Dissertations / Theses on the topic 'Navigation models'

Thesis (M.S. in Software Engineering)--Naval Postgraduate School, December 2008.
Thesis Advisor(s): Kolsch, Mathias. "December 2008." Description based on title screen as viewed on January 30, 2009. Includes bibliographical references (p. 51-52). Also available in print.

The rodent navigation system has been the focus of study for over a century. Discoveries made lately have provided insight on the inner workings of this system. Since then, computational approaches have been used to test hypothesis, as well as to improve robotics navigation and learning by taking inspiration on the rodent navigation system. This dissertation focuses on the study of the multi-scale representation of the rat’s current location found in the rat hippocampus. It first introduces a model that uses these different scales in the Morris maze task to show their advantages. The generalization power of larger scales of representation are shown to allow for the learning of more coherent and complete policies faster. Based on this model, a robotics navigation learning system is presented and compared to an existing algorithm on the taxi driver problem. The algorithm outperforms a canonical Q-Learning algorithm, learning the task faster. It is also shown to work in a continuous environment, making it suitable for a real robotics application. A novel task is also introduced and modeled, with the aim of providing further insight to an ongoing discussion over the involvement of the temporal portion of the hippocampus in navigation. The model is able to reproduce the results obtained with real rats and generates a set of empirically verifiable predictions. Finally, a novel multi-query path planning system is introduced, inspired in the way rodents represent location, their way of storing a topological model of the environment and how they use it to plan future routes. The algorithm is able to improve the routes in the second run, without disrupting the robustness of the underlying navigation system.

Robots are no longer constrained to cages in factories and are increasingly taking on roles alongside humans. Before robots can accomplish their tasks in these dynamic environments, they must be able to navigate while avoiding collisions with pedestrians or other robots. Humans are able to move through crowds by anticipating the movements of other pedestrians and how their actions will influence others; developing a method for predicting pedestrian trajectories is a critical component of a robust robot navigation system. A current state-of-the-art approach for predicting pedestrian trajectories is Social-LSTM, which is a recurrent neural network that incorporates information about neighboring pedestrians to learn how people move cooperatively around each other. This thesis extends and modifies that model to output parameters for a multimodal distribution, which better captures the uncertainty inherent in pedestrian movements. Additionally, four novel architectures for representing neighboring pedestrians are proposed; these models are more general than current trajectory prediction systems and have fewer hyper-parameters. In both simulations and real-world datasets, the multimodal extension significantly increases the accuracy of trajectory prediction. One of the new neighbor representation architectures achieves state-of-the-art results while reducing the number of both parameters and hyper-parameters compared to existing solutions. Two techniques for incorporating the trajectory predictions into a planning system are also developed and evaluated on a real-world dataset. Both techniques plan routes that include fewer near-collisions than algorithms that do not use trajectory predictions. Finally, a Python library for Agent-Based-Modeling and crowd simulation is presented to aid in future research.

Augmented reality is a field of technology in which the real world is overlaid with additional information from a computer generated display. Enhancements to augmented reality technology presently support limited mobility which is expected to increase in the future to provide much greater real world functionality. This work reports on a set of experiments that investigate performance in search and rescue navigating tasks using augmented reality. Augmentation consisted of a spatially and temporally registered map of a maze that was overlaid onto a real world maze. Participants were required to traverse the maze, answer spatially oriented questions in the maze, acquire a target object, and exit. Pre and post hoc questionnaires were administered. Time and accuracy data from one hundred twenty participants were collected across six treatments. The between subject treatments, which had an equal number of male and female participants, were a control condition with only a compass, a control condition with a paper map available prior to maze traversal and four experimental conditions consisting of combinations of egocentric and exocentric maps, and a continuously on and on demand map display. Data collected from each participant consisted of time to traverse the maze, percent of the maze covered, estimations of euclidian distance and direction, estimations of cardinal direction, and spatial recall. Data was also collected via pre and post hoc questionnaires. Results indicate that best performance with respect to time was in the control condition with a map. The small size of the maze could have facilitated this result through route memorization. Augmented reality can offer enhancement to performance as navigational tasks become more complex and saturate working memory. Augmented reality showed best performance in accuracy by facilitating participants' coverage of the maze. Exocentric maps generally exhibited better performance than egocentric maps. On demand displays also generally resulted in better performance than continuously on displays. Gender differences also were evident with males exhibiting better performance than females. Participants reporting an initial tendency to not rotate maps exhibited better performance than those reporting a tendency to rotate maps. Enhancements being made to augmented reality and related technologies will result in more features, improved form factor for users, and improved performance in the future. Guidelines provided in this work seek to ensure augmented reality systems continue to progress in enhancing performance
Ph.D.
Other
Arts and Sciences
Modeling and Simulation

Pour les véhicules intelligents, un système de perception est un élément clé pour caractériser en temps réel un modèle de l’environnement de conduite autour du véhicule. Lors de la modélisation de l’environnement, les informations relatives aux obstacles doivent être gérées prioritairement car les collisions peuvent être mortelles pour les autres usagers de la route ou pour les passagers à bord du véhicule considéré. La caractérisation de l’espace occupé est donc cruciale mais pas suffisante pour les véhicules autonomes puisque le système de contrôle a besoin de trouver l’espace navigable pour assurer une planification sure de trajectoire. En effet, afin de naviguer sur les routes publiques avec d’autres utilisateurs, le véhicule doit aussi suivre les règles de circulation qui sont décrites, par exemple, par des marquages au sol peints sur la chaussée. Dans ce travail, nous nous concentrons sur une approche fondée sur des grilles égocentrées pour modéliser l’environnement. L’objectif est d’obtenir un modèle unifié contenant les informations d’obstacle avec des règles sémantiques de la route. Pour modéliser les informations d’obstacle, l’occupation est assurée par l’interprétation des informations des différents capteurs comme les valeurs des cellules. Pour modéliser la sémantique de l’espace navigable, nous proposons d’introduire la notion de grille de voies qui consiste à intégrer l’information sémantique de voie dans les cellules de la grille. La combinaison de ces deux niveaux d’information donne ainsi un modèle d’environnement plus raffiné. Lors de l’interprétation des données des capteurs en information d’obstacle, il faut manipuler des incertitudes dues à de l’ignorance ou des erreurs. L’ignorance est liée à la perception des nouveaux espaces dans la zone de perception et les erreurs proviennent de mesures bruitées et d’estimations imprécises de la pose. Dans cette recherche, la théorie de la fonction de croyance est adoptée pour faire face aux incertitudes et nous proposons des modèles évidentiels pour différents types de capteurs comme des lidars et des caméras. Les grilles de voie contiennent des informations sémantiques sur les voies provenant des marquages au sol, par exemple. À cette fin, nous proposons d’utiliser une carte a priori qui contient des informations détaillées sur la route comme l’orientation de la route et les marquages des voies. Ces informations sont extraites de la carte en utilisant une estimation de pose fournie par un système de localisation. Dans le modèle proposé, nous intégrons dans les grilles les informations de voie en tenant compte de l’incertitude de la pose estimée. Les algorithmes proposés ont été implémentés et testés sur des données réelles obtenues sur des routes publiques. Nous avons développé des algorithmes Matlab et C ++ avec le logiciel PACPUS développé au laboratoire
For intelligent vehicle applications, a perception system is a key component to characterize in real-time a model of the driving environment at the surrounding of the vehicle. When modeling the environment, obstacle information is the first feature that has to be managed since collisions can be fatal for the other road users or for the passengers on-board the considered vehicle. Characterization of occupation space is therefore crucial but not sufficient for autonomous vehicles since the control system needs to find the navigable space for safe trajectory planning. Indeed, in order to run on public roads with other users, the vehicle needs to follow the traffic rules which are, for instance, described by markings painted on the carriageway. In this work, we focus on an ego-centered grid-based approach to model the environment. The objective is to include in a unified world model obstacle information with semantic road rules. To model obstacle information, occupancy is handled by interpreting the information of different sensors into the values of the cells. To model the semantic of the navigable space, we propose to introduce the notion of lane grids which consist in integrating semantic lane information into the cells of the grid. The combination of these two levels of information gives a refined environment model. When interpreting sensor data into obstacle information, uncertainty inevitably arises from ignorance and errors. Ignorance is due to the perception of new areas and errors come from noisy measurements and imprecise pose estimation. In this research, the belief function theory is adopted to deal with uncertainties and we propose evidential models for different kind of sensors like lidars and cameras. Lane grids contain semantic lane information coming from lane marking information for instance. To this end, we propose to use a prior map which contains detailed road information including road orientation and lane markings. This information is extracted from the map by using a pose estimate provided by a localization system. In the proposed model, we integrate lane information into the grids by taking into account the uncertainty of the estimated pose. The proposed algorithms have been implemented and tested on real data acquired on public roads. We have developed algorithms in Matlab and C++ using the PACPUS software framework developed at the laboratory

Motion planning for planetary rovers must consider control uncertainty in order to maintain the safety of the platform during navigation. Modelling such control uncertainty is challenging on unstructured terrain, and especially on deformable terrain, due to the complex interaction between the platform and its environment. In this thesis, we propose to enhance stochastic transition models for planning, where the outcomes of the control actions are learnt from experience and represented statistically using probability density functions. These transition models that capture control uncertainty are known as Stochastic Mobility Prediction Models (SMPM). Rovers may traverse a mixture of rigid and deformable terrain. However, current SMPMs are only capable of estimating one dimension of control uncertainty in rigid terrain. We propose to enhance the SMPM by Learning from Exteroception, a training method that relies on sample executions of motion primitives on representative terrain and the corresponding platform configurations collected along the executed path. This method enables the estimation of the outcome of future control actions on deformable terrain. The SMPM is further enhanced by using multi-output Gaussian process regression by simultaneously considering the correlation between multiple dimensions of uncertainty. The enhanced SMPM is integrated into a Markov decision process framework and dynamic programming is used to construct a control policy for navigation to a goal region in a terrain map. We consider both rigid and deformable terrain, consisting of uneven ground, small rocks, and non-traversable rocks. Over 300 experimental trials are reported using a planetary rover platform in a Mars-analogue environment. Our results demonstrate increased path safety and reliability by the improved traversal cost and actions executed; due to the SMPM improvement in predicting control action outcomes.

