Personal Navigation System for Indoor Applications

Navigation is usually associated with marine and aviation domains. Except for some lighthouses for orientation or landmarks near the coast, navigation instruments are essential because routes are virtual. Therefore, current position of ships and aircrafts must be drawn on the map. Land navigation is generally bound to the road infrastructure. Car navigation systems have been introduced to replace the use of road maps in order to assist the driver in the choise of the correct way..

Optimiser la performance de calcul pour la cartographie en temps réel avec un Laser Scanner aéroporté

Cet article est essentiellement la traduction de: Skaloud J. & Schaer P.: Optimizing Computational Performance for Real-Time Mapping with Airborne Laser Scanning, présenté lors de: Technical Commission I Symposium, WG I/5 Commission I, Calgary, June 2010 et publié dans: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences; vol. 38, num. 1, 2010. Il s'inscrit dans la continuité de contributions publiées dans Géomatique Suisse 9/2008 et 3/2009. Dans cet article, on évalue et on optimise les procédures de calcul pour la cartographie en temps réel à partir des mesures d'un laser scanner aéroporté. Les étapes considérées incluent le géoréférencement direct (GRD) du nuage de points, en temps réel et avec la résolution maximale, l'analyse de la couverture et de la densité des bandes scannées, la propagation d'erreur, la classification du sol, la production des modèles numériques de surface (MNS) et de terrain (MNT), ainsi que l'estimation de la qualité du MNT. Pour chaque étape de calcul, différentes approches sont implémentées dans le système "maison" Scan2map. Leur rapidité et leur exactitude sont évaluées en conditions réelles de lever. Les investigations montrent que le GRD est possible en temps réel avec un ordinateur portable usuel pour un rythme du scanner allant jusqu'à 200 kHz. De plus, on montre que l'analyse de la couverture et de la densité du nuage de points exige moins de puissance de calcul. Il en va de même pour le calcul du MNS et la génération des ombres dues au relief. Ainsi, ces tâches peuvent être effectuées rapidement après chaque ligne de vol. En fait, la classification nécessaire pour la production du MNT ainsi que la propagation d'erreur s'avèrent les plus gourmandes en calculs. Il faut donc maximiser leur vitesse d'exécution tout en maintenant leur exactitude. Les solutions retenues sont présentées, de même que des recommandations pour les développeurs ultérieurs

Bayesian Approach for Indoor Pedestrian Localisation

The principal concept of navigation is to start from a known (initial) position and to ensure a continued and reliable localisation of the user during his/her movement. The initial position of the trajectory is usually obtained via GPS or defined by the user. Consider a pedestrian navigation system which contains a GPS receiver and a set of inertial sensors, connected with a map database. In the urban environment and indoors the localisation depends entirely on the measurements from the inertial sensors. The trajectory is defined in a local coordinate system and with an arbitrary orientation. The problem to solve is to determine the users location using the map database and inertial measurements of the navigation system. The idea behind our approach is to find the location and orientation of the trajectory and thus the users location. The proposed solution associates the users trajectory with the map database applying statistical methods in combination with map-matching. Similar geometric forms must be identified in both the trajectory and the link-node model. The trajectory, defined by a set of consecutive points, is transformed to a set of lines thanks to a dedicated motion model. In this research we propose a solution based on statistical methods where the history of the route and actual measurements are treated at the same time. The determination of the absolute position is entirely represented by its probability density function (PDF) in the frame of Bayesian inference. Following this approach the posterior estimation of the users location can be calculated using prior information and actual measurements. Because of the non-linear nature of the estimation problem, non-linear filtering techniques like particle filters (Sequential Monte Carlo methods) are applied

Map-based Autonomous Personal Localization and Tracking

An autonomous localisation and tracking method is a method independent from the reception of external data. In our approach we ignore methods like GPS- and WiFi- positioning and we focus on the use of inertial navigation system (INS) carried by the person and connected to a map database. The walking person is considered as a dynamic system, whose movements are measured by the INS. His trajectory is modified with respect to a dedicated motion model. Users location is estimated in the frame of Bayesian inference and is based on the association of the trajectory to the map database, a technique known as map- matching. Because of the non-linear nature of the estimation problem, non-inear filtering techniques like particle filters (Sequential Monte Carlo methods) are applied. In tracking mode simple geometric constrains will be observed in order to associate every point of the trajectory to element of the map database. In parallel the localisation mode rest active in order to keep the knowledge on the history of measurements. The algorithm is tested on the campus of EPFL; the process of localisation is entirely autonomous and gives promising results. That method of localisation can be applied to many pedestrian navigation tasks, in particular for the needs of the fire-brigades and security services

