Traditionellt har större fartyg bestyckade med ekolod använts för att utföra batymetriska mätningar av sjö- och havsbottnar. Att utföra mätningar i grunda vatten har varit problematiskt eftersom större fartyg inte kan nå dessa grunda vatten. För att tackla det problemet har mindre obemannade ytfarkoster (USV) utvecklats för att mäta grunda vatten. Dessa USVs hjälper även till vid områden nära stenar som inte har fått uppdaterade djupvärden. Den här undersökningens syfte är att utvärdera hur en Seafloor HydroLite TM enkelstrålsekolod monterad på en USV skiljer sig från insamlingsmetoderna GNSS och med måttband. Den syftar även till att utvärdera vilken interpolationsteknik som är mest lämpad för skapande av djupmodeller med enkelstrålsekolodsdata. Det kommer också studeras hur tvärsektioner påverkar djupmodellerna skapade med enkelstrålsekolod. De experimentella mätningarna med GNSS, måttband och enkelstrålsekolod utfördes i sjön Öjaren som ligger utanför Sandviken. I undersökningen inmättes totalt 91 punkter med GNSS och måttband samt 8 mätstråk och 9 tvärsektioner med enkelstrålsekolod monterad på en USV. Djupmodellerna skapades i Surfer 10 med interpolationsteknikerna kriging, natural neighbor och triangulation with linear interpolation. Alla beräkningar genomfördes i Microsoft Excel och data insamlat med måttband ansågs vara det sanna värdet vid jämförelsen mellan insamlingsmetoderna. Resultaten visade att djupmodellerna skapade med GNSS-data är snarlika till djupmodellerna skapade med måttbandsdata samt att djupmodellerna med GNSS-data visar på den minsta skillnaden mot djupmodellerna skapade med enkelstrålsekolodsdata. Resultatet från jämförelsen mellan interpolationsteknikerna visar på att användandet av de olika interpolationsteknikerna inte har en signifikant påverkan på djupmodellen. Våra slutsatser av undersökningen blev att användande av ett enkelstrålsekolod kan bidra till att skapa en mer detaljerad djupmodell än om enbart GNSS eller måttbandsdata används. Det är också en mer kostnadseffektiv metod eftersom mer data kan samlas in på kortare tid. Det kan dock uppstå felmätningar vid insamlade av data med enkelstrålsekolod som kan vara svåra att upptäcka. Tilläggande av tvärsektioner kan bidra till att skapa en ännu mer detaljerad djupmodell och kan användas som kontrollpunkter vid kontroll av enkelstrålsekolodsdata. / Traditionally, large vessels armed with echo sounders have been used to conduct bathymetric surveys of the seas and oceans. Conducting surveys of shallow water have been troublesome since larger vessels cannot reach and survey shallow waters. To tackle that problem smaller unmanned surface vessels (USV) have been developed to survey shallow waters. It also helps in the areas closest to rocks that do not have updated depth measurements. This study aims to assess how a Seafloor HydroLite TM single-beam echo sounder mounted on a USV differs from other surveying methods. It also aims to evaluate which interpolation methods is most suitable for creating depth models by utilizing single-beam echo sounder data. It will also be studied how cross section lines affect the created depth using the USV. The experimental surveys with GNSS, measuring tape and single-beam echo sounder were used in the lake Öjaren that is located outside of Sandviken. In this study a total of 91 points were collected with GNSS and measuring tape and 8 sounding lines and 9 cross sections lines were collected using echo sounder mounted on the USV. The depth models were created in Surfer 10 using different interpolation methods i.e. kriging, natural neighbor and triangulation with linear interpolation. All calculation were performed in Microsoft Excel and the measurements collected with measuring tape were assumed as a “true” value to evaluate the different surveying techniques. The results showed that the depth model obtained using GNSS data is close to the depth model created using measuring tape data and shows lowest difference in comparison to the USV technique. The results from the comparison between interpolation methods showed that the use of different interpolation methods not have a significant impact on the depth model. The study concludes that the use of a single-beam echo sounder can help to create a more detailed depth model than using GNSS or measuring tape. It is also a cost effective method that helps collect more data in a short time. Though, some errors can appear in the data collected using the single-beam echo sounder that can be hard to detect. The cross section lines can contribute to a more detailed depth model and can be used as control points.

