Indoor Human Navigation Systems: A Survey <s> Representation <s> This paper presents the research for the development of a new travel aid to increase the independent mobility of blind and elderly travellers. This aid will build on the technologies of geographical information systems (GIS) and the Global Positioning System (GPS). The MOBIC Travel Aid (MOTA) consists of two interrelated components : the MOBIC Pre-journey System (MOPS) to assist users in planning journeys and the MOBIC Outdoor System (MooDs) to execute these plans by providing users with orientation and navigation assistance during journeys. The MOBIC travel aid is complementary to primary mobility aids such as the long cane or guide dog. Results of a study of user requirements are presented and their implications for the initial design of the system are discussed. <s> BIB001 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> This paper describes a wearable navigation system based on a haptic directional display embedded in the back of a vest. The system consists of a 4-by-4 array of micromotors for delivering haptic navigational signals to the user's back, an infrared-based input system for locating the user in an environment, and a wearable computer for route planning. User testing was conducted to evaluate the effectiveness of this system as a navigation guide for sighted users in an unfamiliar lab area. It is hoped that such a system can be a useful navigation guide for individuals with severe visual impairments in an unfamiliar environment. Future work will address the specific issues concerning blind navigation. <s> BIB002 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> The research we are reporting here is part of our effort to develop a navigation system for the blind. Our long-term goal is to create a portable, self-contained system that will allow visually impaired individuals to travel through familiar and unfamiliar environments without the assistance of guides. The system, as it exists now, consists of the following functional components: (1) a module for determining the traveler's position and orientation in space, (2) a Geographic Information System comprising a detailed database of our test site and software for route planning and for obtaining information from the database, and (3) the user interface. The experiment reported here is concerned with one function of the navigation system: guiding the traveler along a predefined route. We evaluate guidance performance as a function of four different display modes: one involving spatialized sound from a virtual acoustic display, and three involving verbal commands issued by a synthetic speech display. The virtual display mode fared best in terms of both guidance performance and user preferences. <s> BIB003 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> The position-tracking accuracy of a location-aware mobile system can change dynamically as a function of the user’s location and other variables specific to the tracker technology used. This is especially problematic for mobile augmented reality systems, which ideally require extremely precise position tracking for the user’s head, but which may not always be able to achieve the necessary level of accuracy. While it is possible to ignore variable positional accuracy in an augmented reality user interface, this can make for a confusing system; for example, when accuracy is low, virtual objects that are nominally registered with real ones may be too far off to be of use. To address this problem, we describe the early stages of an experimental mobile augmented reality system that adapts its user interface automatically to accommodate changes in tracking accuracy. Our system employs different technologies for tracking a user’s position, resulting in a wide variation in positional accuracy: an indoor ultrasonic tracker and an outdoor real-time kinematic GPS system. For areas outside the range of both, we introduce a dead-reckoning approach that combines a pedometer and orientation tracker with environmental knowledge expressed in spatial maps and accessibility graphs. We present preliminary results from this approach in the context of a navigational guidance system that helps users to orient themselves in an unfamiliar environment. Our system uses inferencing and path planning to guide users toward targets that they choose. <s> BIB004 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> Drishti is a wireless pedestrian navigation system. It integrates several technologies including wearable computers, voice recognition and synthesis, wireless networks, Geographic Information System (GIS) and Global positioning system (GPS). Drishti augments contextual information to the visually impaired and computes optimized routes based on user preference, temporal constraints (e.g. traffic congestion), and dynamic obstacles (e.g. ongoing ground work, road blockade for special events). The system constantly guides the blind user to navigate based on static and dynamic data. Environmental conditions and landmark information queried from a spatial database along their route are provided on the fly through detailed explanatory voice cues. The system also provides capability for the user to add intelligence, as perceived by, the blind user, to the central server hosting the spatial database. Our system is supplementary to other navigational aids such as canes, blind guide dogs and wheel chairs. <s> BIB005 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> The design of mobile navigation systems adapting to limited resources will be an important future challenge. Since