Utilizing a Global Navigation Satellite System (GNSS) together with an Inertial Navigation System (INS) is today a common integration method to obtain a positioning solution for autonomous systems. Both GNSS and INS have benefits and weaknesses where the best parts from both systems can be combined with a Kalman filter. Because of this complementary nature, it is of interest to look at the robustness of the positioning solution when the Global Navigation Satellite System is temporarily not available. The aim of the thesis has been to investigate different vehicle models and to evaluate their short-time performance using a Dead Reckoning approach. The goal has been to develop a system for a Heavy Duty Vehicle (HDV) and to find out for which time interval a specific model can stay within a certain range when the GNSS is lost. A GNSS outage could for example happen when driving on a highway and passing signs, bridges and especially when driving inside tunnels. Also, for a solution to become commercially interesting, it must be cheap. Therefore, is it common to use so called Micro-Electro-Mechanical-Systems (MEMS) sensors which are of low-cost but suffer from biases, scale factors and temperature dependencies which must be compensated for. The results from the tests show that some models are able to estimate the position with good precision during short time GNSS outages whereas other models do not deliver the required accuracy. The main conclusion is that care should be taken when choosing the vehicle model so that it fits its usage area and the complexity needed to describe its motion. There are also lots of parameters to look at when investigating the best solution, where modeling of the low-cost sensors is one of them.

A new angles-only initial relative orbit determination (IROD) algorithm is derived using three line-of-sight observations. This algorithm accomplishes this by taking a Singular Value Decomposition of a 6x6 matrix to arrive at an approximate initial relative orbit determination solution. This involves the approximate solution of 6 polynomial equations in 6 unknowns. An iterative improvement algorithm is also derived that provides the exact solution, to numerical precision, of the 6 polynomial equations in 6 unknowns. The initial relative orbit algorithm is also expanded for more than three line-of-sight observations with an iterative improvement algorithm for more than three line-of-sight observations. The algorithm is tested for a range of relative motion cases in low earth orbit and geosynchronous orbit, with and without the inclusion of J2 perturbations and with camera measurement errors. The performance of the IROD algorithm is evaluated for these cases and show that the tool is most accurate at low inclinations and eccentricities. Results are also presented that show the importance of including J2 perturbations when modelling the relative orbital motion for accurate IROD estimates. This research was funded in part by the Air Force Research Lab, Albuquerque, NM.

Modern applications of mobile robots require them to have the ability to safely and effectively navigate in human environments. New challenges arise when these robots must plan their motion in a human-aware fashion. Current methods addressing this problem have focused mainly on the activity forecasting aspect, aiming at improving predictions without considering the active nature of the interaction, i.e. the robot’s effect on the environment and consequent issues such as reciprocity. Furthermore, many methods rely on computationally expensive offline training of predictive models that may not be well suited to rapidly evolving dynamic environments. This thesis presents a novel approach for enabling autonomous robots to navigate socially in environments with humans. Following formulations of the inverse planning problem, agents reason about the intentions of other agents and make predictions about their future interactive motion. A technique is proposed to implement counterfactual reasoning over a parametrised set of light-weight reciprocal motion models, thus making it more tractable to maintain beliefs over the future trajectories of other agents towards plausible goals. The speed of inference and the effectiveness of the algorithms is demonstrated via physical robot experiments, where computationally constrained robots navigate amongst humans in a distributed multi-sensor setup, able to infer other agents’ intentions as fast as 100ms after the first observation. While intention inference is a key aspect of successful human-robot interaction, executing any task requires planning that takes into account the predicted goals and trajectories of other agents, e.g., pedestrians. It is well known that robots demonstrate unwanted behaviours, such as freezing or becoming sluggishly responsive, when placed in dynamic and cluttered environments, due to the way in which safety margins according to simple heuristics end up covering the entire feasible space of motion. The presented approach makes more refined predictions about future movement, which enables robots to find collision-free paths quickly and efficiently. This thesis describes a novel technique for generating "interactive costmaps", a representation of the planner’s costs and rewards across time and space, providing an autonomous robot with the information required to navigate socially given the estimate of other agents’ intentions. This multi-layered costmap deters the robot from obstructing while encouraging social navigation respectful of other agents’ activity. Results show that this approach minimises collisions and near-collisions, minimises travel times for agents, and importantly offers the same computational cost as the most common costmap alternatives for navigation. A key part of the practical deployment of such technologies is their ease of implementation and configuration. Since every use case and environment is different and distinct, the presented methods use online adaptation to learn parameters of the navigating agents during runtime. Furthermore, this thesis includes a novel technique for allocating tasks in distributed robotics systems, where a tool is provided to maximise the performance on any distributed setup by automatic parameter tuning. All of these methods are implemented in ROS and distributed as open-source. The ultimate aim is to provide an accessible and efficient framework that may be seamlessly deployed on modern robots, enabling widespread use of intention prediction for interactive navigation in distributed robotic systems.

Bibliography: leaves 134-148.
An exploratory investigation into the capabilities of hypertext as an educational medium was conducted. To this purpose, a model was advanced in an attempt to provide a theoretical foundation for the explication of hypertext navigation and disorientation in terms of relevant user characteristics. 75 2nd year psychology students from the University of Cape Town participated in a study in order to investigate the claim that the motivational theory of goal orientation has the greatest utility in accounting for the exploitation of links within a hypertext, a necessary precondition for the development of mental models which incorporate both the conceptual and structural elements required for effective learning from, and the reduction of disorientation within, this medium. The results obtained, although compromised, provide some support for this argument. The paper concludes with a discussion of the methodological limitations of the study, as well as possible directions for future research.

Optimization based flight control design tools depend on automatic linearization tools, such as Simulink®’s LINMOD, to extract linear models. In order to ensure the usefulness and correctness of the generated linear model, this linearization must be accurate. So a method of independently verifying the linearized model is needed. This thesis covers the automation of a system identification tool, CIFER®, for use as a verification tool integrated with CONDUIT®, an optimization based design tool. Several test cases are built up to demonstrate the accuracy of the verification tool with respect to analytical results and matches with LINMOD. Several common nonlinearities are tested, comparing the results from CIFER and LINMOD, as well as analytical results where possible. The CIFER results show excellent agreement with analytical results. LINMOD treated most nonlinearity as a unit gain, but some nonlinearities linearized to a zero, causing the linearized model to omit that path. Although these effects are documented within Simulink, their presence may be missed by a user. The verification tool is successful in identifying these problems when present. A section is dedicated to the diagnosis of linearization errors, suggesting solutions where possible.

L'étude et la compréhension de l'évolution des villes est un enjeu sociétal important, notamment pour améliorer la qualité de vie dans une ville toujours plus dense. Le numérique et en particulier les modèles 3D de villes peuvent être des éléments de réponse. Leur manipulation est parfois rendue complexe par la prise en compte de leurs dimensions thématique, géométrique et topologique ainsi que de leur structuration hiérarchique
The study and understanding of cities evolution is an important societal issue, particularly for improving the quality of life in an increasingly dense city. Digital technology and in particular 3D city models can be part of the answer. Their manipulation is however sometimes complex due to their thematic, geometric, topological dimensions and hierarchical structure.In this thesis, we focus on the integration of the temporal dimension and in the enrichment with multimedia documents of these 3D models of the city, in an objective of visualization and navigation on the web. Moreover, we take a particular interest in interoperability (based on standards), reusability (with a shared software architecture and open source components) and reproducibility (to make our experiments durable).Our first contribution is a formalization of the temporal dimension of cities for interactive navigation and visualization on the web. For this, we propose a conceptual model of existing standards for the visualization of cities on the web, which we extend with a formalization of the temporal dimension. We also propose a logical model and a technical specification of these proposals.Our second contribution allows the integration of multimedia documents into city models for spatial, temporal and thematic visualization and navigation on the web. We propose a conceptual model for the integration of heterogeneous and multidimensional geospatial data. We then use it for the integration of multimedia documents and 3D city models.Finally, this thesis took place in a multidisciplinary context via the Fab-Pat project of the LabEx IMU, which focuses on cultural heritage sharing and shaping. In this framework, a contribution combining social sciences and computer science has allowed the design of DHAL, a methodology for the comparative analysis of devices for sharing heritage via digital technology. Dans cette thèse, nous nous intéressons à l'intégration de la dimension temporelle et à l'enrichissement avec des documents multimédia de ces modèles 3D de la ville, dans un objectif de visualisation et de navigation sur le web. Nous portons un intérêt particulier à l'intéropérabilité (en s'appuyant sur des standards), à la réutilisabilité (avec une architecture logicielle partagée et des composants open source) et à la reproductibilité (permettant de rendre nos expérimentations pérennes).Notre première contribution est une formalisation de la dimension temporelle des villes pour une navigation et visualisation interactive sur le web. Pour cela, nous proposons un modèle conceptuel des standards existants pour la visualisation de villes sur le web, que nous étendons avec une formalisation de la dimension temporelle. Nous proposons également un modèle logique et une spécification technique de ces propositions.Notre deuxième contribution permet d'intégrer des documents multimédias aux modèles de villes pour une visualisation et une navigation spatiale, temporelle et thématique sur le web. Nous proposons un modèle conceptuel pour l'intégration de données géospatiales hétérogènes et multidimensions. Nous l'utilisons ensuite pour l'intégration de documents multimédias et de modèles 3D de villes.Enfin, cette thèse s'est déroulée dans un contexte pluridisciplinaire via le projet Fab-Pat, du LabEx IMU, qui s'intéresse au partage de la fabrique du patrimoine. Dans ce cadre, une contribution mêlant sciences sociales et informatique a permis de concevoir DHAL, une méthodologie pour l’analyse comparative de dispositifs pour le partage du patrimoine via le numérique

