Thèses : « Remote sensing by radar »

1

Lemos, Pinto J. de. « Remote sensing in refractive turbulence ». Thesis, University of Hull, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381887.

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Ottavianelli, Giuseppe. « Synthetic aperture radar remote sensing for landfill monitoring ». Thesis, Cranfield University, 2007. http://hdl.handle.net/1826/1805.

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Despite today’s intensive efforts directed at the recycling and recovery of solid wastes, the controlled disposal of refuse into land remains an important and necessary means of effective waste management. The work presented in this thesis investigates the use of Synthetic Aperture Radar (SAR) data to monitor solid waste landfills. The end-users’ interests vary from detecting the presence of a landfill to more specifically monitoring on-site operations and environmental conditions. Following a general literature review on the application of Earth Observation data for landfill monitoring, the identified research objectives are to: 1) assess whether SAR data can support the identification of landfill sites by distinguishing them from other disturbed areas which present similar optical spectral signatures, and 2) assess the possibility of correlating SAR data with onsite operational procedures. Data acquired for the research are: ground observations and measurements examining the spatial, temporal and biophysical characteristics of a landfill that can influence SAR data; historical and new programmed SAR scenes obtained from the ESA ERS-1 and -2 satellites and from Envisat ASAR instrument; ground based SAR (GB-SAR) acquisitions; simulations based on the RT2 backscatter model; additional space-based and airborne optical data to support the analysis and discussion. The examination of both the SAR amplitude spatial structure and the temporal decorrelation of these sites shows that there are three key characteristics that can distinguish them from other disturbed areas with similar optical spectral signatures: the presence of anisotropic features that strongly affect the SAR backscatter; the fact that the coherence magnitude images of these sites are characterised by large decorrelated areas with transient attributes; and their distinctive positive topography. The analysis highlights that one single-polarisation acquisition can hardly provide correct land-cover information, and consequently knowledge on land-use. The research demonstrates the key value of merging together complementary information derived from both the space and time dimensions, achieving fairly accurate land-use classification results. The research also provides an appreciation of the applicability of the developed techniques in an operational framework. These can suffer a number of limitations if a landfill site is located in a particular environment, and/or if meteorological conditions can significantly affect the radar signal, and/or unusual landfilling procedures are applied by the operators. Concluding remarks on the end-users needs point out that there are a number of aspects, ranging from practical and managerial matters to legal and technical issues, that often discourage the utilisation of EO data by new potential users.

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Vizinho, A. « Modern spectral analysis in HF radar remote sensing ». Thesis, University of Sheffield, 1998. http://etheses.whiterose.ac.uk/3462/.

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High-Frequency (HF) radar systems are currently used to collect wave data. By applying spectral analysis methods, such as the Fast Fourier Transform (FFT) method, to the radar backscatter from the ocean surface, the so-called Doppler spectrum is calculated, and from this the directional wave spectrum and wave measurements are obtained. Because of the random nature of the ocean surface, spectral measurements are subject to random variability. In order to reduce variability, and hence to obtain relatively precise estimates, each spectrum is usually calculated by averaging a number of FFT estimates. Naturally, this method requires long data series, and problems may arise. In rapidly varying sea conditions, for example, successive FFT estimates may be quite inconsistent with each other (in non-stationary conditions), and then the spectrum estimate obtained by averaging is not only difficult to interpret but it may also be distorted. It is known that the more recent spectral analysis methods such as methods based on autoregressive (AR) and autoregressive-moving average (ARMA) stochastic models can provide stable estimates from short data sets. Thus these methods are potentially good alternatives to the FFT, as they avoid problems inherent to the use of large data sets. The aim of this thesis is to investigate how some of the modem spectral analysis methods may be used to obtain reliable spectral estimates from small data sets. Unlike the FFT method, the AR- and ARMA-based methods presuppose specific parametric forms for the spectral function, and therefore consist in estimating certain parameters from the data (as opposed to estimating the function itself). The modified covariance method and Burg's method are among several methods of estimating the parameters of the spectral function.

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Vyas, Sarweshwar Prasad. « Radar remote sensing for monitoring sugar beet production ». Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363556.

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5

Perry, Jonathan Redvers. « The radar remote sensing of oceanic internal waves ». Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47220.

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6

Cao, Siyang. « Radar Sensing Based on Wavelets ». The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1416996784.

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7

Mancini, Pierluigi. « The use of polarisation in synthetic aperture radar ». Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307415.

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8

Remund, Quinn P. « Multisensor microwave remote sensing in the cryosphere / ». Diss., CLICK HERE for online access, 2000. http://contentdm.lib.byu.edu/ETD/image/etd7.pdf.

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Ravichandran, Kulasegaram. « Radar imaging using two-dimensional synthetic aperture radar (SAR) techniques / ». abstract and full text PDF (UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446797.

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Thesis (M.S.)--University of Nevada, Reno, 2007.
Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2008]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

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Snapir, Boris. « SAR remote sensing of soil Moisture ». Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9253.

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Synthetic Aperture Radar (SAR) has been identified as a good candidate to provide high-resolution soil moisture information over extended areas. SAR data could be used as observations within a global Data Assimilation (DA) approach to benefit applications such as hydrology and agriculture. Prior to developing an operational DA system, one must tackle the following challenges of soil moisture estimation with SAR: (1) the dependency of the measured radar signal on both soil moisture and soil surface roughness which leads to an ill-conditioned inverse problem, and (2) the difficulty in characterizing spatially/temporally surface roughness of natural soils and its scattering contribution. The objectives of this project are (1) to develop a roughness measurement method to improve the spatial/temporal characterization of soil surface roughness, and (2) to investigate to what extent the inverse problem can be solved by combining multipolarization, multi-incidence, and/or multi-frequency radar measurements. The first objective is achieved with a measurement method based on Structure from Motion (SfM). It is tailored to monitor natural surface roughness changes which have often been assumed negligible although without evidence. The measurement method is flexible, a.ordable, straightforward and generates Digital Elevation Models (DEMs) for a SAR-pixel-size plot with mm accuracy. A new processing method based on band-filtering of the DEM and its 2D Power Spectral Density (PSD) is proposed to compute the classical roughness parameters. Time series of DEMs show that non-negligible changes in surface roughness can happen within two months at scales relevant for microwave scattering. The second objective is achieved using maximum likelihood fitting of the Oh backscattering model to (1) full-polarimetric Radarsat-2 data and (2) simulated multi-polarization / multi-incidence / multi-frequency radar data. Model fitting with the Radarsat-2 images leads to poor soil moisture retrieval which is related to inaccuracy of the Oh model. Model fitting with the simulated data quantifies the amount of multilooking for di.erent combinations of measurements needed to mitigate the critical e.ect of speckle on soil moisture uncertainty. Results also suggest that dual-polarization measurements at L- and C-bands are a promising combination to achieve the observation requirements of soil moisture. In conclusion, the SfM method along with the recommended processing techniques are good candidates to improve the characterization of surface roughness. A combination of multi-polarization and multi-frequency radar measurements appears to be a robust basis for a future Data Assimilation system for global soil moisture monitoring.

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Baran, Ireneusz. « Advanced satellite radar interferometry for small-scale surface deformation detection ». Thesis, Curtin University, 2004. http://hdl.handle.net/20.500.11937/930.

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Synthetic aperture radar interferometry (InSAR) is a technique that enables generation of Digital Elevation Models (DEMs) and detection of surface motion at the centimetre level using radar signals transmitted from a satellite or an aeroplane. Deformation observations can be performed due to the fact that surface motion, caused by natural and human activities, generates a local phase shift in the resultant interferogram. The magnitude of surface deformation can be estimated directly as a fraction of the wavelength of the transmitted signal. Moreover, differential InSAR (DInSAR) eliminates the phase signal caused by relief to yield a differential interferogram in which the signature of surface deformation can be seen. Although InSAR applications are well established, the improvement of the interferometry technique and the quality of its products is highly desirable to further enhance its capabilities. The application of InSAR encounters problems due to noise in the interferometric phase measurement, caused by a number of decorrelation factors. In addition, the interferogram contains biases owing to satellite orbit errors and atmospheric heterogeneity These factors dramatically reduce the stlectiveness of radar interferometry in many applications, and, in particular, compromise detection and analysis of small-scale spatial deformations. The research presented in this thesis aim to apply radar interferometry processing to detect small-scale surface deformations, improve the quality of the interferometry products, determine the minimum and maximum detectable deformation gradient and enhance the analysis of the interferometric phase image. The quality of DEM and displacement maps can be improved by various methods at different processing levels. One of the methods is filtering of the interferometric phase.However, while filtering reduces noise in the interferogram, it does not necessarily enhance or recover the signal. Furthermore, the impact of the filter can significantly change the structure of the interferogram. A new adaptive radar interferogram filter has been developed and is presented herein. The filter is based on a modification to the Goldstein radar interferogram filter making the filter parameter dependent on coherence so that incoherent areas are filtered more than coherent areas. This modification minimises the loss of signal while still reducing the level of noise. A methodology leading to the creation of a functional model for determining minimum and maximum detectable deformation gradient, in terms of the coherence value, has been developed. The sets of representative deformation models have been simulated and the associated phase from these models has been introduced to real SAR data acquired by ERS-1/2 satellites. A number of cases of surface motion with varying magnitudes and spatial extent have been simulated. In each case, the resultant surface deformation has been compared with the 'true' surface deformation as defined by the deformation model. Based on those observations, the functional model has been developed. Finally, the extended analysis of the interferometric phase image using a wavelet approach is presented. The ability of a continuous wavelet transform to reveal the content of the wrapped phase interferogram, such as (i) discontinuities, (ii) extent of the deformation signal, and (iii) the magnitude of the deformation signal is examined. The results presented represent a preliminary study revealing the wavelet method as a promising technique for interferometric phase image analysis.

