11 research outputs found
Géolocalisation en environnements contraints par systèmes inertiel et radio
No full textLes systèmes de navigation par satellites permettent les applications de positionnement en extérieur, dont la navigation routière. Dans les environnements contraints, comme l'intérieur des bâtiments où ces signaux satellitaires sont dégradés, la continuité du service de positionnement est nécessaire. Les applications adaptées aux citoyens modernes avec leurs appareils nomades posent des contraintes fortes de mobilité, de coûts et de limitations des infrastructures existantes. Les larges possibilités de déplacements dans des environnements hétérogènes accroissent les difficultés. Un état de l'art alimenté par une décennie de travaux académiques et industriels présente un ensemble de technologies qui visent disponibilité et performance. L'accent porte ensuite sur les systèmes inertiels pédestres à bas coût, avec une première contribution permettant d'abandonner la détection de pas au profit d'une mobilité facilitée, mais reste limitée par la connaissance de la distance parcourue pendant une phase de calibration. Cette approche nouvelle est confrontée à celle classique au pied, puis éprouvée pour différents capteurs et piétons au travers d'expérimentations répétées en conditions réalistes. Une seconde contribution décline une constellation radio locale pour estimer la distance avec une infrastructure allégée à deux émetteurs. Elle s’inspire d’une conception satellitaire sur radio programmable pour faciliter sa compatibilité avec l’existant et explorer ses performances. Une surveillance du rapport signal à bruit inter-canal améliore la précision du positionnement. Le couplage de ces systèmes asynchrones et distribués est évalué en intérieur sur une plateforme automatiséeThe global navigation satellite systems allow outdoor positioning applications, including car navigation. In challenging environments, such as the buildings where satellite signals are mitigated, georeferenced points of interest or navigation applications require a continuity of the positioning service. The applications adapted to modern citizens and their mobile devices raise strong constraints on mobility, costs and limitations of the existing infrastructure. The wide variety of displacements in heterogeneous environments increases the challenge. A state of the art fed by a decade of academic and industrial works presents a set of technologies that target availability and performance. The emphasis follows on the low cost pedestrian inertial systems, with a first contribution allowing to give up the step detection for the benefit of an easier mobility, but remains limited to the knowledge of the distance traveled during a calibration phase. This new approach is compared with the classical foot-mounted approach, and then benchmarked with several sensors and pedestrians through repeated experiments in real conditions. A second contribution operates a local radio constellation to estimate the distance with a minimal infrastructure with two emitters. The signals and the algorithm are based on a reproduction of satellite systems to ease the compatibility but are implemented on a programmable radio to explore the performances. A monitoring of the difference of carrier to noise ratio between the radio channels improves the distance estimation. The hybridization of these distributed, asynchronous and multi-rates inertial and radio systems is evaluated indoor on a motorized platfor
An IoT-Based GeoData Production System Deployed in a Hospital
No full textNavigation in large hospitals remains a challenge, especially for patients, visitors and, in some cases, for staff, but in particular it is notable in the case of tracking ambulatory equipment. Current techniques generally seek to reproduce what outdoor navigation systems provide, i.e., “good” accuracy. In many cases, especially in hospitals, reliability is much more important than accuracy. We show that it is possible to realize a simple, reliable system with a low accuracy, but which perfectly fulfills the task assigned in the particular case of tracking stretchers. Optimizing the use of hospital equipment requires the knowledge of its movement. The possibility to access equipment location in real time as well as on the knowledge of the time necessary to move it between two locations allows to predict or to estimate the load and possibly to scale the necessary number of stretchers, and thus the availability of the stretcher bearers. In this paper, an approach of the real-time location of these devices is proposed, and it is called “symbolic”. The principle is described, as well as the practical implementation and the data that can be retrieved. In the second part, an analysis of the results obtained is provided in two directions: the location of stretchers and the determination of travel times. The methodology followed is described, and it is shown that a correct positioning rate of 90% is reached, which is slightly lower than expected, explained by the chosen practical implementation. Moreover, the average error on the determination of travel times is approximately ten seconds on 2 to 7 min trips. The “reliability” (the terminology of which is discussed at the end of the paper) of the results is related to the simplicity of the approach
A Geodata Production System To Allow People To Stay At Home
No full textInternational audienceThe well-being of people depends in part on the senseof freedom, and one aspect is certainly the possibility for people toremain at home. However, there is a need for “following” themovements and, if possible, the activity of the person. The problemis that very few home systems make it possible to have these data at areasonable price, and at an acceptable reliability level. We offer asimple to use, reliable and energy self-sufficient person locationsystem. People are the first "targets", but objects could be involved.The system is described and their performance analyzed in realconditions of use. In addition, person’s activity is also investigatedand coupled to some home automation devices
A Case Study On Sensors And Techniques For Pedestrian Inertial Navigation
