Dissertations / Theses on the topic 'Delay-Doppler'
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Halimi, Abderrahim. "From conventional to delay/Doppler altimetry." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/10444/1/halimi.pdf.
Full textDooley, Saul. "Subsample time delay and Doppler estimation." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248768.
Full textFofanah, Ibrahim, and Wannaw Assegu. "Delay Spread Characterization of the Aeronautical Channel." International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581653.
Full textRadio transmission channel influences greatly the quality of transmitted voice and data signal in terms of data rate and robustness. This degradation is as a result of many factors, notable amongst them are having multiple replica of the transmitted signal at the receiver (multipath), changes of frequency as a result of the movement of the aircraft (Doppler shift) and noise. This paper characterizes the scattered components of the aeronautical channel in terms of delay spread. Geometric representation is used to derive expressions for the maximum delay spread using the 2-ray model and the three dimensional model of the scattered path. Furthermore, the delay and Doppler frequencies are described as a function of the horizontal distance to the specular reflection point between a ground station and a test article. The simulated results are compared to measured data of related articles and the value of the maximum delay spread is compared with the proposed intersymbol guard band for Orthogonal Frequency Division Multiplexing (OFDM) in the Integrated Network Enhanced Telemetry (iNET) program to see if this proposition can be adapted to the aeronautical channel.
Granado, Diogo Wachtel. "Comparação entre métodos delay-and-sum e f-k migration para reconstrução de imagens Doppler por ultrassom." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2969.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Financiadora de Estudos e Projetos (FINEP)
Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná
Universidade Tecnológica Federal do Paraná (UTFPR)
Os sistemas de ultrassom para imagens médicas sempre estão em evolução. Na área de imagem Doppler, em que se pode observar o movimento do objeto, principalmente o fluxo sanguíneo, encontram-se algumas técnicas para obtenção de melhor qualidade de imagem. Os principais problemas da técnica Doppler são a complexidade e a quantidade de dados a serem processados para a formação das imagens. Este trabalho buscou avaliar dois métodos para processamento de imagens Doppler. Inicialmente, foram realizados estudos com o beamforming tradicional gerado pela plataforma de pesquisas ULTRA-ORS no laboratório de ultrassom. Após, foram realizados estudos com o equipamento Verasonics Vantage™ utilizando geração de onda de ultrassom planas, plane-wave, com um transdutor linear modelo L11-4v de 128 elementos. Os phantoms utilizados foram o CIRS Doppler String Phantom model 043 e o Doppler Flow Phantoms & Pumping Systems da ATS. Foram implementados algoritmos para reconstrução das imagens em modo B no Matlab® utilizando os métodos delay-and-sum e f-k migration, com a geração de imagens Doppler colorido e Power Doppler. Os dados para geração de imagem modo B com plane-wave foram adquiridos com variação de 1 a 75 ângulos, na faixa entre -8,88° e 8,88°, com passo de 0,24°. Os resultados obtidos com o f-k migration apresentaram maior resolução, com erros de 1,0 % e 0,8 % para as resoluções lateral e axial, respectivamente, enquanto o método DAS apresentou erros de 12,0 % para resolução lateral e 10,0 % para resolução axial. Para geração das imagens Doppler com plane-wave os dados foram adquiridos com variação de 1 a 21 ângulos, na faixa entre -15,0° e 15,0°, com passo de 1,5°. A estimação da velocidade através da técnica Doppler apresentou melhores resultados utilizando-se o método DAS, com erro de 8,3 %, enquanto o método f-k migration apresentou erro de 16,6 %. Analisando-se os resultados obtidos, foi possível verificar que a técnica plane-wave permite a geração de imagens com maior taxa de quadros por segundo do que os métodos tradicionais. Também pode se observar que o método f-k migration gera imagens de maior qualidade com menor número de ângulos de aquisição, cerca de 9 ângulos, porém possui pior desempenho para geração de imagens Doppler quando comparado ao DAS.
