (Pol-InSAR) is a SAR remote sensing discipline with unique and powerful applications related to the vertical structure of natural and man-made volume scatterers. The coherent combination of single- or multi-baseline interferograms acquired at different polarisations provides sensitivity to the vertical distribution o...

Synthetic Aperture Radar Tomography techniques provide 3D information of the forest due to the ability of microwaves to penetrate through vegetation. Recent studies link the radar 3D information to forest 3D structure in order to translate the tomographic results to an ecological interpretation. However, due to the undersampled nature of tomographi...

The future SAR missions such as BIOMASS and Tandem-L will exploit the potential of Synthetic Aperture Radar Tomography to extract 3D forest structure information. Several algorithms can be applied for TomoSAR imaging. This paper analyses the performance of two non-parametric algorithms, Capon Beamforming and Compressive Sensing (CS), for forest str...

Recently a framework for forest structure based on TomoSAR data has been defined. Based on the spatial distribution of the reflectivity peaks, two complementary descriptors are evaluated at a given scale. This paper high- lights the dependence of the structure estimate on scale and shows, through analysis on real and simulated data that the restric...

Remote sensing systems have been demonstrated to be a powerful source of information for monitoring tropical forest ecosystems. In particular, Synthetic Aperture Radar (SAR) and LIght Detection And Ranging (lidar) systems provide measurements sensitive to 3-D forest structure parameters at high spatial and temporal resolutions. This is of critical...

The penetration capability of microwaves into and through vegetation layers allows scattering interactions across the whole vertical vegetation extend. This, combined with the ability of multi-baseline Synthetic Aperture Radar (SAR) techniques to reconstruct the 3D radar reflectivity opens the door to the use of air- and space-borne SAR configurati...

Synthetic Aperture Radar Tomography (TomoSAR) allows the reconstruction of the 3D reflectivity of natural volume scatterers such as forests, thus providing an opportunity to infer structure information in 3D. In this paper, the potential of TomoSAR data at L-band to monitor temporal variations of forest structure is addressed using simulated and ex...

TanDEM-X forms together with TerraSAR-X the first single-pass polarimetric interferometer in space. This allows for the first time the acquisition and analysis of Single-, Dual-, and Quad-Pol-InSAR data without the disturbing effect of temporal decorrelation globally. For this reason, the exploration of TanDEM-X data for forestry is constantly incr...

Synthetic Aperture Radar Tomography (TomoSAR) provides 3D information from the illuminated scene, giving thus the opportunity to infer 3D structure information from forests. In this paper, the temporal variations of forest structure are analyzed in a TomoSAR dataset covering a period of five years over the Traunstein forest, in the south of Germany...

Synthetic Aperture Radar Tomography (TomoSAR) allows the reconstruction of the 3D (radar) reflectivity opening the door for the estimation of 3D forest structure parameters. Future SAR missions will be able to provide global tomographic coverage in relative small revisit times, enabling the monitoring of 3D forest structure dynamics. In this poster...

Microwaves can propagate through vegetation layers, allowing the radar signal to interact with the different physical forest structure elements. Exploiting this property, SAR Tomography techniques provide a 3D profile of the backscattered radar power providing a proxy to the physical forest structure. This capability has been demonstrated by means...

Lidar and radar are remote sensing systems that have proven their potential to accurately monitor forest structure characteristics. Both are active systems. They send their own pulses and measure the time elapsed between the transmission of the pulse and its reception after it has been reflected in a scatterer. However, Lidar employs laser light, w...

When observing a scene, a radar system is sensitive to the morphology of the scatterers, but also to their dielectric properties. Therefore, in the framework of forest monitoring, the presence or absence of leaves, the daily and seasonal water cycle in the different structural elements of the tree, as well as rain may have an influence on the 3D re...

Lidar and radar are remote sensing systems that have proven their potential to accurately monitor forest structure characteristics. Both are active systems. They send their own pulses and measure the time elapsed between the transmission of the pulse and its reception after it has been reflected in a scatterer. However, Lidar employs laser light, w...

When observing a scene, a radar system is sensitive to the morphology of the scatterers, but also to their dielectric properties. Therefore, in the framework of forest monitoring, the presence or absence of leaves, the daily and seasonal water cycle in the different structural elements of the tree, as well as rain may have an influence on the 3D re...

The advancements in processing and inversion of multi-baseline SAR techniques during the last years triggered the development of a new generation of forest monitoring applications by means of SAR remote sensing. At the same time the progress in SAR technology makes possible the implementation and operation of a new generation of spaceborne SAR conf...

SAR tomography (TomoSAR) techniques allow a direct 3D imaging by exploiting angular diversity with different passes of the sensor. One of the main drawbacks of SAR tomography is that the estimation of the vertical reflectivity profile has to be performed through a limited set of multibaseline acquisitions, which requires solving a highly underdeter...

Synthetic Aperture Radar (SAR) signals at low frequencies can penetrate forest. This capability allows, through advanced imaging techniques such as tomography, the extraction of relevant information related to the three dimensional structural parameters of the observed scene. More specifically, through repeated passes of the sensor, a scene is obse...

In the framework of the studies on the Wavemill concept, an End-to-End simulator has been developed in order to asses the different configurations and related sensitivity of a wide-swath interferometric SAR instrument. The simulator, being developed by Starlab under ESA contract, integrates all simulation, processing, and inversion steps involved i...

A generic electromagnetic model for agriculture scenes has been extended and adapted to simulate the X-band SAR response of rice fields during their whole phenological cycle. Simulations of different polarimetric observables have been useful for interpreting time series of dual-pol TerraSAR-X images acquired during 2008 and 2009 over rice fields in...