No full textInternational audienceThe interest in location based services is growing in several applications. The literature exhibits a wide spectrum of technology to complement the well-knwon limitations of satellite based positioning systems in constrained environments such as indoors or urban canyons. This paper focuses on inertial sensors and systems to locate pedestrians indoor without infrastructure. The theoretical background of a recently developped beltmounted inertial navigation system (INS) is carefully depicted here. The approach aims to facilitate the equipment and the mobility of the users while maintaining repeatable performance. Therefore, a comparison of the performance in realistic conditions is carried out between foot-mounted and belt-mounted techniques given an inertial measurement unit (IMU) commercialized by XSens. Then, this commercial IMU and an IMU based on ADXL345 and ITG3200 were compared, given the belt-mounted algorithm, in terms of positioning performance. The results, supported by dozens of experiments involving different participants, show that the belt-mounted technique is as efficient as the foot-mounted one since the average error in position is less than 2% of the travelled distance about 200m. Whereas their costs are very different, the commercial and the integrated IMU reach a similar accuracy. The beltmounted device achieve repeatable and efficient pedestrian indoor positioning in real-time with low-cost inertial sensors
Belt Mounted IMU With Enhanced Distance Estimation For Pedestrian Indoor Positioning
No full textInternational audienceThe approach described here attempts to overcome foot-mounted limitations, contrary to a majority of current implementations of inertial navigation systems (INS). The aim of our development is to maintain repeatable performance, especially without step counting, while carefully dealing with the mobility requirements and the computation cost. The inertial measurement unit (IMU) is belt mounted to facilitate the equipment of the user. The pedestrian trajectory is computed in real time. The resulting position is transmitted and displayed to the user on a smartphone where no specific application is installed. The description of our indoor experiments reveals the potential of this approach, in terms of positioning performance, with more than 75% of our experiments when the relative start-end error remains below 5% of the total traveled distance
A Case Study On Sensors And Techniques For Pedestrian Inertial Navigation
No full textInternational audienceThe interest in location based services is growing in several applications. The literature exhibits a wide spectrum of technology to complement the well-knwon limitations of satellite based positioning systems in constrained environments such as indoors or urban canyons. This paper focuses on inertial sensors and systems to locate pedestrians indoor without infrastructure. The theoretical background of a recently developped beltmounted inertial navigation system (INS) is carefully depicted here. The approach aims to facilitate the equipment and the mobility of the users while maintaining repeatable performance. Therefore, a comparison of the performance in realistic conditions is carried out between foot-mounted and belt-mounted techniques given an inertial measurement unit (IMU) commercialized by XSens. Then, this commercial IMU and an IMU based on ADXL345 and ITG3200 were compared, given the belt-mounted algorithm, in terms of positioning performance. The results, supported by dozens of experiments involving different participants, show that the belt-mounted technique is as efficient as the foot-mounted one since the average error in position is less than 2% of the travelled distance about 200m. Whereas their costs are very different, the commercial and the integrated IMU reach a similar accuracy. The beltmounted device achieve repeatable and efficient pedestrian indoor positioning in real-time with low-cost inertial sensors
Belt Mounted IMU With Enhanced Distance Estimation For Pedestrian Indoor Positioning
No full textInternational audienceThe approach described here attempts to overcome foot-mounted limitations, contrary to a majority of current implementations of inertial navigation systems (INS). The aim of our development is to maintain repeatable performance, especially without step counting, while carefully dealing with the mobility requirements and the computation cost. The inertial measurement unit (IMU) is belt mounted to facilitate the equipment of the user. The pedestrian trajectory is computed in real time. The resulting position is transmitted and displayed to the user on a smartphone where no specific application is installed. The description of our indoor experiments reveals the potential of this approach, in terms of positioning performance, with more than 75% of our experiments when the relative start-end error remains below 5% of the total traveled distance
Acceptabilité et validation par l’usage d’un dispositif de localisation pour favoriser l’autonomie des résidents en EHPAD : retour d’expérience
No full textNational audienceCet article présente l’expérimentation d’un dispositif de sécurisation de la déambulation des ainés au sein d’un EHPAD. L’objectif principal consiste à évaluer la performance du système en matière de localisation et d’accompagnement des résidents ainsi que de son acceptabilité auprès des équipes soignantes et des familles. Pour cela, un protocole a été établi, intégrant plusieurs phases complémentaires de validation technique et médicale, assorties de sessions de formation et de sensibilisation destinées aux utilisateurs. L’approche adoptée inclut également une analyse approfondie des résultats obtenus, combinant indicateurs qualitatifs et quantitatifs. Les premières conclusions tirées de cette expérimentation indiquent une amélioration sensible du bien-être des résidents et une optimisation notable du travail quotidien des professionnels de santé
INS and GNSS fusion enhancement based on a weighted reliabilities approach
No full textInternational audienceThe maturity of outdoor positioning systems based on satellites encourages indoor positioning research to focus on radio technologies. However, specific infrastructures often have to be deployed in this case. Then, inertial sensors appear to be a good relay to radio systems. A system fusing INS and GNSS could thereby compute a position anywhere. Yet, taking advantage of each sensor requires to know which one is the most reliable in real-time. Therefore, a quantification of the sensors' reliabity is introduced in this paper. This approach aims at running both outdoors and indoors. Moreover, the complexity of algorithms is carefully studied here to fit the user mobility requirements. Experiments are conducted in reproducible situations and results show that taking reliabilities into account benefits the hybridization of INS and GNSS for positioning in both convenient and constrained environments
Pedestrian indoor positioning techniques: A survey
No full textNational audienceThis paper is devoted to explain the relevancy of inertial and radio hybridization to perform pedestrian positioning while addressing issues raised in the state of the art. The challenges of pedestrian indoor positioning are depicted, with an emphasize on technologies developed in some given contexts
