This master thesis studied methods for tracking and localising a moving target from an autonomous seeker drone. Feasible methods for automatic control of the seeker drone and different antenna configurations were explored as well. Two different tracking filters and two different controllers were tested for this purpose. The algorithm was developed in Python and MATLAB. The evaluation of the filters and controllers was done both theoretically with simulations but also practically with flight tests. Performance and robustness were measured by examining the estimated target position and the smoothness of the seeker path. Both filters performed satisfactorily, the same conclusion could be made for the automatic controllers as well. Regardless of the sufficient results, for future work there are several aspects which can be improved. The communication with the drone’s motors, the noise models and one of the automatic controllers are all examples of areas which canbe improved further.

The characterization of modern jet engines or stationary gas turbines running with lean combustion by means of swirl-stabilized ames necessitates seedingless optical field measurements of the ame transfer function, i.e. the ratio of the uctuating heat release rate inside the ame volume, the instationary ow velocity at the combustor outlet and the time average of both quantities. For this reason, a high-speed camera-based laser interferometric vibrometer is proposed for spatio-temporally resolved measurements of the ame transfer function inside a swirl-stabilized technically premixed ame. Each pixel provides line-of-sight measurements of the heat release rate due to the linear coupling to uctuations of the refractive index along the laser beam, which are based on density uctuations inside the ame volume. Additionally, field measurements of the instationary ow velocity are possible due to correlation of simultaneously measured pixel signals and the known distance between the measurement positions. Thus, the new system enables the spatially resolved detection of the ame transfer function and instationary ow behavior with a single measurement for the first time. The presented setup offers single pixel resolution with measurement rates up to 40 kHz at an maximum image resolution of 256 px x 128 px. Based on a comparison with reference measurements using a standard pointwise laser interferometric vibrometer, the new system is validated and a discussion of the measurement uncertainty is presented. Finally, the measurement of refractive index uctuations inside a ame volume is demonstrated.

Optical interferometry is a technique by which the diameters and indeed the direct pulsations of stars are routinely being measured. As a follow-on to a 7 year interferometric campaign to measure the pulsations of over 100 mira variables, our team has been using the Spitzer Space Telescope to obtain 95 mid-infrared spectra of 25 miras during their pulsations over one year while simultaneously ascertaining their near-infrared diameters using the Palomar Testbed Interferometer. These data will then be combined with modeling from NLTE and radiative transfer codes to place hard constraints on our understanding of these stars and their circumstellar environments. We present some initial results from this work and discuss the next steps toward fully characterizing the atmosphere, molecular photosphere and dust production in mira variables.

Gravitational-wave astronomy is an emerging field in observational astrophysics concerned with the study of gravitational signals proposed to exist nearly a century ago by Albert Einstein but only recently confirmed to exist. Such signals were theorized to result from astronomical events such as the collisions of black holes, but they were long thought to be too faint to measure on Earth. In recent years, the construction of extremely sensitive detectors—including the Laser Interferometer Gravitational-Wave Observatory (LIGO) project—has enabled the first direct detections of these gravitational waves, corroborating the theory of general relativity and heralding a new era of astrophysics research. As a result of their extraordinary sensitivity, the instruments used to study gravitational waves are also subject to noise that can significantly limit their ability to detect the signals of interest with sufficient confidence. The detectors continuously record more than 200,000 time series of auxiliary data describing the state of a vast array of internal components and sensors, the environmental state in and around the detector, and so on. This data offers significant value for understanding the nearly innumerable potential sources of noise and ultimately reducing or eliminating them, but it is clearly impossible to monitor, let alone understand, so much information manually. The field of machine learning offers a variety of techniques well-suited to problems of this nature. In this thesis, we develop and present several machine learning–based approaches to automate the process of extracting insights from the vast, complex collection of data recorded by LIGO detectors. We introduce a novel problem formulation for transient noise detection and show for the first time how an efficient and interpretable machine learning method can accurately identify detector noise using all of these auxiliary data channels but without observing the noise itself. We present further work employing more sophisticated neural network–based models, demonstrating how they can reduce error rates by over 60% while also providing LIGO scientists with interpretable insights into the detector’s behavior. We also illustrate the methods’ utility by demonstrating their application to a specific, recurring type of transient noise; we show how we can achieve a classification accuracy of over 97% while also independently corroborating the results of previous manual investigations into the origins of this type of noise. The methods and results presented in the following chapters are applicable not only to the specific gravitational-wave data considered but also to a broader family of machine learning problems involving prediction from similarly complex, high-dimensional data containing only a few relevant components in a sea of irrelevant information. We hope this work proves useful to astrophysicists and other machine learning practitioners seeking to better understand gravitational waves, extremely complex and precise engineered systems, or any of the innumerable extraordinary phenomena of our civilization and universe.