Notre pratique courante de la chirurgie orthognathique se heurte aux limites des outils standard de planification et de simulation ainsi qu’à l’absence d’assistance peropératoire. L’objectif de notre travail était de développer de nouveaux outils répondant à cette problématique. Ainsi, dans un premier temps, un algorithme de segmentation semi-automatique a permis une modélisation 3D patient-spécifique rapide et précise. Nous avons ensuite élaboré un logiciel de simulation des parties molles fondé sur un modèle mécanique de type masse-ressort permettant une précision millimétrique. Enfin, nous avons conçu un système de navigation temps-réel fondé sur un guidage électromagnétique mini-invasif doté d’une interface utilisateur intuitive. Son évaluation a montré une réduction de la variabilité inter-opérateurs. En plus de son caractère pédagogique, ce système bénéficiait particulièrement aux débutants. Les chirurgiens ont souligné l’intérêt de ce système, tant pour les dysmorphoses complexes que pour les cas de routine. Ces développements constituent ainsi une suite logicielle susceptible d’améliorer la qualité de prise en charge des patients
In our routine practice of orthognathic surgery, we face the limitations of conventional planning and simulation tools, and the lack of convenient intraoperative assistance. If computer science has provided satisfactory solutions for planning, yet simulation and navigation appear improvable. The aim of our research was to provide novel tools to improve these issues. Therefore, we first developed a semi-automated segmentation pipeline allowing accurate and timeefficient patient-specific 3D modeling. We then conceived 1mm-accurate facial soft tissue simulation software based on a mechanical massspring model. Finally, we developed a real-time navigation system based on minimally-invasive electromagnetic tracking, featuring a novel user-friendly interface. Evaluation showed that our software reduced time and accuracy discrepancy between operators. Along with educational purposes, such a system benefited especially trainees. Surgeons emphasized system relevance in the treatment of both, complex and common deformities. Such developments establish a software suite that could provide significant improvement for patient optimal care

In addition to serving as a brief overview of aspects relevant to reduced-order modeling (in particular balanced-state and modal techniques) as applied to structural finite element models, this work produced tools for visualizing the relationship between the modes of a model and the states of its balanced representation. Specifically, error contour and mean error plots were developed that provide a designer with frequency response information absent from a typical analysis of a balanced model via its Hankel singular values. The plots were then used to analyze the controllability and observability aspects of finite element models of an illustrative system from a modal perspective -- this aided in the identification of computational artifacts in the models and helped predict points at which to halt the truncation of balanced states. Balanced reduced-order reference models of the illustrative system were implemented as part of a direct adaptive control algorithm to observe the effectiveness of the models. It was learned that the truncation point selected by observing the mean error plot produced the most satisfactory results overall -- the model closely approximated the dominant modes of the system and eliminated the computational artifacts. The problem of improving the performance of the system was also considered. The truncated balanced model was recast in modal form so that its damping could be increased, and the settling time decreased by about eighty percent.

This dissertation addresses attitude control and inertial navigation of autonomous underwater vehicles (AUVs). We present theoretical justification for using simplified models, derive system identification algorithms, and verify our results through extensive field trials. Although this research focuses on small AUVs with limited instrumentation, the results are useful for underwater vehicles of any size. For attitude control of aircraft systems, second-order equivalent pitch-axis models are common and extensively studied. However, similar analysis has not been performed for the pitch-axis motion of underwater vehicles. In this dissertation, we study the utility and the limitations of second-order approximate models for AUVs. We seek to improve the flight performance and shorten the time required to re-design a control algorithm when the shape, mass-distribution, and/or net buoyancy of an AUV/payload configuration changes. In comparison to commonly implemented AUV attitude controllers, which neglect roll motion and address pitch and yaw dynamics separately, we derive a novel linear time-varying model that explicitly displays the coupling between pitch and yaw motion due to nonzero roll angle and/or roll rate. The model facilitates an Hâ control design approach that explicitly addresses robustness against those coupling terms and significantly reduces the effect of pitch and yaw coupling. To improve AUV navigation, we investigate algorithms for calibrating a triaxial gyroscope using angular orientation measurements and formally define AUV trajectories that are persistently exciting and for which the calibration coefficients are uniformly observable. To improve AUV guidance, we propose a near real-time ocean current identification method that estimates a non-uniform flow-field using only sparse flow measurements.
Ph. D.

The purpose of this study was to gain insights of which design guidelines are vital for developing anavigation solution with Augmented Reality from a usability perspective. We wanted to raise awarenessof how the technology could be used to enable both indoor and outdoor navigation.Design Science Research (DSR) was applied as the research methodology, and created prerequisites toidentify problems connected to Luleå University of Technology’s existing map. The study applied the 7steps of the design thinking process, which made it possible to identify the problems. Through surveysand qualitative interviews in combination with observations, it was possible to create an overall picture ofthe problems to understand the users needs. Based on the feedback from the user tests, the prototype couldbe developed and improved.In the second step, 4 themes were set up based on the empirical data collected, which were Navigation,Augmented Reality, General design and Feedback. These themes followed as a common threadthroughout the study and were used to structure the design guidelines and to develop the prototype. Ourstudy shows the importance of throughout the process carry out a consistent design when designing digitalservices. Through this the user can see connections and understand how the application is structured. Toestablish user participation is important at an early stage of the design process, because it contributes togaining insights into deficiency and positive aspects of the prototype, which in turn contributes to meetingthe user needs. One difficulty identified in the empirical data was problems in distinguishing differentfloors in already existing navigation solutions. In order to solve this problem we found it important tocomplement the 2D view in the solution. In the study, this was supplemented by a parallel AR view and atext showing the number of the floor in the 2D view.Keywords:
Denna studie syftade till att skapa förståelse kring vilka designprinciper som utifrån ettanvändbarhetsperspektiv är avgörande när det kommer till utvecklandet av en navigationslösning medAR-funktionalitet. Studien riktade sig mot att öka medvetenhet kring hur tekniken skulle kunna användasför att agera som hjälpmedel i inom-och utomhusnavigation.Med Design Science Research (DSR) som forskningsmetod, skapades förutsättningar för att kunnaidentifiera problematik med Luleå tekniska universitets befintliga karta. I studien tillämpadesdesigntänkande-processens 7 steg, vilket möjliggjorde för att kunna identifiera dessa problem. Genomenkäter och kvalitativa intervjuer i kombination med observationer gick det att skapa en bild överproblematiken kopplat till Luleå tekniska universitets befintliga karta. Utifrån enkäterna skapades även enförståelse över vilka behov som finns utifrån användarnas perspektiv och genom användartester kundeprototypen utvecklas och förbättras.I det andra steget av designtänkande-processen sattes 4 teman upp utifrån studiens empiri, närmarebestämt Navigation, Augmented Reality, Allmän design samt Feedback. Dessa teman följde som en rödtråd genom studien och användes för att strukturera designprinciperna och utforma prototypen. Vår studievisar på vikten av att genomgående genomföra en konsekvent design vid utformandet av digitala tjänster.Genom detta kan användaren se samband och förstå hur applikationen är uppbyggd. Det gick även attkonstatera att användarmedverkan i ett tidigt skede av designprocessen bidrar till att få insikter i bristeroch positiva aspekter av prototypen som i sin tur leder till att kunna uppfylla användarnas behov. Ettproblem som identifierades var svårigheter att urskilja våningsplan i befintliga navigationslösningar. Föratt kunna urskilja våningsplan fann studien det avgörande att hitta ett komplement till 2D-vyn i ennavigationslösning. Inom prototypen kompletterades detta genom en parallell AR-vy samt text i 2D-vyn.

The architectural industry today struggles with how to best show their models to interested suitors opposite the construction industry which have the advantage of the fact that they can build physical models of houses which they can then show. This is where BIM comes into the picture. By extracting the graphics fromthese models and visualising them in a web browser this studyhas by creating a viewer with different navigation techniques sought to find out which techniques where most efficient for navigating models in the viewer. This was done with the help of user tests which results show that when it comes to projections, users were more efficient with perspective projection than orthogonal projections, however, user interviews show that users could still find a use for orthographic projection as it was better for displaying floor plans. Egocentric perspective were more efficient than allocentric perspective, but most users preferred egocentric perspective inside the models and allocentric projection outside of it. As for clipping objects and using clip planes, it is a closer race as users completed the task faster with clip plane but to a greater extent with culling of objects. However, most users wanted to use both technologies at the same time so that they could complement each other.

This study used airborne gravity data, the 2008 Earth Gravity Model (EGM08) and Shuttle Radar Topographic Mission (SRTM) digital elevation data in a ‘Remove-Compute-Restore’ process to determine absolute vertical reference system for Ethiopia. This gives a geopotential height at any isolated field point where there is a Global Navigation Satellite System (GNSS) measurement without reference to a vertical network or a regional datum point. Previously, height was determined conventionally by connecting the desired field point physically to a nearby bench mark of a vertical network using co-located measurements of gravity and spirit levelling. With the use of precise GNSS positioning and a gravity model this method becomes obsolesce. The new approach uses the ‘Remove-Restore’ process to eliminate longer to shorter wavelengths from the measured gravity data using EGM08 and geometrical and condensed gravity models of the SRTM data. This provides small, smooth and localised residuals so that the interpolation and integration involved is reliable and the Stokes-like integral can be legitimately restricted to a spherical cap. A very fast, stable and accurate computational algorithm has been formulated by combining ‘hedgehog’ and ‘multipoint’ models in order to make tractable an unavoidably huge computational task required to remove the effects of about 1.5 billion! SRTM topographic mass elements representing Ethiopia and its immediate surroundings at 92433 point airborne gravity observations. The compute stage first uses an iterative Fast Fourier Transform (FFT) to predict residual gravity at aircraft height as a regular grid on to the surface of the ellipsoidal Earth and then it used a Fourier operation equivalent to Stokes’ integral to transform the localised gravity disturbance to residual potential. The restore process determines the geopotential number on or above the Earth’s surface where practitioners need it by restoring the potential effects of the removed masses. The accuracy of the geopotential number computed from gravity and topography was evaluated by comparing it with the one derived directly from EGM08 and precise geodetic levelling. The new model is in a good agreement across 100 km baseline with a standard deviation of 56 10−2 2 −2 × m s and 39 10−2 2 −2 × m s relative to EGM08 and levelling, respectively ( 10−2 2 −2 m s is approximately equivalent to 1mm of height). The new method provides an absolute geopotential height of a point on or above the Earth’s surface in a global sense by interpolating from geopotential models prepared as the digital grids carried in a chip for use with the GNSS receiver in the field.

