Дисертації з теми "Radar in Banda X"
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Ramirez, Yusvelis Maribel Barzaga. "Inferência de hidrometeoros a partir de um radar meteorológico de dupla polarização banda X." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-12092018-143854/.
Повний текст джерелаThis study presents a methodology for inferring hydrometeors from polarimetric mea- surements of a X band double polarization meteorological radar. The methodology consists of a theoretical approach based on numerical simulations with a Mie scattering model (T-Matrix and Mueller) and an experimental approach based on the application of a classification algorithm of hydrometeors (Dolan and Rutledge [2009]). The theoretical simulations were used to study the effects of droplet size distribution, hydrometeor tem- perature, elevation angle and mixture of hydrometeors from radar reflectivity factor (Z), differential reflectivity (Z DR ), specific differential phase (K DP ) and correlation coefficient ( HV ). The values of Z DR are 0.5 dBZ higher for the X band frequency than for the S band frequency. From Z greater than 45 dBZ, K DP starts to get higher than 0. When Z is greater than 25 dBZ, HV starts to decrease. No significant variations are observed for the graupel, however for hail, K DP is greater than 0 when Z is greater than 15 dBZ, but these values were much lower than for water. Temperature effects are only noticed when Z is greater than 60 dBZ. When analyzing the effect of elevation, it is observed that Z DR decreases with increasing elevation, being more sensitive to Z larger; the same effect is observed for K DP and HV . These variations are more sensitive to water and hail than to the graupel. Comparing the exponential and gamma distributions to consider the effects of droplet size distribution in the case of rain, it is noted that the exponential distribution is larger than the gamma when the droplets increase in size and decrease in concentration, due to the fact that in the simulation was used N 0 fixed. When analyzing the effects of co-existence of water and graupel, we have that the water droplets dominate the Z signal when Z is greater than 30 dBZ, K DP will be positive (negative) when Z is greater (lower) than 35 dBZ of water, since Z of the graupel is less than 10 dBZ and HV tends to be close to 1 when more graupel is observed. For the mixture of hail and water, Z of water dominates that of hail when Z is greater than 45 dBZ, K DP is larger (smaller) than zero when Z is larger (smaller) than 25 dBZ since Z of hail is less than 10 dBZ and Z DR of water (hail) dominates hail (water) when Z is greater (lower) than 45 dBZ. In the experimental part, two cases observed during the field experiment of the RAIN Project in Vale do Paraíba on February 8 and March 22, 2012 were used. The classification of hydrometeors according to Dolan and Rutledge [2009] indicated the presence of rain near the surface coming of graupel and hail. Above 5 km were identified the presence of graupel, hail and ice crystals. When examining the regions classified as hail and graupel within the region of 0 and 15 C with the theoretical results, it is possible to explain the concomitant presence of water and hail and water and graupel in these regions.
Ferreira, José Everardo Julião. "Desenvolvimento, análise numérica e estudo experimental de metamateriais na banda X." Instituto Tecnológico de Aeronáutica, 2009. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=938.
Повний текст джерелаMohan, Abishek. "Bistatic Radar Land Clutter Characterization at X-band." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440174330.
Повний текст джерелаBEZERRA, Cristiane Santos. "Clima de ondas e correntes no litoral de boa viagem (recife – pe): aplicação do sistema de radar náutico de banda-x." Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/10557.
Повний текст джерелаMade available in DSpace on 2015-03-05T12:03:40Z (GMT). No. of bitstreams: 2 Dissertação BEZERRA,C. S. 2013.pdf: 7476726 bytes, checksum: 97af6d034dd0d2747df21f2cfd5e7912 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013
CNPq
As ondas e correntes representam a mais constante forma de transporte de energia no mar, fornecendo energia para uma vasta gama de processos litorâneos os quais exercem papel preponderante na morfologia da linha de costa e, por conseguinte na determinação das feições litorâneas. Além disso, representam ameaça às construções costeiras, às atividades de lazer e às operações navais. Diante deste cenário a presente dissertação de mestrado pretende contribuir através da análise temporal e espacial das ondas wind sea e swell, assim como das correntes atuantes no litoral de Boa Viagem (Recife – PE), a partir de dados de parâmetros físicos de ondas (altura máxima – Hmax, altura significativa – Hs, Período de pico – Tp, e direção média – ) e correntes (direção e intensidade), os quais foram obtidos a partir de imagens polares de radar náutico de banda-X, gerados a partir de um sistema denominado Wave and Surface Current Monitoring System - WaMoS II. O radar esteve em funcionamento entre o mês de abril de 2010 a abril de 2011. A partir das análises realizadas foi possível observar a ocorrência conjunta de ondas do tipo wind sea e swell no litoral de Boa Viagem, sendo que esta última foi bastante expressiva nos meses de junho e outubro de 2010, além dos meses entre dezembro de 2010 a março de 2011, sendo provenientes em sua maioria de leste. As ondas wind sea apresentaram uma altura significativa predominante entre 1 e 2 m, sendo provenientes de leste-sudeste. Além disso, foi possível observar uma variação na direção e diminuição na altura das ondas ao longo da plataforma interna de Boa Viagem, causadas pela variação na batimetria e pela presença de recifes de arenito. Para as correntes não se observou diferença na direção das mesmas nas duas áreas de análise, porém no que se refere a intensidade, esta foi maior na área mais afastada da costa (área 3) do que na área sobre o canal (área 1). De uma forma geral, neste trabalho foi possível identificar as características predominantes, em cada mês ao longo de todo período estudado, das ondas wind sea, as quais estão sempre presente no litoral de Boa Viagem, bem como as características de swell identificando seu período de maior atuação neste litoral; foi possível verificar como as características das ondas estão se alterando conforme se aproximam da costa; e também observar o padrão das correntes atuantes no litoral; e a altura máxima das ondas que incidem sobre a região. E diante de comparações com boia e modelo, foi possível comprovar a eficiência da medição de ondas a partir de radar e do sistema WaMoS II para o litoral de Boa Viagem (Recife – PE).
