Dissertations / Theses on the topic 'Doppler continuous wave antennae'

A suite of new collision avoidance systems (CAS) is presented for use in heavy vehicles whose structure and size necessarily impede driver visibility is introduced. The main goal of the project is to determine the appropriate use of each of the commercially available technologies and, where possible, produce a low cost variant suitable for use in proximity detection on large mining industry haul trucks. CAS variants produced were subjected to a field demonstration and, linked to the output from the earlier CAS 1 project, (a production high-definition in-cabin video monitor and r/f tagging system). The CAS 2 system used low cost Doppler continuous wave radar antennae coupled to the CAS 1 monitor to indicate the presence of an object moving at any speed above 3 Km/h relative to the antennae. The novelty of the CAS 3 system lies in the design of 3 interconnected, modules. The modules are 8 radar antennae (as used in CAS 2) modules located on the truck, software to interface with the end user (i.e. the drivers of the trucks) and a display unit. Modularisation enables the components to be independently tested, evaluated and replaced when in use. The radar antennae modules and the system as a whole are described together with the empirical tests conducted and results obtained. The tests, drawing on Monte-Carlo simulation techniques, demonstrate both the 'correctness' of the implementations and the effectiveness of the system. The results of the testing of the final prototype unit were highly successful both as a computer simulation level and in practical tests on light vehicles. A number of points, (as a consequence of the field test), are reviewed and their application to future projects discussed.

A suite of new collision avoidance systems (CAS) is presented for use in heavy vehicles whose structure and size necessarily impede driver visibility is introduced. The main goal of the project is to determine the appropriate use of each of the commercially available technologies and, where possible, produce a low cost variant suitable for use in proximity detection on large mining industry haul trucks. CAS variants produced were subjected to a field demonstration and, linked to the output from the earlier CAS 1 project, (a production high-definition in-cabin video monitor and r/f tagging system). The CAS 2 system used low cost Doppler continuous wave radar antennae coupled to the CAS 1 monitor to indicate the presence of an object moving at any speed above 3 Km/h relative to the antennae. The novelty of the CAS 3 system lies in the design of 3 interconnected, modules. The modules are 8 radar antennae (as used in CAS 2) modules located on the truck, software to interface with the end user (i.e. the drivers of the trucks) and a display unit. Modularisation enables the components to be independently tested, evaluated and replaced when in use. The radar antennae modules and the system as a whole are described together with the empirical tests conducted and results obtained. The tests, drawing on Monte-Carlo simulation techniques, demonstrate both the 'correctness' of the implementations and the effectiveness of the system. The results of the testing of the final prototype unit were highly successful both as a computer simulation level and in practical tests on light vehicles. A number of points, (as a consequence of the field test), are reviewed and their application to future projects discussed.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith Business School
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Thesis (M.S. in Combat Systems Sciences and Technology)--Naval Postgraduate School, December 2007.
Thesis Advisor(s): Borden, Brett. "December 2007." Description based on title screen as viewed on January 22, 2008. Includes bibliographical references (p. 77-78). Also available in print.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2017.
This thesis reports on the research and development of techniques applied to mitigate interference from switch-mode power supplies in sampling receivers and also more specifically for FMCW radar receiver applications. During the system testing phase of an FMCW Radar at Reutech Radar Systems (RRS), it was found that a large false target was emerging on the Range-Doppler Map (RDM). It was concluded that the problem was originating from interference caused by the switch-mode power supplies (SMPS), which supply DC power to the radar receiver subsystem. This then created the need for a new DC power supply, which is able to minimize the interference, as well as, mitigate the effects of the interference caused by the switching of the power supply. The mitigation techniques and power supply development was divided four main sections, namely, research, simulation, design and evaluation. The research involved obtaining background information on sampling receivers, sampling theory, Range-Doppler Processing, switch-mode power supplies, their effects and mitigation thereof. In the simulation phase, the research was utilised to simulate the various interference mitigation techniques. A power supply PCB was then designed in the design phase to practically illustrate the techniques being utilised. Lastly, during evaluation, this PCB was evaluated against the criteria set out in the research phase. The results demonstrated that the technique of synchronising the PWM clock to the Sampling frequency and SRF yielded a significant reduction in the SMPS noise on the Range-Doppler Map.

