Comparison of SAGE and classical multi-antenna algorithms for multipath mitigation in real-world environment

The performance of the Space Alternating Generalized Expectation Maximisation (SAGE) algorithm for multipath mitigation is assessed in this paper. Numerical simulations have already proven the potential of SAGE in navigation context, but practical aspects of the implementation of such a technique in a GNSS receiver are the topic for further investigation. In this paper, we will present the first results of SAGE implementation in a real world environmen

Dis-orientation: spatial abilities performance in London

This report investigates the relation of the Spatial Configuration with the orientation performance of the individual in urban Navigation. Spatial Orientation is defined as a function of the mind involving ‘awareness of place’ in the environment, and is a key aspect of Navigation in terms of maintaining a sense of where the subject is relative to its goal as it is moving. The aim of this thesis is to shed light on Spatial Orientation performance and how it is linked to spatial and syntactic properties of space. This topic is intrinsic in the Space Syntax theory due its fundamental relation between spatiality and human activity. The research method used was a set of questionnaires done in London specifically in Covent Garden and Soho areas, asking people to point to five Landmarks and North. The results were overlaid with spatial analysis and compared through directions diagrams and statistical data analysis. The findings show relations between the Spatial Configuration and the given Landmarks directions with grid angularity, grid visibility and familiarity with the place. The discussion is developed through the research findings and theories of spatial Navigation, Wayfinding and spatial cognition, putting forward varied interpretations related with the research topic and the selected areas. The report concludes that the Spatial Orientation in Soho and Covent Garden is determined by Spatial Configuration of the place and related with the grid structure. Furthermore, it is argued that the Navigation System in Central London is based in Path Integration rather than Landmark recognition and it is dependant on the familiarity of the subject with the Space of Navigation

Quicklook Air Mobility Modeling

This research is a framework for understanding issues in modeling the military aspect of space, with particular regard to capturing its value. Space power is a difficult and far-reaching topic, with implications that go beyond the military aspects. The United States military increasingly relies on space-based systems and information for success in daily operations. Telecommunications, navigation and timing, intelligence, surveillance, reconnaissance, and weather prediction are instances of services that have become dependent on satellite systems. If this reliance on space is not fully understood, U.S. national security will be at risk as the result of space information degradation or denial. This research effort attempts to break new ground in organizing the interactions and interdependencies among space doctrine, space systems, system owner/operators, and space-based information users. An illustrative example, using GPS, is then examined to explore the approach. Analysis of GPS as it affects JDAM accuracy is modeled using the GPS Interference And Navigation Tool (GIANT)

Mapping the e-Learning Assessment Domain: Concept Maps for Orientation and Navigation

Concept or Topic Maps have long been used as a method of categorizing and organizing information about a domain. Building them can help people conceptualize an area and spot trends or gaps, and as a presentation method they quickly provide an overview and general impression of a space. We are currently constructing a Reference Model of the Assessment Domain that takes the form of a highly interlinked dynamic website. This represents the assessment domain via the software, projects, standards and use cases of which it is composed. In this paper we present our efforts to create complimentary concept maps of the assessment domain, not as an overview, but for navigation and orientation within the domain. These concept maps, which model resources and activities independently, have been corroborated with practitioners in the e-learning community

Space Subdivision For Indoor Navigation: A Systematic Literature Review

Along with the increasing demand for indoor navigation, many attempts were made to improve indoor navigation performance. Information about the room becomes important, because one of the characteristics of indoor navigation is the dynamic indoor conditions. Space subdivision is an effort made to make indoor navigation even more accurate. The purpose of this study is to create a systematic literature review (SLR) regarding the topic of space subdivision for indoor navigation which is based on a SLR method, previously defined research question. This study examines several previous works specifically in the field of space subdivision for indoor navigation with the SLR. This research is expected to be the basis for further research to improve the quality of indoor navigation based on space subdivision

Space Weather and Rail: Findings and Outlook

Space weather caused by solar activity can disrupt and damage critical infrastructures in space and on the ground. Space-weather impacts to the power grid, aviation, communication, and navigation systems have already been documented. Since society relies increasingly on the services these critical infrastructures provide, awareness of the space weather threat needs to be increased and the associated risks assessed. While most research on impacts of space weather focuses on the power grid, the Global Navigation Satellite System (GNSS), and aviation, railway networks are also a potential area for concern. Anomalies in signalling systems have been observed during geomagnetic storms, and rail transport depends on power, communications, and progressively on GNSS for timing and positioning. In order to raise awareness of this topic, and to further explore the vulnerability of rail systems to space weather, the European Commission’s Joint Research Centre, the Swedish Civil Contingencies Agency, the UK Department for Transport, and the US National Oceanic and Atmospheric Administration jointly organised the “Space weather and rail” workshop in London on 16-17 September 2015. The workshop was attended by representatives from the railway sector, insurance, European and North American government agencies, academia, and the European Commission. This report presents the main findings and conclusions of this workshop.JRC.G.5-Security technology assessmen

A hierarchical anti-Hebbian network model for the formation of spatial cells in three-dimensional space.