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Agaba, Doreen. « System design of the MeerKAT L - band 3D radar for monitoring near earth objects ». Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26890.

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This thesis investigates the current knowledge of small space debris (diameter less than 10 cm) and potentially hazardous asteroids (PHA) by the use of radar systems. It clearly identifies the challenges involved in detecting and tracking of small space debris and PHAs. The most significant challenges include: difficulty in tracking small space debris due to orbital instability and reduced radar cross-section (RCS), errors in some existing data sets, the lack of dedicated or contributing instruments in the Southern Hemisphere, and the large cost involved in building a high-performance radar for this purpose. This thesis investigates the cooperative use of the KAT-7 (7 antennas) and MeerKAT (64 antennas) radio telescope receivers in a radar system to improve monitoring of small debris and PHAs was investigated using theory and simulations, as a cost-effective solution. Parameters for a low cost and high-performance radar were chosen, based on the receiver digital back-end. Data from such radars will be used to add to existing catalogues thereby creating a constantly updated database of near Earth objects and bridging the data gap that is currently being filled by mathematical models. Based on literature and system requirements, quasi-monostatic, bistatic, multistatic, single input multiple output (SIMO) radar configurations were proposed for radio telescope arrays in detecting, tracking and imaging small space debris in the low Earth orbit (LEO) and PHAs. The maximum dwell time possible for the radar geometry was found to be 30 seconds, with coherent integration limitations of 2 ms and 121 ms for accelerating and non-accelerating targets, respectively. The multistatic and SIMO radar configurations showed sufficient detection (SNR 13 dB) for small debris and quasi-monostatic configuration for PHAs. Radar detection, tracking and imaging (ISAR) simulations were compared to theory and ambiguities in range and Doppler were compensated for. The main contribution made by this work is a system design for a high performance, cost effective 3D radar that uses the KAT-7 and MeerKAT radio telescope receivers in a commensal manner. Comparing theory and simulations, the SNR improvement, dwell time increase, tracking and imaging capabilities, for small debris and PHAs compared to existing assets, was illustrated. Since the MeerKAT radio telescope is a precursor for the SKA Africa, extrapolating the capabilities of the MeerKAT radar to the SKA radar implies that it would be the most sensitive and high performing contributor to space situational awareness, upon its completion. From this feasibility study, the MeerKAT 3D distributed radar will be able to detect debris of diameter less than 10 cm at altitudes between 700 km to 900 km, and PHAs, with a range resolution of 15 m, a minimum SNR of 14 dB for 152 pulses for a coherent integration time of 2.02 ms. The target range (derived from the two way delay), velocity (from Doppler frequency) and direction will be measured within an accuracy of: 2.116 m, 15.519 m/s, 0.083° (single antenna), respectively. The range, velocity accuracies and SNR affect orbit prediction accuracy by 0.021 minutes for orbit period and 0.0057° for orbit inclination. The multistatic radar was found to be the most suitable and computationally efficient configuration compared to the bistatic and SIMO configurations, and beamforming should be implemented as required by specific target geometry.

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Lavalle, Marco. « Full and Compact Polarimetric Radar Interferometry for Vegetation Remote Sensing ». Phd thesis, Université Rennes 1, 2009. http://tel.archives-ouvertes.fr/tel-00480972.

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Cette thèse aborde principalement le rôle que jouent les radars polarimétrique et interférométrique dans les applications de géosciences, tout particulièrement sur les forêts. Il est démontré que les modèles actuels simples de la corrélation spatiale des milieux naturels sont capables d'estimer de manière robuste la hauteur de la forêt et sa biomasse; lorsque la topographie est peu prononcée. La corrélation temporelle y est traitée plus précisément en définissant une fonction de corrélation temporelle dépendant de la hauteur de la canopée. Les effets de cette amélioration sur la modélisation directe et inverse sont discutés. Une expression simplifiée de ces modèles est proposée et validée dans le cas des basses fréquences. Nous utilisons à la fois des données polarimétriques satellitales, ainsi que des simulations numériques de rétrodiffusion afin d'illustrer les résultats. Pour les radars en polarimétrie compacte, la pseudo reconstruction est généralisée au cas interférométrique et son efficacité est démontrée seulement pour certaines combinaisons entre les composantes volumiques et les composantes du sol. Enfin, la qualité des données est abordée, en montrant que la rotation de Faraday peut être estimée et corrigée à partir des échos radar non focalisés et que les trièdres maillées peuvent servir d'étalonnage radiométrique des données à double polarisation.

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Melton, Darryl C. « Remote sensing and validation of surface currents from HF radar ». Thesis, Monterey, California. Naval Postgraduate School, 1995. http://hdl.handle.net/10945/35170.

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Radial current data from the CODAR HF radar network around Monterey Bay, California, were analyzed for the period of August-December 1994. Previous studies in Monterey Bay used total vector current data. Long-term percent coverage maps showed that coverage decreased radially, vice range, from the site. Through statistical exarnination of radial current data from the Santa Crux and Point Piiios SeaSonde sites and the Moss Landing CODAR site, comparisons along and around the baseline between systems were used to assess system performance. Significant discrepancies were discovered in the directional information from the Point Pinos and Moss Landing sites. Point Pinos' error was approximately 10 counterclockwise and Moss Landing's error was approximately 5 counterclockwise. RMS differences among even the best correlated baseline pairs were approximately 15 cm/s. Data from the baseline was used to select vector currents when the baseline difference was less than 10 cm/s for comparisons with independent nearby moored current observations. This subsampled data did not show significantly better correlation with the moored data than the full data set. Analysis of the radial error estimates provided by the system algorithms determined that no correlation exists between absolute value difference of the radial velocities along the baselines between systems and these built in error estimates

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Cassidy, Scott L. « Millimetre-wave FMCW radar for remote sensing and security applications ». Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7856.

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This thesis presents a body of work on the theme of millimetre-wave FMCW radar, for the purposes of security screening and remote sensing. First, the development of an optimised software radar signal processor will be outlined. Through use of threading and GPU acceleration, high data processing rates were achieved using standard PC hardware. The flexibility of this approach, compared to specialised hardware (e.g. DSP, FPGA etc…), allowed the processor to be rapidly adapted and has produced a significant performance increase in a number of advanced real-time radar systems. An efficient tracker was developed and was successfully deployed in live trials for the purpose of real-time wave detection in an autonomous boat control system. Automated radar operation and remote data telemetry functions were implemented in a terrain mapping radar to allow continuous monitoring of the Soufrière Hills volcano on the Caribbean island of Montserrat. This work concluded with the installation of the system 3 km from the volcano. Hardware modifications were made to enable coherent measurement in a number of existing radar systems, allowing phase sensitive measurements, including range-Doppler, to be performed. Sensitivity to displacements of less than 200 nm was demonstrated, which is limited by the phase noise of the system. Efficient compensation techniques are presented which correct for quadrature mixer imbalance, FMCW chirp non-linearity, and scanner drive distortions. In collaboration with the Home Office, two radar systems were evaluated for the stand-off detection of concealed objects. Automatic detection capability, based on polarimetric signatures, was developed using data gathered under controlled conditions. Algorithm performance was assessed through blind testing across a statistically significant number of subjects. A detailed analysis is presented, which evaluates the effect of clothing and object type on detection efficiency.

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Chini, Marco <1973&gt. « Radar and optical remote sensing techniques for earthquake damage mapping ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/863/1/Tesi_Chini_Marco.pdf.

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Chini, Marco <1973&gt. « Radar and optical remote sensing techniques for earthquake damage mapping ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/863/.

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Horritt, Matthew Stephen. « Enhanced flood flow modelling using remote sensing techniques ». Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265834.

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Lin, I.-I. « Spatial texture of visible and radar imagery of terrestrial ice masses ». Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363289.

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Voytenko, Denis. « Glaciological Applications of Terrestrial Radar Interferometry ». Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5856.