Ichiba, Abdellah. "Données radar bande X et gestion prédictive en hydrologie urbaine." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1007/document.
Повний текст джерелаThe main goal of this thesis was to achieve a reliable management tool of storm water storage basins using high resolution X-band radar. It turned out that it required several research developments. The analysed case study includes a retention basin of 10000 m3 located in Val de Marne county downstream of a 2.15 km2 urban catchment. It has a twofold goal: storm water decontamination and flood protection by volume storage. Operationally the management strategies associated with these two aims are conflicting; hence, a predictive management has been set up: a routine exploitation of the basin in the anti-pollution mode, and a switch to the flood protection mode when needed. It should be based a reliable knowledge of short-term rainfall forecasts. A common way to respond to operational needs of the predictive management is to set up a warning system based on the use of radar data. For example, the CALAMAR system relies on the use of single-polarization raw radar data, coming from Meteo-France radar network, being processed with the conventional Z-R conversion methods followed by a calibration with rain gauge. However, the reliability of such warning systems has been subject to debate, often due to a questionable quality of the resulting radar rainfall estimates, compared to local rain gauges. Therefore a new methodology for more meaningful comparison of radar rainfall field products was developed during this PhD project. Being rooted to the multifractal theory, it allows a comparison of the structure and the morphology of rainfall fields in both space and time through scales. It was initially tested on CALAMAR and Meteo-France rainfall products before being applied for results confirmation on initial data from a X band radar, acquired by Ecole des Ponts ParisTech in the framework of the European project RainGain and providing data at higher resolution (up to 100 m in space and 1 min in time). The obtained results not only highlight the crucial influence of raw data processing on the scaling behaviour, but also permit to pre-define the conditions when the CALAMAR optimization may worsen the quality of rainfall estimates. Such conditions would be very difficult to detect with widely used conventional methods, which rely on a very limited number of radar pixels (only those containing rain gauges). Further extensions of the proposed methodology open new horizons for the rainfall data merging. While the scientific literature, notably around the TOMACS experiment in Japan and CASA one in the United States, highlights the operational benefits of higher resolution rainfall measurements thanks to X-band radars, its impact on the performance of hydrological models still remains a subject of debate. Indeed previous research, mainly based on conceptual models remains inconclusive. To overcome these limitations, we used two models relying on two very distinct modelling approaches: CANOE (semi-distributed and conceptual) and Multi-Hydro (fully distributed and physically based research model developed at ENPC). An operational version of CANOE and a new much finer configuration, which increases the sensitivity of the model to spatio-temporal variability of small-scale rainfall, were used. Several extensions of the Multi-Hydro were developed, including an optimization of its resolution, which greatly improves its whole functionality. It appears from this work that by taking into account the spatial and temporal variability of small-scale rainfall, the performance of hydrologic models can be increased up to 20%.Overall, we believe that this dissertation contributes to the development of new, reliable, operational tools to use in their full extent the high-resolution X-band data
Dufton, David Richard Lloyd. "Quantifying uncertainty in radar rainfall estimates using an X-band dual polarisation weather radar." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/15486/.
Повний текст джерелаMohungoo, Ajmal Ismail. "An airborne X-band synthetic aperture radar receiver design and implementation." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/17438.