This graduate project compares legacy simplified general perturbation model (SGP4) code developed by NASA Johnson Space Center, Orbital Debris Program Office, to a recent public release of SGP4 code by David Vallado. The legacy code is a subroutine in a larger program named PREDICT, which is used to predict the location of orbital debris in GEO. Direct comparison of the codes showed that the new code yields better results for GEO objects, which are more accurate by orders of magnitude (error in meters rather than kilometers). The public release of SGP4 also provides effective results for LEO and MEO objects on a short time scale. The public release code was debugged and modified to provide instant functionality to the Orbital Debris Program Office. Code is provided in an appendix to this paper along with an accompanying CD. A User’s Guide is presented in Chapter 7.

Syftet med denna undersökning är att finna för- och nackdelar med olika menymodeller och hur de bör se ut för att fungera optimalt på hemsidor för kommuner i Dalarnas län. Resultatet togs fram med hjälp av semistrukturerade kvalitativa intervjuer och användartester. Deltagarna i denna undersökning valdes ut med hjälp av bekvämlighetsurvalet och består av studenter från Högskolan Dalarna. Den analysmetod som användes för att analysera den data som samlades in var en konventionell analysmetod. För att svara på den första frågeställningen om vilken menymodell som var vanligast bland Dalarnas samtliga kommunsidor genomfördes en jämförelse av dessa 15 kommunsidor. Det visade sig att den vanligaste menymodellen på kommunsidor i Dalarna var horisontell och bred med understruken text när muspekaren rörde sig över den, med linjärt typsnitt och utan ikoner. Positionen på hemsidorna är främst centrerad. Efter detta genomfördes användartester och semi-strukturerade intervjuer med testpersoner som fann för- och nackdelar hos specifika menymodeller. Valet av menymodell som bör användas på en kommunal webbplats beror på hur mycket information som fanns att sortera ut. De för- och nackdelar som återfanns på hamburgermenyn var att den sparade utrymme, men var svår att överblicka och klicka rätt på. Card-gridmenyn hade tydlig uppdelning men krävde många klick för att komma till målet.  Drop-downmenyn hade en bra överblick men upplevdes kompakt och vissa rubriker hade med fördel varit klickbara.
The purpose of this study is to find the pros and cons of different menu models and how they should look to function optimally on websites for municipalities in Dalarna County. The results were obtained using semistructured qualitative interviews and user tests. The participants in this study were selected using the convenience selection and consist of students from Dalarna University. The assay method used to analyze the data collected was a conventional assay method. In order to answer the first question about which menu model was most common among all Dalarna municipalities, a comparison of these 15 municipalities was conducted. It turned out that the most common menu model on municipal pages in Dalarna was horizontal and broad with underlined text when the mouse pointer moved over it, with linear typeface and without icons. The position on the websites is mainly centered. After that, user tests and semistructured interviews were conducted with test persons who found the pros and cons of selected menu models. The choice of menu model that should be used on a municipal website depends on how much information there was to sort out. The pros and cons found on the hamburger menu were that it saved space but was difficult to overlook and click right. The card grid menu had a clear breakdown but required many clicks to find where to go. The drop-down menu had a good overview but felt compact and some headlines had advantageously been clickable.

Orientadores: Luiz Roberto Lopes, Celso Dario Ramos
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-21T03:53:07Z (GMT). No. of bitstreams: 1 Alves_JoseRoberto_D.pdf: 4105947 bytes, checksum: af11b64c91070282e755c061d50774e9 (MD5) Previous issue date: 2012
Resumo: Introdução - Com os estudos de Gould et al. (1960), Cabanas (1977) e Morton et al. (1992), estabeleceu-se o conceito da pesquisa do linfonodo sentinela. Esse se baseia na teoria de que ao identificar a presença ou ausência de metástase no primeiro linfonodo que recebe a drenagem linfática a partir do tumor (sentinela), poderia representar o estado de acometimento dos outros linfonodos. Isto evitaria a realização desnecessária de linfadenectomias. Com o passar dos anos, foi consagrada para ser aplicada em casos de melanoma e câncer de mama. Nesta última década, tenta-se estender os princípios da utilização da pesquisa de linfonodo sentinela para os cânceres do aparelho digestivo. Entretanto, no caso do estômago, existem algumas dificuldades, como: presença de sistema de drenagem linfática multidirecional, ocorrência de metástases saltatórias e identificação de mais de um linfonodo sentinela por indivíduo. Objetivo - Criar e padronizar um modelo animal para o treinamento de pesquisa de linfonodos sentinelas em estômago. Método - Trinta e dois coelhos, saudáveis, foram submetidos à anestesia exclusivamente intramuscular. Por meio de laparotomia, foi injetado na subserosa da parede anterior do corpo gástrico, 0,1 ml de fitato marcado com tecnécio-99m (0,2 mCi), em seguida pelo mesmo orifício, de 0,2 ml de Azul Patente V® 2,5%. A cavidade abdominal foi avaliada, "in vivo", para pesquisa de suspeitas de linfonodos azuis (corados em azul) e com detector manual de radiação gamma aos 5, 10 e 20 minutos para detecção de suspeitas de linfonodos radioativos (radioatividade identificada superior a 10X o valor apresentado pelo fundo). Após 20 minutos, realizou-se ressecção e exérese total do estômago, baço e suspeitas de linfonodos, para posterior avaliação da radioatividade "ex vivo". A seguir, encaminharam-se as suspeitas de linfonodos para estudo histológico para identificação de tecido linfóide. Resultados - Foram identificados linfonodos em 30 coelhos (93,75%) com média de 2,2 por animal. Das 90 suspeitas de linfonodos detectadas, em 70 casos (77,77%) obteve-se confirmação histológica para tecido linfóide. Dessas, a maioria foi identificada e localizada na região entre o esôfago e o fundo gástrico durante a avaliação "in vivo" aos 5 minutos. Dois coelhos faleceram durante os experimentos (Taxa de mortalidade = 6,25%). Conclusão - O modelo experimental em coelhos para pesquisa de linfonodos sentinelas em estômago por métodos combinados foi factível, de fácil execução e baixa mortalidade, podendo ser usado para treinamento
Abstract: Introduction - The concept of sentinel lymph node was established by the studies of Gould et al. (1960), Cabanas (1977) and Morton et al. (1992). It is based on the theory that, whenever the presence or absence of metastasis is identified in the first lymph node that receives the lymphatic drainage from the tumor (sentinel) the status of involvement of other lymph nodes might be infered. This could avoid the performance of unnecessary lymphadenectomies. Over the years, its use was consecrated by its application in melanoma and breast cancer. In the last decade, attempts have been made to extend the principles of sentinel lymph node investigation to cancers of the digestive tract. In the case of stomach cancer, additional difficulties were found, such as multiple and aberrant lymphatic routes, the occurrence of skip metastasis and the possible identification of more than one sentinel lymph node in the same patient. Aim - To develop and evaluate an animal model for training sentinel lymph node navigation in the stomach. Methods - Thirtytwo healthy rabbits, were prepped and given intramuscular anesthesia. Through a formal laparotomy, they received a subserosal injection of 0.1 ml of phytate labeled with technetium-99m (0.2 mCi) in the anterior wall of the gastric corpus, followed by 0.2 ml of Blue Patent ® V 2.5%, through the same puncture site. Suspicious lymph nodes were searched in-vivo at 5, 10 and 20 minutes, both visually (Blue Patent stained lymph nodes) and with a manual gamma radiation detector (to detect suspected radioactive lymph nodes, displaying radioactivity levels over 10X the value displayed by the background). En-block resection of the stomach, spleen, visible limph nodes and local fat tissue was then performed and the specimen was assessed "ex vivo" for radioactivity. Suspected lymph nodes were sent for histological study to evaluate the presence of lymphoid tissue. Results - Radiolabeled or stained lymph nodes were identified in 30 rabbits (93.75%) with an average of 2.2 specimens per animal; of the 90 suspicious lymph nodes detected, histology confirmed lymphoid tissue in 70 cases (77.77%). Most lymph nodes were identified at the 5-minute in-vivo evaluation and their most common location was found to be in the region between the esophagus and the gastric fundus. Two rabbits died during the procedure resulting in a 6.25% mortality. Conclusion - The rabbit model proved adequate for training in sentinel node navigation in the stomach by combined methods (dye and radiocolloid) being easy to execute and associated with low mortality
Doutorado
Fisiopatologia Cirúrgica
Doutor em Ciências

Les travaux présentés dans cette thèse portent sur l'étude d'une méthode de fusion multi-capteurs pour l'estimation de la localisation 3-D et l'attitude d'un véhicule terrestre. Nous avons développé et validé, en situation réelle, une méthode de fusion centralisée basée sur une modélisation d'état à partir de mesures GNSS/INS provenant du capteur ublox EVK-M8U. Le système de mesure est également alimenté par des données cartographiques routières OSM et d'élévation issues des modèles numériques ASTER/World 30. Certaines mesures sont modélisées par des équations présentant de fortes non-linéarités que nous avons choisies de traiter par filtrage particulaire. La prise en compte des données cartographiques est faite de manière statistique à partir de la métrique de Mahalanobis. En outre, nous avons développé une nouvelle méthode de gestion des modèles numériques d'élévation (MNE), désignée par la méthode de "Fenêtre Glissante Adjacente" (FGA) afin de limiter l'impact des artefacts présents dans ces données. Durant l'étape de gestion du MNE, nous avons mis en oeuvre des approches géométriques (TIN, FGA) qui permettent de rendre plus robuste la correction d'altitude et favorise un accroissement des performances en estimation du paramètre d'inclinaison des segments de la carte routière numérique
Te work presented in this thesis concerns the study of a multi-sensor fusion method for the estimation of 3-D localization and the attitude of a land vehicle. We have developed and validated, in a real situation, a centralized fusion method based on state modeling from GNSS/INS measurements delivered by the ublox EVK-M8U sensor. The measurement system is also completed by OSM digital road maps and elevation data from the ASTER/World 30 digital models. Some measurements are modeled by equations with strong non-linearities which we have chosen to process by particle filtering. The cartographic data are taken into account statistically from the metric of Mahalanobis. In addition, we have developed a new method for managing digital elevation models (DEM), known as the "Fenêtre Glissante Adjacente" (FGA) method, in order to limit the impact of the artifacts that are found in this data. During the DEM management step, we implemented geometric approaches (TIN, FGA) which make the altitude correction more robust and favors an increase in performance in estimating the inclination parameter of the segments of the digital road maps

