http://hdl.handle.net/2117/1443 Thu, 23 May 2013 11:49:13 GMT 2013-05-23T11:49:13Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18353 Title: Determination of the overlap factor and its enhancement for medium-size tropospheric lidar systems: a ray-tracing approach Authors: Kumar, Dhiraj; Rocadenbosch Burillo, Francisco Abstract: The problem of overlap factor (OVF) computation and its near-range sensitivity for medium-size aperture ( f ∕ 10 , f ∕ 11 ) bi-axial tropospheric lidar systems using ray-tracing sim- ulation software is presented. The method revisits both detector and fiber optics coupling alter- natives at the telescope focal-plane along with the insertion of a field lens. A sensitivity analysis is carried out as a function of laser divergence, field lens, and detector/fiber positions, detector size, and the fiber ’ s core diameter and numerical aperture. The ray-tracing approach presented here is straightforward and a comparatively much simpler solution than analytical-based meth- ods. Parametric simulations are carried out to show that both approaches are coincident. Insertion of a field lens proves to be an elegant and low sensitivity solution for OVF enhancement, par- ticularly, in the near-range of the lidar Fri, 15 Mar 2013 15:03:19 GMT http://hdl.handle.net/2117/18353 2013-03-15T15:03:19Z Kumar, Dhiraj; Rocadenbosch Burillo, Francisco no The problem of overlap factor (OVF) computation and its near-range sensitivity for medium-size aperture ( f ∕ 10 , f ∕ 11 ) bi-axial tropospheric lidar systems using ray-tracing sim- ulation software is presented. The method revisits both detector and fiber optics coupling alter- natives at the telescope focal-plane along with the insertion of a field lens. A sensitivity analysis is carried out as a function of laser divergence, field lens, and detector/fiber positions, detector size, and the fiber ’ s core diameter and numerical aperture. The ray-tracing approach presented here is straightforward and a comparatively much simpler solution than analytical-based meth- ods. Parametric simulations are carried out to show that both approaches are coincident. Insertion of a field lens proves to be an elegant and low sensitivity solution for OVF enhancement, par- ticularly, in the near-range of the lidar http://hdl.handle.net/2117/18321 Title: Processing multidimensional SAR and hyperspectral images with binary partition tree Authors: Alonso González, Alberto; Valero, Silvia; Chanussot, Jocelyn; López Martínez, Carlos; Salembier Clairon, Philippe Jean Abstract: The current increase of spatial as well as spectral resolutions of modern remote sensing sensors represents a real opportunity for many prac tical applications but also generates important challenges in terms of image processing. In particular, the spatial correlation between pixels and/or the spectral correlation between spectral bands of a given pixel cannot be ignored. The traditional pixel-based representation of images does not facilitate the handling of these correlations. In this paper, we discuss the inter est of a particular hierarchical region-based representation of images based on binary partition tree (BPT). This representation approach is very flexible as it can be applied to any type of image. Here both optical and radar images will be discussed. Moreover, once the image representation is computed, it can be used for many different applications. Filtering, segmentation, and classifica- tion will be detailed in this paper. In all cases, the interest of the BPT representation over the classical pixel-based representa- tion will be highlighted Thu, 14 Mar 2013 19:10:03 GMT http://hdl.handle.net/2117/18321 2013-03-14T19:10:03Z Alonso González, Alberto; Valero, Silvia; Chanussot, Jocelyn; López Martínez, Carlos; Salembier Clairon, Philippe Jean no The current increase of spatial as well as spectral resolutions of modern remote sensing sensors represents a real opportunity for many prac tical applications but also generates important challenges in terms of image processing. In particular, the spatial correlation between pixels and/or the spectral correlation between spectral bands of a given pixel cannot be ignored. The traditional pixel-based representation of images does not facilitate the handling of these correlations. In this paper, we discuss the inter est of a particular hierarchical region-based representation of images based on binary partition tree (BPT). This representation approach is very flexible as it can be applied to any type of image. Here both optical and radar images will be discussed. Moreover, once the image representation is computed, it can be used for many different applications. Filtering, segmentation, and classifica- tion will be detailed in this paper. In all cases, the interest of the BPT representation over the classical pixel-based representa- tion will be highlighted http://hdl.handle.net/2117/17691 Title: Digital coherent receiver for orbital angular momentum demultiplexing Authors: Belmonte Molina, Aniceto; Pérez Torres, Juan Abstract: We put forward a type of receiver for coherent detection of the photon orbital angular momentum (OAM). A coherent array receiver, consisting of multiple subapertures, with each subaperture coupled to a single-mode fiber, maps the complex optical field in the image plane. Using digital samplers connected to each array element, the local electrical signals resulting from the detection process can be measured coherently, moving the complexity of the full OAM measurement from the optical domain to the digital domain. By computer processing the coherent electrical patterns obtained, one can retrieve full information (amplitude and phase) of the different OAM components that constitute any incoming beam Tue, 12 Feb 2013 18:28:00 GMT http://hdl.handle.net/2117/17691 