Повний текст джерелаThis dissertation focuses on the design and implementation of an X-band receiver for use in the South African Synthetic Aperture Radar (SASAR II) project. The SAR will be used to demonstrate the capability of building a high resolution X-hand imaging radar in South Africa. The design starts by investigating the maximum power return from different targets over a swath width with changing incidence angles. A receiver-power-level table and diagram were constructed, with the power return from at trihedral corner reflector as maximum input power and thermal noise as the minimum input power to the receiver. The output of the receiver, which has to be fed to the input of an analogue-to-digital converter (ADC), is limited by the ADC's maximum operating input power. Amplifiers, attenuators and mixers were chosen to implement a dual-stage downconversion from a radio frequency (RF) of 9300 MHZ to a 2nd IF of 1300 MHZ and then to a 1st IF of 158 MHz. A sensitivity time control (STC) is implemented in the receiver to cater for the limited dynamic range of the ADC. The power return varies with range and hence, time. Thus, an STC will correct for low return power, at far range, by boosting the received signal and attenuating large return power, at close range, ideally providing a fairly constant power return at the receiver output. A manual gain control (MGC) is also needed in the receiver, such that none of the components are driven into saturation. The gain control is switched on when large targets are expected to fall in the swath width, otherwise it is switched to a minimum for targets with tow backscattered power. The tests that were carried out on the receiver components showed that all the components operated very close to their specifications. The cascaded filters work well in tailoring the front-end 3-dB bandwidth to close to the required 3-dB bandwidth. The receiver was designed to have enough gain to boost the maximum power received to within the operating range of the ADC, without saturating any components in the receiver. The noise figure test showed a noise figure of 4.20 dB. This is 1.73 dB higher than the calculated noise figure of 2.47 dB which is a result of an underestimation of the losses in the system.
Moes, Henderikus Jan. "A low noise PLL-based frequency synthesiser for X-band radar." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1337.
Повний текст джерелаKabeche, Fadela. "Développement d'une méthode de détection de la turbulence atmosphérique par radar aéroporté en bande X." Versailles-St Quentin en Yvelines, 2009. http://www.theses.fr/2009VERS0049.
Повний текст джерелаWe focus on this thesis on the definition, development and evaluation of a method that we call DTCOR (Detection of Convective Turbulence by Radar). This method detects in real time the turbulent structures whose sizes are between 300m and 3km, using an airborne X-band Doppler radar. This work is realized in the frame of an industrial project whose goal is the development of a new concept of radar that would be implemented on the airliners. The technique is based on a variational formalism with physical constraints in order to obtain the wind field and its derivatives. This method is evaluated on two sets of data (radial velocities and reflectivities), the first one synthesized from analytical form representing the main features of these turbulent structures (wavelength and amplitude) and the second on real data from a campaign of airborne observations
Domaszczynski, Piotr. "Performance evaluation of a network of polarimetric X-Band radars used for rainfall estimation." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/3286.
Повний текст джерелаPeixoto, Guilherme Gomes. "Assinaturas de sinais de radar de alvos simples e de modelos de alvos complexos: um estudo na banda X em câmara anecóica." Instituto Tecnológico de Aeronáutica, 2006. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=334.
Повний текст джерелаZwiebel, Jimmy. "Etude de l'impact orographique sur la structure microphysique horizontale et verticale des précipitations." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22642/document.
Повний текст джерелаDuring Fall 2012, a complementary observational network has been deployed in the Cévennes region (South of France) for the Special Observation Period (SOP) of the HyMeX project. This network has been specifically designed to study the structure and heterogeneity of precipitations and, in particulat, the impact of orography on this structure. Firstly, the analysis of the Drop Size Distribution (DSD) at the ground et along a vertical profile from ground observations allow us to describe precisely the rainfall structure along a topographical gradient. In order to understand the influence of a relief on this structure, we focus our study on the microphysical process associated with the structure of precipitations. To do so, we define three rainfall regime et study the vertical evolution of the DSD along the topographical gradient. Variations in number and size of the DSD can be associated with different microphysical or dynamical process. Finally, we estimate the capacity of a bulk atmospheric model such as WRF to represent the rainfall structure and associated mechanisms above a mountainous area
Seck, Ibrahim. "Estimation et prévision immédiate des précipitations sur un bassin urbain." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC055.