typically several different means of transportation have to be combined in order to reach a destination, the user interface of such a system has to adapt to the user's changing situation. This applies especially to the alternating use of different technologies to detect the user's position, which should be as seamless as possible. This article presents a hybrid navigation system that relies on different technologies to determine the user's location and that adapts the presentation of route directions to the limited technical resources of the output device and the limited cognitive resources of the user. <s> BIB006 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> In this paper we present a new system that assists blind users in orienting themselves in indoor environments. We developed a sensor module that can be handled like a flashlight by a blind user and can be used for searching tasks within the three-dimensional environment. By pressing keys, inquiries concerning object characteristics, position, orientation and navigation can be sent to a connected portable computer, or to a federation of data servers providing models of the environment. Finally these inquiries are acoustically answered over a text-to-speech engine. <s> BIB007 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> In this paper, we discuss application possibilities of augmented reality technologies in the field of mobility support for the deaf blind. We propose the navigation system called virtual leading blocks for the deaf-blind, which consists of a wearable interface for Finger-Braille, one of the commonly used communication methods among deaf-blind people in Japan, and a ubiquitous environment for barrier-free application, which consists of floor-embedded active radio-frequency identification (RFID) tags. The wearable Finger-Braille interface using two Linux-based wristwatch computers has been developed as a hybrid interface of verbal and nonverbal communication in order to inform users of their direction and position through the tactile sensation. We propose the metaphor of "watermelon splitting" for navigation by this system and verify the feasibility of the proposed system through experiments. <s> BIB008 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> Walking is the most fundamental means of human transportation. Unlike travel by car, walking is not planar, but rather stereoscopic. We therefore developed a real navigation system for pedestrian point-to-point navigation. We propose herein a method of 3D pedestrian navigation, in which position detection is driven mainly by dead reckoning. The proposed method enables ubiquitous round-the-clock 3D positioning, even inside buildings or between tall buildings. In addition, pedestrian navigation is customized by changing the costs of the road network links. Finally, a positioning data accumulation system is implemented so that we can log tracks and easily incorporate new roads or attributes in the future. <s> BIB009 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> Location-based mobile services have been in use, and studied, for a long time. With the proliferation of wireless networking technologies, users are mostly interested in advanced services that render the surrounding environment (i.e., the building) highly intelligent and significantly facilitate their activities. In this paper our focus is on indoor navigation, one of the most important location services. Existing approaches for indoor navigation are driven by geometric information and neglect important aspects, such as the semantics of space and user capabilities and context. The derived applications are not intelligent enough to catalytically contribute to the pervasive computing vision. In this paper, a novel navigation mechanism is introduced. Such navigation scheme is enriched with user profiles and the adoption of an ontological framework. These enhancements introduce a series of technical challenges that are extensively discussed throughout the paper. <s> BIB010 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> The Context sensitive Indoor Navigation System (CoINS) implements an architecture to develop context-aware indoor user guidance services and applications. This paper presents a detailed discussion on algorithms and architectural issues in building an indoor guidance system. We first start with the World Model and required mapping to 2D for the process of path calculation and simplification. We also compare several algorithm optimizations applied in this particular context. The system provides the infrastructure to support different techniques of presenting the path and supporting user orientation to reach a certain destination in indoor premises. <s> BIB011 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> We present a robot-assisted wayfinding system for the visually impaired in structured indoor environments. The system consists of a mobile robotic guide and small passive RFID sensors embedded in the environment. The system is intended for use in indoor environments, such as office buildings, supermarkets and airports. We describe how the system was deployed in two indoor environments and evaluated by visually impaired participants in a series of pilot experiments. We analyze the system's successes and failures and outline our plans for future research and development. <s> BIB012 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> This paper describes, path planning and following algorithms for use in indoor navigation for the blind and visually impaired. Providing indoor navigational assistance for this