2013-02-12T18:28:00Z Belmonte Molina, Aniceto; Pérez Torres, Juan no We put forward a type of receiver for coherent detection of the photon orbital angular momentum (OAM). A coherent array receiver, consisting of multiple subapertures, with each subaperture coupled to a single-mode fiber, maps the complex optical field in the image plane. Using digital samplers connected to each array element, the local electrical signals resulting from the detection process can be measured coherently, moving the complexity of the full OAM measurement from the optical domain to the digital domain. By computer processing the coherent electrical patterns obtained, one can retrieve full information (amplitude and phase) of the different OAM components that constitute any incoming beam http://hdl.handle.net/2117/17647 Title: Study on aerosol properties over Madrid (Spain) by multiple instrumentation during SPALI10 lidar campaign Authors: Molero, Francisco; Sicard, Michaël; Navas Guzmán, Francisco; Preissler, J.; Amodeo, Aldo; Freudenthaler, Volker; Fernández, J.A.; Tomás Martínez, Sergio; Granados, M.; Wagner, F.; Giunta, Aldo; Mattis, I.; Pujadas, Manuel; Comerón Tejero, Adolfo; Alados Arboledas, Lucas; Guerrero Rascado, Juan Luis; D'Amico, Giuseppe; Lange, Diego; Kumar, Dhiraj; Pappalardo, Gelsomina; Giner Nos, Joaquín José; Muñoz Porcar, Constantino; Rocadenbosch Burillo, Francisco Abstract: Cuatro sistemas lidar Raman multifrecuencia (Madrid, Granada, Barcelona y Evora), tomaron medidas simultáneamente a un sistema de referencia (Potenza) para verificar su funcionamiento durante la campaña de intercomparación: SPALI10, (SPAin Lidar Intercomparison 2010) que tuvo lugar en Madrid entre el 18 de Octubre y el 5 de Noviembre de 2010. Estos sistemas lidar Raman multifrecuencia proporcionan propiedades ópticas de los aerosoles con resolución vertical. Los perfiles suministrados por los sistemas lidar se compararon con información complementaria proporcionada por otra instrumentación, tal como la distribución de tamaños de los aerosoles medida de manera continua a nivel de superficie o la caracterización de la columna de aerosoles Tue, 12 Feb 2013 09:56:33 GMT http://hdl.handle.net/2117/17647 2013-02-12T09:56:33Z Molero, Francisco; Sicard, Michaël; Navas Guzmán, Francisco; Preissler, J.; Amodeo, Aldo; Freudenthaler, Volker; Fernández, J.A.; Tomás Martínez, Sergio; Granados, M.; Wagner, F.; Giunta, Aldo; Mattis, I.; Pujadas, Manuel; Comerón Tejero, Adolfo; Alados Arboledas, Lucas; Guerrero Rascado, Juan Luis; D'Amico, Giuseppe; Lange, Diego; Kumar, Dhiraj; Pappalardo, Gelsomina; Giner Nos, Joaquín José; Muñoz Porcar, Constantino; Rocadenbosch Burillo, Francisco no Aerosols, Lidar, Size Distributions Cuatro sistemas lidar Raman multifrecuencia (Madrid, Granada, Barcelona y Evora), tomaron medidas simultáneamente a un sistema de referencia (Potenza) para verificar su funcionamiento durante la campaña de intercomparación: SPALI10, (SPAin Lidar Intercomparison 2010) que tuvo lugar en Madrid entre el 18 de Octubre y el 5 de Noviembre de 2010. Estos sistemas lidar Raman multifrecuencia proporcionan propiedades ópticas de los aerosoles con resolución vertical. Los perfiles suministrados por los sistemas lidar se compararon con información complementaria proporcionada por otra instrumentación, tal como la distribución de tamaños de los aerosoles medida de manera continua a nivel de superficie o la caracterización de la columna de aerosoles http://hdl.handle.net/2117/17550 Title: Cancellation of scattering mechanisms in PolInSAR: application to underlying topography estimation Authors: López Martínez, Carlos; Papathanassiou, Kostantinos Abstract: This paper investigates the polarimetric dependence of the interferometric complex correlation and proposes amethodology for cancelling individual scattering mechanisms, in terms of the complex correlation coefficient phase, under the assumption of the random volume over ground model. This allows the estimation of the ground topography on forested and vegetated areas. The first part of the analysis considers the separation of the volume from the ground (including the double-bounce scattering mechanism). This process identifies the polarization states, without constraining them to be equal in both polarimetric acquisitions, which allow to cancel either the volume scattering contribution or the ground contribution. In order to have access to the interferometric phase of the remaining or isolated scattering mechanism, the polarimetric phase contribution of this scattering mechanism has to be removed in a second step. In the case of forested areas, the previous methodology is considered from two different point of views. For the estimation of the underlying ground topography, the cancellation of the volume scattering contribution makes possible to access the interferometric phase associated to the ground contribution. In addition, the interferometric information associated to the volume scattering contribution is estimated based on the cancellation of the ground contribution. The proposed techniques are analyzed on the basis of simulated and experimental polarimetric interferometric synthetic aperture radar data, demonstrating that the ground topography, as well as the height associated to the volume contribution, are asymptotically nonbiased and dependent on the shape of the particles of the random volume. In case of spheres (η = 0), the ground-to-volume ratio presents large values favoring the accurate estimation of the topographic phase. For the case of dipole like particles (η = 0.5), the ground-to-volume ration decreases producing a coherence |ρ| in the order of 0.1, making necessary a large speckle filtering to obtain a reliable estimation of the topographic phase. Thu, 31 Jan 2013 16:12:21 GMT http://hdl.handle.net/2117/17550 2013-01-31T16:12:21Z