This thesis presents the investigations conducted in the use of ultrasonic technology to measure two-phase flow in both horizontal and vertical pipe flows which is important for the petroleum industry. However, there are still key challenges to measure parameters of the multiphase flow accurately. Four methods of ultrasonic technologies were explored. The Hilbert-Huang transform (HHT) was first applied to the ultrasound signals of air-water flow on horizontal flow for measurement of the parameters of the two- phase slug flow. The use of the HHT technique is sensitive enough to detect the hydrodynamics of the slug flow. The results of the experiments are compared with correlations in the literature and are in good agreement. Next, experimental data of air-water two-phase flow under slug, elongated bubble, stratified-wavy and stratified flow regimes were used to develop an objective flow regime classification of two-phase flow using the ultrasonic Doppler sensor and artificial neural network (ANN). The classifications using the power spectral density (PSD) and discrete wavelet transform (DWT) features have accuracies of 87% and 95.6% respectively. This is considerably more promising as it uses non-invasive and non-radioactive sensors. Moreover, ultrasonic pulse wave transducers with centre frequencies of 1MHz and 7.5MHz were used to measure two-phase flow both in horizontal and vertical flow pipes. The liquid level measurement was compared with the conductivity probes technique and agreed qualitatively. However, in the vertical with a gas volume fraction (GVF) higher than 20%, the ultrasound signals were attenuated. Furthermore, gas-liquid and oil-water two-phase flow rates in a vertical upward flow were measured using a combination of an ultrasound Doppler sensor and gamma densitometer. The results showed that the flow gas and liquid flow rates measured are within ±10% for low void fraction tests, water-cut measurements are within ±10%, densities within ±5%, and void fractions within ±10%. These findings are good results for a relatively fast flowing multiphase flow.

Continuous-wave (CW) Doppler recordings of ascending aortic maximal blood flow acceleration (PkA), maximal velocity (PkV) and systolic velocity integral (SVI) were taken at each stage of a graded exercise treadmill test on two separate days with 30 physically active adult males. Signals were measured (Quinton Exerdop) for all cardiac cycles in the 3rd minute of each stage using a hand-held probe positioned at the suprasternal notch. A dedicated microcomputer, programmed to select "valid" beats on the basis of value consistency in the sample set, determined the acceptability of signals. No significant differences were found between the three trial means within each stage on either day for PkA, PkV or SVI. Significant (p <.01) intraclass reliability estimates ranged from r = 0.89 to 0.97 (Pk.A), r = 0.90 to 0.98 (PkV) and r = 0.85 to 0.95 (SVI) . Coefficients of variation were calculated at each stage to estimate the relative consistency of each measure. A gradual reduction of the coefficient of variation was observed for each blood flow measure between stages one and four. The test-retest (between days) reliability coefficients for PkA, PkV and SVI for stages one to four ranged between r = 0.51 to 0.78 (P <.004), but correlations for the pre-exercise baseline and stages five and six were lower. These results indicate that (1) PkA, PkV and SVI demonstrate greater measurement stability within each stage of a graded exercise test than is the case between separate days of measurement at the same stage; and (2) there is modest day-to-day response stability for clinical testing with the Doppler parameter of PkV. Reliability/stability was best in exercise stages which encompass the speed and grade range of 45.0 m•min⁻¹/10%. - 111.7 m•min⁻¹/14%, i.e., those in which all subjects can walk.
Master of Science

Expectations for turbine-mounted lidar are increasing. The installation of lidars in wind turbine nacelles for measuring incoming winds, preventing wind gusts and increasing energy productions is after recently studies, technically and economically feasible. Among available lidar types, the most studied were continuous wave lidars because they were the most reliable apparatus when this initiative began. However, after studying technical considerations and checking commercial lidars, it was found that pulsed lidarslead this technology due to their promising results. The purpose of this report is to fill the gap between the interest in this technology and the absence of any academic papers that analyzes continuous-wave and pulsed lidars forthe mounted lidar concept. Hence, this report discusses the importance of turbine mounted lidars for wind power industry, different possible configurations and explains why specifically pulsed lidars are becoming more important for the mounted lidarmarket.

