Development of the navigation system for the visually impaired by using optical beacons

Optical wireless (OW) technology has attracted significant interest for indoor positioning in the past decade. An emerging form of this technology makes use of angle-of-arrival (AOA) measurements to carry out positioning via triangulation off of an optical beacon grid. Such AOA-based OW positioning systems can yield accurate position estimates—but only given sufficient attention to the optical receiver. The design, operation, and implementation of such a receiver are presented in this work. The optical receiver is designed to have a sufficiently small AOA error, being σAOA = 1°, over a wide angular field-of-view (FOV), being 100°. The design allows the optical receiver to carry out positioning based off a 3 × 3 grid of optical beacons, where each optical beacon is uniquely identified using multiple frequency and color channels. The optical beacons are widely spaced to fully utilize the optical receiver's wide angular FOV. The overall AOA-based OW positioning system exhibits a position error of 1.7 cm, which is comparable to those obtained by more complex positioning systems. Thus, the presented AOA-based technologies can play a role in emerging indoor positioning systems.

It is possible for the visually impaired to walk their known area independently by using a white cane. However, in their unknown area, they cannot walk without help of others even if they can use a white cane very well. In such cases, not only a visually impaired person but he/she who assists them receives many stress in dairy activity. Therefore, many types of independent walking assist system for the visually impaired are developing. Our objective of this study is the development of an auto navigation system for the visually impaired which assists independent walking of them. This system measures the position of a visually impaired person (a user) by using GPS (Global Positioning System) and navigates him/her to the destination like as a car navigation system. In our system, a location data is stored in the map database and a position of user are analyzed and optimal route for a user to the destination is calculated. Our system guides a user to the destination along this route, and notifies the user of this route and some information for the safety walking by artificial voice. Three normal subjects were tested with our navigation system. All subjects were blind folded by an eye mask and equipped a navigation system. As a result, our system worked well and all subjects were able to walk to the destination following guidance voice. So, we are developing a new navigation system which is installed on a cellular phone. In Japan, there are some cellular phones that include GPS. And most of application programs for cellular phone are written by JAVA. Therefore, GPS included in a cellular phone will be used and every functions of the navigation system will be written by JAVA. In this paper, we also reports about this new navigation system.

The challenges of optical wireless positioning are addressed in this paper by a thorough investigation of angle of arrival (AOA) positioning characteristics. The overall positioning precision for AOA positioning is studied in terms of two contributing factors—being angular precision and geometric dilution of precision (DOP). Angular precision is characterized for an optical wireless receiver having an especially wide angular field-of-view (FOV). Geometric DOP is characterized for optical beacons deployed in the form of triangle, square, and hexagon cell geometries. The mean and standard deviation of the positioning errors are extracted from the positioning error distributions for each of the three cell geometries. It is found that the overarching goal to establish low and uniform positioning error distributions can be met by implementing an optical wireless receiver with a wide angular FOV and by implementing the optical beacon geometry with a correspondingly small height-to-side-length ratio. The prospects of these findings are discussed for future optical wireless positioning systems.

With recent progress of mobile devices and indoor positioning technologies, it becomes possible to provide location-based services in indoor space as well as outdoor space. It is in a seamless way between indoor and outdoor spaces or in an independent way only for indoor space. However, we cannot simply apply spatial models developed for outdoor space to indoor space due to their differences. For example, coordinate reference systems are employed to indicate a specific position in outdoor space, while the location in indoor space is rather specified by cell number such as room number. Unlike outdoor space, the distance between two points in indoor space is not determined by the length of the straight line but the constraints given by indoor components such as walls, stairs, and doors. For this reason, we need to establish a new framework for indoor space from fundamental theoretical basis, indoor spatial data models, and information systems to store, manage, and analyse indoor spatial data. In order to provide this framework, an international standard, called IndoorGML has been developed and published by OGC (Open Geospatial Consortium). This standard is based on a cellular notion of space, which considers an indoor space as a set of non-overlapping cells. It consists of two types of modules; core module and extension module. While core module consists of four basic conceptual and implementation modeling components (geometric model for cell, topology between cells, semantic model of cell, and multi-layered space model), extension modules may be defined on the top of the core module to support an application area. As the first version of the standard, we provide an extension for indoor navigation.