López Martínez, Carlos; Papathanassiou, Kostantinos no Polarimetric SAR interferometry, SAR interferometry (InSAR), SAR polarimetry, underlying topography This paper investigates the polarimetric dependence of the interferometric complex correlation and proposes amethodology for cancelling individual scattering mechanisms, in terms of the complex correlation coefficient phase, under the assumption of the random volume over ground model. This allows the estimation of the ground topography on forested and vegetated areas. The first part of the analysis considers the separation of the volume from the ground (including the double-bounce scattering mechanism). This process identifies the polarization states, without constraining them to be equal in both polarimetric acquisitions, which allow to cancel either the volume scattering contribution or the ground contribution. In order to have access to the interferometric phase of the remaining or isolated scattering mechanism, the polarimetric phase contribution of this scattering mechanism has to be removed in a second step. In the case of forested areas, the previous methodology is considered from two different point of views. For the estimation of the underlying ground topography, the cancellation of the volume scattering contribution makes possible to access the interferometric phase associated to the ground contribution. In addition, the interferometric information associated to the volume scattering contribution is estimated based on the cancellation of the ground contribution. The proposed techniques are analyzed on the basis of simulated and experimental polarimetric interferometric synthetic aperture radar data, demonstrating that the ground topography, as well as the height associated to the volume contribution, are asymptotically nonbiased and dependent on the shape of the particles of the random volume. In case of spheres (η = 0), the ground-to-volume ratio presents large values favoring the accurate estimation of the topographic phase. For the case of dipole like particles (η = 0.5), the ground-to-volume ration decreases producing a coherence |ρ| in the order of 0.1, making necessary a large speckle filtering to obtain a reliable estimation of the topographic phase. http://hdl.handle.net/2117/17453 Title: A new space technology for ocean observation: the SMOS mission Authors: Font Ferré, Jordi; Ballabrera Poy, Joaquim; Camps Carmona, Adriano José; Corbella Sanahuja, Ignasi; Duffo Ubeda, Núria; Duran Martínez, Israel; Emelianov Kolomitski, Mikhail; Enrique González, Luis; Fernández Gallego, Pedro; Gabarró Prats, Carolina; González, Cristina; González, Veronica; Gourrion, J.; Guimbard, S.; Hoareau, N.; Julià, A; Kalaroni, S.; Konstantinidou, Anna; Aretxabaleta, L.; Martínez, Justino; Miranda, Jorge Miguel; Monerris Belda, Alessandra; Montero, Sergio; Mourre, B.; Pablos Hernández, Míriam; Pérez Villar, Fernando; Piles Guillem, Maria; Portabella, M.; Sabia, R.; Salvador, Joaquin; Talone, Marco; Torres Torres, Francisco; Turiel Martínez, Antonio; Vall-Llossera Ferran, Mercedes Magdalena; Villarino Villarino, Ramón Abstract: Capability for sea surface salinity observation was an important gap in ocean remote sensing in the last few decades of the 20th century. New technological developments during the 1990s at the European Space Agency led to the proposal of SMOS (Soil Moisture and Ocean Salinity), an Earth explorer opportunity mission based on the use of a microwave interferometric radiometer, MIRAS (Microwave Imaging Radiometer with Aperture Synthesis). SMOS, the first satellite ever addressing the observation of ocean salinity from space, was successfully launched in November 2009. The determination of salinity from the MIRAS radiometric measurements at 1.4 GHz is a complex procedure that requires high performance from the instrument and accurate modelling of several physical processes that impact on the microwave emission of the ocean’s surface. This paper introduces SMOS in the ocean remote sensing context, and summarizes the MIRAS principles of operation and the SMOS salinity retrieval approach. It describes the Spanish SMOS high-level data processing centre (CP34) and the SMOS Barcelona Expert Centre on Radiometric Calibration and Ocean Salinity (SMOS-BEC), and presents a preliminary validation of global sea surface salinity maps operationally produced by CP34. Mon, 21 Jan 2013 17:31:17 GMT http://hdl.handle.net/2117/17453 2013-01-21T17:31:17Z Font Ferré, Jordi; Ballabrera Poy, Joaquim; Camps Carmona, Adriano José; Corbella Sanahuja, Ignasi; Duffo Ubeda, Núria; Duran Martínez, Israel; Emelianov Kolomitski, Mikhail; Enrique González, Luis; Fernández Gallego, Pedro; Gabarró Prats, Carolina; González, Cristina; González, Veronica; Gourrion, J.; Guimbard, S.; Hoareau, N.; Julià, A; Kalaroni, S.; Konstantinidou, Anna; Aretxabaleta, L.; Martínez, Justino; Miranda, Jorge Miguel; Monerris Belda, Alessandra; Montero, Sergio; Mourre, B.; Pablos Hernández, Míriam; Pérez Villar, Fernando; Piles Guillem, Maria; Portabella, M.; Sabia, R.; Salvador, Joaquin; Talone, Marco; Torres Torres, Francisco; Turiel Martínez, Antonio; Vall-Llossera Ferran, Mercedes Magdalena; Villarino Villarino, Ramón no Interferometry, Microwave radiometry, Ocean salinity, Remote sensing, Salinity maps, SMOS mission, Validation Capability for sea surface salinity observation was an important gap in ocean remote sensing in the last few decades of the 20th century. New technological developments during the 1990s at the European Space Agency led to the proposal of SMOS (Soil Moisture and Ocean Salinity), an Earth explorer opportunity mission based on the use of a microwave interferometric radiometer, MIRAS (Microwave Imaging Radiometer with Aperture Synthesis). SMOS, the first satellite ever addressing the observation of ocean