Search

The Soil Moisture and Ocean Salinity (SMOS) mission of the European Space Agency (ESA), together with NASA’s Soil Moisture Active Passive (SMAP) mission, is providing a wealth of information to the user community for a wide range of applications. Although both missions are still operational, they have significantly exceeded their design life time. For this reason, ESA is looking at future mission concepts, which would adequately address the requirements of the passive L-band community beyond SMOS and SMAP. This article proposes one mission concept, TriHex, which has been found capable of achieving high spatial resolution, radiometric resolution, and accuracy, approaching the user needs. This is possible by the combination of aperture synthesis, formation flying, the use of general circular orbits, and alias-free imaging.

This study presents an approach for the quantification of cloud–aerosol transition-zone broadband longwave radiative effects at the top of the atmosphere (TOA) during daytime over the ocean, based on satellite observations and radiative transfer simulation. Specifically, we used several products from MODIS (MODerate Resolution Imaging Spectroradiometer) and CERES (Clouds and the Earth’s Radiant Energy System) sensors for the identification and selection of CERES footprints with a horizontally homogeneous transition-zone and clear-sky conditions. For the selected transition-zone footprints, radiative effect was calculated as the difference between the instantaneous CERES TOA upwelling broadband longwave radiance observations and corresponding clear-sky radiance simulations. The clear-sky radiances were simulated using the Santa Barbara DISORT (DIScrete Ordinates Radiative Transfer program for a multi-Layered plane-parallel medium) Atmospheric Radiative Transfer model fed by the hourly ERA5 reanalysis (fifth generation ECMWF ReAnalysis) atmospheric and surface data. The CERES radiance observations corresponding to the clear-sky footprints detected were also used for validating the simulated clear-sky radiances. We tested this approach using the radiative measurements made by the MODIS and CERES instruments on board the Aqua platform over the southeastern Atlantic Ocean during August 2010. For the studied period and domain, transition-zone radiative effect (given in flux units) is on average equal to 8.0 ± 3.7 W m−2 (heating effect; median: 5.4 W m−2 ), although cases with radiative effects as large as 50 W m−2 were found This research has been supported by the Ministerio de Ciencia e Innovación (grant no. PID2019-105901RB-I00) and the Generalitat de Catalunya (grant no. 2018FI_B_00830).

In multitemporal synthetic aperture radar (SAR) and polarimetric SAR (PolSAR), coherence is a capital parameter to exploit common information between temporal acquisitions. Yet, its use is limited to high coherences. This article proposes the analysis of low-coherence scenarios by introducing a reinterpretation of coherence. It is demonstrated that coherence results from the product of two terms accounting for coherent and radiometric changes, respectively. For low coherences, the first term presents low values, preventing its exploitation for information retrieval. The information provided by the second term can be used in these circumstances to exploit common information. This second term is proposed, as an alternative to coherence, for information retrieval for low coherences. Besides, it is shown that polarimetry allows the temporal optimization of its values. To prove the benefits of this approach, multitemporal SAR and PolSAR data classification is considered as a tool, showing that improvements of the classification overall accuracy may range between 20% and 50%, compared to classification based on coherence. This work was supported in part by the National Natural Science Foundation of China under Grant 61871413, in part by the China Scholarship Council under Grant 2020006880033, and in part by the Project INTERACT funded by the Spanish MCIN/AEI/10.13039/501100011033 under Grant PID2020-114623RB-C32.

The ability to enhance the spatial resolution of measurements collected by a conical-scanning microwave radiometer (MWR) is discussed in terms of noise amplification and improvement of the spatial resolution. Simulated (and actual) brightness temperature profiles are analyzed at variance of different intrinsic spatial resolutions and adjacent beams overlapping modeling a simplified 1-D measurement configuration (MC). The actual measurements refer to Special Sensor Microwave Imager (SSM/I) data collected using the 19.35 and the 37.00 GHz channels that match the simulated configurations. The reconstruction of the brightness profile at enhanced spatial resolution is performed using an iterative gradient method which allows a fine tuning of the level of regularization. Objective metrics are introduced to quantify the enhancement of the spatial resolution and noise amplification. Numerical experiments, performed using the simplified 1-D MC, show that the regularized deconvolution results in negligible advantages when dealing with low-overlapping/fine-spatial-resolution configurations. Regularization is a mandatory step when addressing the high-overlapping/low-spatial-resolution case and the spatial resolution can be enhanced up to 2.34 with a noise amplification equal to 1.56. A more stringent requirement on the noise amplification (up to 0.6) results in an improvement of the spatial resolution up to 1.64.

Earth Observation (EO) is key for climate and environmental monitoring at global level, and in specific regions where the effects of global warming are more noticeable, such as in polar regions, where ice melt is also opening new commercial maritime routes. Soil moisture is also useful for agriculture and monitoring the advance of desertification, as well as biomass and carbon storage. Global Navigation Satellite System - Reflectometry (GNSS-R) and L-band microwave Radiometry are passive microwave remote sensing techniques that can be used to perform these types of measurements regardless of the illumination and cloud conditions, and -since they are passive- they are well suited for small satellites, where power availability is a limiting factor. GNSS-R was tested from space onboard the UK-DMC and the UK TechDemoSat-1, and several missions have been launched using GNSS-R as main instrument, as CyGNSS, BuFeng-1, or the FSSCAT [1] mission. These missions aim at providing soil moisture [2], ocean wind speed [3], and flooding mapping of the Earth. L-band microwave radiometry data has also been retrieved from space with SMOS and SMAP missions, obtaining sea ice thickness, soil moisture, and ocean salinity data [4]. The 3Cat-4 mission was selected by the ESA Academy "Fly your Satellite" program in 2017. It aims at combining both GNSS-R and L-band Microwave Radiometry at in a low-power and cost-effective 1-Unit (1U) satellite. Moreover, the 3Cat-4 can also detect Automatic Identification System (AIS) signals from vessels. The single payload is the Flexible Microwave Payload 1 (FMPL-1) [5] that performs the signal conditioning and signal processing for GNSS-R, L-Band microwave radiometry and AIS experiments. The spacecraft has three payload antennas: (1) a VHF monopole for AIS signals; (2) an uplooking antenna for the direct GPS signals; (3) a downlooking antenna that captures reflected GPS signals, and for the Microwave Radiometer. The downlooking antenna is a deployable helix antenna called the Nadir Antenna and Deployment Subsystem (NADS) which has a volume of less than 0,3U when stowed, achieving an axial length of more than 500 mm when deployed. As part of this mission, the design of the NADS antenna, its RF performance, as well as the environmental tests performed in terms of structural and thermal space conditions will be presented.