type of users presents additional challenges not faced by conventional guidance systems, due to the personal nature of the interactions. The algorithms are part of an overall Indoor Navigation Model that is used to provide assistance and guidance in unfamiliar indoor environments. Path planning uses the A* and Dijkstra's shortest path algorithms, to operate on an "Intelligent Map", that is based on a new data structure termed "cactus tree" which is predicated on the relationships between the different objects that represent an indoor environment. The paths produced are termed "virtual hand rails", which can be used to dynamically plan a path for a user within a region. The path following algorithm is based on dead reckoning, but incorporates human factors as well as information about the flooring and furnishing structures along the intended planned path. Experimental and simulating results show that the guiding/navigation problem becomes a divergent mathematical problem if the positional information offered by the positioning and tracking systems does not reach a certain requirement. This research explores the potential to design an application for the visually impaired even when to- date 'positioning and tracking' system cannot offer reliable position information that highly required by this type of application. <s> BIB013 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> Many navigation systems for visually impaired people have been developed, but few can provide dynamic interactions and adaptability to changes. The aim of this working life project is to create an innovative navigation service solution that will improve the quality of life of the visually impaired. For example, a university campus might be such a large and rambling place that visually impaired people can not always find the services or rooms they want to. Therefore, we are devising new service solutions that exploit the technical features of modern WLAN systems in an innovative way. This paper describes the LaureaPOP system that focuses on the indoor navigation service design in a wireless local area network environment. <s> BIB014 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> In this paper, a novel tour-guiding system is introduced, based on our space-identifying ubiquitous infrastructure, where positioning devices are deployed ubiquitously to identify the place of users. In this infrastructure, we can flexibly construct information service related to the places of interest in the city by modeling the space of the real world as a set of relations among the discrete places, and attaching space-identifying devices to them. Our developed tour-guiding system introduces many art works in a large commercial complex in Japan. Based on the benefit of the infrastructure, this system can provide detailed navigation service as well as art introduction service in both indoor and outdoor environments, and can guide the users to reach their interested art works. Currently, this system is already used in practice for a commercial service. In this paper, the design of this system is described and its navigation capability is verified through a user test in the real environment to discuss the effectiveness of our approach. <s> BIB015 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> We describe a body-worn sensor suite, environment representation, set of algorithms, and graphical-aural interface designed to provide human-centered guidance to a person moving through a complex space. The central idea underlying our approach is to model the environment as a graph of visually distinctive places (graph nodes) connected by path segments (graph edges). During exploration, our algorithm processes multiple video-rate inputs to identify visual features and construct the “place graph” representation of the traversed space. The system then provides visual and/or spoken guidance in user-centered terms to lead the user along existing or newly-synthesized paths. Our approach is novel in several respects: it requires no precise calibration of the cameras or multi-camera rig used; it generalizes to any number of cameras with any placement on the body; it learns the correlation between user motion and evolution of image features; it constructs the place graph automatically; and it provides only coarse (rather than precise metrical) guidance to the user. We present an experimental study of our methods applied to walking routes through both indoor and outdoor environments, and show that the system provides accurate localization and effective navigation guidance. <s> BIB016 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> Ad hoc solutions for tracking and providing navigation support to emergency response teams is an important and safety-critical challenge. We propose a navigation system based on a combination of foot-mounted inertial sensors and ultrasound beacons. We evaluate experimentally the performance of our dead reckoning system in different environments and for different trail topologies. The inherent drift observed in dead reckoning is addressed by deploying ultrasound beacons as landmarks. We study through simulations the use of the proposed approach in guiding a person along a defined path. ::: Simulation results show that satisfactory guidance performance is achieved despite noisy ultrasound measurements, magnetic interference and uncertainty in ultrasound node locations. The models used for the simulations are based on experimental data and the authors' experience with actual sensors. The simulation results will be used to inform future development of a full real time system. <s> BIB017 </s> Indoor Human Navigation Systems: A Survey <s> Representation <s> This paper proposes a framework to enable intuitive navigation guidance for complex buildings which are huge in size and their space boundaries contain non-convex shape including non-navigable areas inside. Our approach utilizes ‘topological’ way-finding method to generate paths. This can be done by means of the integration of building information model (BIM) with our new algorithm to subdivide the spaces. The second main principle is to improve the visual information by using a new method to render all three dimensional views possibly observed in a building beforehand. This has been realized by imaging serviced using client-server architecture with supercomputer computation power. <s> BIB018