Повний текст джерелаGood quality rainfall estimations and nowcasts are an essential prerequisite for the development of reliable flash flood warning systems, especially for urban catchments, where the socioeconomic consequences of hazardous precipitation events are high. The risks posed by such extreme events are further heightened because of climate change. In this context, this thesis aims to investigate the potential of using a small weather radar in combination with the local rain gauge and national radar networks to improve the quantitative precipitation estimation (QPE) of rainfall, and to deliver reliable nowcasts. This research was carried out in the flood prone urban catchment of Clermont Ferrand-Riom.To improve QPEs with a high spatiotemporal resolution (5 minutes and a 100 m), the performance of geostatistical interpolation techniques has been investigated using rain gauge data as a primary variable and X-band radar data as a secondary variable for the kriging with an external drift and conditional merging techniques. Radar data was used for the inference of climatological variograms for each precipitation type (stratiform, convective or mixed) for all geostatistical interpolation techniques including ordinary kriging. The long-term evaluation of these techniques shows the benefit of using the geostatistical approach to merge rain gauge and radar data, especially to capture the spatial variability of rainfall. Additionally, two methods were examined to combine the X-band LAWR (Local Area Weather Radar) data with the PATNTHERE product (Rainfall sums with a resolution of 5 minutes and 1 km, provided by the national weather service Météo-France). The first method uses the PANTHERE product (using mainly a C-band radar over the area of interest) to correct X-band data from attenuation effects, and the second one consists of applying a quantile-quantile correction to the X-band data using the PANTHERE product to take advantage of its overall better measurement accuracy, both methods have shown satisfactory results in terms of reducing bias of X-band radar data in comparison with rain gauge data.In the second section of this research, a feature-based forecasting method has been applied to two rainfall events in order to investigate the ability of the X-band LAWR of providing reliable nowcasts. The method includes several steps aimed at identifying, tracking, and then interpolating the features of rainfall cells such as area, speed, and average precipitation intensity. The application of this method on two case studies shows that it provided satisfactory results for forecast lead times up to 30 minutes but efficiency degrades for further time frames.In conclusion, the research carried out in this thesis indicates that local X-band LAWR have great potential for rain estimates and forecast and should be considered in the development of flash flood warning systems, especially for urban catchments
Kacou, Modeste Huberson Ahiba. "Analyse des précipitations en zone sahélienne à partir d'un radar bande X polarimétrique." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2560/.
Повний текст джерелаThis PhD work is on Quantitative Precipitation Estimation (QPE) based on Active Remote-Sensing in Africa. As part of the Megha-Tropiques Satellite Ground Validation (MTGV) field campaigns a X-band dual-polarization Doppler radar was deployed in Sahel, West-Africa : during 2010 in Niamey, Niger and during 2012-2013, in Ouagadougou, Burkina Faso. Altogether 200 convective systems were observed jointly by the radar and by a network of rain gauges. Based on this data set, a comparative study of several rainfall estimators that use X-band polarimetric radar data is presented. In tropical convective systems as encountered in Sahel, microwave attenuation by rain is significant and QPE at X-band is a challenge. Here, four algorithms based on the combined use of reflectivity, differential reflectivity and differential phase shift are evaluated against rain gauges. The comparisons are carried out for a range of space-time scales. Several comparison methods are proposed. Classical statistical scores are used to evaluate the rainfall time series derived from the radar by comparison with the rain gauges. The spatial structure of the fields and the frequency distributions of the rain rates are also compared. These are important parameters to consider when the rain-fields are to be used for hydrological applications or for satellite validation. The results show that the best performances are for the estimator based on the differential phase shift (KDP); another acceptable solution is the estimation based on the specific attenuation (AH). The overall agreement between the radar derived rainfields and the gauges is high. This PhD work confirms that X-band polarimetric radar is a (relatively) cost effective and quality option for monitoring hydro-meteorological risks in the Tropics
Davids, Vernon Pete. "Implementation of a wideband microstrip phased array antenna for X-band radar applications." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1100.
Повний текст джерелаThis thesis presents the design, analysis and implementation of an eight-element phased array antenna for wideband X-band applications. The microstrip phased array antenna is designed using eight quasi-Yagi antennas in a linear configuration and is printed on RT/Duroid 6010LM substrate made by Rogers Corporation. The feeding network entails a uniform beamforming network as well as a non-uniform -25 dB Dolph-Tschebyscheff beamforming network, each with and without 45° delay lines, generating a squinted beam 14° from boresight. Antenna parameters such as gain, radiation patterns and impedance bandwidth (BW) are investigated in the single element as well as the array environment. Mutual coupling between the elements in the array is also predicted. The quasi-Yagi radiator employed as radiating element in the array measured an exceptional impedance bandwidth (BW) of 50% for a S11 < -10 dB from 6 GHz to 14 GHz, with 3 dB to 5 dB of absolute gain in the frequency range from 8 GHz to 11.5 GHz. The uniform broadside array measured an impedance BW of 20% over the frequency band and a gain between 9 dB to 11 dB, whereas the non-uniform broadside array measured a gain of 9 dB to 11 dB and an impedance BW of 14.5%. Radiation patterns are stable across the X-band. Beam scanning is illustrated in the E-plane for the uniform array as well as for the non-uniform array.
Bekkali, Moulhime El. "Capteurs cinémométriques à antennes plaquées en bande X - applications." Lille 1, 1991. http://www.theses.fr/1991LIL10102.