The Australian Height Datum (AHD) was established in 1971, and is the basis for all physical heights in Australia. However, a complete revision of the AHD has never occurred, despite problems that, although not always obvious to surveyors at the local level, have come to prominence through the introduction of Global Navigation Satellite Systems (GNSS) and gravimetric quasi/geoid models. Improvements in GNSS, quasi/geoid and sea surface topography (SSTop) models, plus moderate upgrades to the Australian Levelling Network (ANLN) since 1971 now allow a meaningful revision of the AHD to be made. This thesis first conducts an investigation of AHD/ANLN errors, culminating in the realisation of an Australian Experimental Vertical Datum (AEVD).An assessment of 1366 ANLN loops reveals 15-20 misclosures >0.5 m (up to 0.93 m), situated primarily in the interior of the continent. GNSS¡quasi/geoid information was included in a second loop-based assessment, adding redundancy in an attempt to isolate errors within the levelling sections. These assessments indicate that the ANLN database requires corrections and updating by State and Territory geodetic agencies, including the replacement of average two-way levelled height differences between benchmarks (BMs) currently in the database with forward and reverse levelled height differences. A simulation of the effects of refraction on the AHD and ANLN suggest that height errors of up to 0.4 m in central Australia may result from neglecting to apply refraction corrections to the ANLN. However, the metadata required to properly correct the ANLN for refraction is not currently available.A major objective of this thesis is to identify the causes of the north-south slope observed in the AHD when compared with geoid models. The CARS2006 climatology (oceanographic) and Rio05 combined mean dynamic topography (geodetic and oceanographic) SSTop models along with the EGM2008 and gravimetric component of AUSGeoid09 (AGQG09) SSTop estimates at tide-gauges are shown to effectively remove the north-south slope. This indicates that the north-south AHD slope was caused solely by fixing the Australian levelling survey to mean sea level (MSL) at 30 mainland tide-gauges. In addition, it was found that the vertical offset between mainland AHD and Tasmanian AHD (vertical datums separated by the sea) is negligible. The CARS2006 SSTop model provided the best estimates of SSTop at tide-gauges and was used in the final realisation of the AEVD as an SSTop correction when the AEVD is constrained to 32 AHD tide-gauges, also unifying the mainland and Tasmanian levelling networks.To determine the height system best suited to the AEVD, gravity at ANLN BMs was computed from EGM2008 and also from terrestrial gravity held in the Australian National Gravity Database (ANGD). Despite problems with both, "reconstructed" BM gravity from EGM2008 demonstrated the best results and is used for gravimetric height corrections applied to the ANLN. Differences between Helmert orthometric and normal-orthometric heights (used for the AHD) were up to 0.44 m at heights >2,000 m in the Australian Alps. However, differences between normal and normal-orthometric heights were <30 mm across most of Australia, but reached 0.17 m in the Australian Alps. Normal heights were considered most appropriate for the AEVD because of the sensitivity of Helmert orthometric heights to the poor quality of ANGD- and EGM2008- derived gravity, and normal-orthometric heights being inconsistent with quasigeoid models, particularly at elevations >1,000 m.A combined least-squares adjustment (CLSA) of the ANLN (with normal height corrections applied to the levelling) was conducted using MSL + CARS2006 at 32 AHD tide-gauges and GNSS-AGQG09 at 277 GNSS stations as weighted constraints to realise the AEVD. An outlier detection process was undertaken first, to attempt to identify the problem levelling sections of the ANLN and re-weight them so they have less infuence in the CLSA. Validation of the AEVD used GNSS-AGQG09 at 765 GNSS stations not used in the CLSA. RMS of the differences at the 765 GNSS stations between the AEVD and GNSS-AGQG09 were ±0.098 m (considered external accuracy), compared to an RMS of ±0.207 m for differences between the AHD and GNSS-AGQG09, indicating an improvement of the AEVD over the AHD.

In this thesis, a new guidance method for fighter aircrafts and a new guidance method for missiles are developed. Also, guidance and control systems of the aircraft and the missile used are designed to simulate the generic engagement scenarios between the missile and the aircraft. Suggested methods have been tested under excessive simulation studies. The aircraft guidance method developed here is a rule based missile evasion method. The main idea to develop this method stems from the maximization of the miss distance for an engagement scenario between a missile and an aircraft. To do this, an optimal control problem with state and input dependent inequality constraints is solved and the solution method is applied on different problems that represent generic scenarios. Then, the solutions of the optimal control problems are used to extract rules. Finally, a method that uses the interpolation of the extracted rules is given to guide the aircraft. The new guidance method developed for missiles is formulated by modifying the classical proportional navigation guidance method using the position estimates. The position estimation is obtained by utilization of a Kalman based filtering method, called interacting multiple models.

Selbstorganisierte drahtlose (ad hoc) Multihopnetzwerke können als einfach einsetzbare, robuste und rekonfigurierbare Kommunikationsinfrastruktur zum Beispiel in Katastrophenszenarien eingesetzt werden. Solche drahtlosen Netzwerke nutzen die Luft als geteiltes Kommunikationsmedium, was bedeutet, dass die Parameter des Netzwerks sehr orts- und zeitveränderlich sowie verrauscht sind. Intelligente Roboter können als Netzwerkknoten diese Herausforderungen bewältigen, indem sie sensomotorische Interaktion ausnutzen. Für einzelne Roboter wurde ein Algorithmus zur Exploration unbekannter Netzwerke entwickelt. Außerdem wurde gezeigt, dass eine Klasse gradientenbasierter Navigationsalgorithmen für den Fall von Signalstärkemessungen konvergiert. Es wurde zudem gezeigt wie diese Art von Algorithmen sich auf andere Aufgaben als das Finden von Netzwerkknoten erweitern lassen. Zusätzlich wurde ein Algorithmus basierend auf internen Modellen, der dem Roboter zum Beispiel ermöglicht Netzwekknoten finden oder zwei Netzwerkknoten zu überbrücken, entwickelt. Alle Algorithmen wurden in Simulation oder mit echten Robotern implementiert und evaluiert. Für den Fall mehrerer Roboter existieren bereits viele interessante Algorithmen in der Literatur. Allerdings wird im Moment keiner dieser Algorithmen in realen Systemen eingesetzt. Einer der Gründe hierfür ist, dass naive Sachwarmalgorithmen meist nicht sicher und zuverlässig genug sind. Um dieses Problem zu lösen wurde eine Architektur, die auf internen Modellen basiert und interne Simulation nutzt, untersucht. Es wurden zwei Testszenarien analysiert: Im ersten Experiment sollte ein Roboter andere Roboter davor bewahren zu Schaden zu kommen und dabei gleichzeitig seine eigene Sicherheit gewährleisten und eine Aufgabe erfüllen. Im zweiten Experiment musste ein Roboter durch einen Korridor navigieren ohne mit anderen Robotern zusammenzustoßen. Die vorgeschlagene Architektur hat sich als sehr effektiv erwiesen.
Self-organized wireless multihop (ad hoc) networks can form an easily deployable, robust and reconfigurable communication infrastructure, which can be employed for example in a disaster scenario, when static communication infrastructure has been destroyed. As such wireless networks use the air as a shared physical medium, the parameters of these networks often show very space- and time-varying noisy characteristics. Intelligent robotic network nodes can overcome these problems posed by these dynamics and measurement noise by exploiting sensorimotor interaction. For single robots, an algorithm for network exploration of unknown networks for large scale outdoor scenarios has been developed. Furthermore, a class of gradient-based algorithms for navigation in wireless networs hase been shown to converge for the case of signal strength measurements. Additionally, it was shown how these algorithms can be extended to other tasks than locating a network node. Additionally, an internal model-based algorithm to solve tasks like locating a node or bridging two nodes has been developed. All algorithms have been implemented and evaluated either in simulation or on real robots. For the case of multiple robots, a lot of interesting algorithms for example for optimal placement of mobile network nodes have been presented in literature. However, none of them are being used in real world scenarios. One of the reasons for that is insufficient safety and fault tolerance of naive algorithms. To overcome this problem the use of an internal model-based architecture using internal simulation has been investigated. Two test scenarios have been investigated using this architecture: in the first experiment a robot had to prevent other robots from coming to harm while ensuring its own safety and fulfilling a task. In a second experiment, a robot had to navigate through a narrow corridor without colliding with other robots. The proposed architecture has been shown to be very effective.