This thesis describes the theoretical development, design, and implementation of a novel measurement system, called a Sampling Swept Time Delay Short Pulse (SSTDSP) wireless channel sounder, capable of real time in field performance characterization of high speed fixed wireless links. The SSTDSP sounder has been designed to provide vital performance metrics for fixed point high data rate applications in the 28 GHz LMDS band at a fraction of the cost and complexity of existing wideband channel sounders. The SSTDSP sounder monitors the behavior of the LMDS channel by sampling the impulse response of the channel in real time. This digitized impulse response is used to assemble a power delay profile and render real-time channel performance metrics such as the mean excess delay, RMS delay spread, maximum excess delay for a given multipath threshold, and coherence bandwidth. The SSTDSP sounder is capable of recording these metrics through three modes of operation - continuous channel monitoring, single instant channel snapshot, or data logging. Swept time delay time dilation processing is combined with precise sample and hold gating to reduce the analog to digital converter sampling rate required to digitize the nanosecond short pulses from 2 Gsps to 1 Msps, while retaining the required effective Nyquist sampling rate of 2 Gsps. This dramatically reduces the memory, digital signal processing, and data logging storage requirements as well as the overall cost of the sounder system. The thesis presents the theory behind channel sounding and discusses whether there is a "bounce path" available to LMDS. Several existing channel sounding methods are compared for this application. A number of specific design and performance criteria from each of these methods are synthesized to produce the Sampling Swept Time Delay Short Pulse Sounder architecture. The design and implementation process used to realize the SSTDSP sounder is presented, including a system overview, module details, and algorithm development details. A calibration and measurement test procedure is outlined and system verification results are presented. Current work in progress on the test platform and future improvements to the modular system are outlined, as well as conclusions and future implications of the system. / Master of Science

No description available.

Made available in DSpace on 2015-03-26T13:28:36Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1715165 bytes, checksum: ba96ef5c3249cefde8551b95cd57d667 (MD5) Previous issue date: 2014-11-25 / With developments in recent years, methods for bathymetric surveys using acoustic sensors (echo sounders) and signals transmitted by satellite navigation receivers, it becomes possible to describe the submerged same level of detail which is embossed with the surface relief describes terrestrial. A graphical representation of the underwater relief occurs from Digital Elevation Models (DEMs) generated by interpolating seeking, from measurements, predict the depth at unsampled locations. The geometrical information taken from bathymetric surveys, the volume of liquid water or mud present, for example in a reservoir, is the most relevant. This study sought to determine the products generated by single beam bathymetric survey, as well as the methods of kriging interpolation and Topo to Raster. The study areas were a box of decanting of the water treatment plant and a dam lake of Furnas, where surveys were conducted, with total station and bathymetric surveys, with a single beam echo sounder which operates at frequencies 33 kHz and 210 kHz . In the settling box, first bathymetric survey was conducted (Lbat 1). Then be emptied and cleaned the box and before filling it again, surveying, (Ltop) was performed with total station. Immediately after filling, without water and mud decanted, another bathymetric survey (Lbat 2) was performed. To survey the dam lake of Furnas, held automated bathymetric survey, ie, using the GNSS technology for positioning. First, the data from the survey, we evaluated the methods of kriging interpolation and Topo to Raster in the DEM generation of the settling box. The conclusion was that the interpolator Top to Raster conditioning showed remarkable deformations at the edges and in the center of the study area and should be discarded. The next stage of this work was to evaluate the accuracy of DEMs generated by applying kriging on data from single beam bathymetric survey, Lbat 2, using the frequencies of 33 kHz and 210 kHz. Possession of DEMs were calculated discrepancies between information from them and points of surveying. The results showed an accuracy of about 5 cm in mean depths of 3.21 m, and that as the surveys were conducted after cleaning the box, with clean water, there was no significant difference in the accuracy of DEMs generated with depths raised to the frequencies 33 kHz and 210 kHz. Then the DEMs were generated by kriging for the first bathymetric survey, Lbat 1, when solid waste resulting from the settling process still existed. Volumes were calculated and compared to evaluate the frequency of 33 kHz echo sounder to determine the volume of