For blind people it is very difficult to orientate in an urban area. Especially in an unknown environment they cannot move independently and need the help of a sighted person. With the development of a navigation system tailored to the special needs of blind people their mobility will increase. Blind people make high demands on all components of the navigation system. These requirements and possible solutions are worked out in a project with the collaboration of blind people. The development aims at a prototype of a navigation system which covers the overall spectrum of navigational components. This comprises an appropriate modeling of the navigational environment, fast routing algorithms generating lists of maneuvers, suitable positioning tools, reliable map matching algorithms for route checking, and finally, adequate guidance instructions.

Abstract. Recent years have witnessed the rapid development of navigation systems. They gradually become the default way of navigating in our daily life. Despite benefiting from their convenience, we may be negatively influenced by them (Parush et al. 2007). Current navigation systems usually draw too much of users' attention to the mobile devices, which leads to users’ lacking interaction with the environment. It is often the case that people easily forget travelled route and get lost without navigation systems (Reilly et al. 2008). Empirical study shows that by dividing attention, navigation systems impair users’ spatial memory, and thus impact their navigation skills (Gardony et al. 2013). Since a higher engagement with the environment can improve users’ spatial knowledge acquisition without decreasing efficiency (Brügger et al. 2017), navigation systems should incorporate important environmental features.As objects of visual, cognitive or structural importance (Sorrows & Hirtle 1999), landmarks have been extensively studied, and considered as an important environmental feature to be incorporated into navigation systems (Nuhn & Timpf 2018, Richter 2017, Duckham et al. 2010, Raubal & Winter 2002). They serve as references to provide users with more natural and pleasant navigating experience (Richter & Winter 2014). However, most of landmark-related studies are in outdoor environment. Although researchers have attempted to classify and assess indoor landmarks (Ohm 2014, Viaene 2014), it is still very difficult to determine suitable ones. As a subset of semantic indoor landmarks, existing navigational aids (e.g. signs and floor plans) are designed to assist navigation. Among them, signs are most preferred by users (Wang et al. 2017). Being the signs that give necessary information to route users to possible destinations, directional signs contribute most to wayfinding (Gibson 2009). With route information explicitly presented by them, they are relevant environmental features to be incorporated into indoor navigation systems.In this study, we therefore propose to incorporate directional signs into indoor navigation systems, in order to guide users’ attention back to the environment, to facilitate their spatial learning and improve their spatial knowledge acquisition.We incorporated directional signs into a proof-of-concept indoor navigation system. First, we integrated directional signs and their semantics into a graph-based model. A directional sign was modelled as a node. Each destination on the sign was linked with the sign by an edge. In order to differentiate it from the normal edge, it was marked as semantic edge. Thus, the semantics of the sign was modelled directly into the graph, instead of being stored as attributes in a previous version of our study (Wang & Gartner 2018). Then, a top-K shortest path algorithm was employed to find candidate routes (Yen 1971). In the end, the route with the largest coverage of semantic edges was suggested to the user. The users would then be explicitly guided to follow the directional signs in the environment.In the next step, we will evaluate the efficiency and effectiveness of the proposed navigation system by an empirical study with human subjects. Within the experiment, we will also investigate on whether this kind of guidance can succeed in drawing users’ attention back to the environment and support their spatial knowledge acquisition.