The Remote sensing and Interference detector with radiomeTry and vegetation Analysis (RITA) is one of the Remote Sensing payloads selected as winners of the 2nd GRSS Student Grand Challenge in 2019, to fly on board of the 3U AlainSat-1. This CubeSat is being developed by the National Space Science and Technology Center (NSSTC), United Arab Emirates University. RITA has been designed as an academic mission, which brings together students from different backgrounds in a joint effort to apply very distinct sensors in an Earth Observation mission, fusing their results to obtain higher-accuracy measurements. The main payload used in RITA is a Total Power Radiometer such as the one on board the FSSCat mission. With these radiometric measurements, soil moisture and ice thickness will be obtained. To better characterize the extensive Radio-Frequency Interferences received by EO satellites in protected bands, several RFI Detection and Classification algorithms will be included to generate a worldwide map of RFI. As a novel addition to the 3Cat family of satellites and payloads, a hyper-spectral camera with 25 bands ranging from 600 to 975 nm will be used to obtain several indexes related to vegetation. By linking these measurements with the soil moisture obtained from the MWR, pixel downscaling can be attempted. Finally, a custom- developed LoRa transceiver will be included to provide a multi-level approach to in-situ sensors: On-demand executions of the other payloads will be able to be triggered from ground sensors if necessary, as well as simple reception of other measurements that will complement the ones obtained on the satellite. The antennas for both the MWR and the LoRa experiments have been developed in-house, and will span the entirety of one of the 3U sides of the satellite. In this work, the latest development advances will be presented, together with an updated system overview and information about the operations that will be conducted. Results obtained from the test campaign are also presented in the conference.

El caràcter d’aquest treball està encarat de forma explícita a la recerca i té com a objectiu determinar si és possible fer una predicció de la viabilitat dels tractaments de radioteràpia a través de la informació que s’obté de les diferents mètriques que defineixen aquests tractaments. Amb aquest enfocament es van definir dues etapes del projecte. La primera consistia en l’estudi de les mètriques i la segona en el desenvolupament d’un model predictiu que fos capaç de predir amb les mètriques seleccionades en l’estudi de l’etapa anterior quins tractaments són els que superen els índexs deviabilitat establerts. A trets generals podem dir que els objectius marcats s’han assolit: S’han estudiat les mètriques i s’han extret conclusions interessants que marquen un nou full de ruta per seguir la investigació. La principal conclusió és que la correlació entre la viabilitat del tractament i les mètriques de complexitat analitzades indica que, d’existir relació entre elles, aquesta no és lineal, per tant s’hauria de seguir la investigació utilitzant regressions no lineals o altres mètodes. A més, s’ha descobert una característica important de les dades que és la multicolinealitat i s’ha determinat que intentar-la solventar pot comportar en la majoria dels casos la pèrdua d’informació rellevant. És per això que s’ha establert que per a futurs estudis, és imprescindible fer ús de totes les mètriques. Amb la utilització dels mètodes de Machine Learning inclosos dins la llibreria de Scikitlearn de Python s’ha aconseguit obtenir un model que és capaç de predir en un 72% d’efectivitat quins són els tractaments que passen els índexs de viabilitat per poder ser utilitzats en pacients sense necessitat de fer proves amb maniquí. Tot i no ser un bon resultat donada la finalitat del predictor, ja que l’existència de falsos positius n’impossibiliten el seu ús en casos reals, s’ha pogut demostrar que no és possible fer una predicció de la viabilitat dels tractaments de radioteràpia utilitzant els mètodes de boscos aleatoris, màquines de suport vectorial, o KNN. Una aposta per seguir treballant en el desenvolupament d’un model que sigui capaç d’identificar els tractaments òptims per a ser utilitzats en pacients seria ampliar les fronteres del marc en què s’engloba aquest treball i fer ús d’altres tècniques en intel·ligència artificial com poden ser les xarxes neurals

Fruit detection and localization will be essential for future agronomic management of fruit crops, with applications in yield prediction, yield mapping and automated harvesting. RGB-D cameras are promising sensors for fruit detection given that they provide geometrical information with color data. Some of these sensors work on the principle of time-of-flight (ToF) and, besides color and depth, provide the backscatter signal intensity. However, this radiometric capability has not been exploited for fruit detection applications. This work presents the KFuji RGB-DS database, composed of 967 multi-modal images containing a total of 12,839 Fuji apples. Compilation of the database allowed a study of the usefulness of fusing RGB-D and radiometric information obtained with Kinect v2 for fruit detection. To do so, the signal intensity was range corrected to overcome signal attenuation, obtaining an image that was proportional to the reflectance of the scene. A registration between RGB, depth and intensity images was then carried out. The Faster R-CNN model was adapted for use with five-channel input images: color (RGB), depth (D) and range-corrected intensity signal (S). Results show an improvement of 4.46% in F1-score when adding depth and range-corrected intensity channels, obtaining an F1-score of 0.898 and an AP of 94.8% when all channels are used. From our experimental results, it can be concluded that the radiometric capabilities of ToF sensors give valuable information for fruit detection. This work was partly funded by the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (ERDF) under Grants 2017SGR 646, AGL2013-48297-C2-2-R and MALEGRA, TEC2016-75976-R. The Spanish Ministry of Education is thanked for Mr. J. Gené’s predoctoral fellowships (FPU15/03355). We would also like to thank Nufri and Vicens Maquinària Agrícola S.A. for their support during data acquisition, and Adria Carbó for his assistance in Faster R-CNN implementation.