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Terrestrial Radar Interferometry (TRI) is a relatively new ground-based technique that combines the precision and spatial resolution of satellite interferometry with the temporal resolution of GPS. Although TRI has been applied to a variety of fields including bridge and landslide monitoring, it is ideal for studies of the highly-dynamic terminal zones of marine-terminating glaciers, some of which are known to have variable velocities related to calving and/or ocean-forced melting. My TRI instrument is the Gamma Portable Radar Interferometer, which operates at 17.2 GHz (1.74 cm wavelength), has two receiving antennas for DEM (digital elevation model) generation, and images the scenes at minute-scale sampling rates. Most of this TRI work has focused on two glaciers: Breiðamerkurjökull in Iceland and Helheim in Greenland. Monitoring the displacement of stationary points suggests velocity measurement uncertainties related to the instrument and atmosphere of less than 0.05 m/d. I show that the rapid sampling rate of the TRI can be used to observe velocity variations at the glacier terminus and assess the impact and spatial distribution of tidal forcing. Additionally, iceberg tracking in the amplitude imagery may provide insight about ocean currents near the terminus.

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Meyer, Melissa G. « Remote sensing of localized ion acoustic waves with multistatic passive radar / ». Thesis, Connect to this title online ; UW restricted, 2006. http://hdl.handle.net/1773/6062.

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González, Sanpedro Mª del Carmen. « Optical and radar remote sensing applied to agricultural areas in europe ». Doctoral thesis, Universitat de València, 2008. http://hdl.handle.net/10803/9876.

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The global population growth, as well as the social and economic importance that the agricultural sector has in many regions of the world, makes it very important to develop methods to monitor the status of crops, to improve their management, as well as to be able to make early estimates of the agricultural production. One of the main causes of uncertainty in the production of crops is due to the weather, for example, in arid and semiarid regions of the world, periods of drought can generate big losses in agricultural production, which may result in famine. Thus, FAO, during their summit in June 2008, stressed the need to increase agricultural production as a measure to strengthen food security and reduce malnutrition in the world.Concern for increasing crop production, has generated, during the last decades, significant changes in agricultural techniques. For example, there has been a widespread use of pesticides, genetically modified crops, as well as an increase in intensive farming. In turn, the market influences crop rotations, and as a consequence, changes in the spatial distribution of crops are very common. Therefore, in order to make estimates of agricultural production, it is also necessary to map regularly the crop fields, as well as their state of development.The aim of this thesis is to develop methods based on remote sensing data, in the radar and optical spectral regions, in order to monitor crops, as well as a to map them. The results of this thesis can be combined with other techniques, especially with models of crop growth, to improve the prediction of crops.The optical remote sensing methods for classifying and for the cartography of crops are well established and can be considered almost operational. The disadvantage of the methods based on optical data is that they are not applicable to regions of the world where cloud coverage is frequent. In such cases, the use of radar data is more advisable. However, the classification methods using radar data are not as well established as the optical ones, therefore, there is a need for more scientific studies in this field. As a consequence, this thesis focuses on the classification of crops using radar data, particularly using AIRSAR airborne data and ASAR satellite data.

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Jung, Hahn Chul. « Wetland Hydrodynamics Using Interferometric Synthetic Aperture Radar, Remote Sensing, and Modeling ». The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1291661296.

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Ouellette, Jeffrey D. « Topics in Remote Sensing of Soil Moisture Using L-Band Radar ». The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437587673.

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Gonzalez, Sanpedro Maria del Carmen. « Optical and radar remote sensing applied to agricultural areas in Europe ». Toulouse 3, 2008. http://www.theses.fr/2008TOU30228.

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L'objectif de la thèse est de développer des méthodes de cartographie et de suivi des cultures basées sur des données de télédétection, radar et optique. Les résultats pourront être combinés avec d'autres techniques, notamment avec des modèles de croissance des cultures, pour améliorer la prévision des récoltes. Quatre instruments différents, 3 sur satellite (LANDSAT-TM, ENVISAT-MERIS, ENVISAT-ASAR) et 1 aéroporté (AIRSAR) sont utilisés dans trois régions d'étude en Europe (Barrax, Toulouse et Flevoland). Les travaux sont présentés en deux parties, optique et radar. Dans la première partie, les données LANDSAT sont utilisées pour l'inversion du LAI à Barrax (Castilla-La Mancha) à l'aide du modèle de transfert radiatif PROSPECT+SAIL. Les résultats sont validés avec des mesures expérimentales acquises au cours de la campagne sur le terrain ESA SPARC-2003, montrant une bonne corrélation. Une méthode est ensuite proposée pour inverser le LAI et la chlorophylle à partir de données MERIS. La méthode implique une inversion du modèle, PROSPECT+SAIL avec une contrainte temporelle (une courbe pour l'ensemble du cycle de culture est inversée). Les résultats montrent que cette méthode fonctionne mieux que les inversions date par date. Toutefois, l'inversion de la chlorophylle nécessite encore une étude plus approfondie. Dans la partie radar, une méthode de classification basée sur les connaissances des mécanismes de rétrodifusion est proposée. Elle utilise des données polarimétriques en bande C de l'instrument AIRSAR. La méthode est appliquée à des images dans le Flevoland (Pays-Bas). Les résultats indiquent que ces méthodes peuvent être plus robustes que les méthodes statistiques usuelles. .
El aumento de la población mundial, así como la importancia social y económica que el sector agrícola tiene en muchas regiones del mundo, hace que sea muy importante desarrollar métodos que permitan hacer un seguimiento del estado de los cultivos, mejorar la gestión de los mismos, así como poder realizar una estimación temprana de la producción. La principal causa de incertidumbre en la producción de las cosechas es debida a las condiciones meteorológicas, por ejemplo, en las regiones áridas y semiáridas del mundo los períodos de sequía generan grandes pérdidas en la producción agrícola, la cuales se traducen en hambrunas. Así, la FAO, durante su cumbre de Junio 2008, insistió en la necesidad de aumentar a producción agrícola como una medida para reforzar la seguridad alimentaria y reducir la desnutrición en el mundo. La preocupación por aumentar la producción de cultivos, ha generado, durante las últimas décadas, importantes cambios en las técnicas agrícolas. Por ejemplo, se ha producido un uso generalizado de productos fitosanirios, de cultivos modificados genéticamente, así como un aumento de la agricultura intensiva. A su vez, la rotación de cultivos está cada vez más influenciada por el mercado, siendo los cambios en la distribución espacial de los cultivos muy frecuentes. Por lo tanto, para poder hacer estimaciones de la producción agrícola, es necesario producir eriódicamente mapas de cultivos, así como cartografiar su estado de desarrollo. La presente tesis doctoral tiene como objetivo desarrollar métodos basados en datos de teledetección, en la región del óptico y en la región del radar, que permitan realizar un seguimiento de los cultivos, así como una cartografía de los mismos. Los resultados de esta tesis pueden combinarse con otras técnicas, especialmente con los modelos de crecimiento de cultivo, para mejorar la predicción de las cosechas. Los métodos de teledetección para la clasificación y la cartografía de cultivos utilizando datos en la región del óptico están bien establecidos y pueden considerarse casi operacionales. La desventaja de estos estudios basados en datos ópticos es que no pueden aplicarse a regiones donde la cobertura nubosa es frecuente. En esos casos, la utilización de datos radar es más recomendable. Sin embargo, los métodos de clasificación utilizando datos radar no están tan bien establecidos y es necesario realizar más estudios científicos en este campo. Es por ello, que esta tesis se centra en la clasificación de cultivos mediante datos radar, concretamente datos aerotransportados AIRSAR y datos ASAR del satélite ENVISAT. El seguimiento de los cultivos mediante teledetección se basa en la estimación de parámetros biofísicos y su evolución en el tiempo. Estos parámetros son, entre otros, LAI (índice de área foliar), clorofila y biomasa. En esta tesis se han utilizado datos del satélite LANSAT-TM para la inversión de LAI, y datos ENVISAT-MERIS para la estimación de LAI y clorofila

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Long, David G., Bryan Jarrett, David V. Arnold et Jorge Cano. « BYU SAR : A Low Cost Compact Synthetic Aperture Radar ». International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/611615.

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International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada
Synthetic Aperture Radar (SAR) systems are typically very complex and expensive. They generate enormous quantities of data, requiring very high capacity data storage, transmission, and processing systems. We have developed an experimental SAR system with a very simple design which includes near-real-time onboard processing. This system is based on recent developments in low-cost, high-rate analog-to-digital (A/D) and digital-to-analog (D/A) data conversion systems. Most of the system is based on off-the-shelf components. A very simple RF subsystem is used. The system has been successfully operated from a moving surface vehicle and exhibits a range resolution of 2.5 m though this could be improved to 1.5 m at the expense of higher sidelobes. The four look azimuth resolution is 0.4 m. This paper describes the system as well as our plans for upgrading the system for aircraft operation and improved resolution.