salinity from space, was successfully launched in November 2009. The determination of salinity from the MIRAS radiometric measurements at 1.4 GHz is a complex procedure that requires high performance from the instrument and accurate modelling of several physical processes that impact on the microwave emission of the ocean’s surface. This paper introduces SMOS in the ocean remote sensing context, and summarizes the MIRAS principles of operation and the SMOS salinity retrieval approach. It describes the Spanish SMOS high-level data processing centre (CP34) and the SMOS Barcelona Expert Centre on Radiometric Calibration and Ocean Salinity (SMOS-BEC), and presents a preliminary validation of global sea surface salinity maps operationally produced by CP34. http://hdl.handle.net/2117/17451 Title: PAU-SA: a synthetic aperture interferometric radiometer test bed for potential improvements in future missions Authors: Ramos Pérez, Isaac; Camps Carmona, Adriano José; Bosch Lluís, Xavier; Rodríguez Álvarez, Nereida; Valencia Domènech, Enric; Hyuk, Park; Forte Veliz, Giuseppe Francesco; Vall-Llossera Ferran, Mercedes Magdalena Abstract: The Soil Moisture and Ocean Salinity (SMOS) mission is an Earth Explorer Opportunity mission from the European Space Agency (ESA). Its goal is to produce global maps of soil moisture and ocean salinity using the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS). The purpose of the Passive Advanced Unit Synthetic Aperture (PAU-SA) instrument is to study and test some potential improvements that could eventually be implemented in future missions using interferometric radiometers such as the Geoestacionary Atmosferic Sounder (GAS), the Precipitation and All-weather Temperature and Humidity (PATH) and the Geostationary Interferometric Microwave Sounder (GIMS). Both MIRAS and PAU-SA are Y-shaped arrays with uniformly distributed antennas, but the receiver topology and the processing unit are quite different. The purpose of this work is to identify the elements in the MIRAS’s design susceptible of improvement and apply them in the PAU-SA instrument demonstrator, to test them in view of these future interferometric radiometer missions. Mon, 21 Jan 2013 17:20:43 GMT http://hdl.handle.net/2117/17451 2013-01-21T17:20:43Z Ramos Pérez, Isaac; Camps Carmona, Adriano José; Bosch Lluís, Xavier; Rodríguez Álvarez, Nereida; Valencia Domènech, Enric; Hyuk, Park; Forte Veliz, Giuseppe Francesco; Vall-Llossera Ferran, Mercedes Magdalena no microware, interferometric radiometer, calibration, soil moisture and ocean salinity, SMOS, Passive Advanced Unit Synthetic Aperture (PAU-SA) The Soil Moisture and Ocean Salinity (SMOS) mission is an Earth Explorer Opportunity mission from the European Space Agency (ESA). Its goal is to produce global maps of soil moisture and ocean salinity using the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS). The purpose of the Passive Advanced Unit Synthetic Aperture (PAU-SA) instrument is to study and test some potential improvements that could eventually be implemented in future missions using interferometric radiometers such as the Geoestacionary Atmosferic Sounder (GAS), the Precipitation and All-weather Temperature and Humidity (PATH) and the Geostationary Interferometric Microwave Sounder (GIMS). Both MIRAS and PAU-SA are Y-shaped arrays with uniformly distributed antennas, but the receiver topology and the processing unit are quite different. The purpose of this work is to identify the elements in the MIRAS’s design susceptible of improvement and apply them in the PAU-SA instrument demonstrator, to test them in view of these future interferometric radiometer missions. http://hdl.handle.net/2117/17449 Title: Calibration, performance, and imaging tests of a fully digital synthetic aperture interferometer radiometer Authors: Ramos Pérez, Isaac; Forte Veliz, Giuseppe Francesco; Camps Carmona, Adriano José; Bosch Lluís, Xavier; Valencia Domènech, Enric; Rodríguez Álvarez, Nereida; Hyuk, Park; Vall-Llossera Ferran, Mercedes Magdalena Abstract: This work presents the calibration, characterization, and imaging tests of the Passive Advanced Unit-Synthetic Aperture instrument (PAU-SA). PAU-SA is a fully digital -shaped two-dimensional synthetic aperture interferometric radiometer operating at the Global Positioning System (GPS) L1 band ( GHz), conceived as a test-bed for potential technological improvements in future instruments. Calibration of instrumental offsets is performed by looking to a microwave absorber and the “cold” sky. Since the instrument operates in the GPS L1 band, GPS satellites are imaged therefore, a new way to compute the Flat Target Response (FTR) has been devised. Internal phase/amplitude calibration is performed using a new technique that consists of injecting pseudo-random noise signals. Different paths from the input switch to the antennas are calibrated by means of an external beacon. A near-field to far-field transformation is applied to compensate for differences in the propagation paths. Finally, absolute amplitude calibration is achieved by imaging the GPS satellites constellation when pointing to the zenith. Evaluation of the images’ quality in terms of angular resolution, radiometric resolution and precision, show the goodness of the techniques applied to compensate for instrumental errors, the imaging capabilities of the instrument, and demonstrate their applicability in future missions. Mon, 21 Jan 2013 16:58:17 GMT http://hdl.handle.net/2117/17449 2013-01-21T16:58:17Z Ramos Pérez, Isaac; Forte Veliz, Giuseppe Francesco; Camps Carmona, Adriano José; Bosch Lluís, Xavier; Valencia Domènech, Enric; Rodríguez Álvarez, Nereida; Hyuk, Park; Vall-Llossera Ferran, Mercedes Magdalena no Calibration, GPS, image reconstruction, interferometric radiometer, performance, pseudo-random noise