The change in the state of sky from cloudy to cloudless (or vice versa) comprises an additional phase called 'transition zone,' in which the characteristics of the particle suspension lay between those corresponding to pure clouds and atmospheric aerosols. This phase, however, is usually considered, in atmospheric monitoring and modeling, as an area containing either aerosol or thin clouds. A sensitivity analysis has been performed to assess the longwave radiative effects resulting from different approximations to the transition zone for three radiation parameterizations included in the Weather Research and Forecasting Model. The parameterizations produce important differences (up to 60 W m−2) between radiative effects of optically thin layers of aerosols and clouds (as surrogates for transition zone suspensions) in the longwave region, both at the top and bottom of the atmosphere. Also, differences are greater if the suspension of particles is located at higher altitudes, but smaller in high humidity conditions This study is funded by the Spanish Ministry of Economy and Competitiveness (project NUBESOL, CGL2014‐55976‐R), Spanish Ministry of Science and Innovation (project NUBESOL‐2, PID2019‐105901RB‐I00), and University of Girona (project PONTUdG2019/05). Babak Jahani holds a FI‐AGAUR PhD grant (2018FI_B_00830) provided by the Government of Catalonia (Universities and Research Secretariat) and the European Union

Los nanosatélites han experimentado un importante crecimiento en estos últimos años desde que fueron estandarizados en 2000. El UPC-NanoSat Lab, que se encuentra en el Campus Nord de la Universidad Politécnica de Cataluña, pretende explorar y desarrollar aplicaciones innovadoras y técnicas de teledetección para nanosatélites siempre desde el punto de vista del aprendizaje para los estudiantes permitiéndoles concebir, diseñar, implementar, testear y operar los subsistemas que conforman un CubeSat. El proyecto 3CAT-4, apoyado por el programa „Fly Your Satellite!‟ de la Agencia Europea del Espacio (ESA), está previsto que finalice y sea lanzado el verano de 2021 con la implementación de tres experimentos para la observación de la Tierra: un Radiómetro de microondas en banda L, un reflectómetro de señales GNSS (Sistema Global de Navegación por Satélite), y un receptor AIS (Sistema de Identificación Automático). Durante el lapso temporal de esta tesis, se ha llevado a cabo la verificación del radiómetro de microondas a temperatura ambiente y en temperaturas adversas a parte de la verificación del subsistema de comunicaciones (COMMS) a temperatura ambiente. Els nanosatèl·lits han experimentat un important creixement en aquests darrers anys des de que van ser estandarditzats al 2000. El UPC-NanoSat Lab, que es troba al Campus Nord de la Universitat Politècnica de Catalunya, pretén explorar i desenvolupar aplicacions innovadores i tècniques de teledetecció per a nanosatèl·lits sempre des del punt de vista d‟ensenyament pels estudiants permetent-los concebre, dissenyar, implementar, testejar i operar els subsistemes que conformen un CubeSat. El projecte 3CAT-4, recolzat pel programa „Fly Your Satellite!‟ de l‟Agència Europea de l‟Espai (ESA), està previst que sigui finalitzat i llest pel seu llançament a l‟estiu del 2021 amb la implementació de tres experiments per a l‟observació de la Terra: un Radiòmetre de microones a la banda L, un reflectòmetre de senyals GNSS (Sistema Global de Navegació per Satèl·lit), i un receptor AIS (Sistema d‟Identificació Automàtic). Durant el lapse temporal d‟aquesta tesis, s‟ha dut a terme la verificació del radiòmetre de microones a temperatura ambient i en temperatures adverses a part de la verificació del subsistema de comunicacions (COMMS) a temperatura ambient. Since their standardization around 2000, nanosatellites have experienced an enormous growth. The UPC-NanoSat Lab, located in Campus Nord of the Universitat Politècnica de Catalunya, aims to explore and develop innovative applications and remote sensing techniques for nanosatellites always focusing on students teaching allowing them to conceive, design, implement, test and operate the subsystems that conforms a CubeSat. 3CAT-4 project, supported by European Space Agency (ESA) „Fly Your Satellite!‟ programme, is planned to be finished and ready to launch in spring of 2021 with the implementation of three experiments for Earth observation: an L-band Microwave Radiometer, a GNSS (Global Navigation Satellite Systems) Reflectometer, and an AIS (Automatic Identification System) receiver. During the time lapse of this thesis, it has been performed the verification of the L-band Microwave Radiometry experiment at ambient temperature and at adverse temperatures apart from the communications subsystem (COMMS) verification at ambient temperature.

This thesis is about the best strategy to get public funding in European calls for highly innovative projects. Using the example of a project application which takes part in the Fast Track to Innovation (FTI) call of the European Commission’s H2020 framework program, a series of improvements based on success stories and on the criteria of the evaluators are proposed to have more possibilities of obtaining funding. The project wants to bring the product PODSTAR to the market, which is an online dosimetry platform for medical staff during interventional radiology. At the beginning of the project, the product is in TRL 6, wanting to fund its jump to the market through this call. In the final section, national level financing alternatives are sought and the usefulness of these tax incentives is reflected in addition to highlighting the most important points when writing an application of this type.

SOLPI has developed an airborne hyperspectral imaging solution to measure spectral signatures which can be used in applications like agriculture and construction. The system needs an illuminant reference that will be used to compute the reflectance from camera's radiance values. However, light conditions change over time; and in order to get an accurate spectral signature,the changes of the illuminant need to be taken into account to compensate those changes. The aim of this project is to research and propose a solution to measure this illuminant changes to later compensate the reflectance calculation.