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

De nos jours, les mesures sans contact du signal cardiaque du patient en utilisant le radar Doppler a suscité un intérêt considérable chez les chercheurs, surtout que les électrocardiographes traditionnels avec des électrodes fixes ne sont pas pratiques dans certains cas comme les nourrissons ou les victimes de brûlure. En raison de la sensibilité des micro­ondes à de petits mouvements, le radar a été utilisé comme système de surveillance de l'activité cardio-pulmonaire humaine. Selon l'effet Doppler, un signal de fréquence constante est transmis vers la cible ayant un déplacement variable puis réfléchi. Le signal réfléchit possède une variation de phase par rapport au temps. Dans notre cas, la cible est la poitrine du patient; Le signal réfléchi de la poitrine de la personne contient le signal cardiorespiratoire. Le système est basé sur un analyseur de réseau vectoriel et deux antennes cornet. Le S21 est calculé en utilisant un analyseur de réseau. La variation de phase de S21 contient des informations de l'activité cardio-pulmonaire. Des techniques de traitement sont utilisées pour extraire le signal cardiaque de la variation de la phase de S21 . Cette thèse présente une étude comparative dans la détection des signaux de battements cardiaques au niveau de la puissance rayonnée et de la fréquence opérationnelle. Les puissances rayonnées sont comprises entre 3 et -17 dBm et les fréquences opérationnelles utilisées sont 2.4, 5.8, 1 0 et 20 GHz. Cela permet de spécifier la fréquence opérationnelle optimale, qui donne un compromis entre la puissance minimale émise ainsi que la complexité du système de mesure. De plus, une étude comparative entre plusieurs méthodes de traitement de signal est proposée pour extraire la meilleure méthode qui permet de mesurer le signal cardiaque et par suite extraire ses paramètres. Des techniques de traitement basées sur des transformées en ondelettes ou le filtrage classique sont présentées et utilisées afin de faire une comparaison entre elles. Le paramètre extrait dans cette thèse est le taux des battements cardiaques. Les mesures ont été effectuées simultanément avec un électrocardiographe afin de valider les mesures du signal cardiaque. Puisque la personne peut se déplacer d'une pièce à une autre à l'intérieur de son domicile, des mesures des quatre côtés de la personne et derrière un mur sont réalisées. Ajoutons une approche de modélisation fondée sur la mesure cardio-respiratoire pour une personne qui exerce une marche en avant. De plus, une comparaison entre un système à micro-ondes à simple et deux antennes pour une personne qui prend son souffle est effectuée afin de tester la précision du système à antenne unique par rapport au a la deuxième. Par suite, des mesures sont effectuées pour une personne qui respire en utilisant un système à une seule antenne
Nowadays, contact-less monitoring patient's heartbeat using Doppler radar has attracted considerable interest of researchers, especially when the traditional electrocardiogram (ECG) measurements with fixed electrodes is not practical in some cases like infants at risk or sudden infant syndrome or burn victims. Due to the microwave sensitivity toward tiny movements, radar has been employed as a noninvasive monitoring system of human cardiopulmonary activity. According to Doppler effect, a constant frequency signal reflected off an object having a varying displacement will result in a reflected signal, but with a time varying phase. In our case, the object is the patient's chest; the reflected signal of the person's chest contains information about the heartbeat and respiration. The system is based on a vector network analyzer and 2 horn antennas. The S21 is computed using a vector network analyzer. The phase variation of S21 contains information about cardiopulmonary activity. Processing techniques are used to extract the heartbeat signal from the S21 phase. This thesis presents a comparative study in heartbeat detection, considering different radiated powers and frequencies. The radiated powers used are between 3 and -17 dBm and the operational frequencies used are 2.4, 5.8, 10 and 20 GHz. This helps to make a compromise between the minimum power emitted and the complexity of the measurement system. In addition, a comparative study of several signal processing methods is proposed to extract the best technique for heartbeat measurement and thus to extract its parameters. Processing techniques are based on wavelet transforms and conventional filtering in order to make a comparison between them. The parameter extracted in this thesis is the heartbeat rate HR. Measurements were performed simultaneously with a PC-based electrocardiograph to validate the heartbeat rate measurement. Since the person can move from a room to another inside his home, measurements from the four sides of the person and behind a wall are performed. In addition, a modeling approach based on cardio-respiratory measurement for a person who is walking forward is presented. Furthermore, a comparison between single and two-antenna microwave systems for a non-breathing person is carried out to test the accuracy of the single-antenna system relative to the two ­antenna microwave system. After that, measurements are performed using one antenna microwave system for a person who breathes normally

This masters thesis is focused around the designing and implementation of an anpplication that can extract information on speed of vehicles from radar data. The radar measurements were done by using a continous wave radar. The emphasis is placed on the computation of the angle in which the car approaches the radar and on the speed correction based on this angle. The final design was implemented in Matlab. The evaluation of the implemented solution was done on reference data.