Повний текст джерелаDa, Silva Rocha Paz Igor. "Quantification de l'hétérogénéité des précipitations et mesure radar bande-X pour améliorer les prévisions des inondations." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1025/document.
Повний текст джерелаThe focus of this thesis was to bring a nonlinear geophysical approach to urban hydrology. It aimed the study of rainfall non-linearity scaling and intermittency, achieving a stochastic very short-range forecast (nowcast) method, as well as its application to hydrological processes in (semi-) urban environments. The overall hydrological modelling part concerned the Bièvre Valley, which is a 110 km2 semi-urbanized area in the southwest of Paris region. Therefore, three different studies were performed within this area using two hydrological models: the conceptually-based semi-distributed model InfoWorks CS over the total Bièvre catchment, and the physically-based fully-distributed model developed at École des Ponts ParisTech called Multi-Hydro over two sub-catchments. The main goals were to better understand the impacts of spatio-temporal variability of rainfall data by using two products (the Météo-France C-band radar data with a resolution of 1 km x 1 km x 5 min; and the ENPC DPSRI X-band radar data at a 250 m x 250 m x 3.41 min resolution) as input to the models, and to identify the capacities of each model to deal with better resolution data, such as the X-band one. Then, the obtained results demonstrate that the reliability of the hydrological simulations are intrinsically dependent on rainfall data features. Moreover, the X-band radar data could measure higher peaks of rainfall rates and the fully-distributed model was more sensitive to better resolution rainfall data. Afterwards, different weather rainfall radar data from completely different sites (Brazil, France, Japan) were statistically analysed and compared in order to improve the general comprehension of rainfall scaling behaviour. In addition, the Intersection Theorem was applied to highlight the impacts of spatial variability of a virtual rain gauge network. The latter was generated by considering the location of each Bièvre Valley sub-catchment mass centre. Thus, it was possible to identify that the fractality of the virtual network led to an important information loss of the rainfall fields, biasing their statistics. This indicates that the common process (largely found in literature) of radar data calibration using rain gauges should be properly take into account this fractality. Finally, a new stochastic nowcast approach was proposed, using the continuous in scale cascade Universal Multifractals (UM) model. This method was applied to weather rainfall radar data from the Brazilian Amazon region and Paris. Although it is still under development and needs some improvements, the first results obtained with this forecast model presented here in this thesis are really encouraging and once more corroborate to the need of high spatio-temporal resolution data to cope flash floods
AIRIAU, OLIVIER. "Etude bistatique en bande x d'une liaison radar en mouvement dans un environnement maritime." Nantes, 2000. http://www.theses.fr/2000NANT2012.
Повний текст джерелаAlgafsh, 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.
Повний текст джерелаAltan, Hakki Ilhan. "X-band High Power Ferrite Phase Shifters." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612410/index.pdf.
Повний текст джерелаBrundage, William D. "VLA X-Band Preparation for Voyager 2 at Neptune." International Foundation for Telemetering, 1987. http://hdl.handle.net/10150/615320.
Повний текст джерелаThe Very Large Array (VLA) radio telescope, located in west-central New Mexico, obtains high-resolution radio images of astronomical objects by using Fourier aperture synthesis with 27 antennas. With the addition of X-band to its receiving capabilities by 1989, and when arrayed with the Goldstone Deep Space Communications Complex (GDSCC), the VLA will double the Deep Space Network (DSN) receiving aperture in the U. S. longitude for signals from Voyager 2 at Neptune. This paper describes the VLA and the installation of the X-band system, its operation and performance for Voyager data reception, and its capabilities for other science at X-band.
Wigertz, Fredrik. "Using linear regression and neural network to forecast sewer flow from X-band radar data." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-442629.
Повний текст джерелаDet föreligger höga krav på tillgänglighet och bearbetning av väderdata för att kunna optimera tekniska system i förhållande till väder och klimat. Att kunna förutsäga ändrat inkommande flöde till avloppsreningsverk möjliggör för kontrollsystem att kunna motverka negativa konsekvenser på reningsprocesserna på grund av det ändrade flödet. X-band radardata kan användas för att prognoser av flöden med hjälp av olika modeller.Ett neuralt nätverk, reproducerar komplexa mönster mellan olika dataset genom en struktur med flera lager och en mängd överföringsfunktioner. Målsättningen med det här projektet var att utvärdera hur ett komplext neuralt nätverk presterar jämfört med en enklare regressionsmodell i att förutsäga avloppsflöde med hjälp av högupplöst X-band radardata. I projektet undersöktes också hur tillgång av olika radardata kunde bidra till modellens prestanda. Modellerna utvärderades endast under regnflödesperioder. Data över avloppsflödet som användes i projektet kom från Avedøre avloppsreningsverk i Köpenhamn. Reningsverket drivs av BIOFOS. Radardata kom från HOFOR. Det neurala nätverket som användes har utvecklats av Informetics på plattformen Tensorflow. Slutsatser som kunde dras i projektet var att det neurala nätverket och den linjär regressionsmodellen var lika bra på att förutsäga när en regnflödesperiod startade. Det neurala nätverket kunde förutsäga det momentana flödet bättre än regressionsmodellen, medan det omvända gällde för att uppskatta den totala flödesvolymen under en hel regnflödesperiod. Genom att använda ytterligare regndata, upp till 30 kilometer från radarstationen, jämfört med att endast använda data från avrinningsområdet kunde en 20–30 minuters förbättring av den möjliga prognostiden påvisas. En tänkbar prognostiden för att förutsäga avloppsflödet till Avedøre avloppsreningsverk visades ligga omkring 4 timmar.