Dans ce manuscrit, nous rapportons les développements, théoriques et expérimentaux, en cours à TRT, visant la réalisation d'un accéléromètre à atomes froids. Cet interféromètre utilise un gaz ultra-froid non-dégénéré qui est piégé au voisinage d'une puce atomique pendant toute la séquence d’interrogation.Nous décrivons un protocole d'interrogation permettant de rendre le capteur sensible aux accélérations. Ce protocole est constitué d'une séquence de Ramsey avec une séparation spatiale des deux états de l'interféromètre. Le signal et le contraste de cet interféromètre sont modélisés et l'utilisation de raccourci à l'adiabaticité est considérée pour réaliser une séparation et une recombinaison rapide des deux états. Nous décrivons aussi une implémentation de cet interféromètre sur une puce atomique. Elle repose sur la création de deux potentiels habillés micro-onde, un pour chacun des deux états de l'interféromètre.Le dispositif de refroidissement des atomes, mis en place pendant cette thèse, est décrit. Des atomes de rubidium 87 sont refroidis jusqu'à la condensation de Bose-Einstein dans l'état $left|2,2right>$. Un protocole de type textit{stimulated Raman adiabatic passage} utilisant des champs micro-ondes, permet ensuite de transférer les atomes (condensés ou thermiques) vers l'état $left|2,1right>$. Cette source atomique a permis de réaliser des mesures du contraste des franges de Ramsey en fonction de la symétrie des potentiels piégeant les deux états de l'interféromètre. Le temps de décroissance du contraste mesuré permet de valider les développements théoriques sur le contraste de l'interféromètre. / In this manuscript we report the theoretical and experimental developments, in progress at TRT, aiming at the realisation of a cold atom accelerometer. This accelerometer uses an ultra-cold non-degenerated gas which is trapped in the vicinity of an atom chip during the whole interrogation sequence.We describe an interrogation protocol allowing the sensor to be sensitive to acceleration. This protocol uses a Ramsey sequence with a spatial separation of the two interferometer states. The signal and the contrast of this interferometer are derived and the use of shortcut to adiabadicity is considered to enable fast splitting and merging of the two states. We also describe a design of the accelerometer on an atom chip. This design use two dressed microwave potentials, one for each of the two interferometer states.We described the atom cooling experiment built during this thesis. Atoms of rubidium 87 have been cooled to Bose-Einstein condensation in state $left|2,2right>$. A stimulated Raman adiabatic passage protocol using microwave fields, allows to transfer an atomic cloud (condensed or thermal) to the state $left|2,1right>$. With this atomic source the contrast of the Ramsey fringes as a function of the symmetry between the interferometer traps have been measured. The measured contrast falling time is in good agreement with the theoretical prediction for the interferometer contrast.