Les travaux de cette thèse ont pour but de développer un prototype d’éco-pilote, nommé EcoNav, permettant d’optimiser la vitesse d’un bateau afin de réduire sa consommation de carburant. EcoNav est composé de plusieurs modules dont : un modèle hydraulique 2D simulant l’écoulement hydrodynamique (vitesse du courant et hauteur d’eau) le long du trajet du bateau; - un modèle de résistance à l’avancement servant à alimenter un modèle de prédiction de la consommation de carburant; - un algorithme d’optimisation permettant de trouver le profil optimal de vitesse. Afin de pouvoir estimer la consommation de carburant, un modèle numérique de la résistance à l’avancement en milieu confiné a été développé durant la première partie de cette thèse. Ce modèle numérique 3D simule l’écoulement du fluide autour du bateau et permet de calculer les forces agissant sur sa coque. La résolution des équations RANS est couplée avec un algorithme de quasi-Newton afin de trouver la position d’équilibre du bateau et calculer son enfoncement. Cette méthode est validée en comparant les résultats numériques avec des résultats expérimentaux issus d’essais en bassin de traction. L’influence de l’enfoncement sur la résistance à l’avancement et la précision de la méthode est étudiée en comparant les résultats numériques obtenus avec et sans enfoncement. La précision des modèles empiriques de prédiction de la résistance à l’avancement est également comparée à celle du modèle numérique. Enfin, le modèle numérique est utilisé afin de déterminer si le confinement en largeur ou en profondeur ont une influence identique sur l’augmentation de résistance à l’avancement. Les résultats de cette étude permettent d’établir si le confinement de la voie d’eau peut être caractérisé à l’aide d’un paramètre unique (coefficient de blocage par exemple) ou bien deux paramètres permettant de distinguer le confinement latéral et vertical. Dans la seconde partie de cette thèse, les méthodes numériques utilisées pour le modèle d’éco-pilote sont décrites et comparées afin de sélectionner celles qui sont le plus adaptées à chaque module. EcoNav est ensuite utilisé afin de modéliser un cas réel : celui du bateau automoteur Oural navigant sur la Seine entre Chatou et Poses (153 km). La consommation optimisée est comparée à la consommation non optimisée, calculée à partir des vitesses AIS observées sur le tronçon étudié. L’influence de la trajectoire du bateau et de son temps de parcours sur sa consommation sont également étudiés. Les résultats de ces investigations ont montré qu’optimiser la vitesse du bateau permet d’obtenir une réduction de la consommation de carburant de l’ordre de 8 % et qu’optimiser la trajectoire du bateau ainsi que prendre en compte des informations en temps réel (disponibilité des écluses, trafic sur le fleuve) peuvent permettre de réaliser des économies de carburant supplémentaires
An eco-driving prototype, named EcoNav, is developed with the aim of optimizing a vessel speed in order to reduce fuel consumption for a given itinerary. EcoNav is organized in several modules : - a 2D hydraulic model simulating the flow conditions (current speed and water depth) along the itinerary; - a ship resistance model calculating the thrust necessary to counteract the hydrodynamic forces ; - a fuel consumption model calculating the fuel consumption corresponding to the thrust input; - a non linear optimization algorithm calculating the optimal speed profile. In order to evaluate the fuel consumption of an inland vessel, a ship resistance numerical model is developed in the first part of this PhD. This 3D numerical model simulates the flow around an inland self-propelled vessel and evaluates the hydrodynamic forces acting on the hull. A RANS solver is coupled with a quasi-Newton approach to find the equilibrium position and calculate ship sinkage. This method is validated by comparing the results of numerical simulations to towing tank tests. The numerical results with and without sinkage are also compared to study the influence of sinkage on ship resistance and on the accuracy of the method. Additionally, some empirical models are investigated and compared with the accuracy of the numerical method. Finally, the numerical model is used to determine if channel with and water depth restriction contribute to the same amount of ship resistance increase for the same level of restriction. The results of that investigation give insight to whether channel restriction can be characterized by a unique parameter (for instance the blockage ratio) or two parameters to distinguish water depth and channel with effects. In the second part of this PhD, the numerical methods used in the speed optimization model are described and validated. The speed optimization model is then used to simulate a real case: the itinerary of the self-propelled ship Oural on river Seine, between Chatou and Poses (153 km). The optimized fuel consumption is compared with the non-optimized fuel consumption, based on AIS speed profile retrieved on this itinerary. The effects of the ship trajectory and travel duration on fuel consumption are also investigated. The results of those investigations showed that optimizing the ship speed lead to an average fuel saving of 8 % and that using an optimal track and including real time information such as lock availability and river traffic can lead to additional fuel savings

In the case of one car following another to a destination, it is very effective at getting the second vehicle to the destination quickly; however, the driver of the second car may not learn the route. Yet, for individuals, such as firefighters, law enforcement, and military personnel, it is imperative that a route be learned quickly and accurately and that an awareness of the situation is maintained while they traverse the given route. This leads to three questions, (a) will navigation aids affect initial route navigation; (b) will navigation aids affect retention; and (c) will navigation aids affect situation awareness while en route? The hypotheses of this study were that navigation aids would significantly increase the speed at which a person can initially navigate a route, but the use of the aids would significantly decrease the retention of the route navigated. The findings of this study support the hypotheses. The results suggest that participants that followed a confederate and participants that were given verbal directions were quicker and made fewer errors than participants that reviewed a map or initially figured the route out on their own (control group). The study also showed that as the participants navigated the route for a second time with no navigational assistance, the ones that reviewed a map or that were in the control group outperformed participants that initially had a confederate to follow or were given verbal directions their first time through. Finally, no real effects were found on the participants' situation awareness during the retention portion of the study.
Ph.D.
Other
Engineering and Computer Science
Modeling and Simulation

L'arrivée de la norme MPEG-7 pour les vidéos exige la création de structures de haut niveau représentant leurs contenus. Le travail de cette thèse aborde l'automatisation de la fabrication d'une partie de ces structures. Comme point de départ, nous utilisons des outils de segmentation des objets en mouvement. Nos objectifs sont alors : retrouver des objets similaires dans la vidéo, utiliser les similarités entre plans caméras pour construire des regroupements de plans en scènes. Une fois ces structures construites, il est facile de fournir aux utilisateurs finaux des outils de visualisation de la vidéo permettant des navigations interactives : par exemple sauter au prochain plan ou scène contenant un personnage. La difficulté principale réside dans la grande variabilité des objets observés : changements de points de vues, d'échelles, occultations, etc. La contribution principale de cette thèse est la modélisation de la variabilité des observations par un mélange de densités basée sur la théorie du mélange gaussien. Cette modélisation permet de capturer les différentes apparences intra-plan de l'objet suivi et de réduire considérablement le nombre des descripteurs de bas niveaux à indexer par objet suivi. Autour de cette contribution se greffent des propositions qui peuvent être vues comme des mises en oeuvre de cette première pour différentes applications : mise en correspondance des objets suivis représentés par des mélanges gaussiens, fabrication initiale des catégories de tous les objets présents dans une vidéo par une technique de classification non supervisée, extraction de vues caractéristiques et utilisation de la détection d'objets similaires pour regrouper des plans en scènes
The arrival of the MPEG-7 standard for videos requires the creation of high level structures representing their content. The work of this thesis approaches the automatic building of a part of these structures. As a starting point, we use the tools for segmentation of moving objects. Our objectives are then to find similar objects in the video and subsequently use the similarities between camera shots to group shots into video scenes. Once these structures have been built, it is easy to provide video visualization tools for the end users which permit interactive navigation like jumping to the next shot or scene containing a person. The main difficulty lies in the great variability of observed objects: changes in point of view, scales, collusions, etc. The principal contribution of this thesis is the modeling of the variability of observations by a mixture of densities based on the Gaussian mixture theory. This modeling captures various intra-shot appearances of a tracked object and considerably reduces the number of low-level descriptors to be indexed by each tracked object. The proposed formulation led to an implementation designed for different applications: matching of tracked object models represented by Gaussian mixtures, initial building of categories of all objects present in a video by a non-supervised classification technique, extraction of characteristic views and use of detected similar objects for grouping shots into scenes. Keywords: Hyperlinked video, MPEG-7, Object recognition and classification, Variability modeling, Gaussian mixture models, Interactive video navigation, Video structure

Cette thèse explore le développement et la validation des systèmes de navigation autonome dans un environnement de réalité mixte (RM), avec pour objectif de combler l’écart entre la simulation virtuelle et les tests en conditions réelles. Les travaux mettent l’accent sur le potentiel des environnements en réalité mixte pour tester les systèmes autonomes de manière sûre, efficace et économique. La thèse est structurée en plusieurs parties, et commence par une revue des technologies de pointe dans la navigation autonome et les applications en réalité mixte. En utilisant des modèles à base de règles et des modèles d’apprentissage, des expérimentations visent à évaluer les performances des robots autonomes dans des environnements simulés, réels et de RM. Un des objectifs principaux est de réduire le « reality gap »—c’est-à-dire la différence entre les comportements observés en simulation et ceux observés dans des applications réelles—en intégrant des éléments réels avec des composants virtuels dans des environnements de RM. Cette approche permet des tests et une validation plus proche des contraintes réelles sans les risques associés aux essais physiques. Une partie importante du travail est consacrée à la mise en œuvre et au test d’une stratégie d’augmentation hors ligne visant à améliorer les capacités de perception des systèmes autonomes à l’aide des informations de profondeur. De plus, l’apprentissage par renforcement est appliqué pour évaluer son potentiel dans les environnements de RM. La thèse démontre que ces modèles peuvent apprendre efficacement à naviguer et à éviter les obstacles dans des simulations virtuelles et obtenir des résultats similaires lorsqu’ils sont transférés dans des environnements de RM, soulignant la flexibilité du cadre pour différents modèles de systèmes autonomes. À travers ces expériences, la thèse montre le potentiel des environnements de réalité mixte comme une plateforme polyvalente et robuste pour faciliter le développement des technologies de navigation autonome, offrant une approche plus sûre et plus évolutive pour la validation des modèles avant leur déploiement dans le monde réel
This thesis explores the development and validation of autonomous navigation systems within a mixed-reality (MR) framework, aiming to bridge the gap between virtual simulation and real-world testing. The research emphasizes the potential of MR environments for safely, efficiently, and cost-effectively testing autonomous systems. The thesis is structured around several chapters, beginning with a review of state-of-the-art technologies in autonomous navigation and mixed-reality applications. Through both rule-based and learning-based models, the research investigates the performance of autonomous robots within simulated, real, and MR environments. One of the core objectives is to reduce the "reality gap"—the discrepancy between behaviors observed in simulations versus real-world applications—by integrating real- world elements with virtual components in MR environments. This approach allows for more accurate testing and validation of algorithms without the risks associated with physical trials. A significant part of the work is dedicated to implementing and testing an offline augmentation strategy aimed at enhancing the perception capabilities of autonomous systems using depth information. Furthermore, reinforcement learning (RL) is applied to evaluate its potential within MR environments. The thesis demonstrates that RL models can effectively learn to navigate and avoid obstacles in virtual simulations and perform similarly well when transferred to MR environments, highlighting the framework’s flexibility for different autonomous system models. Through these experiments, the thesis establishes MR environments as a versatile and robust platform for advancing autonomous navigation technologies, offering a safer, more scalable approach to model validation before real-world deployment