Guzel, Kutlay. "X-band High Power Solid State Rf Switch." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614654/index.pdf.
Повний текст джерелаand CST®
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Zarookian, Ruffy. "Feasibility of Spectrum Sharing Between Airborne Weather Radar and Wireless Local Area Networks." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35841.
Повний текст джерелаMaster of Science
Erdol, Tuncay. "X-band Rf Switch Implementation In Substrate Integrated Waveguide." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615057/index.pdf.
Повний текст джерелаs capacitances. Thus switch also functions as a filter when it is in &ldquo
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state. At forward bias of diodes, capacitances of the filter are short circuited to obtain a good isolation. The same circuit structure is used to design a tunable filter and an RF power limiter which also functions as a filter. Several RF functions usually used in RF frontends (power limiting, filtering, switching) are combined in a single circuit which helps miniaturization of the frontend. The circuit can be produced with standard PCB and chip&
wire technology. The circuits developed have comparable performances with microstrip counterparts and they are advantageous to use in microwave systems using SIW as the basic transmission medium and need filtering functionality.
Coetzer, Darren Grant. "Design and implementation of a X-band transmitter and frequency distribution unit for a synthetic aperture radar." Thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6713.
Повний текст джерелаSingh, Abhijeet. "Weather Radar-Based Terrain Referenced Navigation and Integrity Monitoring Using Image Processing and Tracking Techniques." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1195164741.
Повний текст джерелаBrammeier, John R. "On the performance of X-band dual-polarization radar-rainfall estimation algorithms during the SMAPVEX-16 field campaign." Thesis, University of Iowa, 2019. https://ir.uiowa.edu/etd/6915.
Повний текст джерелаMuirhead, Fiona. "Exploiting sparsity for persistent scatterer detection to aid X-band airborne SAR tomography." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28880.
Повний текст джерелаAubert, Maelle. "Caractérisation de l'état de surface des sols nus agricoles par imagerie radar TerraSAR-X." Phd thesis, AgroParisTech, 2012. http://tel.archives-ouvertes.fr/tel-00764268.
Повний текст джерелаDumoulin, Guy. "Effets de la géométrie de surface de champs agricole sur des images radar aéroportées en bande X et C." Mémoire, Université de Sherbrooke, 1987. http://hdl.handle.net/11143/11137.
Повний текст джерелаDiss, Stéphanie. "Apport de l'imagerie radar pour la connaissance spatio-temporelle des champs de pluie : utilisation pour une modélisation prédictive des crues." Paris 6, 2009. http://www.theses.fr/2009PA066038.
Повний текст джерелаGorrab, Azza. "Développement et validation de méthodologies pour le suivi des états de surface des sols agricoles nus par télédétection radar (bande X)." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30039/document.