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Alahmadi, Mohammed. « A Recursive Approach for Adaptive Parameters Selection in AMultifunction Radar ». The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448981863.

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Baran, Ireneusz. « Advanced satellite radar interferometry for small-scale surface deformation detection ». Curtin University of Technology, Department of Spatial Sciences, 2004. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15717.

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Synthetic aperture radar interferometry (InSAR) is a technique that enables generation of Digital Elevation Models (DEMs) and detection of surface motion at the centimetre level using radar signals transmitted from a satellite or an aeroplane. Deformation observations can be performed due to the fact that surface motion, caused by natural and human activities, generates a local phase shift in the resultant interferogram. The magnitude of surface deformation can be estimated directly as a fraction of the wavelength of the transmitted signal. Moreover, differential InSAR (DInSAR) eliminates the phase signal caused by relief to yield a differential interferogram in which the signature of surface deformation can be seen. Although InSAR applications are well established, the improvement of the interferometry technique and the quality of its products is highly desirable to further enhance its capabilities. The application of InSAR encounters problems due to noise in the interferometric phase measurement, caused by a number of decorrelation factors. In addition, the interferogram contains biases owing to satellite orbit errors and atmospheric heterogeneity These factors dramatically reduce the stlectiveness of radar interferometry in many applications, and, in particular, compromise detection and analysis of small-scale spatial deformations. The research presented in this thesis aim to apply radar interferometry processing to detect small-scale surface deformations, improve the quality of the interferometry products, determine the minimum and maximum detectable deformation gradient and enhance the analysis of the interferometric phase image. The quality of DEM and displacement maps can be improved by various methods at different processing levels. One of the methods is filtering of the interferometric phase.
However, while filtering reduces noise in the interferogram, it does not necessarily enhance or recover the signal. Furthermore, the impact of the filter can significantly change the structure of the interferogram. A new adaptive radar interferogram filter has been developed and is presented herein. The filter is based on a modification to the Goldstein radar interferogram filter making the filter parameter dependent on coherence so that incoherent areas are filtered more than coherent areas. This modification minimises the loss of signal while still reducing the level of noise. A methodology leading to the creation of a functional model for determining minimum and maximum detectable deformation gradient, in terms of the coherence value, has been developed. The sets of representative deformation models have been simulated and the associated phase from these models has been introduced to real SAR data acquired by ERS-1/2 satellites. A number of cases of surface motion with varying magnitudes and spatial extent have been simulated. In each case, the resultant surface deformation has been compared with the 'true' surface deformation as defined by the deformation model. Based on those observations, the functional model has been developed. Finally, the extended analysis of the interferometric phase image using a wavelet approach is presented. The ability of a continuous wavelet transform to reveal the content of the wrapped phase interferogram, such as (i) discontinuities, (ii) extent of the deformation signal, and (iii) the magnitude of the deformation signal is examined. The results presented represent a preliminary study revealing the wavelet method as a promising technique for interferometric phase image analysis.

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Lee, Gyu Won. « Errors in rain mearurement by radar : effect of variability of drop size distributions ». Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19509.

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In this work, the various sources of errors in radar rain estimation are quantified and procedures are developed to reduce them. The few topics explored here are: the variability of drop size distributions (DSDs), radar calibration, and errors in polarimetric rain estimation. The findings resulting from this study include 1) a new filtering technique that reduces the spurious DSD sampling variability while maintaining the physical variability, 2) a generalization of previously suggested DSD models in terms of scaling concepts, 3) the experimental evidence of the physical interpretation of DSD evolution and of R-Z relationships, 4) the time scale dependence of the DSD variability and its implication for radar rain estimation, 5) the quantification of error sources in polarimetric rain estimation and its feasibility in operational environment, and 6) a complete set of stable radar calibration methods and their theoretical limits. All error statistics from this work will be used as a guideline in radar rain estimation.

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Ramnath, Vinod. « Estimation of soil moisture using active microwave remote sensing ». Master's thesis, Mississippi State : Mississippi State University, 2003.

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Chang, Hsing-Chung Surveying &amp Spatial Information Systems Faculty of Engineering UNSW. « Differential interferometric synthetic aperture radar for land deformation monitoring ». Publisher:University of New South Wales. Surveying & ; Spatial Information Systems, 2008. http://handle.unsw.edu.au/1959.4/42602.

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Australia is one of the leading mineral resource extraction nations in the world. It is one of the worlds top producers of nickel, zinc, uranium, lithium, coal, gold, iron ore and silver. However, the complexity of the environmental issues and the potentially damaging consequences of mining have attracted public attention and political controversy. Other types of underground natural resource exploitation, such as ground water, gas or oil extractions, also cause severe land deformation on different scales in space and time. The subsidence due to underground mining and underground fluid extractions has the potential to impact on surface and near surface infrastructure; as well as water quality and quantity, that in turn has the potential to impact on threatened flora and fauna, and biodiversity conservation. Subsidence can also impact natural and cultural heritage. To date, most of land deformation monitoring is done using conventional surveying techniques, such as total stations, levelling, GPS, etc. These surveying techniques provide high precision in height at millimetre accuracy, but with the drawbacks of inefficiency and costliness (labour intensive and time consuming) when surveying over a large area. Radar interferometry is an imaging technique for measuring geodetic information of terrain. It exploits phase information of the backscattered radar signals from the ground surface to retrieve the altitude or displacements of the objects. It has been successfully applied in the areas of cartography, geodesy, land cover characterisation, mitigation of natural or man-made hazards, etc. The goal of this dissertation was to develop a system which integrated differential interferometric synthetic aperture radar (DInSAR), ground survey data and geographic information systems (GIS) as a whole to provide the land deformation maps for underground mining and water extraction activities. This system aimed to reinforce subsidence assessment processes and avoid or mitigate potential risks to lives, infrastructure and the natural environment. The selection of suitable interferometric pairs is limited to the spatial and temporal separations of the acquired SAR images as well as the characteristics of the site, e.g. slope of terrain, land cover, climate, etc. Interferometric pairs with good coherence were selected for further DInSAR analysis. The coherence analysis of both C- and L-band spaceborne SAR data was studied for sites in the State of New South Wales, Australia. The impact of the quality of the digital elevation models (DEM), used to remove the static topography in 2-pass DInSAR, were also analysed. This dissertation examined the quality of the DEM generated using aerial photogrammetry, InSAR, and airborne laser scanning (ALS) against field survey data. Kinematic and real-time kinematic GPS were introduced here as an efficient surveying method for collecting ground truth data for DEM validation. For mine subsidence monitoring, continuous DInSAR mine subsidence maps were generated using ERS-1/2, Radarsat-1 and JERS-1 data with the assumption of negligible horizontal displacement. One of the significant findings of this study was the results from the ERS-1/2 tandem DInSAR, which showed an immediate mine subsidence of 1cm occurred during a period of 24 hours. It also raised the importance of SAR constellations for disaster mitigation. In order to understand the 3-D displacement vectors of mine deformation, this dissertation also proposed a method using the SAR data acquired at 3 independent incidence angles from both ascending and descending orbits. Another issue of the high phase gradient, induced by the mine subsidence, was also addressed. Phase gradient was clearly overcome by having the L-band ALOS data with an imaging resolution of 10m, which is better than the imaging resolution of 18m of the previous generation of the Japanese L-band SAR satellite, JERS-1. The ground survey data over a similar duration was used for validation. Besides mine subsidence monitoring the land deformation caused by groundwater pumping were also presented. In contrast to mine subsidence, the underground water extraction induced subsidence has the characteristics of a slow rate of change and less predictable location and coverage. Two case studies were presented. One was at the geothermal fields in New Zealand and another was the urban subsidence due to underground water over exploitation in China. Both studies were validated against ground survey data. Finally, SAR intensity analysis for detecting land deformation was demonstrated when DInSAR was not applicable due to strong decorrelation. The region of land surface change, which may be caused by human activities or natural disasters, can be classified. Two cases studies were given. The first study was the surface change detection at an open-cut mine. The second one was the 2004 Asian tsunami damage assessment near Banda Aceh. The results presented in this dissertation showed that the integrated system of DInSAR, GIS and ground surveys has the potential to monitor mine subsidence over a large area. The accuracy of the derived subsidence maps can be further improved by having a shorter revisit cycle and better imaging resolution of the newly launched and planned SAR satellites and constellation missions. The subsidence caused by groundwater pumping can be monitored at an accuracy of millimetre by utilising the technique of persistent scatterer InSAR.

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Fransson, Johan. « Analysis of synthetic aperture radar images for forestry applications / ». Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://www.resgeom.slu.se/fjarr/personal/jf/.

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Wang, Weili. « Remote sensing of swell and currents in coastal zone by HF radar ». Thesis, Toulon, 2015. http://www.theses.fr/2015TOUL0011/document.