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works ESA’s Soil Moisture and Ocean Salinity (SMOS) mission was launched 2 Nov 2009 and, to date, is still in good health, providing valuable L-band observations of the Earth surface [1]. A number of products are obtained from these, including thin sea ice [2], frost/thaw soils [3], high winds [4], ocean surface wind [5] and Sun brightness temperature [6], besides the main mission measurements of soil moisture and sea surface salinity [7][8]. This paper deals with the description and early results of some technology activities conducted by ESA applying the lessons learnt by SMOS and in preparation of an advanced L-band radiometer mission

Drone-based Dual band TPR radiometer for Snow Water Content determination

A method for determining rapid variations in atmospheric optical depth is proposed. The method is based upon computation of the ratio between close-time spectral measurements of solar direct flux. Use of the ratio avoids the need for absolute calibration of the instruments and minimizes the effects of changes in instrumental conditions (such as temperature or mechanical adjustments) and in air mass. The technique has been applied to some campaigns of measurement for sky conditions ranging from clear skies to scattered-to-broken cloudiness, performed at high frequency (~1Hz) with a system of three array spectrometers, capable of performing very rapid spectral acquisitions, in the 400 to 1700 nm band, thus covering the visible and extending to the near-infrared spectral ranges. Results demonstrate the capacity of this instrumentation and method to detect rapid variation of optical depth, as well as rapid changes in its spectral pattern. The optical depth variability depends on the particular state of the sky and is connected to particle condensation and evaporation processes and to the changes in water vapor content in the transition region between cloud-free and cloudy regions. Thus, the method is suitable for analyzing rapid processes involving particles, either aerosol or cloud droplets, and water vapor, in the cloud boundaries This research was developed within the framework of projects NUBESOL (CGL2014-55976-R), funded by the Spanish Ministry of Economy and Competitiveness and NUBESOL-2 (PID2019-105901RB-I00), funded by the Spanish Ministry of Science and Innovation. Projects PUG2015A and PONTUdG2019/05 of the University of Girona also provided support for some aspects of the research

This project consists on design and implement a dual-polarization L-band radiometer with RFI detection and mitigation using a software defined radio (SDR) as a back-end. Volume and power consumption should be minimized as the platform is a small satellite with stringent requirements. El proyecto consiste en diseñar e implementar un radiometro con doble polarización en la banda L con detección y mitigación de RFI utilizando una radio definida por software (SDR) como back-end. El volumen y el consumo de energía deben minimizarse ya que la plataforma es un satélite pequeño con requisitos estrictos. El projecte consisteix en dissenyar i implementar un radiometre amb doble polarització a la banda L amb detecció i mitigació de RFI utilitzant una radio definida per software (SDR) com a back-end. El volum i el consum d'energia s'han de minimitzar ja que la plataforma és un satèl·lit petit amb requisits estrictes.

Long-term monitoring of the evolution of the artificial night sky brightness is a key tool for developing science-informed public policies and assessing the efficacy of light pollution mitigation measures. Detecting the underlying artificial brightness trend is a challenging task, since the typical night sky brightness signal shows a large variability with characteristic time scales ranging from seconds to years. In order to effectively isolate the weak signature of the effect of interest, determining the potential long term drifts of the radiance sensing systems is crucial. If these drifts can be adequately characterized, the raw measurements could be easily corrected for them and transformed to a consistent scale. In this short note we report on the progressive darkening of the signal recorded by SQM detectors belonging to several monitoring networks, permanently installed outdoors for periods ranging from several months to several years. The sensitivity drifts were estimated by means of parallel measurements made at the beginning and at the end of the evaluation periods using reference detectors of the same kind that were little or no exposed to weathering in the intervening time. Our preliminary results suggest that SQM detectors installed outdoors steadily increase their readings at an average rate of +0.034 magSQM/arcsec^2 per MWh/m^2 of exposure to solar horizontal global irradiation, that for our locations translates into approximately +0.05 to +0.06 magSQM/arcsec^2 per year., Comment: 5 pages, 1 figure. ArXiv identifier added, some minor misprints corrected

Radio Frequency Interference (RFI) is currently a major problem in Communications and Earth Observation, but it is even more dramatic in Microwave Radiometry because of the low power levels of the received signals. Its impact has been attested in several Earth Observation missions. On-board mitigation systems are becoming a requirement to detect and remove affected measurements, increasing thus radiometric accuracy and spatial coverage. However, RFI mitigation methods have not been tested yet in the context of some particular radiometer topologies, which rely on the use of coarsely quantized streams of data. In this study, the impact of quantization and sampling in the performance of several known RFI mitigation algorithms is studied under different conditions. It will be demonstrated that in the presence of clipping, quantization changes fundamentally the time-frequency properties of the contaminated signal, strongly impairing the performance of most mitigation methods. Important design considerations are derived from this analysis that must be taken into account when defining the architecture of future instruments. In particular, the use of Automatic Gain Control (AGC) systems is proposed, and its limitations are discussed.

This Thesis belongs to a scientific project realized by the TRYO Company, which is part of the aerospace sector of the SENER Group. It describes the design, analysis, measurements and results of one of the back-end modules EQM (Elecrical Qualification Model) of ICI (Ice Cloud Imager) radiometer, which is embarked in the satellites which form the space mission of MetOp-SG (MetOp Second Generation Program). The back-end module will operate at the sub-millimetre wave band of 325GHz, after down converters and contains the last part of the channels: amplifiers, filters, detectors and video section. The methodology and the development of the project start from customer requirements, the design of prototypes which will be integrated of the back-end and the detailed design, tuning, measurements, and validation of the main tests. Electromagnetic simulations tools as ADS [1] and HFSS [2] are used and also instrumentation as Vectorial Network Analyzers, Spectrum Analyzers, Noise Figure Analyzers, Noise Generators, oscilloscopes and both data acquisition and data processing software. We expose the final results and the statement of compliance of the project requirements. Finally, the measurements and the performance of the back-end module are shown and we draw our conclusions.

MERITXELL is a ground-based multisensor instrument that includes a multiband dual-polarization radiometer, a GNSS reflectometer, and several optical sensors. Its main goals are twofold: to test data fusion techniques, and to develop Radio-Frequency Interference (RFI) detection, localization and mitigation techniques. The former is necessary to retrieve complementary data useful to develop geophysical models with improved accuracy, whereas the latter aims at solving one of the most important problems of microwave radiometry. This paper describes the hardware design, the instrument control architecture, the calibration of the radiometer, and several captures of RFI signals taken with MERITXELL in urban environment. The multiband radiometer has a dual linear polarization total-power radiometer topology, and it covers the L-, S-, C-, X-, K-, Ka-, and W-band. Its back-end stage is based on a spectrum analyzer structure which allows to perform real-time signal processing, while the rest of the sensors are controlled by a host computer where the off-line processing takes place. The calibration of the radiometer is performed using the hot-cold load procedure, together with the tipping curves technique in the case of the five upper frequency bands. Finally, some captures of RFI signals are shown for most of the radiometric bands under analysis, which evidence the problem of RFI in microwave radiometry, and the limitations they impose in external calibration.