The medical ultrasound equipment is always evolving. In the field of Doppler imaging, which object movement and mainly blood flow of vessels can be measured, there are some techniques to improve image quality. The main problems of the Doppler technique are the complexity and the amount of data to be processed for the image reconstruction. The aim of this work was to evaluate two methods for Doppler images processing. Initially, studies were carried out with the traditional beamforming technique, generated by the research platform ULTRA-ORS in the ultrasound laboratory. Then, with the Verasonics Vantage™ equipment, it was generated ultrasound plane waves with a linear transducer L11-4v of 128 elements. Two Doppler phantoms were used, the CIRS Doppler String Phantom model 043 and the Doppler Flow Phantoms & Pumping Systems from ATS. Algorithms for B mode image reconstruction were developed in Matlab® using the methods Delay-and-Sum and f-k Migration to generate Color Doppler and Power Doppler images. The B mode images with plane-wave were generated from the data acquired with 1 to 75 angles, ranging from -8.88° to 8.88° and 0.24º step. The f-k migration’s results presented higher resolutions than DAS method, with errors of 1.0 % and 0.8 % for lateral and axial resolutions, respectively, while the DAS method presented errors of 12.0 % for lateral resolution and 10.0 % for axial resolution. The data for color Doppler images with plane-wave generation were acquired with 1 to 21 angles, ranging from -15.0° to 15.0°and 1.5° step. The Doppler velocity estimation using the DAS method showed better results (error of 8.3 %) than the f-k migration (error of 16.6 %). Analyzing the obtained results, it was possible to see that the plane wave imaging technique allows the improvement of the frame-rate, being faster than traditional methods. Additionally, it was verified that f-k migration method produces images with better quality using less steering angles, approximately 9 angles, but it shows worse performance when generating Doppler images.
Williams, Steve. "Advanced Hardware-in-the-Loop Testing Assures RF Communication System Success." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604299.
Full textRF Communication (COMMS) systems where receivers and transmitters are in motion must be proven rigorously over an array of natural RF link perturbations such as Carrier Doppler shift, Signal Doppler shift, delay, path loss and noise. These perturbations play significant roles in COMMS systems involving satellites, aircraft, UAVs, missiles, targets and ground stations. In these applications, COMMS system devices must also be tested against increasingly sophisticated intentional and unintentional interference, which must result in negligible impact on quality of service. Field testing and use of traditional test and measurement equipment will need to be substantially augmented with physics-compliant channel emulation equipment that broadens the scope, depth and coverage of such tests, while decreasing R&D and test costs and driving in quality. This paper describes dynamic link emulation driven by advanced antenna and motion modeling, detailed propagation models and link budget methods for realistic, nominal and worst-case hardware-in-the-loop test and verification.
Naftali, Eran 1971. "First order bias and second order variance of the Maximum Likelihood Estimator with application to multivariate Gaussian data and time delay and Doppler shift estimation." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/88334.
Full textŠulc, Martin. "Rozpoznávání pohybujícího se objektu pomocí MIMO radaru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220219.
Full textLollini, Emanuele. "Analysis of multi-station technique for noise reduction in Deep Space Doppler tracking." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amslaurea.unibo.it/25914/.
Full textSng, Sin Hie. "Radio channel modeling for mobile ad hoc wireless networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FSng.pdf.
Full textThesis advisor(s): Murali Tummala, Roberto Cristi. Includes bibliographical references (p. 71). Also available online.
Mauuary, Didier. "Détection, estimation et identification pour la tomographie acoustique océanique : étude théorique et expérimentale." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0033.
Full textShang, Lei, and lei shang@ieee org. "Modelling of Mobile Fading Channels with Fading Mitigation Techniques." RMIT University. Electrical and Computer Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20061222.113303.
Full text"Pulse-diverse radar waveform design for delay-doppler estimation." 2000. http://library.cuhk.edu.hk/record=b5890289.