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L’environnement maritime du littoral implique de nombreux processus complexes, mais le manque de données en haute résolution couvrant une large zone sur une longue période est souvent l’obstacle principal à des recherches plus approfondies. Le radar haute-fréquence (HF) est un moyen de faire de la télédétection afin d’obtenir pratiquement en temps réel de l’information sur la surface de la mer et sur une large zone. Ainsi l’étude de l’inversion des paramètres marins à partir de données issues de radars HF est réellement porteuse de sens. Cette thèse fait l’usage d’un jeu de données collectées durant 13 mois par deux réseaux de radar HF à commande de phase pour étudier les caractéristiques de signaux d’échos de la mer, étudier les données à traiter et les méthodes d’inversion, calculer les paramètres de la surface de la mer et évaluer la précision de l’inversion radar des paramètres de la houle.Cette thèse se réfère à l’onde de sol radar HF, dont les ondes radio interagissent avec l’océan du fait de la diffraction de résonance de Bragg. Nous passons en revue l’historique et les applications du radar HF. Nous rappelons les bases de la théorie des ondes électromagnétiques. Nous décrivons les principes d’inversion des courants de surface de la mer, direction du vent et paramètres de houles. La faisabilité de l’inversion de paramètres de houle est examinée. A partir de l’analyse théorique et des études statistiques de nombreux échantillons de données, cette thèse propose une série de méthodes sur le traitement du signal brut et le contrôle de qualité, ce qui inclut la détermination du niveau de bruit, le moyennage des données dans l’espace et le temps, l’identification correcte des pics spectraux, le seuil de largeur de pic, etc. Respectant les caractéristiques de différents processus physiques, les inversions de courant et de vent utilisent des spectres collectés toutes les 20 minutes ; l’inversion des paramètres de houle utilise des spectres moyennés sur 1 heure. Les statistiques des spectres utilisés pour le calcul des paramètres de houle sont présentées pour chacune des stations. Un ensemble de programme efficaces de calculs automatiques avec une complexité algorithme réduite sont développés pour réaliser le traitement et en tirer les paramètres marins.Les vitesses de courants radiales sont obtenues à partir d’une unique station radar. Les champs de vecteurs de courants sont obtenus en combinant chaque station. On montre une année de débit moyen dans la mer d’Iroise, ainsi que le calcul de la vorticité et de la divergence. On étudie un ensemble de données d’un mois du radar SeaSonde de Qingdao. Les schémas de débit moyen, ainsi que la vorticité et la divergence sur un mois sont présentés.La direction relative du vent par rapport à la direction de visée du radar est mesurée à travers le ratio des amplitudes des pics de Bragg. Différents modèles empiriques sont employés pour obtenir la vitesse relative du vent par inversion radar. Les résultats présentés sont en accord avec les estimations prédites par le modèle. Différents modèles de distribution directionnelle sont utilisés pour mesurer le facteur de diffusion pour la mer d’Iroise.Cette thèse se concentre sur l’étude des paramètres de houle. Les résultats sont validés à l’aide de bouées et de données du modèle de vagues (Wavewatch III). L’estimation montre que la précision de la fréquence de houle est très bonne, la précision sur la hauteur significative de houle est très raisonnable et la précision sur la direction absolue de la houle est faible. La cohérence des mesures par chacune des stations radars est vérifiée par comparaison entre les deux. L’utilisation conjointe des échantillons est également prise en charge pour réaliser l’inversion. L’utilisation de deux radars n’améliore pas seulement la précision, mais résout aussi l’ambiguïté de direction relative de houle à partir d’une unique station et donne la direction absolue de vague avec une certaine précision
Nearshore marine environment contains many complex processes, but the lack of high-resolution data over a large area during a long time is often the primary obstacle to further research. High-frequency (HF) radar is a mean of remote sensing which obtains continuous near-real time sea surface information over a large area. Thus the study of inversion of marine parameters from HF radar data is very meaningful. Thisthesis makes use of a 13-month-long dataset collected by two phased array HF radar to investigate the characteristics of the sea echo signals, study the data processing and inversion methods, compute sea surface parameters and evaluate the accuracy of radarinversion of swell parameters.The thesis refers to the ground wave HF radar, whose radio waves interact with ocean by Bragg resonance scattering. The development history and applications of HF radar is introduced. The basic theory of electromagnetic wave is reviewed. The principles of inversion of sea surface current, wind direction and swell parameters are described. The feasibility of the swell parameter inversion is investigated. Based on theoretical analysis and statistical studies of a large number of samples, the thesis proposes a series of methods on raw signal processing and quality control, including the determination of the noise level, data averaging in space and time, the proper identification of spectral peaks, the peak width threshold, etc. Respecting the characteristics of different physical processes, inversions of current and wind use spectra collected every 20 min; inversion of swell parameters uses one-hour averaged spectra. The statistics of qualified spectra for swell parameter calculations are presented for both stations. A set of efficient, with a reduced computational cost, automatic computing programs are developed to do the processing and derive marine parameters. Radial current velocities are derived from single radar station. Current vector fields are obtained by combination of both stations. One-year mean flow field in the Iroise Sea is shown, together with the computation of vorticity and divergence. A one-month SeaSonde radar dataset off Qingdao is studied. One-month mean flow pattern together with vorticity and divergence are presented.Relative wind direction with respect to radar look direction is measured through ratio of Bragg peaks amplitudes. Different empirical models are employed to derive radar-inverted relative wind direction. Results show reasonable agreement with model estimations. Different directional distribution models are used to measure the spreading factor for the Iroise Sea. The thesis focuses on the study of swell parameters. Results are validated by buoy and wave model (WAVEWATCH III) data. The assessments show that the accuracy of swell frequency is very good, the accuracy of swell significant waveheight is reasonable, and the accuracy of relative swell direction is low.Consistency of measurements by both radar stations is verified by comparison between the two. This also supports the use of double samples to do the inversion. Use of two radars not only further improves the accuracy but also solves the ambiguity of relative swell direction from single station and gives the absolute wave direction to a certain precision. The thesis proposes a constant relative directionmethod to derive swell significant waveheight, based on the studies of radar integral equation and the inverted results of relative swell direction. This proposal is demonstrated to improve the agreement of radar inversion and buoy/model provided significant waveheight and increases significantly the number of samples. The thesis investigates the accuracy of swell parameters obtained by HF radar. Contributions of random errors in radar observations are quantified. Comparing the differences between radar and buoy/model estimations gives assessments of the contribution of radar intrinsic uncertainty and contribution of other factors

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Yoho, Peter K. « Satellite scatterometers : calibration using a ground station and statistical measurement theory / ». Diss., CLICK HERE for online access, 2003. http://contentdm.lib.byu.edu/ETD/image/etd306.pdf.

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Nitzsche, Christopher R. « Ground penetrating radar and geomorphic analysis of Paleo Beach ridges in Lorain County, Ohio ». Thesis, Kent State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1555283.

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Compaleo, Joshua. « Accurate Clutter Power Modeling Technique for Very LowGrazing Angles with RFC Capable Radar Design and Demonstration ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595563370860726.

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Durán, Alárcon Claudio. « Ground-based remote sensing of Antarctic and Alpine solid precipitation ». Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU024/document.