Three-dimensional (3D) spatial cells in the mammalian hippocampal formation are believed to support the existence of 3D cognitive maps. Modeling studies are crucial to comprehend the neural principles governing the formation of these maps, yet to date very few have addressed this topic in 3D space. Here we present a hierarchical network model for the formation of 3D spatial cells using anti-Hebbian network. Built on empirical data, the model accounts for the natural emergence of 3D place, border, and grid cells, as well as a new type of previously undescribed spatial cell type which we call plane cells. It further explains the plausible reason behind the place and grid-cell anisotropic coding that has been observed in rodents and the potential discrepancy with the predicted periodic coding during 3D volumetric navigation. Lastly, it provides evidence for the importance of unsupervised learning rules in guiding the formation of higher-dimensional cognitive maps

Supporting Information Visualization Through Topic Maps

We are living a phenomenon of accelerated information production with different accessing sources. Hence users are faced with a growing problem: accessing (navigation) and filtering specific information contained in large datasets, which are increasing in size. Procedures such as data filtering and gathering are now simplified through a new concept known as Topic Maps. The application of Virtual Reality technologies enables to present and interact with multidimensional information in a 3D space. In this paper we present INSPHERE, a new visual metaphor for information visualization, based on both, Virtual Reality techniques, and “geographical information maps” provided by Topic Maps

Development of Innovative GNC Algorithms for Aerospace Applications

The main context of the present dissertation is the SAPERE STRONG (Space Advanced Project for Excellence in Research and Enterprise – Sistemi, Tecnologie e Ricerche per l’Operatività Nazionale Globale) project, founded by Italian Ministry of University and Research (MIUR) with the goal to improve Italian access to Space and Space Exploration. For this purpose, extension of the launch capability of the Vega launcher is included in the project, realized with a Space-Tug which is used to deploy in the nominal orbit a payload spacecraft. This thesis has the objective to develop an advanced orbital simulator as a tool which makes the designer able to develop and test the Guidance, Navigation and Control (GNC) software for the Space-Tug spacecraft. The GNC software is developed in collaboration with the leader industrial company of the project, Thales Alenia Space. Thales Alenia Space (TAS) is in charge of developing the Navigation and Control Function and the main structure of flight software, while Politecnico di Torino collaborates with the development of the Guidance function and the orbital simulator. During the whole project has been planned an internship of 1500 hours inside the offices of TAS in Torino. The project includes also a visiting period of international institution. In the specific frame of this Ph. D. thesis, has been spent three months at the University of Sevilla, with the purpose of study and design of a Galileo receiver as an additional input for determination of position in advanced navigation systems, since the Galileo constellation is near to be fully operative in the next future. Details related to all the activities executed during this internship will be presented in Appendix B. The main objective of this dissertation is the development of innovative GNC algorithms, focusing mainly on the Guidance problem, for aerospace application. An extensive literature review of existing guidance law, control techniques, actuators for attitude and trajectory control, sensors and docking mechanism and techniques has been performed. The Guidance topic has been analyzed focusing on the missile-derived Proportional Navigation Guidance (PNG) algorithm, Zero-Effort-Miss/Zero-Effort-Velocity (ZEM/ZEV) algorithm and Lambert guidance. Feasibility, performance, pros and cons have been extensively studied in this work, especially in an experimental fashion, and new solutions and implementation strategies have been proposed. The literature review has been completed for Control and Navigation issues, as well. Control strategies, actuation systems and algorithm have been investigated, starting from the classical proportional/Integrative/Derivative (PID) controllers, to more recent and innovative control law, such as Linear Quadratic Regulator (LQR). As for the Control function, the Navigation topic, intended as navigation filters and algorithms, has been studied in the last period of this work, while the navigation problem form the hardware side (i.e. sensors) has been deeply analyzed in the present work. In addition to the GNC investigation, the simulation topic has been studied as well, since one of the goals of this dissertation is the realization of an orbital simulator. The orbital simulator is a complete 6 degrees-of-freedom simulator, based on the relative equation of motion (Hill’s equations) for the trajectory computation and based on the classical rigid body equation, including the quaternion notation, for the computation of the attitude dynamics. The orbital environment is well defined, including all common disturbances found in Low Earth Orbits (LEO) and affecting the dynamics of an orbiting body. A complete set of sensors is implemented, including an accurate model of common measurement errors affecting the sensors included in the spacecraft configuration (Inertial Measurement Unit, Star Tracker, GPS, Radio Finder, Lidar and Camera). Actuators are carefully modeled, including a reaction wheels system and a reaction control thrusters system. Errors derived for misalignment of the wheels system and non-nominal inertia and shooting and misalignment errors for the thrusters systems are modeled as well

Predicting the Next Best View for 3D Mesh Refinement

3D reconstruction is a core task in many applications such as robot navigation or sites inspections. Finding the best poses to capture part of the scene is one of the most challenging topic that goes under the name of Next Best View. Recently, many volumetric methods have been proposed; they choose the Next Best View by reasoning over a 3D voxelized space and by finding which pose minimizes the uncertainty decoded into the voxels. Such methods are effective, but they do not scale well since the underlaying representation requires a huge amount of memory. In this paper we propose a novel mesh-based approach which focuses on the worst reconstructed region of the environment mesh. We define a photo-consistent index to evaluate the 3D mesh accuracy, and an energy function over the worst regions of the mesh which takes into account the mutual parallax with respect to the previous cameras, the angle of incidence of the viewing ray to the surface and the visibility of the region. We test our approach over a well known dataset and achieve state-of-the-art results.Comment: 13 pages, 5 figures, to be published in IAS-1