Full textThesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references (leaves 123-127).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Application of Time Delay and Doppler Shift Estimation in Active Radar --- p.1
Chapter 1.2 --- Joint Time delay and Doppler Shift Estimation Algorithm based on Correlation --- p.4
Chapter 1.3 --- A Brief Review of Radar Signal Design --- p.6
Chapter 1.3.1 --- Suppression of Range Sidelobes Level --- p.6
Chapter 1.3.2 --- Reduction of Ambiguity of Delay-Doppler Plane --- p.8
Chapter 1.4 --- Goal and Outline of the Thesis --- p.9
Chapter 2 --- CAF and Pulse Diversity for Radar Signals --- p.11
Chapter 2.1 --- Radar Ambiguity Function --- p.12
Chapter 2.1.1 --- Properties of Radar Ambiguity Function --- p.12
Chapter 2.1.2 --- Ideal Ambiguity Function --- p.13
Chapter 2.2 --- Composite Ambiguity Function (CAF) --- p.14
Chapter 2.2.1 --- Properties of Composite Ambiguity Function --- p.15
Chapter 2.3 --- CAF of Joint Phase and Frequency Shift Keying (PSK-FSK) Mod- ulated Signal --- p.17
Chapter 2.4 --- Summary --- p.21
Chapter 3 --- CAF Algorithm and Its Performance Analysis --- p.22
Chapter 3.1 --- CAF Algorithm for Time Delay and Doppler Shift Estimation --- p.23
Chapter 3.2 --- The Cramer-Rao Lower Bound of the CAF Algorithm --- p.24
Chapter 3.3 --- Performance Analysis of the CAF Algorithm --- p.28
Chapter 3.4 --- Global Accuracy --- p.31
Chapter 3.5 --- Numerical Results for Derivation of CAF Algorithm --- p.35
Chapter 3.5.1 --- Simulation Results of CRLB for Various Multi-pulse Signals --- p.35
Chapter 3.5.2 --- Simulation Results of Global Accuracy for Various Multi- pulse Signals --- p.36
Chapter 3.5.3 --- Simulation on Global Accuracy with Different Parameters --- p.37
Chapter 3.6 --- Summary --- p.39
Chapter 4 --- Optimum Pulse-Diverse Waveforms Design --- p.46
Chapter 4.1 --- Criteria for Optimum Waveforms --- p.46
Chapter 4.2 --- Optimum Signals Based on Joint Phase and Frequency Shift Key- ing (PSK-FSK) Modulated Signal --- p.48
Chapter 4.3 --- Genetic Algorithm (GA) --- p.50
Chapter 4.4 --- Numerical Results --- p.54
Chapter 4.4.1 --- "Comparison of Optimized PSK, FSK and PSK-FSK Signals" --- p.55
Chapter 4.4.2 --- Simulation on Large Number of Pulses for Pulse-diverse Waveform Set --- p.59
Chapter 4.4.3 --- Simulation Results of CAF algorithm for Time Delay and Doppler Shift Estimation --- p.63
Chapter 4.4.4 --- Various Distribution of Ambiguity Volume on the Delay- Doppler Plane --- p.70
Chapter 4.5 --- Summary --- p.74
Chapter 5 --- Wideband CAF (WCAF) and Its Analysis --- p.75
Chapter 5.1 --- WCAF Algorithm for Time Delay and Doppler Stretch Estimation --- p.76
Chapter 5.2 --- Theory of Wavelet Packets --- p.77
Chapter 5.3 --- Design of Wideband Optimum Waveforms for WCAF Algorithm --- p.80
Chapter 5.4 --- Performance Evaluation --- p.82
Chapter 5.4.1 --- The Cramer-Rao Lower Bound of WCAF Algorithm --- p.83
Chapter 5.4.2 --- The Global Accuracy of WCAF Algorithm --- p.84
Chapter 5.4.3 --- Numerical Results --- p.86
Chapter 5.5 --- Summary --- p.89
Chapter 6 --- Conclusion and Suggestion for Future Research --- p.90
Chapter 6.1 --- Conclusion --- p.90
Chapter 6.2 --- Suggestion for Future Research --- p.93
Chapter A --- Derivation of Ambiguity Function and CAF --- p.94
Chapter A.1 --- Properties of Radar Ambiguity Function --- p.94
Chapter A.2 --- Properties of Composite Ambiguity Function --- p.96
Chapter B --- Derivation of Fisher Information Matrix of CAF Algorithm --- p.98
Chapter C --- Derivation of Performance Analysis of CAF Algorithm --- p.103
Chapter C.1 --- Derivation of TD and DS Estimate by Proposed Estimator --- p.103
Chapter C.2 --- Derivation the Asymptotic Variance of The Estimates --- p.106
Chapter D --- Derivation of Probability of Decision Error --- p.113
Chapter E --- PSK-FSK Modulating Code of Various Multi-pulse Signals --- p.116
Chapter F --- Derivation of Wavelet-Based Wideband CAF --- p.120
Chapter F.1 --- Volume of Wideband Ambiguity Function --- p.120
Chapter F.2 --- Volume of Wideband Composite Ambiguity Function --- p.121
Bibliography --- p.123
"Joint time delay and doppler stretch estimation using wavelet transform." 1997. http://library.cuhk.edu.hk/record=b6073054.