La détection des exoplanètes et de l’environnement d’étoiles jeunes tel que les disques de débris fait face à deux difficultés majeures : d’une part, la faible distance angulaire entre le compagnon (ou le disque) et son étoile hôte, et d’autre part, le contraste élevé entre les deux composantes en terme de flux. L’interférométrie est une des techniques permettant de palier ces deux problématiques en apportant une détection à la fois à haute résolution angulaire et à haute dynamique. C’est tout particulièrement le cas dans la mise en oeuvre de l’interférométrie annulante, aussi appelée interférométrie en frange noire, lors de laquelle on vient éteindre le flux de l’étoile principale grâce aux propriétés de cohérence de la lumière.On recombine la lumière issue de deux télescopes ou plus de sorte à faire interférer destructivement les photons provenant de l’étoile principale et constructivement pour les photons venant du compagnon ou du disque environnant. Mon travail de thèse s’inscrit dans ce cadre, avec l’étude de données observationnelles de huit disques de débris réalisées au Very Large Telescope, grâce à la technique interférométrique de masquage de pupille. Lors de cette étude j’ai réalisé la réduction des données interférométriques et une analyse des termes de clôtures de phase. Puisque aucun compagnon n’a été détecté dans les données, j’en ai déduit les limites de détection en termes de luminosité et de masse estimée à l’aide d’isochrones issue de modèle d’évolution.Ma thèse à également consisté en une composante expérimentale, avec la conception et l’étalonnage de l’instrument FIRST-IR (Fibered Imager foR a Single Telescope InfraRed) en laboratoire, à l’Observatoire de Meudon. Cet instrument est un interféromètre qui associe la technique de réarrangement de pupille fibré et la recombinaison de la lumière paroptique intégrée. Le type d’optique intégrée étudié ici est un composant optique planaire sur lequel des guides d’ondes ont été gravés. l’optique intégrée est de type nuller et prend en entrée le flux de quatre sous-pupilles. Les guides sont agencés selon une certaine architecture permettant de réaliser dans un premier temps une fonction annulante sur trois bases puis une mesure des franges d’interférence sur les trois voies annulées. J’ai réalisé un étalonnage complet de cette optique intégrée ainsi que des mesures de clôture de phase.En conclusion, j’ai pu montrer la viabilité de l’instrument FIRST-IR avec ce nouveau concept d’optique intégrée de type nuller. En particulier j’ai démontré que la mesure de la clôture de phase reste stable pour une cible point source, quel que soit le taux d’annulation interférométrique appliqué. / The detection of exoplanets and young stars environment such as debris disks deals with two major difficulties: on one hand, the low angular distance between companion (or disk) and its host star, and on the other hand, the high contrast of flux between the two components. Interferometry is one of the techniques that solves these two issues. It is particularly the case in the application of nulling interferometry, in which we extinguish the flux from the main star thanks to coherence properties of the light.My thesis work takes part in this context, with the study of eight debris disks observationnal data made at the Very Large Telescope, using the Sparse Aperture Maskig interferometric technique. I achieved the data reduction and the analysis of closure phases. As no companion was found in the data, I derived detection limits in terms of luminosity and estimated mass.My thesis also consisted in an instrumental part, with the conception of the FIRST-IR (Fibered Imager foR a Single Telescope InfraRed) instrument in laboratory. This instrument is an interferometer which associates fibered pupil remapping technique and integrated optic based recombination of light.To conclude, I have shown the viability of FIRST-IR instrument using this new integrated optic based nuller architecture. Particularly, I demonstrated that closure phase remains stable for a source point target, regardless of the nulling level applied.

L'objectif de cette thèse est d'étudier la faisabilité de l'interférométrie par rétro-injection optique (IRO) pour la mesure de vitesse en dynamique des matériaux. La dynamique des matériaux est l'étude du comportement des matériaux soumis à des chocs (chocs laser, chocs plan,compression isentropique, projectiles, etc.). Dans ces conditions, nous cherchons à mesurer des vitesses pouvant aller jusqu'à 10 km/s. La technique IRO est couramment utilisée comme capteur embarqué pour mesurer de faibles vitesses dans divers domaines. Cependant, très peu d'études ont été réalisées sur les limites hautes vitesses de ce type de capteur. La rétro-injection optique provoque des effets non linéaires dans la cavité laser : elle perturbe la puissance d'émission optique. Suivant le taux de rétro-injection optique, le laser peut présenter un comportement chaotique et il n'est alors plus possible de récupérer l'information de la vitesse et/ou du déplacement de la cible à partir des signaux. Nous avons pour cela développé des modèles mathématiques et réalisé un grand nombre de simulations numériques afin d'évaluer les performances et les limitations de ce système. Nous avons notamment étudié l'influence de la réflectivité de la cible, de la longueur et de la fréquence de la modulation de la cavité externe. / The purpose of this thesis is to study the feasibility of optical feedback interferometry (OFI) for measuring velocities for dynamical material's behaviour studies. Dynamical material's behaviour studies permit to analyse the shocked material when subjects to shocks (laser shocks, isentropic compression, projectiles, etc.). In these conditions, we seek to measure velocities up to 10 km/s. The OFI technique is regularly used as an embedded system to measure slow velocities in various fields. However, very few studies have been performed for determining velocities measurement limits for this system. As a matter of fact, the optical feedback induces nonlinear effects into the laser's cavity : it disrupts the laser's emitted optical power. Depending on the optical feedback strength, the laser can show chaotic behaviour, then it is no longer possible to get the information for the target's velocity or displacement regarding the signal. In this study, we have been developing mathematical models and performing a wide range of numerical simulations to study the performances and the limits of the OFI technique. We have been also studying the influence of the targets reflectivity, the length and the modulation frequency of the external cavity.