The project has been directed towards improving the accuracy and safety of marine navigation and ship handling, whilst contributing to reduced manning and improved fuel costs. Thus, the aim of the work was to investigate, design and develop an adaptable mathematical model that could be used in an integrated navigation system (INS) and an automatic collision avoidance system (ACAS) for use in marine vehicles. A general overview of automatic navigation is undertaken and consideration is given to the use of microprocessors on the bridge. Many of these systems now require the use of mathematical models to predict the vessels' manoeuvring characteristics: The different types and forms of models have been investigated and the derivation of their hydrodynamic coefficients is discussed in detail. The model required for an ACAS should be both accurate and adaptable, hence, extensive simulations were undertaken to evaluate the suitability of each model type. The modular model was found to have the most adaptable structure. All the modular components of this model were considered in detail to improve its adaptability, the number of non-linear terms in the hull module being reduced. A novel application, using the circulation theory to model the propeller forces and moments, allows the model to be more flexible compared to using traditional B-series four-quadrant propeller design charts. A new formula has been derived for predicting the sway and yaw components due to the propeller paddle wheel effect which gives a good degree of accuracy when comparing simulated and actual ship data, resulting in a mean positional error of less than 7%. As a consequence of this work, it is now possible for an ACAS to incorporate a ship mathematical model which produces realistic manoeuvring characteristics. Thus, the study will help to contribute to safety at sea.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California
Embedded GIS in Intelligent Navigation System is a special information system. This paper puts forward several basic principles and constraints during design for Embedded GIS at first, and then analyzes the feature of embedded platform and the function of Intelligent Navigation System, and presents a realization scheme of Embedded GIS.

Web pages serve a huge number of internet users in nearly every area. An adequate testing is needed to address the problems of web domains for more efficient and accurate services. We present an automated tool to test web applications against execution errors and the errors occured when many users connect the same server concurrently. Our tool, called NaMoX, attains the clickables of the web pages, creates a model exerting depth first search algorithm. NaMoX simulates a number of users, parses the developed model, and tests the model by branch coverage analysis. We have performed experiments on five web sites. We have reported the response times when a click operation is eventuated. We have found 188 errors in total. Quality metrics are extracted and this is applied to the case studies.

While facing different tasks in space, the necessity to create a reliable way of navigation in space is required. The model is developed to analyze the availability of the navigation satellites in space
National Aviation University

The clothoid, also known as the Cornu spiral, is a curve generated by linearly increasing or decreasing curvature as a function of arc length. The clothoid has been widely accepted as a logical curve for transitioning from straight segments to circle arcs in roads and railways, because a vehicle following the curve at constant speed will have a constant change of centripetal acceleration. Clothoids have also been widely adopted in planning potential paths for autonomous vehicle navigation. They have been viewed as useful representations of possible trajectories that are dynamically feasible. Surprisingly, the assumptions that underlie this choice appear to be lightly treated or ignored in past literature. This thesis will examine three key assumptions that are implicitly made when assuming that a vehicle will follow a clothoid path. The first assumption is that the vehicle's steering mechanism will produce a linear change in turning radius for a constant rate input. This assumption is loosely referred to as the "bicycle model" and it relates directly to the kinematic parameters of the steering mechanism. The second assumption is that the steering actuator can provide a constant steering velocity. In other words, the actuator controlling the steering motion can instantaneously change from one rate to another. The third assumption is that the vehicle is traveling at a constant velocity. By definition, the clothoid is a perfect representation of a vehicle traveling at constant velocity with a constant rate of change in steering curvature. The goal of this research was to examine the accuracy of these assumptions for a typical Ackermann-steered ground vehicle. Both theoretical and experimental results are presented. The vehicle that was used as an example in this study was a modified Club Car Pioneer XRT 1500. This Ackermann-steered vehicle was modified for autonomous navigation and was one of Virginia Tech's entries in the DARPA 2005 Grand Challenge. As in typical operation, path planning was conducted using the classic clothoid curve model. The vehicle was then commanded to drive a selected path, but with variations in speed and steering rate that are inherent to the real system. The validity of the three assumptions discussed above were examined by comparing the actual vehicle response to the planned clothoid. This study determined that the actual paths driven by the vehicle were generally a close match to the originally planned theoretical clothoid path. In this study, the actual kinematics of the Ackermann vehicle steering system had only a small effect on the driven path. This indicates that the bicycle model is a reasonable simplification, at least for the case studied. The assumption of constant velocity actuation of the steering system also proved to be reasonably accurate. The greatest deviation from the planned clothoid path resulted from the nonlinear velocity of the vehicle along the path, especially when accelerating from a stop. Nevertheless, the clothoid path plan generally seems to be a good representation of actual vehicle motion, especially when the planned path is updated frequently.
Master of Science

This thesis regards the problem of optimal management of water resources in inland navigation networks from a control theory perspective. In particular, the main objective to be attained consists in guaranteeing the navigability condition of the network, i.e., ensuring that the water levels are such that vessels can travel safely. More specifically, the water levels must be kept within an interval around the setpoint. Other common objectives include minimizing the operational cost and ensuring a long lifespan of the equipment. However, inland navigation networks are large-scale systems characterized by a number of features that complicate their management, namely complex dynamics, large time delays and negligible bottom slopes. In order to achieve the optimal management, the efficient control of the hydraulic structures, e.g., gates, weirs and locks, must be ensured. To this end, a control-oriented modeling approach is derived based on an existing simplified model obtained from the Saint-Venant equations. This representation reduces the complexity of the original model, provides flexibility and allows to coordinate current and delayed information in a systematic manner. However, the resulting model formulation belongs to the class of delayed descriptor systems, for which standard control and state estimation tools would need to be extended. Instead, model predictive control and moving horizon estimation can be easily adapted for this formulation, as well as being able to deal with physical and operational constraints in a natural manner. Due to the large dimensionality of inland navigation networks, a centralized implementation is often neither possible nor desirable. In this regard, non-centralized approaches are considered, decomposing the overall system in subsystems and distributing the computational burden among the local agents, each of them in charge of meeting the local objectives. Given the fact that inland navigation networks are strongly coupled systems, a distributed approach is followed, featuring a communication protocol among local agents. Despite the optimality of the computed solutions, state estimation will only be effective provided that the sensors acquire reliable data. Likewise, the control actions will only be applied correctly if the actuators are not impacted by faults. Indeed, any error can lead to an inefficient management of the system. Therefore, the last part of the thesis is concerned with the design of supervisory strategies that allow to detect and isolate faults in inland navigation networks. All the presented modeling, centralized and distributed control and state estimation and fault diagnosis approaches are applied to a realistic case study based on the inland navigation network in the north of France to validate their effectiveness.
Cette thèse contribue à répondre au problème de la gestion optimale des ressources en eau dans les réseaux de navigation intérieure du point de vue de la théorie du contrôle. Les objectifs principales à atteindre consistent à garantir la navigabilité des réseaux de voies navigables, veiller à la réduction des coûts opérationnels et à la longue durée de vie des équipements. Lors de la conception de lois de contrôle, les caractéristiques des réseaux doivent être prises en compte, à savoir leurs dynamiques complexes, des retards variables et l’absence de pente. Afin de réaliser la gestion optimale, le contrôle efficace des structures hydrauliques doit être assuré. A cette fin, une approche de modélisation orientée contrôle est dérivée. Cependant, la formulation obtenue appartient à la classe des systèmes de descripteurs retardés, pour lesquels la commande prédictive MPC et l’estimation d’état sur horizon glissant MHE peuvent être facilement adaptés à cette formulation, tout en permettant de gérer les contraintes physiques et opérationnelles de manière naturelle. En raison de leur grande dimensionnalité, une mise en œuvre centralisée n’est souvent ni possible ni souhaitable. Compte tenu du fait que les réseaux de navigation intérieure sont des systèmes fortement couplés, une approche distribuée est proposée, incluant un protocole de communication entre agents. Malgré l’optimalité des solutions, toute erreur peut entraîner une gestion inefficace du système. Par conséquent, les dernières contributions de la thèse concernent la conception de stratégies de supervision permettant de détecter et d’isoler les pannes des équipements. Toutes les approches présentées sont appliquées à une étude de cas réaliste basée sur le réseau de voies navigables du nord e la France afin de valider leur efficacité.
La present tesi versa sobre el problema de la gestió òptima dels recursos hídrics en vies de navegació interior des de la perspectiva de la teoria de control. Concretament, l’objectiu principal radica en garantir la condició de navegabilitat del s is tema. Dit d’una altra manera, es vol garantir que els nivells d’aigua siguin tals que les embarcacions puguin navegar-hi de forma segura. Aquest objectiu s’assoleix mantenint els nivells a l’interior d’un interval construït al voltant del punt d’operació. Altres objectius comuns en aquest context as piren a minimitzar els cos tos associats a l’operació dels equips, així com a prolongar-ne la seva vida útil. Ara bé, les vies de navegació interior són sistemes a gran escala caracteritzats per dinàmiques complexes, grans retards temporals i pendents negligibles, aspectes que en dificulten la gestió. Per tal d’assolir la ges tió òptima, s’ha de garantir un control eficient de les estructures hidràuliques tals com comportes, dics i rescloses. Amb aquesta finalitat, es deriva un modelat del sistema orientat a control basat en un model existent simplificat, obtingut a partir de les equacions de Saint-Venant. Aquesta nova representació redueix la complexitat del model original, proporciona flexibilitat i permet coordinar informació actual i retardada de manera sistemàtica. Malgrat això, la formulació resultant pertany a la classe de sistemes descriptors amb retard, per als quals les tècniques de control i d’estimació estàndards necessiten ser esteses. En canvi, el control predictiu basat en models i l’estimació d’estat amb horitzó lliscant es poden adaptar fàcilment a la formulació proposada. A més, són capaços de tractar amb restriccions físiques i operacionals de forma natural. Degut a les grans dimensions de les vies de navegació interior, una implementació centralitzada no resulta, tot sovint, ni possible ni desitjada. Per tal de pal·liar aquest problema, es consideren mètodes no centralitzats. D’aquesta manera, es descompon el sistema global en subsistemes i es distribueix la càrrega computacional del problema centralitzat entre els agents locals, de manera que cadascun d’ells s’encarrega de fer complir els objectius locals . En tant que les vies de navegació interior són sistemes fortament connectats, se segueix un plantejament distribuït, incloent un protocol de comunicació entre els agents locals. Malgrat la optimalitat dels resultats que les estratègies proposades puguin proporcionar, l’estimació d’estat només serà efectiva a condició que els sensors proveeixin informació fiable. Igualment, les accions de control únicament es podran aplicar correctament si els actuadors no estan afectats per fallades. En efecte, qualsevol error pot conduir a una gestió ineficaç del sistema. És per aquest motiu que la darrera part de la tes i tracta s obre el disseny d’estratègies de supervisió, que permetin detectar i aïllar fallades en vies de navegació interior. Tots els resultats de modelat, control i estimació d’es tat centralitzats i distribuïts, així com de diagnòstic de fallades, s’apliquen a un cas d’estudi realista, basat en les vies de navegació interior del nord de França, per tal de provar-ne la seva eficàcia.
La presente tesis versa sobre el problema de la gestión óptima de los recursos hídricos en vías de navegación interior desde la perspectiva de la teoría de control. En concreto, el objetivo principal consiste en garantizar la condición de navegabilidad del sistema, es decir, garantizar que los niveles de agua de los canales sean tales que las embarcaciones puedan navegar de forma segura. Dicho objetivo se consigue manteniendo los niveles dentro de un intervalo alrededor del punto de operación. Otros objetivos comunes consisten en minimizar los costes asociados a la operación de los equipos, así como a extender su vida útil. Hay que tener en cuenta que las vías de navegación interiores son sistemas a gran escala caracterizados por dinámicas complejas, grandes retardos temporales y pendientes prácticamente nulas, lo que dificulta su gestión. Para alcanzar la gestión óptima, se debe garantizar un control eficiente de las estructuras hidráulicas tales como compuertas, diques y esclusas, y para ello se deriva un modelado del sistema orientado a control, basado en un modelo simplificado ya existente, obtenido a partir de las ecuaciones de Saint-Venant. Esta nueva representación reduce la complejidad del modelo original, proporciona flexibilidad y permite coordinar información actual y retardada de forma sistemática. Sin embargo, la formulación resultante pertenece a la clase de sistemas descriptores con retardos, para los cuales las técnicas de control y de estimación de estado estándares necesitan ser extendidas. En cambio, el control predictivo basado en modelos y la estimación de estado con horizonte deslizante pueden ser fácilmente adaptadas para la formulación propuesta, además de permitir lidiar con restricciones físicas y operacionales de forma natural. Hay que tener en cuenta que, debido a las grandes dimensiones de las vías de navegación interior, una implementación centralizada no es, a menudo, ni posible ni deseada, y para paliar este problema se consideran los enfoques no centralizados. De este modo, se descompone el sistema global en subsistemas y se distribuye la carga computacional del problema centralizado entre los agentes locales, de manera que cada uno de ellos se encarga de cumplir los objetivos locales. Como las vías de navegación interior son sistemas fuertemente conectados, se sigue un enfoque distribuido, incluyendo un protocolo de comunicación entre los agentes. También se ha de considerar que la estimación de estado sólo será efectiva a condición de que los sensores provean información fiable. Asimismo, las acciones de control únicamente se podrán aplicar correctamente si los actuadores no están afectados por fallas. En efecto, cualquier avería puede conducir a una gestión ineficaz del sistema. Es por ello que la última parte de la tesis trata sobre el diseño de estrategias de supervisión que permitan detectar y aislar fallas en vías de navegación interior. Todos los resultados de modelado, control y estimación de estado centralizados y distribuidos, así como de diagnóstico de fallas, se aplican a un caso de estudio realista basado en las vías de navegación interior del norte de Francia para probar su eficacia.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics and Dept. of Electrical Engineering and Computer Science, 1991.
Includes bibliographical references (p. 125-127).
by Ali J. Azarbayejani.
M.S.