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Les précipitations solides jouent un rôle crucial dans le système climatique terrestre, ainsi que dans le maintien des écosystèmes et le développement des activités humaines. Les incertitudes associées aux estimations quantitatives des précipitations ainsi que celles concernant les projections des modèles climatiques font de cette composante du cycle hydrologique un sujet de recherche important. La télédétection permet de suivre les précipitations et les nuages dans des régions où les observations in situ sont rares et dispersées, mais avec une résolution temporelle limitée ainsi qu’une zone aveugle près du sol pour les capteurs spatiaux, et une visibilité limitée dans la basse atmosphère en terrain complexe pour les radars au sol. Les objectifs de cette thèse sont les suivants : 1) caractériser les nuages et les précipitations en Antarctique, en détectant la présence d’eau liquide surfondue et de particules de glace près du sol à l'aide d'un lidar 532-nm, polarisé, au sol ; 2) caractériser la structure verticale des précipitations dans deux régions contrastées mais importantes de la cryosphère, l’Antarctique et les Alpes, dans la basse troposphère, en utilisant des radars au sol.Dans cette étude, une méthode de détection des hydrométéores dans les nuages et les précipitations est proposée à l'aide de données lidar complétées par celles d’un <> (MRR) en bande K pour améliorer la détection des précipitations, ces deux instruments étant déployés à la station Dumont d'Urville (DDU) en Antarctique de l’Est. Une méthode fondée sur le facteur de dépolarisation lidar, le coefficient de rétrodiffusion atténué et l'utilisation d’un partitionnement en k-moyennes est développée. La classification des particules des nuages et des précipitations permet de documenter la distribution verticale de l'eau liquide surfondue, ainsi que des particules de glace sous différentes formes. La comparaison entre les classifications obtenues depuis le sol et celles obtenues à partir des données satellitaires montre des formes similaires pour la distribution verticale de l'eau liquide surfondue dans les nuages.La structure verticale des précipitations près de la surface est analysée à l'aide des moments Doppler obtenus à partir de trois MRRs situés à DDU, à la station Princess Elisabeth (PE) à l'intérieur de l'Antarctique de l’Est, et à la station du Col de Porte (CDP) dans les Alpes françaises. Ces analyses montrent que le climat local joue un rôle important dans la structure verticale des précipitations. En Antarctique, les forts vents catabatiques soufflant du haut plateau jusqu'à la côte diminuent le facteur de réflectivité radar près de la surface en raison de la sublimation des flocons de neige. Les moments Doppler fournissent aussi de riches informations pour comprendre les processus liés aux précipitations, tels que l'agrégation et le givrage, observés notamment à DDU et au Col de Porte.Les résultats montrent également qu'à l'intérieur du continent Antarctique, une partie significative (47%) des profils de précipitations présentent une sublimation complète avant la surface en raison des conditions atmosphériques sèches, alors que sur la côte de l'Antarctique, cela ne concerne qu’environ un tiers des profils (36%). Dans les Alpes, ce pourcentage est réduit à 15%. La majeure partie de la sublimation est observée en dessous de l'altitude où les profils de CloudSat sont contaminés par la proximité du sol. Par conséquent, ce phénomène ne peut pas être entièrement décelé depuis l'espace avec les capteurs actuels.Cette thèse contribue à l'étude de la structure verticale des précipitations neigeuses dans la basse troposphère ; elle est utile pour l'évaluation des produits de télédétection concernant les précipitations qui peuvent présenter de fortes limitations à la proximité de la surface
Solid precipitation plays an important role in the Earth's climate system, as well as for the maintenance of ecosystems and the development of human society. The large uncertainty in precipitation estimates and the discrepancies within climate model projections make this component of the hydrological cycle important as a research topic. Remote sensing allows to monitor precipitation and clouds in regions where in-situ observations are scarce and scattered, but with limited temporal resolution and a blind zone close to the ground level for spaceborne sensors, and limited visibility in the lower atmosphere in complex terrain for ground-based radars. The objectives of this dissertation are the following: 1) to characterize cloud and precipitation in Antarctica, detecting the presence of supercooled liquid and ice particles near the ground level using a ground-based 532-nm depolarization lidar; 2) to characterize the vertical structure of the precipitation in two contrasted but important regions of the cryosphere, Antarctica and the Alps, in the low troposphere using ground-based radars.In this study, a cloud and precipitation hydrometeor detection method is proposed using lidar data, complemented with a K-band micro rain radar (MRR) to improve the detection of precipitation, both instruments deployed at the Dumont d'Urville (DDU) station in East Antarctica. A method based on lidar depolarization and attenuated backscattering coefficient and the use of k-means clustering is developed for the particle classification. The classification of cloud and precipitation particles provides the vertical distribution of supercooled liquid water, as well as planar oriented ice and randomly oriented ice particles. The comparison between ground-based and satellite-derived classifications shows consistent patterns for the vertical distribution of supercooled liquid water in clouds.The vertical structure of precipitation near the surface is analyzed using the Doppler moments derived from three MRR profiles at DDU, the Princess Elisabeth (PE) station, at the interior of East Antarctica, and at the Col de Porte (CDP) station, in the French Alps. These analyses demonstrate that local climate plays an important role in the vertical structure of the precipitation. In Antarctica, the strong katabatic winds blowing from the high plateau down to the coast decrease the radar reflectivity factor near the surface due to the sublimation of the snowfall particles. Doppler moments also provide rich information to understand precipitation processes, such as aggregation and riming, as observed at DDU and CDP.The results also show that in the interior of the Antarctic continent a significant part (47%) of the precipitation profiles completely sublimate before reaching the surface, due to the dry atmospheric conditions, while in the coast of Antarctica it corresponds to about the third part (36%). In the Alps, this percentage is reduced to 15%. The major occurrence of particle sublimation is observed below the altitude where CloudSat profiles are contaminated by ground clutter. Therefore, this phenomenon cannot be fully captured from space with the current generation of sensors.This dissertation contributes to the study of the vertical structure of snowfall in the low troposphere, useful for the evaluation of precipitation remote sensing products, which may have severe limitations in the vicinity of the surface

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Holmberg, Andreas. « Combination analysis of multispectral and radar satellite data ». Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185506.

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Remote sensing technologies, such as satellite imagery, have proven to be a powerful tool for land cover classification when combined with machine learning algorithms. Depending on which type of sensor is used for the imagery, different properties of land cover classes may be distinguished. Because of this, a data set containing a combination of data from different sensors could potentially further improve the classification accuracy. To determine if adding data from the radar sensor on the satellite constellation Sentinel-1 to data from the multispectral optical sensor on the satellite constellation Sentinel-2 could improve the accuracy of land cover classification, a tool for combining data from both satellites was developed. The classification accuracy using the combined data was then compared to using non-combined Sentinel-2 data with a neural network and a random forest classifier. We found that the random forest classifier produced a higher accuracy than the neural network for both the combined data and non-combined data. The combined data increased the accuracy further compared to the non-combined data. However, the increase produced by the combined data was small and most likely not worth the extra computational power required to implement Sentinel-1 data to Sentinel-2 data.

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Algafsh, Abdullah. « Calibration of airborne L-, X-, and P-band fully polarimetric SAR systems using various corner reflectors ». Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26937.

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Synthetic aperture radar polarimetry is one of the current developments in the field of remote sensing, due to the ability of delivering more information on the physical properties of the surface. It is known as the science of acquiring, processing and analysing the polarisation state in an electromagnetic field. The increase of information with respect to scalar radar comes at a price, not only for the high cost of building the radar system and processing the data or increasing the complexity of the design, but also for the amount of effort needed to calibrate the data. Synthetic aperture radar polarimetric calibration is an essential pre- processing stage for the correction of distortion interference which is caused by the system inaccuracies as well as atmospheric effects. Our goal, with this thesis, is to use multiple passive point targets to establish the difference between fully, and compact polarimetric synthetic aperture radar systems on both calibration, and the effects of penetration. First, we detail the selection, design, manufacture, and deployment of different passive point targets in the field for acquiring X- and P-band synthetic aperture radar data in the Netherlands. We started by presenting the selection and design of multiple passive point targets. These were a combination of classic trihedral and dihedral corner reflectors, as well as gridded trihedral and dihedral corner reflectors. Additionally, we detailed the construction of these corner reflectors. The number of constructed corner reflector totalled sixteen, where six are for X-band and six for P-band, as well as four gridded corner reflectors for X-band. Finally, we present the deployment of the corner reflectors at three different sites with carefully surveyed and oriented positions. a Then, we present the calibration of three different fully polarimetric synthetic aperture radar sensors. The first sensor is the L-band synthetic aperture radar sensor and we acquired data using two square trihedral corner reflectors. The calibration includes an evaluation of two crosstalk methods, which are the Quegan and the Ainsworth methods. The results showed that the crosstalk parameters for the Quegan method are all between -17 dB to -21 dB before calibration, while there is a small improvement in the range of 3 dB after calibration. While the Ainsworth method shows around -20 dB before calibration, and around -40 dB after calibration. Moreover, the phase, channel imbalance, and radiometric calibration were corrected using the two corner reflectors. Furthermore, the other two synthetic aperture radar sensors are X- and P-band synthetic aperture radar sensors, and we acquired polarimetric data using our sixteen corner reflectors. The calibration includes the crosstalk estimation, and correction using the Ainsworth method and the results showed the crosstalk parameters before calibration for X-band are around -23 dB, and they are around -43 dB after calibration, while crosstalk parameters before calibration for P-band are around -10 dB, and they are around -30 dB after calibration. The calibration also includes the phase, channel imbalance, and radiometric calibration, as well as geometric correction and signal noise ration measurement, for both X- and P-band. Next, we present the performance of gridded trihedral and dihedral corner reflectors using an X-band synthetic aperture radar system. The results showed both gridded trihedral and dihedral reflectors are perfect targets for correcting the amplitude compared to classical corner reflectors; however, it is not possible to use the gridded reflectors to correct the phase as we need a return from two channels to have a zero-phase difference between the polarisation channels H - V. Furthermore, we detail the compact polarimetric calibration over three com- pact polarimetric modes using a square trihedral corner reflector for the X-band dataset. The results showed no change in the π/mode while a 90ᵒ phase bias showed in the CTLR mode. Finally, the DCP mode showed a 64.43° phase difference, and it was corrected to have a zero phase, and the channel imbalance was very high at 45.92, the channels were adjusted to have a channel imbalance of 1. b Finally, an experiment to measure the penetration and reduction of P-band signal from a synthetic aperture radar system was performed using two triangular trihedral corner reflectors. Both of them have 1.5 m inner leg dimensions. The first triangular trihedral corner reflector was deployed in a deciduous grove of trees, while the other one was deployed a 10 m distance away on a grass covered field. After system calibration based on the reflector in the clear, the results showed a reduction of 0.6 dB in the HH channel, with 2.28 dB in the W channel. The larger attenuation at W is attributable to the vertical structure of the trees. Additionally, we measured the polarimetric degradation of the triangular trihedral corner reflector immersed in vegetation (trees). Further, after calibration, the co-polarisation phase difference is zero degrees for the triangular corner reflector which was outside the trees, and 62.85ᵒ for the corner reflector inside the trees. The designed and fabricated X- and P-band SAR can work operationally with the calibration parameters obtained in this thesis. The data generated through the calibration experiments can be exploited for further applications.

