Indoor Human Navigation Systems: A Survey <s> Dead-Reckoning <s> This paper proposes a walking navigation system for the blind. The system is based on a comparison of data obtained by a pedometer and a terrestrial magnetic sensor and prearranged teaching data of a route to a destination. The system gives an appropriate instruction (using voice and buzzer sound) during a user's walk. This paper mainly describes experiments designed to clarify the characteristics of the system. The results show that the nodes of a walking route for teaching should be less than 50 m, since the maximum error of the system is about 10% in a walking distance of 50 m. The experiments also show that the walkers (sighted men with eye masks) were guided by the system along a course of about 900 m, taking about 40 to 50 mins. © 1998 Scripta Technica. Syst Comp Jpn, 28(13): 36–45, 1997 <s> BIB001 </s> Indoor Human Navigation Systems: A Survey <s> Dead-Reckoning <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> BIB002 </s> Indoor Human Navigation Systems: A Survey <s> Dead-Reckoning <s> Pedestrians must often find their way in unfamiliar urban environments or complex buildings. In these cases they need guidance to reach their desired destination, for example a specific room in a local authorities' building, a counter, or a department at an university. The goal of location-based mobile services is to provide such guidance on demand (anywhere, anytime), individually tailored to the actual information needs and presented in preferred forms. Thereby the navigation service requires positioning and tracking capabilities of a mobile user with a certain positioning accuracy and reliability. In particular, navigating in urban areas is a very challenging task as pedestrians move in spaces where none of the known positioning techniques works continuously in standalone mode and the movement is in a much more complex space than 2D networks (i.e. on pedestrian paths and along roads, outdoor and indoor, through underground passages, etc.). To solve this challenging task of continuous position determination, a combination of different location technologies is required. The integration of the sensors should be performed such that all the sensors are tightly coupled in the sense of a so-called multi-sensor system. In a new research project in our University entitled "Pedestrian Navigation Systems in Combined Indoor/Outdoor Environments (NAVIO)" we are working on the improvement of such navigation services. The project is mainly focusing on the information aspect of location-based services, i.e. on the user's task at hand and support of the user's decisions by information provided by such a service. Specifications will allow selection of appropriate sensor data and to integrate data when and where needed, to propose context-dependent routes fitting to partly conflicting interests and goals as well as to select appropriate communication methods in terms of supporting the user guiding by various multimedia cartography forms. To test and to demonstrate our approach and results, the project takes a use case scenario into account, i.e. the guidance of visitors to departments of the Vienna University of Technology. First results of our project are presented in this paper. <s> BIB003 </s> Indoor Human Navigation Systems: A Survey <s> Dead-Reckoning <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> BIB004 </s> Indoor Human Navigation Systems: A Survey <s> Dead-Reckoning <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> BIB005 </s> Indoor Human Navigation Systems: A Survey <s> Dead-Reckoning <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> BIB006
Dead reckoning localization techniques estimate a user's lo0cation based on a previously estimated or known position. While the user is moving, the dead-reckoning system estimates the user's location through the aggregation of odometry readings. Odometry readings can be acquired through a combination of sensors such as accelerometers, magnetometers, compasses, and gyroscopes BIB006 BIB002 BIB004 BIB003 or using a user's specific walking pattern (such as the user's average walking speed) BIB005 . An initial location is typically determined using GPS BIB002 , Radio-frequency identification (RFID) tags BIB004 , or cellular phone positioning BIB003 . Since the location estimation is a recursive process, inaccuracy in location estimation results in errors that accumulate over time. The accumulated error can be corrected using environmental knowledge BIB002 , RFID tags BIB004 , ultrasound beacons BIB006 , and map-matching BIB004 BIB001 . The users' position can be synchronized using direct sensing localization techniques such as RFID tags or pattern-matching localization techniques such as through the recognition of visual landmarks. A benefit of these approaches over direct sensing techniques is a lower installation cost as a smaller number of identifiers have to be installed. The inaccuracy of dead reckoning and the need to combine it with other localization techniques are the main drawbacks of this method. If a system uses RFID for error correction, the system has all the disadvantages of the RFID localization such as change in the infrastructure and the need for users to carry a RFID reader. If map matching or landmarks are used for error correction, some previous knowledge of the environment is required, which might be costly to prepare.