©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Radio–frequency interference (RFI) signals are a well-known threat for microwave radiometry (MWR) applications. In order to alleviate this problem, different approaches for RFI detection and mitigation are currently under development. Since RFI signals are man made, they tend to have their power more concentrated in the time–frequency (TF) space as compared to naturally emitted noise. The aim of this paper is to perform an assessment of different TF RFI mitigation techniques in terms of probability of detection, resolution loss (RL), and mitigation performance. In this assessment, six different kinds of RFI signals have been considered: a glitch, a burst of pulses, a wide-band chirp, a narrow-band chirp, a continuous wave, and a wide-band modulation. The results show that the best performance occurs when the transform basis has a similar shape as compared to the RFI signal. For the best case performance, the maximum residual RFI temperature is 14.8 K, and the worst RL is 8.4%. Moreover, the multiresolution Fourier transform technique appears as a good tradeoff solution among all other techniques since it can mitigate all RFI signals under evaluation with a maximum residual RFI temperature of 21 K, and a worst RL of 26.3%. Although the obtained results are still far from an acceptable bias Misplaced < 1 K for MWR applications, there is still work to do in a combined test using the information gathered simultaneously by all mitigation techniques, which could improve the overall performance of RFI mitigation.

The aim of this project was the implementation of a software to position and obtain the desired measurements by a radiometer called MERITXELL. To satisfy the goals, this project was divided in three blocks (radiometer control, positioning, and graphical user interface). The radiometer control had the function to control the spectrum analyser of the radiometer backend and configure the switches to select the matched loads or the antennas desired and obtain the temperatures of the sensor of these elements. The target of the radiometer positioning was point the radiometer bore sight in the desired directions selected by the user and receive the information sent by the positioning system. The goal of the graphical user interface was to implement the previous functionalities as user friendly as possible and process the information received by the two previous blocks to show them to the user. Once the software is finished, many usable measurements to detect radiofrequency interferences are obtained. El objetivo de este proyecto ha sido implementar un software encargado de orientar y obtener las medidas deseadas por el radiómetro llamado MERITXELL. Para poder satisfacer estas necesidades este proyecto estaba dividido en tres bloques (control del radiómetro, posicionamiento del mismo e interfaz gráfica). El control del radiómetro consiste en controlar el analizador de espectros del radiómetro, además de configurar los interruptores que conmutan entre las diferentes cargas adaptadas y las antenas y obtener la temperatura de los sensores que miden la temperatura de estos elementos. El posicionamiento del radiómetro tiene la función de ubicar el radiómetro en la orientación deseada por el usuario, además de recibir la información enviada por el sistema de posicionamiento. La interfaz gráfica consiste en generar las instrucciones para realizar las funcionalidades anteriores de la manera más sencilla para el usuario además de procesar la señal recibida por los dos bloques anteriores para mostrarla al usuario. Una vez finalizado el software, se han podido obtener medidas útiles para la detección de interferencias de radiofrecuencia. L’objectiu d’aquest projecte ha sigut implementar un software encarregat de d’orientar i obtenir les mesures desitjades per el radiòmetre anomenat MERITXELL. Per poder satisfer aquestes necessitats aquest projecte està dividit en tres blocs (control del radiòmetre, posicionament del mateix e interfície gràfica) El control del radiòmetre consisteix en control·lar l’analitzador d’espectres del radiòmetre, a més a més de configurar els interruptors que commuten entre les diferents càrregues adaptades i les antenes, també podem obtenir les temperatures dels sensors que mesuren la temperatura d’aquests elements. El posicionament del radiòmetre té la funció d’orientar el radiòmetre en les direccions desitjades per l’usuari, a més de rebre la informació enviada pel sistema de posicionament. L’ interfície gràfica consisteix en generar les instruccions per realitzar les funcionalitats anteriors de la manera més senzilla com sigui possible per l’usuari, a més de processar el senyal rebut pels blocs anteriors per mostrar-la a l’usuari. Un cop finalitzat el software, s’han pogut obtenir mesures útils per la detecció d’interferències de radiofreqüència.