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Barrowes, Benjamin E. « YSCAT backscatter distributions / ». Diss., CLICK HERE for online access, 1999. http://contentdm.lib.byu.edu/ETD/image/etd2.pdf.

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Huang, Yue. « Tomographic processing of polarimetric and interferometric SAR data for urban and forestry remote sensing ». Rennes 1, 2011. http://www.theses.fr/2011REN1S075.

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This dissertation addresses the tomographic processing of Multi-Baseline Polarimetric and Interferometric SAR (MB-PolInSAR) data for urban and forestry remote sensing applications as well as for the characterization of objects embedded in natural environments. Diverse MB-PolInSAR signal models are rigorously formulated with statistical properties of the observed scattering responses. Weighted subspace fitting (WSF) methods are proposed to adaptively deal with different scattering natures. Based on noise subspace fitting, a polarimetric adaptive estimator and its efficient solution are developed. A method based on autofocus is developed to automatically correct interferometric phase errors due to baseline fluctuations and enhances the tomographic focusing. L-Band dual-baseline PolInSAR data over urban areas are used to illustrate the effectiveness of both polarimetric adaptive estimator and automatic phase correction method. Regarding forestry remote sensing, a novel hybrid tomographic approach is proposed in the frame of biomass estimation study. The application of this approach to P-Band MB-PolInSAR data demonstrates that tropical forest heights and the underlying ground topography can be accurately estimated. WSF methods are incorporated in a novel approach that separates the response of objects embedded in forests from surrounding environments. Its performance is demonstrated using simulated and real L-band data
Cette thèse aborde le traitement tomographique de données SAR polarimétriques et interférométrique (PolInSAR) pour la télédétection d’environnements urbains et forestiers, ainsi que pour la caractérisation d’objets intégrés dans des milieux volumiques. Divers modèles de données MB-PolInSAR sont rigoureusement formalisés en considérant les propriétés statistiques de réponses de diffuseurs. Les méthodes à sous-espaces sont proposées pour adaptativement traiter des diffuseurs de différentes natures. Basé sur l’étude du sous-espace du bruit, un estimateur polarimétrique est développé ainsi qu’une solution analytique qui permet de réduire très fortement la complexité de calcul. Une méthode basée sur l’autofocalisation est développée pour corriger automatiquement les erreurs de phases interférométriques dues à des fluctuations de trajectoires de vol et puis améliorer la focalisation tomographique. Les données acquises en bande L en configuration dual-base entièrement polarimétrique sont utilisées pour illustrer l’efficacité de l’estimateur adaptatif polarimetrique et la méthode de la correction automatique de phase dans le cadre de l’étude d’environnements urbains. Pour la télédetection forestière, une approche tomographique hybride est proposée afin d’estimer la biomasse. En utilisant des données MB-PolInSAR en bande P, la hauteur des forêts tropicales et la topographie du terrain sous-jacent sont précisément estimés par l’approche hybride proposée. Les méthodes en sous-espaces sont insérées dans une nouvelle approche de détection d’objets intégrés dans des milieux volumiques qui permet de séparer la réponse d’un objet de l’environnement qui l’entoure. Sa performance est demontrée en utilisant des données simulées et d’autres acquises en bande L

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Schmitz, Jeffrey Todd 1962. « Estimating surface precipitation over Mexico by calibrating satellite infrared imagery and airborne radar ». Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278163.

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An algorithm for estimating daily surface rain volumes from hourly GOES infrared images has been developed using data obtained during the Southwest Area Monsoon Project(SWAMP). Daily surface rain volumes will be estimated using derived positive linear relationships between digital infrared counts and cloud radar reflectivities. These relations provide estimates of radar reflectivities corresponding to hourly infrared images, which in term, using an assumed reflectivity-rainrate(ZR) relation(Z = 55R1.6), will are to generate hourly precipitation fields from which daily rain volumes are computed. The linear relations employed are determined through a regression analysis on digital IR counts of GOES imagery and airborne internal radar reflectivity samples. This study also explores the existence of an average linear relation between infrared pixel values and radar reflectivities.

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Isleifson, Dustin. « Simulation and measurement techniques for microwave remote sensing of sea ice ». IEEE, 2010. http://hdl.handle.net/1993/4812.

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This dissertation presents new research into the study of simulation and measurement techniques for microwave remote sensing of sea ice. We have embarked on a major study of the microwave propagation and scattering properties of sea ice in an attempt to link the physics of the sea ice medium to experimentally obtained concomitant scatterometer measurements. During our fieldwork, we studied the polarimetric backscattering response of sea ice, focusing on newly-formed sea ice under a large assortment of surface coverage. Polarimetric backscattering results and physical data for 40 stations during the fall freeze-up of 2003, 2006, and 2007 are presented. Analysis of the co-polarization correlation coefficient showed its sensitivity to sea ice thickness and surface coverage and resulted in a statistically significant separation of ice thickness into two regimes: ice less than 6 cm thick and ice greater than 8 cm thick. A case study quantified the backscatter of snow-infiltrated frost fl owers on new sea ice, showing that the presence of the frost flowers enhanced the backscatter by more than 6 dB. In our simulation work, an efficient method for simulating scattering from objects in multi-layered media was incorporated into a scattered-field formulation of the FVTD method. A total-field 1D-FDTD solution to the plane-wave propagation through multi-layered meda was used as a source. The method was validated for a TE-polarized incident-field through comparisons with other numerical techniques involving examples of scattering from canonically-shaped objects. Methods for homogenization of inhomogeneous media were developed and validated using well-known dielectric mixture models. A Monte Carlo Method for simulating scattering from statistically rough surfaces was developed and was validated through favorable comparison with the SPM method for rough surface scattering. Finally, we presented a new Monte Carlo Method for simulating sea ice remote sensing that utilized the framework of the FVTD method for scattering simulations. The modeling process was driven by actual physical measurements of sea ice, wherein dielectric and physics-based modeling techniques were employed. The method was demonstrated through a series of case studies where the scattering from newly-formed sea ice was simulated using a TE-polarized incident- eld. Good agreement between experimental scatterometer measurements and simulated results was obtained for co-polarized returns, whereas cross-polarized results indicated that more depolarizing features must be taken into account.

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Johnson, David Graham. « Complex target reconstruction using near-field synthetic aperture radar ». Thesis, The University of Sydney, 2009. http://hdl.handle.net/2123/18351.

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This thesis describes the development of a prototype (imaging) radar system intended for discriminating between rocks of varying size under the severe environmental conditions typically present on a mine-site. Synthetic aperture radar (SAR) systems allow high-resolution measurements to be made using the motion of the sensing platform to provide at least one of the sensing degrees of freedom. They therefore provide a means of reducing the number and cost of mechanically actuated components which is particularly beneficial in a harsh environment such as a mine. A 3-D near-field imaging radar system has been developed utilising the highest available component bandwidth of 2-18GHz. This has allowed two-target range discrimination performance of better than 20mm to be obtained over a single sweptfrequency measurement within a custom-built anechoic test chamber. Bistatic antennas in an inverse-SAR configuration have been used to demonstrate the concept of a multistatic spherical-SAR system, which with a single transmitter has advantages in both cost and complexity over the equivalent multiple-transmit/receive configuration. The Fourier-domain point-target focussing templates for this bistatic configuration have then been derived using the method of stationary phase based on the earlier work of Fortuny. Further algorithms have then been developed for the calculation of templates corresponding to spheres of a particular radius, for both monostatic and bistatic configurations. Full 3-D reconstruction of complex-target topography has then been achieved through a novel sphere-summation process, with extensive simulated and experimental results obtained and analysed for both a set of spheres and a more realistic scenario consisting of a pile of rocks of varying shape and size.

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Piles, Guillem Maria. « Multiscale soil moisture retrievals from microwave remote sensing observations ». Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/77910.