As the number of spacecraft in simultaneous operation continues to grow, there is an increased dependency on ground-based navigation support. The current baseline system for deep space navigation utilizes Earth-based radiometric tracking, which requires long duration, often global, observations to perform orbit determination and generate a state update. The age, complexity, and high utilization of the assets that make up the Deep Space Network (DSN) pose a risk to spacecraft navigation performance. With increasingly complex mission operations, such as automated asteroid rendezvous or pinpoint planetary landing, the need for high accuracy and autonomous navigation capability is further reinforced. The Network-Based Navigation (NNAV) method developed in this research takes advantage of the growing inter-spacecraft communication network infrastructure to allow for autonomous state measurement. By embedding navigation headers into the data packets transmitted between nodes in the communication network, it is possible to provide an additional source of navigation capability. Simulation results indicate that as NNAV is implemented across the deep space network, the state estimation capability continues to improve, providing an embedded navigation network. To analyze the capabilities of NNAV, an analysis and simulation framework is designed that integrates navigation and communication analysis. Model-Based Systems Engineering (MBSE) and Agent-Based Modeling (ABM) techniques are utilized to foster a modular, expandable, and robust framework. This research has developed the Space Navigation Analysis and Performance Evaluation (SNAPE) framework. This framework allows for design, analysis, and optimization of deep space navigation and communication architectures. SNAPE captures high-level performance requirements and bridges them to specific functional requirements of the analytical implementation. The SNAPE framework is implemented in a representative prototype environment using the Python language and verified using industry standard packages. The capability of SNAPE is validated through a series of example test cases. These analyses focus on the performance of specific state measurements to state estimation performance, and demonstrate the core analytic functionality of the framework. Specific cases analyze the effects of initial error and measurement uncertainty on state estimation performance. The timing and frequency of state measurements are also investigated to show the need for frequent state measurements to minimize navigation errors. The dependence of navigation accuracy on timing stability and accuracy is also demonstrated. These test cases capture the functionality of the tool as well as validate its performance. The SNAPE framework is utilized to capture and analyze NNAV, both conceptually and analytically. Multiple evaluation cases are presented that focus on the Mars Science Laboratory's (MSL) Martian transfer mission phase. These evaluation cases validate NNAV and provide concrete evidence of its operational capability for this particular application. Improvement to onboard state estimation performance and reduced reliance on Earth-based assets is demonstrated through simulation of the MSL spacecraft utilizing NNAV processes and embedded packets within a limited network containing DSN and MRO. From the demonstrated state estimation performance, NNAV is shown to be a capable and viable method of deep space navigation. Through its implementation as a state augmentation method, the concept integrates with traditional measurements and reduces the dependence on Earth-based updates. Future development of this concept focuses on a growing network of assets and spacecraft, which allows for improved operational flexibility and accuracy in spacecraft state estimation capability and a growing solar system-wide navigation network.

This thesis presents a new strategy in achieving highly reliable and accurate position solutions fulfilling the requirements of Location-Based Services (LBS) pedestrians’ applications. The new strategy is divided into two main parts. The first part integrates the available positioning technology within the surrounding LBS application context by introducing an adaptive LBS framework. The context can be described as a group of factors affecting the application behaviour; this includes environmental states, available resources and user preferences. The proposed adaptive framework consists of several stages, such as defining the contextual factors that have a direct effect on the positioning performance, identifying preliminary positioning performance requirements associated with different LBS application groups, and introducing an intelligent positioning services selection function. The second part of this work involves the design and development of a novel positioning model that is responsible for delivering highly reliable, accurate and precise position solutions to LBS users. This new model is based on the single frequency GPS Standard Positioning Service (SPS). Additionally, it is incorporated within the adaptive LBS framework while providing the position solutions, in which all identified contextual factors and application requirements are accounted. The positioning model operates over a client-server architecture including two main components, described as the Localisation Server (LS) and the Mobile Unit (MU). Hybrid functional approaches were developed at both components consisting of several processing procedures allowing the positioning model to operate in two position determination modes. Stand-alone mode is used if enough navigation information was available at the MU using its local positioning device (GPS/EGNOS receiver). Otherwise, server-based mode is utilised, in which the LS intervenes and starts providing the required position solutions. At the LS, multiple sources of GPS augmentation services were received using the Internet as the sole augmentation data transportation medium. The augmentation data was then processed and integrated for the purpose of guaranteeing the availability of valid and reliable information required for the provision of accurate and precise position solutions. Two main advanced position computation methods were developed at the LS, described as coordinate domain and raw domain. The positioning model was experimentally evaluated. According to the reported results, the LS through the developed position computation methods, was able to provide position samples with an accuracy of less than 2 meters, with high precision at 95% confidence level; this was achieved in urban, rural, and open space (clear satellite view) navigation environments. Additionally, the integrity of the position solutions was guaranteed in such environments during more than 90% of the navigation time, taking into consideration the identified integrity thresholds (Horizontal Alert Limits (HAL)=11 m). This positioning performance has outperformed the existing GPS/EGNOS service which was implemented at the MU in all scenarios and environments. In addition, utilising a simulation evaluation facility the developed positioning model performance was quantified with reference to a hybrid positioning service that will be offered by future Galileo Open Service (OS) along with GPS/EGNOS. Using the statistical t-test, it was concluded that there is no significant difference in terms of the position samples’ accuracy achieved from the developed positioning model and the hybrid system at a particular navigation environment described as rural area. The p-value was 0.08 and the level of significance used was 0.05. However, a significant difference in terms of the service integrity for the advantage of the hybrid system was experienced in all remaining scenarios and environments more especially the urban areas due to surrounding obstacles and conditions.