The US Army has a requirement for a highly accurate inertial/TACAN hybrid navigation system. This paper describes the navigation system architecture developed to meet this requirement, the specific hardware selected and the development status. At the beginning of the Integrated Inertial Navigation System (IINS) development program it was anticipated that significant technological advances would take place in its life cycle. In addition, mission requirements were expected to change as the system evolved. Particular attention was therefore given to the IINS system architecture, specifically the partitioning of hardware and software functions as well as the means of data transmittal between the subsystem elements. The paper describes in detail the design trade-offs made as well as hardware selections. The system is configured using several different manufacturers' equipment making the data interface and its configuration control of great importance. The above considerations lead to the conclusion that the appropriate data bus interface standard would be MIL-STD-1553. This interface standard not only facilitates configuration control during system development, but will allow rapid integration with future aircraft systems that will use it as a primary means of data transmittal. The paper describes in detail the signal interface between the subsystem element, onboard mission equipment and flight instruments. The most significant change anticipated in the course of the IINS life cycle is the substitution of Global Positioning System User Equipment for the external update function currently provided by TACAN. Another area where technology insertion may be deemed appropriate is the substitution of a strapdown inertial navigation unit (INU) employing ring laser gyros (RLG) for the currently employed conventional gimballed INU. The INU employed in the IINS is built to a form, fit and function specification, which will allow substitution of a RLG INU when such a unit is qualified and in production. The system hardware and software is structured so that these changes can be accomplished with a minimum of effort. The paper also describes the federated processing structure which allows this flexibility with particular attention to the inertial/TACAN update algorithm and data bus control functions. The paper concludes with a brief summary of the development status of the IINS, currently in full scale engineering development.

Humans spend most of their life in indoor spaces. As indoor spaces are becoming increasingly complex, there are compelling needs for efficient indoor GIS and navigation systems. For indoor navigations, numerous geometric network models have been proposed as navigable spatial models for 3D indoor environments in the past decade. Most of the existing discussions, however, tend to focus on conceptual representations of geometric networks; not enough attention has been given on the generation processes of navigable networks for 3D indoor environments. It is actually nontrivial, considering accurate and complete floor plans, the conventional data sources for building indoor geometric networks, are oftentimes not available for various reasons (e.g., copyright, public safety concerns). With the continue advances of 3D imaging and scanning technologies, 3D data models with fine geometric structures and high quality textures are increasingly available for indoor spaces, thus provide a novel data source for building indoor geometric networks. In this paper, an interactive approach is presented to derive 3D, navigable, geometric network models from these 3D data models. Specifically, this approach includes three steps: decomposing 3D building models in terms of floors, interactively creating geometric network elements (e.g., nodes and edges) and then automatically generating geometric network models. The presented approach is implemented and its advantages are demonstrated with a real world 3D building data.

Initiated and financed by the Canadian Space Agency, Micro-Rover Platform with Tooling Arm (MRPTA) project has targeted the development of a robotic system with remote control and autonomous navigation capabilities for testing a large variety of analogous planetary missions. Although developed for planetary exploration, the navigation system is highly suitable to such areas of application as construction and in mining. Autonomous navigation system is capable of moving the platform to predefined position(s)/orientation(s) while continuously mapping the terrain, assessing its traversability and choosing most appropriate path to follow. Designed according to the JAUS (Joint Architecture for Unmanned Systems) framework, the system consists of several interconnected components. Following components are of particular importance: Pose Estimator (PE), Terrain Evaluator (TE), Map Manager (MP), and Path Planner (PP). The PE uses a minimal sensor configuration consisting of an azimuth gyroscope, inclinometer and wheel odometry. The PE provides reliable pose estimates in spite of pronounced slippage by employing extensive use of fused data. The TE uses a nodding laser scanner which continuously sweeps the area in front of the platform and constructs a “traversability grid” (TG) of the surrounding area. Multiple TGs are constantly constructed along the platform motion path are combined into a terrain map maintained by the MP. The PP uses this map to compute a motion path Obtained path is executed by the motion controller and remains current until it is contradicted by the most recent map – at which point it is re-planned. This paper addresses integration issues, lessons learned and also outlines the possible applications for construction and mining.