Full textThesis (Ph.D.)--Chinese University of Hong Kong, 1997.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
(9354989), Feixiong Huang. "Assimilation of GNSS-R Delay-Doppler Maps into Weather Models." Thesis, 2020.
Find full textLee, Jun. "AR modeling of coherence in time delay and Doppler estimation." Thesis, 1988. http://hdl.handle.net/10945/22914.
Full textThe estimation of time delay and Doppler difference of a signal arriving at two physically separated sensors is investigated in this thesis. Usually, modified cross power spectrum coupled with Doppler compensation is used to detect a common, passive signal received at two separated sensors. Another successful approach uses the cross coherence to achieve this goal. This thesis modifies these two techniques to model the Doppler difference via an autoregressive (AR) technique. Analytical results are derived and experimentally verified via a computer simulation. Performance at high and low signal to noise ratios (SNRs) is examined.
http://archive.org/details/armodelingofcohe00leej
Captain, Korea Air Force
"Iterative maximum likelihood time delay and Doppler estimation using stationary signals." Research Laboratory of Electronics, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/4207.
Full textIncludes bibliographical references (p. 155-156).
Supported by the USA AMCCOM and ARDEC. Supported by the U.S. Army Research Office managed by Battelle. DAAL03-86-D-0001 Supported in part by the Advanced Research Projects Agency monitored by ONR. N00014-85-K-0272
Franco, Giovanna. "The Digital Design and Synthesis of Delay Doppler Maps in GNSS Remote Sensing Receivers." Thesis, 2013. http://spectrum.library.concordia.ca/977706/1/Franco_MaSC_S2014.pdf.
Full text(9167882), Chia-Jung Chang. "ENHANCED TARGET DISCRIMINATION AND DELAY-DOPPLERRESOLUTION IN CHIRP RADAR SYSTEMS." Thesis, 2020.
Find full textMüller-Bender, David. "Nonlinear Dynamics and Chaos in Systems with Time-Varying Delay." 2020. https://monarch.qucosa.de/id/qucosa%3A72483.
Full textIn systems with time-delay, the evolution of a system is not uniquely determined by the state at the current time. The history of the state must be known for a time period of finite duration, where the duration is called delay and determines the memory length of the system. In this work, fundamental effects arising from a temporal variation of the time-delay are investigated. In the first part, two classes of periodically time-varying delays are introduced. They are related to a specific dynamics of a one-dimensional iterated map that is defined by the time-varying delay. Referring to the related map dynamics the classes are called conservative or dissipative. Systems with conservative delay can be transformed into systems with constant delay, and thus have the same characteristic properties as constant delay systems. In contrast, there are fundamental differences, for instance, in the tangent space dynamics, between systems with dissipative delay and systems with constant delay. In the second part, these results are applied to systems with a delay that is considered large compared to the internal relaxation time of the system. It is shown that a mechanism induced by dissipative delays leads to new kinds of regular and chaotic dynamics. The dynamics caused by the so-called resonant Doppler effect is fundamentally different from the behavior known from systems with constant delay. For instance, the chaotic attractors in systems with dissipative delay are very low-dimensional compared to typical ones arising in systems with constant delay. An example of this new kind of low-dimensional dynamics is given by the so-called Laminar Chaos. It is characterized by nearly constant laminar phases of periodic duration, where the amplitude varies chaotically. In the third part of this work, it is shown that Laminar Chaos is a robust phenomenon, which survives perturbations such as noise and can be observed experimentally. Therefore experimental data is provided and a nonlinear delayed Langevin equation is analyzed. Using the robust features that characterize Laminar Chaos, methods for time series analysis are developed, which enable us to detect Laminar Chaos without the knowledge of the specific system that has generated the time series. By these methods Laminar Chaos can be detected even for comparably large noise strengths, where the characteristic properties are nearly invisible to the eye.:1. Introduction 2. Dissipative and conservative delays in systems with time-varying delay 3. Laminar Chaos and the resonant Doppler effect 4. Laminar Chaos: a robust phenomenon 5. Summary and concluding remarks A. Appendix
Gonçalves, Luís Carlos da Cunha Vides. "Underwater acoustic communication system : performance evaluation of digital modulation techniques." Master's thesis, 2012. http://hdl.handle.net/1822/25726.