mud in the box. After analyzing the results, it was found that using only the first bathymetric survey, with the frequencies 33 kHz and 210 kHz, there was detected 186 m3 of sludge, in a total volume of 799 m3 of water and mud which, with the clean water the volume is determined by accurate bathymetry, showing discrepancy of 0.63% for the frequency of 210 kHz and 0.12% for the frequency of 33 kHz. To survey the lake of Furnas DEMs were generated by kriging interpolation method and the Top to Raster, varying the spacing between the regular survey lines using horizontal scan lines to the regular survey lines. Through statistical analysis of the discrepancies between estimated by interpolating depths and depths observed in the scan lines of the bathymetric survey, the kriging showed better results for spacings of 40 and 80 meters. Considering the isobatimétricas between different DEMs created, it is observed that for larger spacings the interpolator to Top Raster presented smoother features when compared to the DEMs generated by kriging. / Com a evolução, nos últimos anos, dos métodos de levantamentos batimétricos utilizando sensores acústicos (ecobatímetros) e receptores de sinais transmitidos por satélites de navegação, torna-se possível descrever o relevo submerso com mesmo nível de detalhe com que se descreve o relevo da superfície terrestre. A representação gráfica do relevo submerso se dá a partir de Modelos Digitais de Elevação (MDEs) gerados por interpoladores que buscam, a partir das medidas realizadas, predizer a profundidade em locais não amostrados. Das informações geométricas extraídas de levantamentos batimétricos, o volume de água ou lama líquida presente, por exemplo em um reservatório, é a mais relevante. Este trabalho busca avaliar produtos gerados pelo levantamento batimétrico monofeixe, assim como os métodos de interpolação krigagem e Topo to Raster. As áreas de estudo foram uma caixa de decantação de estação de tratamento de água e um lago da represa de furnas, onde foram realizados levantamentos topográficos, com estação total e levantamentos batimétricos, com ecobatímetro monofeixe que opera nas frequências 33 kHz e 210 kHz. Na caixa de decantação, primeiramente foi realizado levantamento batimétrico (Lbat 1). Em seguida, esvaziou-se e limpou-se a caixa e, antes de enchê-la novamente, foi realizado um levantamento topográfico, (Ltop), com estação total. Logo após o enchimento, com água e sem lama decantada, foi realizado outro levantamento batimétrico (Lbat 2). Para o levantamento no lago da represa de furnas, realizou-se levantamento batimétrico automatizado, ou seja, empregando a tecnologia GNSS para o posicionamento. Primeiramente, com os dados do levantamento topográfico, se avaliou os métodos de interpolação krigagem e Topo to Raster na geração do MDE da caixa de decantação. A conclusão foi que o interpolador Topo to Raster condicionado apresentou notáveis deformações nas bordas e no centro da área de estudo, devendo ser descartado. A próxima etapa do trabalho foi avaliar a acurácia dos MDEs gerados aplicando krigagem nos dados do levantamento batimétrico monofeixe, Lbat 2, utilizando as frequências de 33 kHz e 210 kHz. De posse dos MDEs foram calculadas as discrepâncias entre informações extraídas deles e os pontos do levantamento topográfico. Os resultados apresentaram uma acurácia em torno de 5 cm, em profundidades médias de 3,21 m, e que, como os levantamentos foram realizados após a limpeza da caixa, com água limpa, não se verificou diferença significativa na acurácia dos MDEs gerados com as profundidades levantadas com as frequências 33 kHz e 210 kHz. Em seguida foram gerados os MDEs pela krigagem para o primeiro levantamento batimétrico, Lbat 1, quando ainda existiam resíduos sólidos resultantes do processo de decantação. Os volumes foram calculados e comparados a fim de avaliar a frequência de 33 kHz do ecobatímetro para determinar o volume de lama na caixa. Após analisar os resultados verificou-se que usando somente o primeiro levantamento batimétrico, com as frequências 33 kHz e 210 kHz, não se detectou 186 m3 de lama, num volume total de 799 m3 de água e lama, e que, com a água limpa, o volume determinado pela batimetria é acurado, apresentando discrepância de 0,63% para a frequência de 210 khz e 0,12% para a frequência de 33 khz. Para o levantamento do lago de furnas foram gerados MDEs pelo método de krigagem e pelo Topo to Raster, variando o espaçamento entre as linhas regulares de sondagem, utilizando linhas de verificação transversais às linhas regulares de sondagem. Através da análise estatística das discrepâncias entre as profundidades estimadas pelos interpoladores e as profundidades observadas nas linhas de verificação do levantamento batimétrico, a krigagem apresentou melhores resultados para espaçamentos de 20 a 80 metros. A diferença entre os volumes determinados para os espaçamentos de 20 a 40 metros foi menor que 2%,. Considerando as isobatimétricas entre os diversos MDEs criados, observa-se que para espaçamentos maiores o interpolador Topo to Raster apresentou feições mais suavizadas quando comparado com os MDEs gerados pela krigagem.