Human navigation systems require storing and retrieving different types of information. The stored information can be used for localization, path planning, generating directions, and providing location information. Depending on the approach employed by the system, this information may include floor plans, the location and description of objects in the indoor environment, locations of identifier tags or data collected using sensors. This can be a simple two dimensional (2D) map of the environment representing walls and doors with room numbers BIB004 BIB009 BIB010 , digital road maps BIB002 BIB005 BIB009 BIB001 , or graph of accessible paths with associated cost for each link BIB015 BIB016 BIB013 . The map can be used for path planning based on the accessible areas or localizing the user. If the system uses a tag based approach to localize the user, tags information is added to the map    . Information about landmarks along the path can be added to the map which can be used when providing direction to the user   BIB010 BIB013 . 2D maps might be the least resource intensive representation and such maps are easy to generate from buildings' blueprints. But adding detailed information regarding objects in the environment and possible hazardous areas, such as low ceilings, to such map might be challenging. Three dimensional (3D) models can be used to represent the environment BIB018 BIB011 . Considerable amount of useful information can be extracted from such models automatically, such as the location of doors, slope of a ramp, or low ceiling. Such models are more expensive to generate but they are language independent and object recognition algorithms can extract information, which helps the system to be deployed globally. 3D models require more storage and processing them for extracting information can be more resource intensive. The information used by a navigation system is typically retrieved either from a local database  BIB017 BIB016 or from a central database through wireless connection BIB008 BIB015 BIB014 BIB010 . Local database approach is potentially more reliable; as they remove the need for a wireless infrastructure to be available, however, any update or change in the physical environment requires changes in all local copies, which results in an inaccurate navigation if local copy is not updated. Storing the information locally might not be feasible for devices with limited storage. Considering the expanding availability of wireless connection with increasing bandwidth, connectivity to a central server might not be a major issue. When the changes in the environment are reflected on the server, clients can have access to the latest representation. Several navigation systems act as an information system that provides information about the user's surroundings. The information provided varies from providing the name of building and rooms BIB006  to a detailed description of the room layout including any objects in that room BIB007 BIB012 BIB003  and even the type of door handle and direction in which it opens  . This information can be used to help the user to avoid obstacles along the path  . This requires storing significantly larger amounts of information than a simple map. The type of information stored depends on the users' needs. While individuals with visual impairments might benefit from detailed information about the direction a door opens, it might be helpful for emergency crew to know the location of the main gas valve in the building, or location of benches for elderly.  Many systems use 2D maps or blueprints to represent the indoor environment to be navigated in. 3D virtual models BIB007 can be potentially employed to more accurately represent indoor environments with multiple levels and features like low ceilings, ramps, uneven floors and rails, which are impediments to navigation for users with visual impairments. 3D models may be more expensive to create than 2D models, though advances in 3D robotic mapping have reduced these costs significantly. Such models still need to be annotated with addressing information, such as room numbers, or landmarks, such as doors. It is interesting to investigate how to extract landmarks, such as doors or staircases, automatically from the geometry of such models. For indoor navigation systems to become ubiquitous they could leverage crowdsourcing efforts and offer an open interface to allow for creating indoor models at a large scale. Thousands of 3D models of the exteriors of public buildings have already been successfully created through crowd-sourcing efforts and which can be found on the virtual globe application Google Earth. Models with interior details such as floor plans and doors are becoming increasingly available to be developed to resolve conflicting annotations or to verify the accuracy of annotations.