Full textThis dissertation aims to describe all the research work performed to study binary digital modulations in the aquatic environment using acoustic waves. The underwater environment is considered an unreliable communication system due to countless factors affecting the propagation of the acoustic waves such as: high attenuation at long distances, low sound speed, existence of great noise diversity, multipath and Doppler effect. These features make it extremely difficult to establish any kind of underwater communication. Thus, initially it is necessary to perform an exhaustive survey of all the research in this area in order to understand how these characteristics may affect communication in underwater environments and subsequently identify the key concepts to future specify this type of communication systems. After that, a study about digital modulations was done in order to identify those that could be possible to conduct on this type of system. After perform an intensive research about this subject it was developed an underwater communication system using MatLab/Simulink tool with specific Xilinx blockset to verify and allow a theoretical study about the behaviour of digital modulations in underwater environment. In order to verify the system performance and the efficiency of the performed study, a comparison between the results obtained in the theoretical system and the results obtained through practical tests was done. Through these practical tests it was possible to observe the influence of the above factors affecting the propagation of acoustic waves in underwater environments. As was initially expected, the obtained results validate and demonstrate the effectiveness of the studies that were performed. Finally, it was still possible to identify some issues that could be addressed later, in the developing of future work in this area of research.
Esta dissertação tem como objetivo descrever todo o trabalho de pesquisa realizado para estudar as modulações binárias digitais em ambientes subaquáticos usando ondas acústicas. O ambiente subaquático é considerado um sistema de comunicações instável, devido a inúmeros factores que afectam a propagação das ondas acústicas tais como: alta atenuação em longas distâncias, a baixa velocidade de som, a existência de uma grande diversidade de ruído, o fenómeno de multipercurso e o efeito de Doppler. Estas características fazem com que seja extremamente difícil estabelecer qualquer tipo de comunicação subaquática. Assim, inicialmente, foi necessário realizar um levantamento exaustivo de todas as pesquisas nesta área, a fim de entender como essas características podem afetar a comunicação em ambientes subaquáticos e, posteriormente, identificar os conceitos-chave para uma futura especificação deste tipo de sistemas de comunicação. Depois disso, foi realizado um estudo sobre modulações digitais a fim de identificar as candidatas a serem usadas neste tipo de sistemas. Depois de realizar uma intensa pesquisa sobre este assunto, foi desenvolvido um sistema de comunicação subaquático usando a ferramenta MatLab/Simulink com blocos específicos Xilinx para verificar e permitir um estudo teórico sobre o comportamento das modulações digitais em ambiente subaquático. De modo a verificar o desempenho do sistema e da e ciência da pesquisa realizada, foi feita uma comparação entre os resultados obtidos no sistema teórico e os resultados obtidos por meio de testes práticos. Através destes testes práticos, foi possível observar a influência dos fatores anteriormente mencionados que afetam a propagação de ondas acústicas em ambientes subaquáticos. Como era inicialmente esperado, os resultados obtidos validam e demonstram a eficácia dos estudos que foram realizados anteriormente. Finalmente, foi ainda possível identificar algumas questões que podem ser abordadas mais tarde, no desenvolvimento de trabalhos futuros nesta área de pesquisa.