This work presents the calibration, characterization, and imaging tests of the Passive Advanced Unit-Synthetic Aperture instrument (PAU-SA). PAU-SA is a fully digital -shaped two-dimensional synthetic aperture interferometric radiometer operating at the Global Positioning System (GPS) L1 band ( GHz), conceived as a test-bed for potential technological improvements in future instruments. Calibration of instrumental offsets is performed by looking to a microwave absorber and the “cold” sky. Since the instrument operates in the GPS L1 band, GPS satellites are imaged therefore, a new way to compute the Flat Target Response (FTR) has been devised. Internal phase/amplitude calibration is performed using a new technique that consists of injecting pseudo-random noise signals. Different paths from the input switch to the antennas are calibrated by means of an external beacon. A near-field to far-field transformation is applied to compensate for differences in the propagation paths. Finally, absolute amplitude calibration is achieved by imaging the GPS satellites constellation when pointing to the zenith. Evaluation of the images’ quality in terms of angular resolution, radiometric resolution and precision, show the goodness of the techniques applied to compensate for instrumental errors, the imaging capabilities of the instrument, and demonstrate their applicability in future missions. http://hdl.handle.net/2117/17448 Title: Exponentiated weibull distribution family under aperture averaging for gaussian beam waves Authors: Barrios Porras, Ricardo Alfonso; Dios Otín, Víctor Federico Abstract: Nowadays, the search for a distribution capable of modeling the probability density function (PDF) of irradiance data under all conditions of atmospheric turbulence in the presence of aperture averaging still continues. Here, a family of PDFs alternative to the widely accepted Log-Normal and Gamma-Gamma distributions is proposed to model the PDF of the received optical power in free-space optical communications, namely, the Weibull and the exponentiated Weibull (EW) distribution. Particularly, it is shown how the proposed EW distribution offers an excellent fit to simulation and experimental data under all aperture averaging conditions, under weak and moderate turbulence conditions, as well as for point-like apertures. Another very attractive property of these distributions is the simple closed form expression of their respective PDF and cumulative distribution function. Mon, 21 Jan 2013 16:50:00 GMT http://hdl.handle.net/2117/17448 2013-01-21T16:50:00Z Barrios Porras, Ricardo Alfonso; Dios Otín, Víctor Federico no KOLMOGOROV PHASE SCREEN, TO-STRONG TURBULENCE, PROBABILITY DENSITY, IRRADIANCE FLUCTUATIONS, SIMULATION, MODEL Nowadays, the search for a distribution capable of modeling the probability density function (PDF) of irradiance data under all conditions of atmospheric turbulence in the presence of aperture averaging still continues. Here, a family of PDFs alternative to the widely accepted Log-Normal and Gamma-Gamma distributions is proposed to model the PDF of the received optical power in free-space optical communications, namely, the Weibull and the exponentiated Weibull (EW) distribution. Particularly, it is shown how the proposed EW distribution offers an excellent fit to simulation and experimental data under all aperture averaging conditions, under weak and moderate turbulence conditions, as well as for point-like apertures. Another very attractive property of these distributions is the simple closed form expression of their respective PDF and cumulative distribution function. http://hdl.handle.net/2117/17165 Title: Optimum intercalibration time in synthetic aperture interferometric radiometers: application to SMOS Authors: Ramos Pérez, Isaac; Bosch Lluís, Xavier; Camps Carmona, Adriano José; González Gambau, Veronica; Rodríguez Álvarez, Nereida; Valencia Domènech, Enric; Hyuk, Park; Vall-Llossera Ferran, Mercedes Magdalena; Forte Veliz, Giuseppe Francesco Abstract: Interpolation strategies for calibration of the Soil Moisture and Ocean Salinity (SMOS) mission of the European Space Agency are tested and compared. Calibration strategy (how and how often) is critical in achieving the required performance of any instrument, but it is even more important in very complex instruments such as the new family of synthetic aperture interferometric radiometers and, in particular, in the Microwave Imaging Radiometer by Aperture Synthesis instrument aboard the SMOS mission. On one hand, frequent calibration reduces the available observation time. On the other hand, the calibration requirements for soil moisture applications are more relaxed than those for ocean salinity, so the intercalibration time requirements are very different. Since SMOS drifts are stationary, half-orbit information is available to perform different interpolation strategies. In this letter, these approaches are tested to estimate the calibration parameters between consecutive calibrations. The average root-mean-square phase error is then used to find the optimum interpolation strategy and intercalibration time. On the other side, in real-time instruments, the “future” calibration data are not available at the time of taking the measurements, and predictors are required to estimate the evolution of the calibration parameters from past data only. For these systems, the extended Kalman filter can be used. The intercalibration time in a real-time instrument is evaluated, and the requirements and performances are compared to offline instruments. Wed, 19 Dec 2012 19:04:02 GMT http://hdl.handle.net/2117/17165 2012-12-19T19:04:02Z Ramos Pérez, Isaac; Bosch Lluís, Xavier; Camps Carmona, Adriano José; González Gambau, Veronica; Rodríguez Álvarez, Nereida; Valencia Domènech, Enric; Hyuk, Park; Vall-Llossera