Повний текст джерелаThe characterization of geometric, water and physical surface soil parameters for semi-arid regions is a key requirement for sustainable agricultural management and natural resources conservation. In this context, the current study aims to estimate the spatio-temporal variability of soil properties (soil moisture, roughness and texture) using multi-temporal X-band radar images acquired at high spatial resolution over bare agricultural site in Tunisia. In the first section of this work, a new roughness parameter was proposed; it was the Zg parameter which combines the three most commonly used soil parameters: root mean surface height "s", correlation length "l", and correlation function shape, into just one parameter. A strong correlation was observed between this new parameter and the radar backscattering simulations. The parameter Zg was validated using large database acquired at several agricultural sites in France. Secondly, the sensitivity of X-band TerraSAR-X and COSMO-SkyMed sensors to soil moisture and different roughness parameters (s, Zs=s2/l and Zg parameters) was analyzed. The radar measurements acquired at different configurations (HH and VV polarizations, incidence angles of 26° and 36°) were found to be highly sensitive to the various soil parameters of interest. After that, the performance of different physical and semi-empirical backscattering models (IEM, Baghdadi-calibrated IEM and Dubois models) is compared with SAR measurements. Considerable improvements in the IEM model performance were observed using the Baghdadi-calibrated version of this model. Thirdly, an empirical change detection approach was developed using TerraSAR-X data and ground auxiliary thetaprobe network measurements for the retrieval of surface soil moisture at a high spatial resolution. The accuracy of the soil moisture retrieval algorithm was determined, and validated successfully over numerous test fields. Maps of soil clay percentages at the studied site were derived from the mean of the seven soil moisture radar outputs (a root mean square error equal to 108 g/kg). To retrieve surface soil roughness, empirical expressions were established between backscattering TerraSAR-X coefficients data and the roughness parameters (s and Zg). By inversing radar signals, resulting surface roughness maps have revealed that is possible to use spatial roughness variability observations at plot scale to identify soil surface changes between multi-temporal images. Finally, a Bare Soil HYdrological balance Model "MHYSAN" was developed to estimate surface evaporation fluxes and soil moisture time series over our study site. The present section of this work highlighted the feasibility of calibrating our proposed MHYSAN model through the use of multi-temporal TerraSAR-X moisture products
Al-Sakka, Hassan. "Contribution à l'étude de la couche limite en ciel clair et sous la précipitation à partir du radar en bande X, CURIE (Canopée Urbaine Radar pour l'étude des Interactions et des Echanges)." Phd thesis, Université de Versailles-Saint Quentin en Yvelines, 2009. http://tel.archives-ouvertes.fr/tel-00681678.
Повний текст джерелаGeoffroy, Mangini. "Etude d'un radar cohérent fonctionnant en mode pulsé : application à la surveillance maritime." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2013. http://tel.archives-ouvertes.fr/tel-00803212.
Повний текст джерелаTridon, Frédéric. "Mesure des précipitations à l'aide d'un radar en bande X non-cohérent à haute résolution et d'un radar en bande K à visée verticale. Application à l'étude de la variabilité des précipitations lors de la campagne COPS." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00777843.
Повний текст джерелаMartinis, Sandro. "Automatic near real-time flood detection in high resolution X-band synthetic aperture radar satellite data using context-based classification on irregular graphs." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-123731.
Повний текст джерелаMiacci, Marcelo Alexandre Souza. "Otimização de medidas de RCS de mísseis nas bandas C e X via técnica de supressão ativa de sinais interferentes." Instituto Tecnológico de Aeronáutica, 2006. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=320.
Повний текст джерелаHolah, Noha. "Potentiel des nouveaux capteurs radar multi-polarisation et polarimétrique pour la caractérisation des états de surface en milieu agricole." Phd thesis, Université d'Orléans, 2005. http://tel.archives-ouvertes.fr/tel-00010194.
Повний текст джерелаBoudevillain, Brice. "Contribution à la définition des caractéristiques d'un radar hydrologique urbain." Phd thesis, Clermont-Ferrand 2, 2003. http://www.theses.fr/2003CLF21415.
Повний текст джерелаBennich, David, William Bredberg, Jimmy Olsson, Stenberg Louis Rulewski, Malin Smith, and Johnny Söderqvist. "En jämförelse mellan fjärranalystekniker och vågbojar för mätning av oceanografiska parametrar i svenska vatten." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-323069.
Повний текст джерелаClauzier, Sébastien. "Conception et réalisation d'antennes intégrables en mâture pour les plateformes navales : applications aux communications V/UHF et à un radar de navigation à balayage électronique en bande X." Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S067.
Повний текст джерелаThe need to communicate and detect potential enemies increases with the extension of maritime conflicts. This need impacts directly the number of antennas on naval platforms. However, this increase of aerials leads to several damaging effects: like coupling or high radar signature. To limit this effect, some companies have developed integrated mast design. This structure limits the coupling effect between aerials by a subdivision of the mast and provides an omnidirectional coverage for all antennas inserted inside the mast. The objective of the thesis is to design two antenna systems for the compact integrated mast (CmastTM) developed by the Constructions Mécanique de Normandie (CMN): a communication antenna in the V/UHF band and an electronically scanning antenna for a maritime navigation radar in X-band. For the communication in the V/UHF band, a broadband conical antenna has been developed (225-400MHz). This antenna provides an optimized radiation pattern to insure the communications between the ship and the aircrafts. An experimental validation has been done with a prototype. In the second study, we have developed an electronically scanning antenna for a navigation radar. This antenna is based on a transmit-array technology including an illuminating feed and an antenna which generates the appropriate radiation pattern. A large part of the study has been done on the feed, which illuminates an array with specific dimensions (1530mmx100mm). Three different near-field focusing feeds have been developed and some of them have been validated experimentally. Then, two architectures of transmit-array antennas have been studied, using two different technologies: printed technology and a mixed technology with waveguide and horn
Orellana, Alvear Johanna Marlene [Verfasser], and Jörg [Akademischer Betreuer] Bendix. "Exploitation of X-band weather radar data in the Andes high mountains and its application in hydrology: a machine learning approach / Johanna Marlene Orellana Alvear ; Betreuer: Jörg Bendix." Marburg : Philipps-Universität Marburg, 2021. http://d-nb.info/1227580185/34.