People who are Blind or Visually Impaired (BVI) have one goal in common: navigate through unfamiliar indoor environments without the intervention of a human guide. The number of blind people in the world is not accurately known at the present, however, based on the 2010 Global Data on Visual Impairments, World Health Organization, approximately 285 million people are estimated to be visually impaired worldwide: 39 million are blind and 246 have low vision, 90% in developing countries, with 82% of blind people aged 50 and above. Available extrapolated statistics about blindness in some countries in the Middle East show ∼102,618 in Iraq, ∼5,358 in Gaza strip, ∼22,692 in Jordan, ∼9,129 in Kuwait, ∼104,321 in Saudi Arabia, and ∼10,207 in the United Arab Emirates. These statistics reveal the importance of developing a useful, accurate, and easy to use navigation system to help this large population of disabled people in their everyday lives. Various commercial products are available to navigate BVI people in outdoor environments based on the Global Positioning System (GPS) where the receiver must has a clear view of the sky. Indoor geo-location, on the other hand, is much more challenging because objects surrounding the user can block or interfere with the GPS signal.In this paper, we present a centralized wireless indoor navigation system to aid the BVI. The system is designed not only to accurately locate, track, and navigate the user, but to also find the safest travel path and easily communicate with the BVI. A centralized approach is adopted because of the lack of research in this area. Some proposed navigation systems require users to inconveniently carry heavy navigation devices; some require administrators to install a complex network of sensors throughout a building; and others are simply impractical in practice. The system consists of four major components: 1) Wireless Positioning Subsystem, 2) Visual Indoor Modeling Interface, 3) Guidance and Navigation Subsystem, and 4) Path-Finding Subsystem. The system is designed not only to accurately locate, track, and navigate the user, but to also find the safest travel path and easily communicate with the BVI.A significant part of the navigation system is the virtual modeling of the building and the design of the path-finding algorithms, which will be the main focus of this research. Ultimately, the proposed system provides the design and building blocks for a fully functional package that can be used to build a complete centralized indoor navigation system, from creating the virtual models for buildings to tracking and interacting with BVI users over the network.

Midcourse Space Experiment attitude system performance for gyro disabled operations

The Air Force Research Laboratory Munitions Directorate (AFRL/MN) is engaged in the development of advanced munition navigation systems. The Navigation Team has a mobile test vehicle (MTV) to accomplish outdoor, low-dynamic testing of developmental navigation systems. Past tests conducted by the MTV required the units under test possess their own navigation system while the MTV provided F-16 data interface emulation via MIL-STD-1553 data bus. A reconfigurable navigation system (RNS) is being developed that accepts data from any inertial measurement unit (IMU), such as micro electromechanical systems (MEMS), and provides the means for navigation evaluation. Implementation of navigation filters will be done with the aid of a user interface while tests of these filters will be done without paying the price of airborne tests. C++ objects for such things as the plant, measurement, and covariance matrices, states, the earth, position, velocity, and transformation matrices are created. This paper discusses the beginning stages of the RNS. It begins with the verification of a strap-down navigator. The timing of the inertial navigation system is explained. Position and velocity accuracy is provided.

Contemporary public buildings are becoming conglomerates of open, semi‐open and closed spaces, with indoor, outdoor and underground sections. For humans and robots to navigate seamlessly through such environments, new flexible approaches need to be developed. Navigation systems generally rely on a network (nodes and edges) as an abstraction of underlying space availability. However, indoor and outdoor networks have different origins. While indoor systems rely on indoor space subdivision approaches, current outdoor systems utilize road‐based network approaches. Linking such networks via particular nodes is possible but restrictive. Many spaces in the built environment are not strictly indoor or outdoor spaces and are thus often omitted from navigation networks, further limiting navigation options. To overcome these shortcomings, we introduce a new space definition framework in which the entire built environment is categorized into indoor, outdoor, semi‐indoor and semi‐outdoor spaces. We provide strict definitions for the four space categories. Our framework allows the same navigation network extraction approaches to be used and therefore enables seamless indoor/outdoor path computation for single or combinations of locomotion modes. The notions of semi‐indoor and semi‐outdoor spaces offer new options for further tailoring of the navigation path with respect to environmental factors, which we demonstrate with two use cases.