Orientador: Nilton Nobuhiro Imai / Banca: Maria de Lourdes Bueno Trindade Galo / Banca: Júlia Celia Mercedes Strauch / Resumo: Este trabalho relata um estudo de caso, no qual se procedeu a um levantamento ecobatimétrico para se obter dados de profundidade do corpo de água e da altura da vegetação aquática submersa, realizado num trecho do Rio Uberaba, que faz parte do Reservatório de Porto Colômbia, abrangendo uma área de aproximadamente 360 mil m². Os dados foram processados e avaliados com o objetivo principal de desenvolver uma abordagem de inferência espacial no mapeamento de macrófitas submersas presentes na região pesquisada. Para isso, verificou-se a viabilidade do uso de interpoladores convencionais para mapear as variáveis coletadas pelo ecobatímetro, avaliou-se o potencial de imagem multiespectral de alta resolução espacial (QuickBird) na detecção da vegetação estudada, realizou-se uma análise espacial para avaliar tendência para esse tipo de ocorrência e, finalmente, estudou-se a possibilidade de se utilizar técnica de geoestatística na inferência da altura de macrófitas submersas da área de estudo. As interpolações convencionais não se mostraram satisfatoriamente adequadas para mapear a variável altura da vegetação submersa, porém, a utilização da interpolação linear por triangulação foi suficiente para representar adequadamente o relevo submerso. A imagem multiespectral se mostrou capaz de detectar aproximadamente 21% de macrófitas submersas. Com relação à análise espacial, os resultados indicaram que a dependência espacial é uma tendência que deve ser levada em consideração, daí ter sido utilizada a geoestatística na abordagem de inferência espacial da vegetação. A análise dos semivariogramas forneceu conhecimento relacionado aos métodos de levantamentos ecobatimétricos. A inferência espacial por krigagem apresentou resultado satisfatório, comparado às interpolações convencionais mencionadas anteriormente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work was accomplished a case study in which an echo sounder survey was conducted to obtain data of water body depth and submerged aquatic vegetation height. The study was realized specifically on a region of Uberaba River with approximately 360.000 m². This river is part of the Porto Colombia reservoir. The data was processed and evaluated with main objective to develop an approach of spatial inference for map submersed macrophyte in the region studied. For this, it was verified the availability of using conventional interpolation to map the variables collected by the echo sounder, it was evaluated the potential of multispectral image with high spatial resolution (QuickBird) to detect the vegetation, it was done a spatial analysis and finally it was verified the possibility of using geostatistic technique to infer the submerged macrophytes height in the study area. The use of linear interpolation by triangulation was enough to represent rightly the underwater topography; however, the conventional interpolations were not satisfactorily to map the submerged vegetation height. The multispectral image was able to detect approximately 21% of submerged macrophytes. About spatial analysis, the results indicated that the spatial dependence must be considered, therefore, it was used the geostatistic in the spatial inference of submerged vegetation. Semivariograms analysis provided important knowledge about methods of echo sounder survey. The spatial inference by kriging showed satisfactory results if compared with conventional interpolations mentioned above. Finally, the approach used to mapping submerged macrophytes height can be applied in other regions and this can help the reservoirs management, allowing improve the knowledge about the local ecosystem and therewith developing an action strategy to contain the spread of submerged aquatic vegetation / Mestre

Made available in DSpace on 2014-06-11T19:22:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-02-25Bitstream added on 2014-06-13T20:48:52Z : No. of bitstreams: 1 rotta_lhs_me_prud.pdf: 9845813 bytes, checksum: 8afe01cd2ab27aa9636ee65187b34e5d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho relata um estudo de caso, no qual se procedeu a um levantamento ecobatimétrico para se obter dados de profundidade do corpo de água e da altura da vegetação aquática submersa, realizado num trecho do Rio Uberaba, que faz parte do Reservatório de Porto Colômbia, abrangendo uma área de aproximadamente 360 mil m². Os dados foram processados e avaliados com o objetivo principal de desenvolver uma abordagem de inferência espacial no mapeamento de macrófitas submersas presentes na região pesquisada. Para isso, verificou-se a viabilidade do uso de interpoladores convencionais para mapear as variáveis coletadas pelo ecobatímetro, avaliou-se o potencial de imagem multiespectral de alta resolução espacial (QuickBird) na detecção da vegetação estudada, realizou-se uma análise espacial para avaliar tendência para esse tipo de ocorrência e, finalmente, estudou-se a possibilidade de se utilizar técnica de geoestatística na inferência da altura de macrófitas submersas da área de estudo. As interpolações convencionais não se mostraram satisfatoriamente adequadas para mapear a variável altura da vegetação submersa, porém, a utilização da interpolação linear por triangulação foi suficiente para representar adequadamente o relevo submerso. A imagem multiespectral se mostrou capaz de detectar aproximadamente 21% de macrófitas submersas. Com relação à análise espacial, os resultados indicaram que a dependência espacial é uma tendência que deve ser levada em consideração, daí ter sido