[pt] Interferometria tem sido utilizada para estudar uma variedade de efeitos físicos, desde os experimentos iniciais de Michelson e Morley que forneceram evidências para a teoria da relatividade restrita até os aparelhos de detecção de ondas gravitacionais utilizado no Laser Interferometer Gravitational-Wave Observatory (LIGO). O Propósito dessa dissertação é entender como explorar anyons e suas características únicas para construir interferômetros. Anyons são quasipartículas bi-dimensionais conhecidas por apresentarem estatística fracionária e possuírem aplicações em modelos de computação quântica. Para estudar sua utilidade no contexto de interferometria nós apresentamos uma perspectiva de computação quântica para experimentos de interferência. Em seguida, introduzimos modelos anyônicos e suas aplicações em computação quântica universal. Propomos um circuito quântico que implementa um certo tipo de interferômetro, e como realizá-lo em diferentes modelos anyônicos. Finalmente, discutimos um modelo de computação quântica baseado em ótica linear de anyons fermiônicos que permitiria a criação de uma versão lógica do nosso interferômetro em termos de um interferômetro físico. / [en] Interferometry has been used to study a variety of physical effects, from the early experiments of Michelson and Morley that provided evidence to special relativity to the more recent gravity-wave detection devices used by the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment. The purpose of this thesis is to understand how one can exploit anyons and its unique characteristics to build interferometers, and understand whether there are immediate advantages in doing so. Anyons are two-dimensional quasiparticles known for their unusual fractional statistics and applications in quantum computing models. To study their usefulness in the context of interferometry, we present a quantum computational approach to interference experiments. Next we give an introduction to anyon models and how they can be used to perform universal quantum computing. We propose a quantum circuit which implements a certain type of interferometer, and how it can be realized in different anyon models. Finally, we discuss a quantum computing model based on linear optics with fermionic anyons that would enable the creation of a logical version of our interferometer in terms of a physical interferometer.

The detection of Earth-like exoplanets and the characterization of their atmospheres is a challenge one needs to solve to assess their habitability and the presence of life in the universe. If this challenge is still unresolved today, even in the era of giant telescopes, it is mainly because of the very high contrast between these exoplanets and their host star and also their proximity. To overcome both of these constraints, a new method combining high-dispersion spectroscopy and nulling interferometry has been imagined. The idea is to use the nulling interferometry to attenuate the star light emission and detect the inner rocky planets with a high angular resolution. The high-dispersion spectroscopy is increasing the exoplanet detectability significantly which enables to relax the star attenuation requirement for an Earth-like observation. Our simulation made for an exoplanet similar to the Earth orbiting Proxima Centauri is giving a condition for the star attenuation ∼10−4 to detect it. Given this condition, we are able to evaluate the unability of a photonic device at our disposal to achieve such performance without dealing with its limitations. If a future project manages to overcome these limitations, this device could be part of a precursor instrument at IPAG to demonstrate experimentally the performance of high-dispersion nulling interferometry. / Upptäckten av jordliknande exoplaneter och karakteriseringen av deras atmosfärer är en utmaning man behöver lösa för att bedöma deras beboelighet och närvaron av liv i universum. Om denna utmaning fortfarande inte är löst idag, även i jätteteleskopens tid, beror det främst på den mycket höga kontrasten mellan dessa exoplaneter och deras värdstjärna och också deras närhet. För att övervinna båda dessa begränsningar har en ny metod som kombinerar högdispersionsspektroskopi och nullingsinterferometri föreställts. Idéen är att använda nullingsinterferometrin för att minska stjärnljusemissionen och upptäcka de inre steniga planeterna med hög vinkelupplösning. Spektroskopin med hög dispersion ökar exoplanetens detekterbarhet betydligt vilket gör det möjligt att minska stjärndämpningsbehovet för en jordliknande observation. Vår simulering för en exoplanet som liknar jorden som kretsar omkring Proxima Centauri ger ett tillstånd för stjärndämpningen att ∼10−4 för att upptäcka den. Med tanke på detta villkor kan vi utvärdera oförmågan hos en fotonisk enhet till vårt förfogande för att uppnå sådan prestanda utan att hantera dess begränsningar. Om ett framtida projekt lyckas övervinna dessa begränsningar kan den här enheten vara en del av ett föregångarinstrument på IPAG för att experimentellt visa prestanda för högdispersionsnullningsinterferometri.

No description available.