With the prevalence of car navigation systems, indoor navigation systems are increasingly attracting attention in the indoor research area. However, the available models for indoor navigation suffer from the problems that architectural constraints are not considered, route planning is only based on 2D planes, users are represented as points without considering their volumes, and different requirements asked for by different users are ignored. Consequently, the routes provided by existing models may not be suitable for different kinds of users like pedestrians, persons in wheelchairs, and persons driving indoor autos. This paper proposes a cube-based model to compute feasible routes for different users according to their widths, heights, and special requirements (e.g., users in wheelchairs prefer the routes without stairs). In this model, an indoor space is first represented by multiple cubes with different types. Then, according to the heights and types of the cubes, possible passages with the maximum widths and heights are generated by merging cubes into large blocks. Based on these blocks, feasible routes are computed by checking the availability of the connectors between different blocks.

The car navigation service has opened through the global positioning system (GPS). People's lives have changed through car navigation services, and this service is indispensable nowadays. GPS provides reliable location accuracy in open space, but its location accuracy is degraded where multipath and other error factors are present. In particular, since GPS signals must be received in order to calculate the position, the navigation system cannot calculate the position in an indoor space such as underground parking lot, subway or tunnel where GPS signals are cut off. When car navigation is performed in an indoor parking lot where GPS signals are not transmitted, the user cannot calculate the current location, so the user has to go out by relying on the traffic sign because he does not know the current location. Also, when the user leave the parking lot, the car navigation system has problems. In an urban canyon, it is difficult to calculate accurate current position due to multipath. Because the route is calculated through the current location and route, the car navigation system provides the wrong route to the user. In addition, when entering a tunnel while using car navigation, the car navigation system calculates the position using the initial tunnel entry velocity estimated by the GPS. As the speed of the user increases or decreases, the position error also increases. Then the position suddenly changes when passing through the tunnel. And it is difficult to provide a proper guidance at the branch road or exit in the tunnel because of the positioning error. People are demanding a complete car navigation service, but the current navigation service provides the wrong route and position information to the user where the GPS signal quality is poor. In order to solve the above problem, in this paper, we have studied to improve the user's position accuracy by using LTE signal and mobile phone internal sensor. In general, observed time difference of arrival (OTDOA) technique is applied for the LTE based positioning. Because this method gives tens of meters of error, it is difficult to be used for the car navigation service. In our research, we estimate the position using the LTE signal strength. The difference from conventional fingerprinting method is that instead of using only current signal strength, the signal strength pattern accumulated while moving is utilized to estimate the user position. The signal strength increases as the user approach the access point (AP), and decreases as the user move away from the AP. Therefore, when a user moves and stores signal strength with respect to a specific AP, a pattern that could occur only in the corresponding region is saved. There are many similar candidates in the database when using only the current signal strength. However, when using a pattern, similar candidates exist only around the true position. And, when using several LTE signals, the positioning accuracy could be increased. Since the user receives multiple LTE signals, the pattern becomes surface. The surface is compared with the database, and the position with the highest correlation value is estimated as the current position. We call this method surface correlation (SC). In order to verify the performance of the proposed method, experiments were conducted in the Gangnam beltway tunnel in Seoul. The testbed consisted of three tunnel and total distance is almost 11.8 Km. In the tunnel, repeater and several antennas are installed to widen the area of the LTE signal. When an LTE signal is received by the vehicle, the largest signal strength is received every time when the vehicle passes the nearest antenna. As a result, for a specific LTE signal, when the vehicle has passed through the LTE signal region, a unique pattern with multiple peaks is generated. In order to estimate the position, we first estimate the position with the SC technique. Then, the estimated position is corrected by comparing the peak of the currently received pattern with the peak of the database. Through this method, the position was estimated with an error of less than 50meter in the tunnel. Conclusion In this research, the LTE signal strength based positioning technology is presented. Especially, this technology, SC, provides the positioning performance that could be used for the car navigation in the tunnel where GPS signal is blocked. We expected that user would be use the accurate car navigation service through this technology in the GPS challenging environment.