碩士
國立臺灣大學
電信工程學研究所
102
Two antenna layouts are realized in two different kinds of fabrication process which are LTCC (low temperature co-fired ceramics) and PCB (printed circuit board) in a limited area for monopulse radar system that includes one transceiving and two receiving antennas. The radar system uses Doppler effect to determine the speed of the target and the monopulse ratio which is determined by radiation modes of sum and difference pattern to detect the angle of the target. Due to limited area, two receiving antennas are forced to place in the distance smaller than a wavelength, the isolation between two receiving antennas becomes a big issue that we can’t be ignored. I obstruct the radiated pattern away from the broadside direction. So we use the antenna theory to reconsider the signal we may receive in order to have a reliable measurement. The operating mechanism and details of the antenna design are discussed. Experimental and simulated results are both presented and discussed. The 3rd and 4th Chapter will discuss the characteristic of the transmission lines fabricated on flexible substrate, because of the difficulty and price issue, multilayer substrate is not comparable with single layer substrate. Take the advantage of the flexibility of the transmission line, we can connect substrate with it to accomplish a new 3D package. In this part, we will first introduce the fabrication process, how to produce these materials and their parameters. Then the second part is the introduction of the measurement. TRL calibration method is used to remove the error caused by equipment we used in measurement. At 4th chapter, it will show scattering parameters. By the measurement results we can get permittivity and loss tangent. Comparison between measurement and simulation will also be presented. The last chapter is the conclusion of this thesis and the future work.

碩士
國立臺灣大學
電子工程學研究所
105
In the clinical applications, Doppler ultrasound is widely used to understand the circulation physiology and the evaluation of cardiovascular hemodynamics. By means of analyzing the amplitude and the frequency shift (Doppler shift) of the received ultrasound signals, it is possible to acquire the information about flow rate and flow direction of blood. Recently, the demand for portable ultrasound imaging system with high performance becomes larger as the medical technology is advanced. In general, commercial products of ultrasound receiver include two receiving mechanisms, time-gain-compensation (TGC) mode and continuous-wave (CW) Doppler mode. These two operation modes have a shared LNA at the circuit input, however, only the circuit system of TGC mode is fully integrated on single chip due to the strict limit of performance. Based on the advantages and the characteristics of a complementary metal-oxide-semiconductor (CMOS) process, a low cost, power-efficient and fully integrated ultrasound receiver in continuous-wave Doppler (CWD) mode is presented in this thesis. The proposed CWD receiver is composed of multi-channel LNAs, mixers, summing amplifier, anti-aliasing filter, audio-frequency analog-to-digital converter (ADC) and clocking circuit for local oscillator (LO) generation. Except the clocking circuit and LNAs, all the circuit blocks include in-phase and quadrature (I/Q) channels. In the circuit designs, the proposed LNA adopts a high-out-swing topology and a linearity-improving skill to lower the total harmonic distortion (THD) and the two-tone third-order intermodulation distortion (IMD3). Combining advantages of the passive mixer and the characteristic of virtual short in an operational amplifier (Op-amp) based inverting amplifier, the mixers used in this design reduce the degradation of dynamic range (DR) during the beamforming and the down-conversion of amplified signals. Besides, a skill of improving the phase margin of common-mode feedback (CMFB) loop in both the summing amplifier and filter which are based on fully differential op-amps is demonstrated. Based on an existing layout skill of using the sandwich capacitor as a unit capacitor in a capacitive digital-to-analog (CDAC) array of successive approximation (SAR) ADC, a hybrid sandwich capacitor is proposed to increase the capacitance of unit capacitor occupying an equal area. In addition, the corresponding layout floor plan and wiring skill inside CDAC is also depicted to effectively control the generation of parasitic capacitors and prevent the linearity of converter from deterioration because of them. Finally, offset-calibrating circuits adopting a digital method are used to remove offsets at outputs of differential circuits. It can not only keep from a decrease in dynamic range (DR) of entire system due to the wrong operation region of transistors but also avoid using lots of off-chip capacitors which is needed in an analog method and would increase the cost.