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La humedad del suelo es la variable que regula los intercambios de agua, energía, y carbono entre la tierra y la atmósfera. Mediciones precisas de humedad son necesarias para una gestión sostenible de los recursos hídricos, para mejorar las predicciones meteorológicas y climáticas, y para la detección y monitorización de sequías e inundaciones. Esta tesis se centra en la medición de la humedad superficial de la Tierra desde el espacio, a escalas global y regional. Estudios teóricos y experimentales han demostrado que la teledetección pasiva de microondas en banda L es optima para la medición de humedad del suelo, debido a que la atmósfera es transparente a estas frecuencias, y a la relación directa de la emisividad del suelo con su contenido de agua. Sin embargo, el uso de la teledetección pasiva en banda L ha sido cuestionado en las últimas décadas, pues para conseguir la resolución temporal y espacial requeridas, un radiómetro convencional necesitaría una gran antena rotatoria, difícil de implementar en un satélite. Actualmente, hay tres principales propuestas para abordar este problema: (i) el uso de un radiómetro de apertura sintética, que es la solución implementada en la misión Soil Moisture and Ocean Salinity (SMOS) de la ESA, en órbita desde noviembre del 2009; (ii) el uso de un radiómetro ligero de grandes dimensiones y un rádar operando en banda L, que es la solución que ha adoptado la misión Soil Moisture Active Passive (SMAP) de la NASA, con lanzamiento previsto en 2014; (iii) el desarrollo de técnicas de desagregación de píxel que permitan mejorar la resolución espacial de las observaciones. La primera parte de la tesis se centra en el estudio del algoritmo de recuperación de humedad del suelo a partir de datos SMOS, que es esencial para obtener estimaciones de humedad con alta precisión. Se analizan diferentes configuraciones con datos simulados, considerando (i) la opción de añadir información a priori de los parámetros que dominan la emisión del suelo en banda L —humedad, rugosidad, temperatura del suelo, albedo y opacidad de la vegetación— con diferentes incertidumbres asociadas, y (ii) el uso de la polarización vertical y horizontal por separado, o del primer parámetro de Stokes. Se propone una configuración de recuperación de humedad óptima para SMOS. La resolución espacial de los radiómetros de SMOS y SMAP (40-50 km) es adecuada para aplicaciones globales, pero limita la aplicación de los datos en estudios regionales, donde se requiere una resolución de 1-10 km. La segunda parte de esta tesis contiene tres novedosas propuestas de mejora de resolución espacial de estos datos: • Se ha desarrollado un algoritmo basado en la deconvolución de los datos SMOS que permite mejorar la resolución espacial de las medidas. Los resultados de su aplicación a datos simulados y a datos obtenidos con un radiómetro aerotransportado muestran que es posible mejorar el producto de resolución espacial y resolución radiométrica de los datos. • Se presenta un algoritmo para mejorar la resolución espacial de las estimaciones de humedad de SMOS utilizando datos MODIS en el visible/infrarrojo. Los resultados de su aplicación a algunas de las primeras imágenes de SMOS indican que la variabilidad espacial de la humedad del suelo se puede capturar a 32, 16 y 8 km. • Un algoritmo basado en detección de cambios para combinar los datos del radiómetro y el rádar de SMAP en un producto de humedad a 10 km ha sido desarrollado y validado utilizando datos simulados y datos experimentales aerotransportados. Este trabajo se ha desarrollado en el marco de las actividades preparatorias de SMOS y SMAP, los dos primeros satélites dedicados a la monitorización de la variación temporal y espacial de la humedad de la Tierra. Los resultados presentados contribuyen a la obtención de estimaciones de humedad del suelo con la precisión y la resolución espacial necesarias para un mejor conocimiento del ciclo del agua y una mejor gestión de los recursos hídricos.
Soil moisture is a key state variable of the Earth's system; it is the main variable that links the Earth's water, energy and carbon cycles. Accurate observations of the Earth's changing soil moisture are needed to achieve sustainable land and water management, and to enhance weather and climate forecasting skill, flood prediction and drought monitoring. This Thesis focuses on measuring the Earth's surface soil moisture from space at global and regional scales. Theoretical and experimental studies have proven that L-band passive remote sensing is optimal for soil moisture sensing due to its all-weather capabilities and the direct relationship between soil emissivity and soil water content under most vegetation covers. However, achieving a temporal and spatial resolution that could satisfy land applications has been a challenge to passive microwave remote sensing in the last decades, since real aperture radiometers would need a large rotating antenna, which is difficult to implement on a spacecraft. Currently, there are three main approaches to solving this problem: (i) the use of an L-band synthetic aperture radiometer, which is the solution implemented in the ESA Soil Moisture and Ocean Salinity (SMOS) mission, launched in November 2009; (ii) the use of a large lightweight radiometer and a radar operating at L-band, which is the solution adopted by the NASA Soil Moisture Active Passive (SMAP) mission, scheduled for launch in 2014; (iii) the development of pixel disaggregation techniques that could enhance the spatial resolution of the radiometric observations. The first part of this work focuses on the analysis of the SMOS soil moisture inversion algorithm, which is crucial to retrieve accurate soil moisture estimations from SMOS measurements. Different retrieval configurations have been examined using simulated SMOS data, considering (i) the option of adding a priori information from parameters dominating the land emission at L-band —soil moisture, roughness, and temperature, vegetation albedo and opacity— with different associated uncertainties and (ii) the use of vertical and horizontal polarizations separately, or the first Stokes parameter. An optimal retrieval configuration for SMOS is suggested. The spatial resolution of SMOS and SMAP radiometers (~ 40-50 km) is adequate for global applications, but is a limiting factor to its application in regional studies, where a resolution of 1-10 km is needed. The second part of this Thesis contains three novel downscaling approaches for SMOS and SMAP: • A deconvolution scheme for the improvement of the spatial resolution of SMOS observations has been developed, and results of its application to simulated SMOS data and airborne field experimental data show that it is feasible to improve the product of the spatial resolution and the radiometric sensitivity of the observations by 49% over land pixels and by 30% over sea pixels. • A downscaling algorithm for improving the spatial resolution of SMOS-derived soil moisture estimates using higher resolution MODIS visible/infrared data is presented. Results of its application to some of the first SMOS images show the spatial variability of SMOS-derived soil moisture observations is effectively captured at the spatial resolutions of 32, 16, and 8 km. • A change detection approach for combining SMAP radar and radiometer observations into a 10 km soil moisture product has been developed and validated using SMAP-like observations and airborne field experimental data. This work has been developed within the preparatory activities of SMOS and SMAP, the two first-ever satellites dedicated to monitoring the temporal and spatial variation on the Earth's soil moisture. The results presented contribute to get the most out of these vital observations, that will further our understanding of the Earth's water cycle, and will lead to a better water resources management.

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Stevens, Nicola Frances. « Lava flow volume and morphology from ERS synthetic aperture radar interferometry ». Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266817.

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Nowak, Michael J. « Mixed Modulation for Remote Sensing with Embedded Navigation ». Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1462295752.

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Chan, Tsz K. « Experimental studies on microwave detection and imaging of targets in clutter using correlation techniques / ». Thesis, Connect to this title online ; UW restricted, 1998. http://hdl.handle.net/1773/6011.

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Akar, Sertac. « Offshore Oil Slick Detection With Remote Sensing Techniques ». Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608889/index.pdf.

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The aim of this thesis is to develop a methodology for detection of naturally occurring offshore oil slicks originating from hydrocarbon seeps using satellite remote sensing techniques. In this scope, Synthetic Aperture Radar (SAR) imagery has been utilized. Case study area was Andrusov High in the Central Black Sea. Hydrocarbon seepage from tectonic or stratigraphic origin at the sea floor causes oily gas plumes to rise up to the sea surface. They form thin oil films on the sea surface called oil slicks. Presence of seeps and surface oil slicks for the offshore basins is a trace of depleted oil traps. Spatial distribution of oil slicks is closely related to sea waves, dominant wind patterns and weathering factors. Even though, there are oil slick detection techniques available with optical remote sensing, laser fluorosensors, and hyperspectral remote sensing, the most efficient results can be obtained from active microwave sensors like synthetic aperture radar (SAR). SAR sensors simply measure the backscattered radiation from the surface and show the roughness of the terrain. Oil slicks dampen the sea waves creating dark patches in the SAR image. In this context an adapted methodology has been proposed, including three levels namely
visual inspection, image filtering and object based fuzzy classification. With visual inspection, targets have been identified and subset scenes have been created. Subset scenes have been categorized into 3 cases based on contrast difference of dark spots to the surroundings. Then object based classification has been utilized with the fuzzy membership functions defined by extracted features of layer values, shape and texture from segmented and filtered SAR subsets. As a result, oil slicks have been discriminated from look-alikes which are the phenomena resembling oil slicks. The overall classification accuracy obtained by averaging three different cases is 83 % for oil slicks and 77 % for look-alikes. The results of this study can considered to be a preliminary work and supplementary information for determining the best operational procedure of offshore hydrocarbon exploration.

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JESUS, WELLINGTON C. de. « Estudo de metodos de inversao em snesoriamento remoto com lasers ». reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9434.

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Made available in DSpace on 2014-10-09T12:26:47Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:00:25Z (GMT). No. of bitstreams: 0
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
FAPESP:06/05182-6

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