Ferran, Mercedes Magdalena; Forte Veliz, Giuseppe Francesco no Calibration, intercalibration time, interferometric radiometers, Soil Moisture and Ocean Salinity (SMOS) Interpolation strategies for calibration of the Soil Moisture and Ocean Salinity (SMOS) mission of the European Space Agency are tested and compared. Calibration strategy (how and how often) is critical in achieving the required performance of any instrument, but it is even more important in very complex instruments such as the new family of synthetic aperture interferometric radiometers and, in particular, in the Microwave Imaging Radiometer by Aperture Synthesis instrument aboard the SMOS mission. On one hand, frequent calibration reduces the available observation time. On the other hand, the calibration requirements for soil moisture applications are more relaxed than those for ocean salinity, so the intercalibration time requirements are very different. Since SMOS drifts are stationary, half-orbit information is available to perform different interpolation strategies. In this letter, these approaches are tested to estimate the calibration parameters between consecutive calibrations. The average root-mean-square phase error is then used to find the optimum interpolation strategy and intercalibration time. On the other side, in real-time instruments, the “future” calibration data are not available at the time of taking the measurements, and predictors are required to estimate the evolution of the calibration parameters from past data only. For these systems, the extended Kalman filter can be used. The intercalibration time in a real-time instrument is evaluated, and the requirements and performances are compared to offline instruments. http://hdl.handle.net/2117/16628 Title: Altimetry with GNSS-R interferometry: first proof of concept experiment Authors: Martín Neira, Manuel; Altena, B.; van Bree, R.; Van Der Marel, H.; Camps Carmona, Adriano José; Rius, Antonio; Nogués Correig, O.; Ribó, S.; Cardellach, Estel; Oliveras, S.; Valencia Domènech, Enric; Hyuk, Park; Tarongí Bauzá, José Miguel Abstract: The Global Navigation Satellite System Reflectometry (GNSS-R) concept was conceived as a means to densify radar altimeter measurements of the sea surface. Until now, the GNSS-R concept relied on open access to GNSS transmitted codes. Recently, it has been proposed that the ranging capability of the technique for ocean altimetric applications can be improved by using all the signals transmitted in the bandwidth allocated to GNSS, which includes open access as well as encrypted signals. The main objective of this study is to provide experimental proof of this enhancement through a 2-day experiment on the Zeeland Bridge (The Netherlands). In the experiment, we used a custom built GNSS-R system, composed of high gain GPS antennas, calibration subsystem, and an FPGAbased signal processor which implemented the new concepts, an X-band radar altimeter and a local geodetic network. The results obtained indicate that the new approach produces a significant improvement in GNSS-R altimetric performance. Wed, 03 Oct 2012 18:32:24 GMT http://hdl.handle.net/2117/16628 2012-10-03T18:32:24Z Martín Neira, Manuel; Altena, B.; van Bree, R.; Van Der Marel, H.; Camps Carmona, Adriano José; Rius, Antonio; Nogués Correig, O.; Ribó, S.; Cardellach, Estel; Oliveras, S.; Valencia Domènech, Enric; Hyuk, Park; Tarongí Bauzá, José Miguel no Bistatic radars, GNSS reflectometry, Ocean altimetry The Global Navigation Satellite System Reflectometry (GNSS-R) concept was conceived as a means to densify radar altimeter measurements of the sea surface. Until now, the GNSS-R concept relied on open access to GNSS transmitted codes. Recently, it has been proposed that the ranging capability of the technique for ocean altimetric applications can be improved by using all the signals transmitted in the bandwidth allocated to GNSS, which includes open access as well as encrypted signals. The main objective of this study is to provide experimental proof of this enhancement through a 2-day experiment on the Zeeland Bridge (The Netherlands). In the experiment, we used a custom built GNSS-R system, composed of high gain GPS antennas, calibration subsystem, and an FPGAbased signal processor which implemented the new concepts, an X-band radar altimeter and a local geodetic network. The results obtained indicate that the new approach produces a significant improvement in GNSS-R altimetric performance. http://hdl.handle.net/2117/16589 Title: Filtering and segmentation of polarimetric SAR data based on binary partition trees Authors: Alonso González, Alberto; López Martínez, Carlos; Salembier Clairon, Philippe Jean Abstract: In this paper,we propose the use of binary partition trees (BPT) to introduce a novel region-based and multi-scale polarimetric SAR (PolSAR) data representation. The BPT structure represents homogeneous regions in the data at different detail levels. The construction process of the BPT is based, firstly, on a region model able to represent the homogeneous areas, and, secondly, on a dissimilarity measure in order to identify similar areas and define the merging sequence. Depending on the final application, a BPT pruning strategy needs to be introduced. In this paper, we focus on the application of BPT PolSAR data representation for speckle noise filtering and data segmentation on the basis of the Gaussian hypothesis, where the average covariance or coherency matrices are considered as a region model. We introduce and quantitatively analyze different dissimilarity measures. In this case, and with the objective to be sensitive to the complete polarimetric information under the Gaussian hypothesis, dissimilarity measures considering the complete covariance or coherency matrices are employed.When confronted to PolSAR