Training in Mapping Changes on an Archaeological Site

The evolution of technologies makes surveying accessible to a broader community of professionals and students. Therefore, teaching geomatics is a continuous challenge. This article presents an original pedagogical approach based on a teaching unit gathering students in architecture, as well as in civil and environmental engineering. Working together to collect and visualize data from the built and natural environment is a very stimulating experience. However it requires multiple competences in data analysis and mapping. At the Ecole Polytechnique Fédérale de Lausanne (EPFL), the Faculté de l'Environnement Naturel, Architectural et Construit (ENAC) has introduced a teaching concept called “Projeter ensemble” which consists in a series of multidisciplinary courses. This paper presents a teaching unit for mapping changes of the natural and built environment, focusing on a project carried out in the antique theatre of Aventicum (now Avenches), which is one of the major Roman settlements in Switzerland. The teaching activity has been proposed for 4 years. During this period, restoration works of the antique theatre have taken place and the archaeological site has been surveyed regularly. Hence it is an excellent opportunity to analyse the evolution of the theatre through the comparison of 3D surface models from different epochs. The students benefit from an exciting field of experiment. They collect real data and build 3D models, which they analyse with adequate software. In this sense, they develop very good skills in data processing and in quality assessment of the mapping products. This teaching unit does not aim at training a few specialists in geomatics. However it contributes towards the critical use of modern mapping tools in widespread domains of activities

Blending a MOOCs with interactive teaching

When Massive Open Online Courses became a hot topic in Europe. The Ecole Polytechnique Fédérale de Lausanne (EPFL) decided to take the challenge and launched an internal call for proposals. At the Geodetic Engineering Lab, we saw a possibility to use contact hours for exercises and fieldwork, rather than telling stories and showing diagrams. External students were considered, but the main purpose was to modernise the first year course "Fundamentals of Geomatics" for approximately 250 civil and environmental engineering students. As the bid was successful, we started with the design of the lectures, followed by the recording sessions in a special studio. Combining photographs, sketches, speeches and quizzes into a video requires a precise script. For one hour of teaching, ten hours of preparation and processing are not always sufficient. The new formula for the course was implemented during the 2014 spring semester. The two hour session remained in the weekly program, with more assistants and other expectations. Regular students took classical mid-term and final exams. At this stage, an incidence of the teaching method on the level reached cannot be ascertained, but neither a miracle, nor a catastrophe took place. Simultaneously, the course was made available worldwide via the Coursera platform. Many people watched the short teaser. Some registered, but few of them did all the assignments and qualified for the statement of accomplishment (issued by Coursera, not EPFL). The activity level of the website was monitored. Some elements of evaluation by the students have been analysed. Reactions are widely spread, from "Bring back the professor!" to "Why not 100% MOOC?". Surely, the second edition will bring a more balanced feedback and motivate some improvements. Having opted for a blended approach, the active promotion of this course outside - Western Africa comes first to mind - depends on partnerships with local universities

Enhancement of Geomatics Education by Using Internet Based Techniques

The Swiss Federal Institute of Technology in Lausanne (EPFL) has introduced the Moodle Learning Management System (LMS) in 2005. Since then, the number of teachers and users has increased rapidly. With more than 350 active courses hosted on Moodle for this autumn semester, its utility is not to be demonstrated anymore. In 2006, the Geodetic Engineering Laboratory (TOPO) has introduced its on-line undergraduate topography course, with more than 26000 connections during the last semester for 160 students. In accordance with EPFL's guidelines (E-Learning Strategy [1])1, and with the support of the Funding Programme for Teaching and Learning, TOPO has developed an e-learning platform, fully integrated into a LMS, for the first course in geomatics. The motivation behind this is to move from teaching and learning in a traditional way to a more interactive way: personalized exercises are completed by students on the Internet and are automatically corrected with help facilities. This concept of e-learning, called Exomatic, stimulates the students to be more autonomous in their learning of, and training in, topographic data processing and analysis. The main module of Exomatic is composed of the generation of Internet-based exercises, the presentation of personalized data in a smart user interface, a collection of answers in HTML form, automated corrections and a smart calculator with graphical hints provided by Geogebra. The system provides evaluations for students and statistical feedback for the teacher on student performance and progress. The objective is to improve the autonomy of students and to facilitate the preparation and corrections of exercises for teachers and assistants. Exomatic is a standard Moodle module, and can potentially be shared by a wider community. This paper presents the structure of the programme and its integration into the course content. Its implementation in the LMS and a first assessment by the students are presented