碩士
輔仁大學
電機工程學系碩士班
103
Since 2000, the highest incident rate of ESRD (End Stage Renal Disease) was reported by Taiwan (dialysis only), increasing 8 – 10 percent per year. There are two types of dialysis: hemodialysis and peritoneal dialysis. In hemodialysis, an artificial kidney is used to remove waste and extra chemicals and fluid from your blood. To get your blood into the artificial kidney, the doctor needs to make an access (entrance) into your blood vessels. This is done by minor surgery to your arm or leg. Sometimes, an access is made by joining an artery to a vein under your skin to make a bigger blood vessel called a arteriovenous fistula. In recent years, blood flow measurement by using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological signal monitor. Recently, a couple of pocket-sized ultrasound scanners have been introduced for portable diagnosis. A 5-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional audio Doppler shift signals were obtained using a portable analog circuit system. Then the Doppler signals were fed directly to a computer for Doppler spectrogram analysis and display in monitor. In order to verify our system, we simulate the state of blood flow by using Harvard’s flow pump for in vitro verification. Finally, the blood flow of volunteer carotid were measured in vivo to verify the performance of portable CW Doppler ultrasound device. All of results compare with commercial ultrasound system and demonstrated the feasibility of our ultrasound system.

碩士
國立中央大學
遙測科技碩士學位學程
102
Radar Doppler has various applications in both military and civil aspect. The target moving parameters such as moving direction, moving velocity and so on can be well estimated through the analysis of radar Doppler effects. A new research called micro-Doppler which is proposed by the famous scholar Victor C. Chen was developed on the basis of micro motion model of objects. Since the human beings and the other creatures usually walk or run with a constant velocity, stride and gait frequency, there are some micro-Doppler signatures on their spectrums. Human gait detection and characteristic extraction mainly utilize the human’s walking dynamic features to modulate the radar echo phase, use time-frequency analysis method to obtain the spectrum, and extract the micro-Doppler signature of human gait from spectrum. Through wall surveillance (TWS) is a kind of detection technology which can penetrate walls and other obstacles. With the ability of through-obstacle detection, TWS has been playing an important role in military reconnaissance, counter-terrorism, hostage rescue, earthquake casualty search and so on. In this study, the micro-Doppler effect of the vibration and rotation is firstly discussed which is depend on the specific micro motion, and followed by the tool of time-frequency analysis. A gait echo model is proposed, which represents the rotation angles, displacements and relative phase relationship of joints, scatterers and the instantaneous Radar Cross Section (RCS). Finally, micro Doppler is combined with TWS for the feasibility of human gait direction determination.

Micro-Doppler is defined as scattering produced by non-rigid-body motion. This dissertation involves the design of a multiple frequency continuous wave (MFCW) radar for micro-Doppler research and detection and classification algorithm design. First, sensor hardware is developed and tested. Various design tradeoffs are considered, with the application of micro-Doppler based detection and classification in mind. A diverse database of MFCW radar micro-Doppler signatures was collected for this dissertation. The micro-Doppler signature database includes experimental data from human, vehicle, and animal targets. Signatures are acquired from targets with varying ranges, velocities, approach angles, and postures. The database is analyzed for micro-Doppler content with a focus on its application to target classification. Joint time-frequency detection algorithms are developed to improve detection performance by exploiting noise-spreading and the micro-Doppler phenomenon. Following detection algorithm development, this dissertation covers the design of micro- Doppler feature extraction, feature selection, and classification algorithms. Feature selection is performed automatically via a Fisher score initialized sequential backward selection algorithm. Classification is performed using two distinct approaches: a generative statistical classification algorithm based on Gaussian mixture models (GMMs) and a discriminative statistical classification algorithm based on support vector machines (SVMs). Classifier performance is analyzed in detail on a micro-Doppler signature database acquired over a three-year period. Both the SVM and GMM classifiers perform well on the radar target classification task (high accuracy, low nuisance alarm probability, high F-measure, etc.). The performance of both classifiers is remarkably similar, and neither algorithm dominates the other in any performance metric when using the chosen feature set. (However, the difference between SVM and GMM classification accuracy becomes statistically significant when many redundant features are present in the feature set.) The accuracy of both classifiers is shown to vary as a function of approach angle, which physically corresponds to the angular dependence of micro-Doppler. The results suggest that overall classifier performance is more sensitive to feature selection than classifier selection (with GMM being more sensitive to redundant features than SVM). Both classifiers are robust enough to handle human targets attempting to evade detection by either army crawling or hands-and-knees crawling.
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