speckle filtering, two pruning strategies are detailed and evaluated. As presented, the BPT PolSAR speckle filter defined filters data according to the complete polarimetric information. As shown, this novel filtering approach is able to achieve very strong filtering while preserving the spatial resolution and the polarimetric information. Finally, the BPT representation structure is employed for high spatial resolution image segmentation applied to coastline detection. The analyses detailed in this work are based on simulated, as well as on real PolSAR data acquired by the ESAR system of DLR and the RADARSAT-2 system. Thu, 27 Sep 2012 15:38:31 GMT http://hdl.handle.net/2117/16589 2012-09-27T15:38:31Z Alonso González, Alberto; López Martínez, Carlos; Salembier Clairon, Philippe Jean no In this paper,we propose the use of binary partition trees (BPT) to introduce a novel region-based and multi-scale polarimetric SAR (PolSAR) data representation. The BPT structure represents homogeneous regions in the data at different detail levels. The construction process of the BPT is based, firstly, on a region model able to represent the homogeneous areas, and, secondly, on a dissimilarity measure in order to identify similar areas and define the merging sequence. Depending on the final application, a BPT pruning strategy needs to be introduced. In this paper, we focus on the application of BPT PolSAR data representation for speckle noise filtering and data segmentation on the basis of the Gaussian hypothesis, where the average covariance or coherency matrices are considered as a region model. We introduce and quantitatively analyze different dissimilarity measures. In this case, and with the objective to be sensitive to the complete polarimetric information under the Gaussian hypothesis, dissimilarity measures considering the complete covariance or coherency matrices are employed.When confronted to PolSAR speckle filtering, two pruning strategies are detailed and evaluated. As presented, the BPT PolSAR speckle filter defined filters data according to the complete polarimetric information. As shown, this novel filtering approach is able to achieve very strong filtering while preserving the spatial resolution and the polarimetric information. Finally, the BPT representation structure is employed for high spatial resolution image segmentation applied to coastline detection. The analyses detailed in this work are based on simulated, as well as on real PolSAR data acquired by the ESAR system of DLR and the RADARSAT-2 system. http://hdl.handle.net/2117/16510 Title: Study of the correlation between columnar aerosol burden, suspended matter at ground and chemical components in a background European environment Authors: Alastuey, A.; Gangoiti, G.; Estelles, Victor; Martínez Lozano, José Antonio; Pey, J.; Sicard, Michaël; Querol, Xavier; Esteve, A.R.; Utrillas, Maria Pilar; Sorribas, M.; Rocadenbosch Burillo, Francisco Abstract: Although routinely monitored by ground based air quality networks, the particulate matter distribution could be eventually better described with remote sensing techniques. However, valid relationships between ground level and columnar ground based quantities should be known beforehand. In this study we have performed a comparison between particulate matter measurements at ground level at different cut sizes (10, 2.5 and 1.0 mm), and the aerosol optical depth obtained by means of a ground based sunphotometer during a multiinstrumental field campaign held in El Arenosillo (Huelva, Spain) from 28 June to 4 July 2006. All the PM fractions were very well correlated with AOD with correlation coefficients that ranged from 0.71 to 0.81 for PM10, PM2.5 and PM1. Furthermore, the influence of the mixing layer height in the correlations was explored. The improvement in the correlation when the vertical distribution is taken into account was significant for days with a homogeneous mixing layer. Moreover, the chemical analysis of the individual size fractions allowed us to study the origin of the particulate matter. Secondary components were the most abundant and also well correlated in the three size fractions; but for PM10 fraction, chemical species related to marine origin were best correlated. Finally, we obtained a relationship between MODIS L3 AOD from collection 5.1 and the three PM cut sizes. In spite of being a relatively clean environment, all the techniques were able to capture similar day to day variations during this field campaign. Mon, 17 Sep 2012 12:16:11 GMT http://hdl.handle.net/2117/16510 2012-09-17T12:16:11Z Alastuey, A.; Gangoiti, G.; Estelles, Victor; Martínez Lozano, José Antonio; Pey, J.; Sicard, Michaël; Querol, Xavier; Esteve, A.R.; Utrillas, Maria Pilar; Sorribas, M.; Rocadenbosch Burillo, Francisco no Although routinely monitored by ground based air quality networks, the particulate matter distribution could be eventually better described with remote sensing techniques. However, valid relationships between ground level and columnar ground based quantities should be known beforehand. In this study we have performed a comparison between particulate matter measurements at ground level at different cut sizes (10, 2.5 and 1.0 mm), and the aerosol optical depth obtained by means of a ground based sunphotometer during a multiinstrumental field campaign held in El Arenosillo (Huelva, Spain) from 28 June to 4 July 2006. All the PM fractions were very well correlated with AOD with correlation coefficients that ranged from 0.71 to 0.81 for PM10, PM2.5 and PM1. Furthermore, the influence of the mixing layer height in the correlations was explored. The improvement in the correlation when the vertical distribution is taken into account was significant for days with a homogeneous mixing layer. Moreover, the chemical analysis of the individual