The first three of a series of new generation satellites operating at L-band microwave frequencies have been launch in the last decade. L-band is particularly sensitive to the presence of water content in the scene under observation, being considered the optimal bandwidth for measuring the Earth's global surface soil moisture (SM) over land and sea surface salinity (SSS) over oceans. Monitoring these two essential climate variables is needed to further improve our understanding of the Earth's water and energy cycles. Additionally, remote sensing at L-band has been proved useful for monitoring the stability in ice sheets and measuring sea ice thickness. The ESA's Soil Moisture and Ocean Salinity (SMOS, 2009-2017) is the first mission specifically launched to monitor SM and SSS. It carries on-board a novel synthetic aperture radiometer with multi-angular and full-polarization capabilities. NASA's Aquarius (2011-2015) was the second mission, devoted to SSS monitoring with a combined real aperture radiometer/scatterometer system that allows correcting for sea surface roughness. NASA's Soil Moisture Active Passive (SMAP, 2015-2018) is the second mission dedicated to measure SM. It carries on-board a real aperture full-polarimetric radiometer and a synthetic aperture radar (SAR) for enhanced spatial resolution and freeze/thaw detection. This Ph.D. Thesis is focused on analyzing the geophysical information that can be obtained from L-band SMOS, Aquarius and SMAP observations. The research activities are structured as follows: -Inter-comparison of radiometer brightness temperatures at selected targets. A novel methodology to measure the consistency between SMOS and Aquarius radiometric data over the entire dynamic range of observations (land, ice and ocean) is proposed. It allows detecting spatial/temporal differences or biases without latitudinal limitations neither cross-overs. This is a necessary step to combine observations from different instruments in a long term dataset for environmental, meteorological, hydrological or climatological studies. -Ice thickness effects on passive remote sensing of Antarctic continental ice. The relationship between Antarctic ice thickness spatial variations and changes detected by SMOS and Aquarius measurements is explored. The emissivity of Antarctica is analyzed to disentangle the role of the geophysical contributions (snow layers at different depths and subglacial lakes) to the observed signal. The stability of the L-band signal in the East Antarctic Plateau, calibration/validation site for microwave satellite missions, is assessed. -Microwave/optical synergy for multi-scale soil moisture sensing. The relationship of SM and land surface temperature (LST) dynamics is evaluated to better understand the fundamental SM-LST link through evapotranspiration and thermal inertia physical processes. A new approach to measure the critical soil moisture from time-series of spaceborne SM and LST is proposed. The synergistic use of SMOS SM and remotely sensed LST for refining SM disaggregation algorithms is also analyzed. -Comparison of passive and active microwave vegetation parameters. Recent research has shown that microwave vegetation opacity, sensitive to biomass and water content, and albedo, related to canopy structure, can be retrieved from passive L-band observations. The relationships between these two parameters and radar-derived vegetation descriptors have been explored using airborne observations from the SMAP Validation Experiment 2012 (SMAPVEX12). The obtained relations could allow for improved SM retrievals in active-passive systems, and also to estimate the vegetation properties at high resolution using SAR observations. The Ph.D. Thesis has been developed within the activities of the Barcelona Expert Centre (BEC). The presented results contribute to the use of L-band remote sensing in different scientific disciplines such as climate, cryosphere, hydrology and ecology., Els primers tres d'una sèrie de satèl·lits de nova generació funcionant a la banda L han sigut llançats a l'última dècada. La banda L es molt sensible a la presència d'aigua a l'escena observada, sent considerada òptima per mesurar la humitat del sòl (SM) i la salinitat del mar (SSS) de manera global a la superfície de la Terra. Monitoritzar aquestes dues variables climàtiques essencials es necessari per millorar el nostre coneixement dels cicles de l'aigua i l'energia. La teledetecció a banda L també ha sigut útil per monitoritzar l'estabilitat de les capes de gel i mesurar el gruix de gel marí. La missió Soil Moisture and Ocean Salinity (SMOS, 2009-2017) de l'ESA és la primera específicament llançada per monitoritzar SM i SSS. Porta un nou radiòmetre d'apertura sintètica amb capacitat multiangular i polarització completa. La missió Aquarius (2011-2015) de la NASA va ser la segona, dedicada a monitoritzar SSS amb un sistema de radiòmetre/escateròmetre d’apertura real que permet corregir la rugositat de la superfície del mar. La missió Soil Moisture Active Passive (SMAP, 2015-2018) de la NASA és la segona dedicada a mesurar SM. Porta un radiòmetre d'apertura real i polarització completa i un radar d'apertura sintètica (SAR) per una millor resolució espaial i detecció de congelació/descongelació. Aquesta tesi està enfocada en analitzar la informació geofísica que pot obtenir-se de les observacions a banda L d'SMOS, Aquarius i SMAP. La seva investigació està estructurada com: -Intercomparació de temperatures de brillantor en zones seleccionades. Es proposa un nou mètode per mesurar la consistència entre les dades radiomètriques d'SMOS i Aquarius sobre el rang dinàmic complet d'observacions (terra, gel, oceà). Això permet detectar diferències espaials/temporals o biaixos sense limitacions latitudinals ni creuaments. Aquest pas es necessari per combinar observacions de diferents instruments en un llarg conjunt de dades per estudis mediambientals, hidrològics o climatològics. -Efecte de gruix de gel en teledetecció de gel continental a l'Antàrtida. S'explora la relació entre les variacions espaials del gruix de gel antàrtic i els canvis detectats a les mesures d'SMOS i Aquarius. L'emissivitat de l'Antàrtida es analitzada per discernir el rol de les contribucions geofísiques (capes de gel a diferents profunditats i llacs subglacials) al senyal observat. S'avalua l'estabilitat del senyal a banda L sobre la zona est de l'altiplà antàrtic, lloc per calibratge/validació de satèl·lits de microones. -Sinèrgia de microones/òptic per teledetecció de SM multiescala. S'avalua la correlació entre la SM i la temperatura de la superfície del sòl (LST) per entendre millor la relació SM-LST a través de processos físics d'evapotranspiració i inèrcia tèrmica. Es proposa un nou mètode per mesurar la humitat crítica utilitzant sèries temporals de SM i LST de satèl·lit. S'analitza l'ús de la SM de SMOS amb la LST de teledetecció per refinar algorismes de desagregació de SM. -Comparació de paràmetres passius i actius de microones relatius a la vegetació. Recent investigació ha mostrat que l'opacitat, sensible a la biomassa i el contingut d'aigua, i l'albedo, relacionat amb l'estructura, poden ser recuperats d'observacions passives a banda L. S'exploren les relacions entre aquests dos paràmetres i estimadors de vegetació derivats de radar utilitzant les observacions d'avió de l'experiment de validació d'SMAP 2012 (SMAPVEX12). Les relacions obtingudes podrien permetre millors recuperacions de SM en sistemes actius/passius i estimar les propietats de la vegetació a alta resolució utilitzant mesures de SAR. La tesi s'ha desenvolupat dins les activitats del Barcelona Expert Centre (BEC). Els resultats presentats contribueixen a l'ús de la banda L a diferents disciplines científiques com la climatologia, la criosfera, la hidrologia i l'ecologia.