Повний текст джерелаCaoudal, Sophie. "Expérimentation Marseille 92-93 : mesure des précipitations en hydrologie urbaine à l'aide d'un radar bande X : le relief comme cible utile pour l'étalonnage et la correction d'atténuation, tests de cohérence des données issues des divers capteurs disponibles." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10156.
Повний текст джерелаBesombes, Florent. "Modélisation électrothermique comportementale d'amplicateurs de puissance microondes pour les applications Radars à bande étroite." Limoges, 2012. https://aurore.unilim.fr/theses/nxfile/default/c747e865-0a15-4d10-bcdb-fef35131b91a/blobholder:0/2012LIMO4002.pdf.
Повний текст джерелаThis work deals with the electrothermal behavioral modeling of microwave power amplifier including the load-pull effects, for narrow band radar applications. An extension of nonlinear scattering functions is proposed for modeling large ouput impedance mismatches in the presence of high frequency memory and thermal effects. Its combines a nonlinear scattering functions cell for the electrical response with a reduced order thermal model. The model has been implemented in the system-level simulator Scilab/Scicos. The model identification from time domain load-pull measurements and thermal simulations of the 3D integration of an X band HBT AsGa/GaInP power amplifier is presented. They demonstrate the model ability to accurately reproduce transients behaviors of the electrical signals and temperature within the power amplifier for arbitrary load impedances
Morton, Matthew Allan. "Development of Monolithic SiGe and Packaged RF MEMS High-Linearity Five-bit High-Low Pass Phase Shifters for SoC X-band T/R Modules." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16190.
Повний текст джерелаBaczkowski, Lény. "Modélisation et caractérisation thermique de transistors de puissance hyperfréquence GaN et conséquences sur la fiabilité de modules radars d’émission/réception en bande X." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10135/document.
Повний текст джерелаThis document deals with the thermal modeling, the thermal characterization and the reliability of the GH25 power transistors for X band applications. The performances and the reliability are linked to the self-heating inside the component. An accurate temperature assessment in real operating conditions is therefore required. For these reasons, a dedicated in-house thermal model has been developed using a parameterized tool to extract the maximum temperature of the transistor. The simulation results have been compared with the temperature measurements in the vicinity of the hotspot. These measurements have been performed using IR thermography, thermoreflectance and Raman spectroscopy to validate the thermal models accuracy in DC, pulsed and for the first time, in CW operating conditions. A new formula based on the real thermal behavior of the transistor has been defined to improve the reliability rate calculation in Radar mode using the FIDES methodology
Gurkan, Nurdan. "Studies On Interaction Of Electromagnetic Waves With Barium Hexaferrite Ceramics." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609613/index.pdf.
Повний текст джерела#8211
(4/3)x)TixO19, BaFe12-xCoxO19 , BaFe12-2xTixCoxO19 (x varying from 0 to 1.5 with an increment of 0.5) by the mixed oxide approach. The powders were used to manufacture small ceramic tiles by sintering each composition at 1250 °
C with soaking times ranging from 1 to 16 hours. XRD work revealed formation of the magnetoplumbite crystal structure in all ceramics. The variations in processing parameters led to differences in microstructure and various dielectric and magnetic properties of the ceramic tiles. The interaction of the ceramics with electromagnetic waves was characterized by using a vector network analyzer in the X and Ku bands. The results revealed that, undoped barium hexaferrite ceramics and those doped with low titanium exhibited good microwave absorption properties.
Barsch, Binjamin. "X-band Doppler simulator for sport projectile radars." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/27870.
Повний текст джерелаOruc, Sacid. "Electronically Tunable Microwave Bandstop Filter Design And Implementation." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612419/index.pdf.
Повний текст джерелаnotch&rsquo
filter designs with low-Q resonators and with tuning capability. Tunability will be provided by the use of electronically tunable capacitors, specifically varactor diodes. For this purpose, firstly direct bandstop filter techniques are investigated and their performances are analyzed. Then phase cancellation approach, which enables high quality bandstop filter design with lossy circuit elements, is introduced and analyzed. Lastly, a novel notch filter design technique called as all-pass filter approach is introduced. This approach allows a systematic design method and enables to design very good tunable notch filter characteristics with low-Q resonators. Three filter topologies using this approach are given and their performances are analyzed. Also prototype tunable notch filters operating in X-Band are designed and implemented by using these three topologies.