size fractions allowed us to study the origin of the particulate matter. Secondary components were the most abundant and also well correlated in the three size fractions; but for PM10 fraction, chemical species related to marine origin were best correlated. Finally, we obtained a relationship between MODIS L3 AOD from collection 5.1 and the three PM cut sizes. In spite of being a relatively clean environment, all the techniques were able to capture similar day to day variations during this field campaign. http://hdl.handle.net/2117/16470 Title: Identification of potential subsidence related to pumping in the Almería basin (SE Spain) Authors: Pulido-Bosch, Antonio; Delgado Marchal, Jose; Sola, Fernando; Vallejos, Angela; Vicente, Fernando; López Sánchez, Juan Manuel; Mallorquí Franquet, Jordi Joan Abstract: Ground subsidence of detrital deposits in the Almer´ıa basin (SE Spain) was studied using the remote sensing technique of Differential Interferometry SAR (DInSAR). This basin is one of the most arid in Europe, receiving an average rainfall of 250 mm per year. Over the last 60 years the region has experienced an enormous agricultural and urban expansion, whose water demand has been largely supplied from groundwater, leading to the current situation of overexploitation of water resources. This paper outlines the likely relationship between groundwater abstraction and subsidence. To this end, 34 ERS and Envisat images, taken between 2003 and 2009, were analysed to estimate ground surface deformations, and hence, compared with water table variations measured in a number of piezometers in the basin. The analysis shows a clear parallelism between the variations in piezometric level and deformation of the ground surface. In addition, the zones of greatest subsidence coincide with those areas where groundwater abstractions are concentrated. Subsidence over the examined period varies from 10 to 30 mm, with extreme values as high as 50 mm, which translates to a rate of between 1Ð7 and 5 mm/year, reaching maximum rates of 8 mm/year at some points. Given such subsidence rates, damage to urban infrastructures are, for the moment, incipient. Wed, 12 Sep 2012 09:56:09 GMT http://hdl.handle.net/2117/16470 2012-09-12T09:56:09Z Pulido-Bosch, Antonio; Delgado Marchal, Jose; Sola, Fernando; Vallejos, Angela; Vicente, Fernando; López Sánchez, Juan Manuel; Mallorquí Franquet, Jordi Joan no Almeria basin, Building damages, Differential SAR interferometry (DInSAR), Subsidence, Water table Ground subsidence of detrital deposits in the Almer´ıa basin (SE Spain) was studied using the remote sensing technique of Differential Interferometry SAR (DInSAR). This basin is one of the most arid in Europe, receiving an average rainfall of 250 mm per year. Over the last 60 years the region has experienced an enormous agricultural and urban expansion, whose water demand has been largely supplied from groundwater, leading to the current situation of overexploitation of water resources. This paper outlines the likely relationship between groundwater abstraction and subsidence. To this end, 34 ERS and Envisat images, taken between 2003 and 2009, were analysed to estimate ground surface deformations, and hence, compared with water table variations measured in a number of piezometers in the basin. The analysis shows a clear parallelism between the variations in piezometric level and deformation of the ground surface. In addition, the zones of greatest subsidence coincide with those areas where groundwater abstractions are concentrated. Subsidence over the examined period varies from 10 to 30 mm, with extreme values as high as 50 mm, which translates to a rate of between 1Ð7 and 5 mm/year, reaching maximum rates of 8 mm/year at some points. Given such subsidence rates, damage to urban infrastructures are, for the moment, incipient. http://hdl.handle.net/2117/16462 Title: Vegetation water content estimation using GNSS measurements Authors: Rodríguez Álvarez, Nereida; Bosch Lluís, Xavier; Camps Carmona, Adriano José; Ramos Pérez, Isaac; Valencia Domènech, Enric; Hyuk, Park; Vall-Llossera Ferran, Mercedes Magdalena Abstract: Global Navigation Satellite Systems (GNSS) opportunity signals reflected at or near the Earth's surface have already shown their potential to perform retrievals of a number of geophysical parameters. Radio occultations using GNSS signals are also used for atmospheric sensing. This letter presents a GNSS technique to retrieve vegetation water content (VWC). This technique measures the received powers of the GPS signals in open sky and under the vegetation layer. From these two powers, the attenuation due to the vegetation is computed, which is related to the VWC. This letter presents the results obtained after deploying the instrument in a walnut-tree stand for 11 months. Mon, 10 Sep 2012 12:07:07 GMT http://hdl.handle.net/2117/16462 2012-09-10T12:07:07Z Rodríguez Álvarez, Nereida; Bosch Lluís, Xavier; Camps Carmona, Adriano José; Ramos Pérez, Isaac; Valencia Domènech, Enric; Hyuk, Park; Vall-Llossera Ferran, Mercedes Magdalena no Global Navigation Satellite Systems (GNSS), vegetation, water content Global Navigation Satellite Systems (GNSS) opportunity signals reflected at or near the Earth's surface have already shown their potential to perform retrievals of a number of geophysical parameters. Radio occultations using GNSS signals are also used for atmospheric sensing. This letter presents a GNSS technique to retrieve vegetation water content (VWC). This technique measures the received powers of the GPS signals in open sky and under the vegetation layer. From these two powers, the attenuation due to the vegetation is computed, which is related to the VWC. This letter presents the results obtained after deploying the instrument in a walnut-tree stand for 11 months.