L’objectiu principal d’aquest treball és entendre que és un sistema LADAR i explicar com funciona. Prestarem molta atenció a la caracterització radiomètrica dels sistemes LADAR, que validarem i simularem amb un sistema LADAR senzill. El programa utilitzat per duu a terme el projecte és el ZEMAX, un programa de disseny òptic molt complert que ens permetrà dissenyar i simular el nostre sistema LADAR. En el context teòric del projecte és parlarà sobre els fonaments dels sistemes LADAR i la equació de rang, que és la principal eina per la caracterització radiomètrica dels sistemes LADAR. Per emmarcar els continguts, s’ha escrit un capítol introductori a la radiometria i la fotometria, on s’expliquen conceptes bàsics de les magnituds i relacions radiomètriques i fotomètriques. El treball també conté un capítol introductori sobre l’ús i les funcions bàsiques del ZEMAX, per tal d’entendre el procés que s’ha seguit en el transcurs del treball. Finalment, a l’apartat de resultats hi ha un capítol de validació d’equacions teòriques mitjançant simulacions amb sistemes òptics senzills amb el ZEMAX. Posteriorment, i per tal de caracteritzar detalladament la radiometria d’un sistema LADAR, és simula amb un disseny senzill propi un sistema modificant diverses variables i característiques del target i de l’ambient.

En aquest projecte final de grau s’estudiarà la radiació que emeten els telèfons mòbils mentre realitzen trucades a altres dispositius. S’analitzaran 3 telèfons de diferents marques, d’aquesta manera es podrà comparar la quantitat de radiació que emeten i se’n trauran conclusions. Es podran mesurar aquestes radiacions realitzant probes al laboratori d’electrònica de la UPC amb l’ajuda d’una càmera anecoica I un receptor de probes, amb el que s’avaluaran les ones radiades en els diferents experiments que es facin. Per poder avaluar els resultats de les mesures, es realitzaran unes gràfiques per cada posició de mesura. En cada una d’aquestes gràfiques es posaran els valors màxims en LR i en FB. D’aquesta manera es podrà observar i comparar a simple vista els màxims valors obtinguts