utilizada a geoestatística na abordagem de inferência espacial da vegetação. A análise dos semivariogramas forneceu conhecimento relacionado aos métodos de levantamentos ecobatimétricos. A inferência espacial por krigagem apresentou resultado satisfatório, comparado às interpolações convencionais mencionadas anteriormente... / In this work was accomplished a case study in which an echo sounder survey was conducted to obtain data of water body depth and submerged aquatic vegetation height. The study was realized specifically on a region of Uberaba River with approximately 360.000 m². This river is part of the Porto Colombia reservoir. The data was processed and evaluated with main objective to develop an approach of spatial inference for map submersed macrophyte in the region studied. For this, it was verified the availability of using conventional interpolation to map the variables collected by the echo sounder, it was evaluated the potential of multispectral image with high spatial resolution (QuickBird) to detect the vegetation, it was done a spatial analysis and finally it was verified the possibility of using geostatistic technique to infer the submerged macrophytes height in the study area. The use of linear interpolation by triangulation was enough to represent rightly the underwater topography; however, the conventional interpolations were not satisfactorily to map the submerged vegetation height. The multispectral image was able to detect approximately 21% of submerged macrophytes. About spatial analysis, the results indicated that the spatial dependence must be considered, therefore, it was used the geostatistic in the spatial inference of submerged vegetation. Semivariograms analysis provided important knowledge about methods of echo sounder survey. The spatial inference by kriging showed satisfactory results if compared with conventional interpolations mentioned above. Finally, the approach used to mapping submerged macrophytes height can be applied in other regions and this can help the reservoirs management, allowing improve the knowledge about the local ecosystem and therewith developing an action strategy to contain the spread of submerged aquatic vegetation

Radar Sounders (RSs) are active sensors that transmit in the nadir electromagnetic (EM) waves with a low frequency in the range of High-Frequency and Very-High-Frequency and relatively wide bandwidth. Such a signal penetrates the surface and propagates in the subsurface, interacting with dielectric interfaces. This interaction yields to backscattered echoes detectable by the antenna that are coherently summed and stored in radargrams. RSs are used for planetary exploration and Earth observation for their value in investigating subsurface geological structures and processes, which reveal the past geomorphological history and possible future evolution. RS instruments have several parameter configurations that have to be designed to achieve the mission science goals. On Mars, radargram visual analyses revealed the icy layered deposits and liquid water evidence in the poles. On the Earth, RSs showed relevant structures and processes in the cryosphere and the arid areas that help to monitor the subsurface geological evolution, which is critical for climate change. Despite the valuable results, visual analysis is subjective and not feasible for processing a large amount of data. Therefore, a need emerges for automatic methods extracting fast and reliable information from radargrams. The thesis addresses two main open issues of the radar-sounding literature: i) assessing target detectability in simulated orbiting radargrams to guide the design of RS instruments, and ii) designing automatic methods for information extraction from RS data. The RS design is based on assessing the performance of a given instrument parameter configuration in achieving the mission science goals and detecting critical targets. The assessment guides the parameter selection by determining the appropriate trade-off between the achievable performance and technical limitations. We propose assessing the detectability of subsurface targets (e.g., englacial layering and basal interface) from satellite radar sounders with novel performance metrics. This performance assessment strategy can be applied to guide the design of the SNR budget at the surface, which can further support the selection of the main EORS instrument parameters. The second contribution is designing automatic methods for analyzing radargrams based on fuzzy logic and deep learning. The first method aims at identifying buried cavities, such as lava tubes, exploiting their geometric and EM models. A fuzzy system is built on the model that detects candidate reflections from the surface and the lava tube boundary. The second and third proposed methods are based on deep learning, as they showed groundbreaking results in several applications. We contributed with an automatic technique for analyzing radargram acquired in icy areas to investigate the basal layer. To this end, radargrams are segmented with a deep learning network into literature classes, including englacial layers, bedrock, and echo-free zone (EFZ) and thermal noise, as well as new classes of basal ice and signal perturbation. The third method proposes an unsupervised segmentation of radargrams with deep learning for detecting subsurface features. Qualitative and quantitative experimental results obtained on planetary and terrestrial radargrams confirm the effectiveness of the proposed methods, which investigate new subsurface targets and allow an improvement in terms of accuracy when compared to other state-of-the-art methods.