The Atmospheric Boundary Layer Height (ABLH) is an important parameter in weather forecasting, meteorology, avionics, and air-quality and dispersion models. Local development of the Atmospheric Boundary Layer (ABL) over the full diurnal cycle is a function of several parameters which, among others, include geographical location of the place, its topography, time of the year, and day and night conditions. There are several remote sensing instruments and methods to retrieve the ABLH, however, none of these can fully measure ABL development under all atmospheric conditions. This Ph.D. thesis deals with estimation of the ABLH over the full diurnal cycle, which includes day-time mixing layer, nocturnal stable boundary layer, and morning/evening transition boundary layer, by using ground-based microwave-radiometer (MWR) and ceilometer (lidar principle) remote-sensing instruments as well as related signal processing techniques. ABLH estimates from Doppler lidar and radiosondes are used as references. Aim of this thesis is also to combine data from these two instruments, thus, exploiting their individual strengths and overcoming their limitations. In this context, this thesis has been structured around three main goals: First, a synergetic method for estimation of the Mixing Layer Height (MLH) is presented. Towards this end, uncertainties in the MLH derived from backscattered ceilometer signals and MWR-retrieved potential temperature profiles are analysed and compared. While the Extended Kalman Filter (EKF) is used as adaptive filter to process backscattered lidar signals from the ceilometer, the parcel method is used with the MWR-retrieved potential temperature profile. Finally, the two methods are combined into a new methodology for synergetic MLH retrieval. Second, methods for the estimation of the nocturnal Stable-Boundary-Layer Height (SBLH) from ceilometer and MWR data, in stand-alone and in synergetic fashion, are investigated. The SBLH from ceilometer backscattered lidar signals is retrieved by using Minimum Variance Regions (MVRs) as signatures of aerosol stratification in the SBL. For the MWR, idealized physical models from the literature are used to estimate the SBLH. Next, a synergetic SBLH retrieval method is developed, which combines measurement data from both instruments. Finally, a preliminary study on the feasibility of Large Eddy Simulation (LES) as a tool for understanding the ABL is presented. To this end, LES-simulated lidar backscatter and potential temperature profiles are compared against instrumental measurements. In addition, a new method for direct retrieval of the MLH from LES-simulated brightness temperature measurements is presented, hence, alleviating the need for physical temperature retrieval first. The impact of retrieval errors on MLH estimates is also investigated. The techniques developed in this Ph.D. have been tested in the HOPE measurement campaign (Jülich, Germany), where different test cases under different atmospheric conditions have been considered., La altura de Capa Límite Atmosférica ("Atmospheric Boundary Layer Height", ABLH) es un parámetro importante en la predicción del tiempo, la meteorología, la aviónica, y los modelos de calidad del aire y dispersión. El desarrollo local de la Capa Límite Atmosférica (ABL) durante el ciclo diurno completo es una función de múltiples parámetros que, entre otros, incluyen la ubicación geográfica del lugar, su topografía, época del año, y las condiciones de día y de noche. Existen múltiples instrumentos de teledetección y métodos para recuperar la ABLH, sin embargo, ninguno de ellos es capaz de medir completamente el desarrollo de la ABL bajo cualquier condición atmosférica. Esta tesis doctoral versa sobre la estimación de la ABLH durante el ciclo diurno completo (capa de mezcla diurna, capa límite estable nocturna, y capa límite en la transición mañana / tarde), mediante radiómetros de microondas (MWR) y ceilómetros (principio lidar) como instrumentos terrestres de teledetección, así como las técnicas de procesado de la señal relacionadas. Como referencia se utilizan las estimaciones de la ABLH procedentes de lidar Doppler y radiosondeos. Meta de esta tesis es también la combinación de los datos procedentes de estos dos instrumentos a fin de explotar sus fortalezas individuales y superar sus limitaciones. En este contexto, la tesis se estructura en torno a tres objetivos principales: En primer lugar, se presenta un método sinérgico para la estimación de la altura de la capa de mezcla (MLH). Con este fin, se analizan y comparan las incertezas en la estimación de la MLH obtenida a partir de las señales retrodispersadas medidas por el ceilómetro y los perfiles de temperatura recuperados por el MWR. Mientras que el filtro de Kalman extendido (EKF) se utiliza como filtro adaptativo para procesar las señales de retrodispersión lidar del ceilómetro, el "parcel method" se utiliza para tratar el perfil de temperatura potencial recuperado por el MWR. Por último, los dos métodos se combinan en una nueva metodología para la recuperación sinérgica de la MLH. En segundo lugar, se investigan métodos, no sinérgicos y sinérgicos, para la estimación de la altura de la capa límite estable (SBLH) nocturna a partir de datos procedente del ceilómetro y del MWR. La SBLH a partir de la señales retrodispersadas medidas por el ceilómetro se recupera utilizando Regiones de Mínima Varianza (MVR) como trazadores de la estratificación de los aerosoles en la SBL. Para el MWR, se utilizan modelos físicos idealizados de la literatura para estimar la SBLH. A continuación, se desarrolla un método sinérgico de recuperación de la SBLH que combina las medidas de ambos instrumentos. Por último, se presenta un estudio preliminar sobre la viabilidad del Large Eddy Simulation (LES) como herramienta de estudio de la ABL. En esta línea, los perfiles de retrodispersión lidar y los perfiles de temperatura potencial simulados mediante LES se comparan con las medidas procedentes de estos dos instrumentos. Además, se presenta un nuevo método para la recuperación directa de la MLH a partir de mediciones de temperatura de brillo simuladas mediante LES, lo cual, evita la necesidad de recuperar el perfil de temperatura física primero. También se investiga el impacto de los errores de inversión en las estimaciones de la MLH. Las técnicas desarrolladas en esta tesis doctoral han sido probadas en la campaña de medidas HOPE (Jülich, Alemania), donde se han considerado diferentes casos de prueba bajo diferentes condiciones atmosféricas, L'altura de Capa Límit Atmosfèrica ("Atmospheric Boundary Layer Height", ABLH) és un paràmetre important en la predicció del temps, la meteorologia, l'aviònica, i els models de qualitat de l'aire i dispersió. El desenvolupament local de la Capa Límit Atmosfèrica (ABL) durant el cicle diürn complet és una funció de múltiples paràmetres que, entre d'altres, inclouen la ubicació geogràfica del lloc, la seva topografia, època de l'any, i les condicions de dia i de nit. Hi ha múltiples instruments de teledetecció i mètodes per recuperar la ABLH, però, cap d'ells és capaç de mesurar completament el desenvolupament de l'ABL sota qualsevol condició atmosfèrica. Aquesta tesi doctoral versa sobre l'estimació de la ABLH durant el cicle diürn complet (capa de mescla diürna, capa límit estable nocturna, i capa límit en la transició matí / tarda), mitjançant radiòmetres de microones (MWR) i ceilòmetres (principi lidar) com a instruments terrestres de teledetecció, així com les tècniques de processament del senyal relacionades. Com a referència s'utilitzen les estimacions de la ABLH procedents de lidar Doppler i radiosondatges. Meta d'aquesta tesi és també la combinació de les dades procedents d'aquests dos instruments a fi d'explotar les seves fortaleses individuals i superar les seves limitacions. En aquest context, la tesi s'estructura al voltant de tres objectius principals: En primer lloc, es presenta un mètode sinèrgic per a l'estimació de l'alçada de la capa de mescla (MLH). Amb aquesta finalitat, s'analitzen i comparen les incerteses en l'estimació de la MLH obtinguda a partir dels senyals retrodispersats mesurats pel ceilòmetre i els perfils de temperatura recuperats pel MWR. Mentre que el filtre de Kalman estès (EKF) s'utilitza com a filtre adaptatiu per processar els senyals de retrodispersió lidar del ceilòmetre, el "parcel method" s'utilitza per tractar el perfil de temperatura potencial recuperat pel MWR. Finalment, els dos mètodes es combinen en una nova metodologia per a la recuperació sinèrgica de la MLH.En segon lloc, s'investiguen mètodes, no sinèrgics i sinèrgics, per a l'estimació de l'alçada de la capa límit estable (SBLH) nocturna a partir de dades procedent del ceilòmetre i del MWR. La SBLH a partir dels senyals retrodispersats mesurats pel ceilòmetre es recupera utilitzant Regions de Mínima Variància (MVR) com a traçadors de l'estratificació dels aerosols a la SBL. Pel MWR, s'utilitzen models físics idealitzats de la literatura per estimar la SBLH. A continuació, es desenvolupa un mètode sinèrgic de recuperació de la SBLH que combina les mesures de tots dos instruments.Finalment, es presenta un estudi preliminar sobre la viabilitat del Large Eddy Simulation (LES) com a eina d'estudi de l'ABL. En aquesta línia, els perfils de retrodispersió lidar i els perfils de temperatura potencial simulats mitjançant LES es comparen amb les mesures procedents d'aquests dos instruments. A més, es presenta un nou mètode per a la recuperació directa de la MLH a partir de mesuraments de temperatura de brillantor simulades mitjançant LES, la qual cosa, evita la necessitat de recuperar el perfil de temperatura física primer. També s'investiga l'impacte dels errors d'inversió en les estimacions de la MLH.Les tècniques desenvolupades en aquesta tesi doctoral han estat provades en la campanya de mesures HOPE (Jülich, Alemanya), on s'han considerat diferents casos de prova sota diferents condicions atmosfèriques.

Development of an Ultralightweight L-band radiometer for UAV platforms from a previouly developed sensors What has been achieved in this study is the improvement of the previous version of the L-band microwave radiometer ARIEL for its location in a drone. Lo que se ha logrado en este trabajo es mejorar la versión anterior del radiometro de microondas en banda L ARIEL para su emplazamiento en un drone. El que s'ha aconseguit en aquest treball és millorar la versió anterior del radiòmetre de microones en banda L ARIEL pel seu embarcament en un drone.

This paper analyzes a simplified image reconstruction method that exclusively takes into account the dominant antenna pattern terms to model image inversion artifacts and mitigate SMOS polarimetric spatial bias over the Ocean. This simplified method, that reduces computation time at the cost of small radiometric performance degradation, is useful to the L1 teams to process a large amount of data when full radiometric accuracy is not required (e.g. stability assessments).

Analysis of the effects of the correction GKJ on SMOS data in the retrieval process of soil moisture Análisis de los efectos de la corrección GKJ en datos SMOS en el proceso de recuperación de humedad en tierra. Anàlisis dels efectes de la correcció GKJ en dades SMOS en el procés de recuperació d'humitat en la terra.