Indoor Positioning and Navigation
Guest Editors' Introduction • Andrea Bottino, Giovanni Malnati, and Paolo Montuschi, Politecnico di Torino, Italy • June 2013
Translated by Osvaldo Perez and Tiejun Huang
Recent advances in technology and a corresponding reduction in costs are driving growth in research into indoor positioning and navigation. In 2011, IT Professional magazine dedicated a very interesting special issue to "Real-Time Location Systems and RFID," guest edited by J. Morris Chang, Yo-Ping Huang, and Simon Liu.
This video by Prof. Chang briefly highlights the contents of that issue.
In 2012, Computing Now news writer George Lawton presented a nice overview of the main insights of "Bringing Location and Navigation Technology Indoors."
We now return to the topic with this overview of how scientific research has been addressing indoor navigation during the past three years. From the Computer Society Digital Library's extensive collection on the subject, we've selected five articles that cover different technologies and application areas. Interested readers can also view the additional reading below and watch the video we prepared on an indoor vision-based navigation system developed at Politecnico di Torino and one of its spin-offs.
Finally, we include a video in which Phil Laplante of Penn State University quickly outlines the importance of indoor positioning and navigation applications.
For additional reading and useful information, visit the Additional Resources page.
To provide actual services in real scenarios, the first challenge is to evaluate user position and orientation. With GPS signals unavailable inside buildings, researchers have investigated a range of localization technologies, including those based on radio signals, perturbations of the earth's magnetic fields, modulated infrared lights, ultrasounds, and features extracted from images taken by phone cameras. In the extended bibliography at the end of this introduction, we include some articles from the broader literature on this topic. Alessandro Mulloni and his colleagues' "Indoor Positioning and Navigation with Camera Phones" is certainly a "must be cited" seminal article on vision-based indoor navigation, which appeared in 2009 in IEEE Pervasive Computing.
For RFID positioning and related applications, IT Professional's March/April 2011 issue includes an excellent collection of articles. Among them, "RFID-Based Guide Gives Museum Visitors More Freedom," by Yo-Ping Huang, Shan-Shan Wang, and F.E. Sandnes, examines an interesting application exploiting RFIDs (radiofrequency identifiers) for indoor navigation.
In "Indoor Tracking and Navigation Using Received Signal Strength and Compressive Sensing on a Mobile Device," Anthea Wain Sy Au and her colleagues describe an efficient solution for improving the accuracy of Wi-Fi-based positioning and navigation. In most cases, radio-wave-based positioning requires developers to build detailed maps of the radio signal values in the building. This approach seeks to reduce the burden of deploying and maintaining such systems.
A possible step forward is to automatically build the radio-signal maps, as suggested by Chenshu Wu and his colleagues in "WILL: Wireless Indoor Localization without Site Survey." From their tests, the authors report an average room-level accuracy of 86 percent for a typical office building, which is competitive with existing designs. This promising work could potentially lead to a boost the adoption of Wi-Fi navigation systems.
Although precisely pinpointing a user's location is the main challenge, researchers must also solve other problems, as well. In fact, indoor navigation is usually just a building block for more comprehensive context-based services that require many pieces of information about users' context, such as their preferences and physical or cognitive capacities, the nature and availability of specific interaction devices, the static and dynamic characteristics of the environments in which they are moving, and the availability of information systems already devoted to supporting business processes inside the building. In "Context-Aware Computing: Beyond Search and Location-Based Services," Pankaj Mehra provides an interesting introduction to the problem, which extends his previous contribution in the August 2010 Computing Now monthly theme.
Another problem is related to the amount of contextual information. When mobile services require delivery of a large volume of location-based data, users can experience significant delays, especially when a considerable number of users must be served through a limited set of access points. In "Adaptive Location-Oriented Content Delivery in Delay-Sensitive Pervasive Applications", Yu Zhang, Zhibin Wu, and Wade Trappe analyze the problem and propose some solutions.
What about the Future?
Although feasible from a strictly technological point of view, indoor navigation services must tackle several issues before they can become ubiquitous. For example, researchers must define a suitable standard naming scheme for indoor locations, reduce the costs of map provisioning and maintenance (for both the physical and logical environments), and standardize third-party navigation services that can be integrated into mobile applications.
The first issue is also known as the reverse geocoding problem — translating a given building's indoor coordinates into textual descriptions. This task's complexity lies in the fact that each building has its own set of naming conventions (which are mostly unknown to their casual visitors), and a globally acceptable generic solution is still far from being standardized.
The second issue acknowledges that map provisioning is expensive and that usage (connectivity, naming, and so on) of indoor spaces is subject to changes more frequently than outdoor spaces. This has an impact on service sustainability. Yet, in most cases, specific tools for consistently and easily maintaining maps and navigation data are missing. In future, a suitable base for managing navigational information can be provided by the ongoing work in architectural engineering concerning the creation and standardization of so-called building information models (BIMs) — digital representations of a facility's functional and physical characteristics.
The last issue highlights the fact that developing, deploying, and maintaining indoor positioning and navigation could have high costs that are difficult for small organizations to afford. In fact, for the outdoor scenario, third parties have already elaborated a business model that allows the provisioning of standard, off-the-shelf, low-cost (or even free) components that can be easily incorporated into web sites and mobile applications. Unfortunately, this approach can't be directly migrated to indoor environments. Therefore, special-purpose solutions must be implemented to confront additional constraints, such as the privacy issues of building interiors versus the public information of road layouts and networks.
Despite its current limitations, indoor navigation's huge potential economic and sociological capabilities are pushing forward the research, development, implementation, and sale of low-cost systems. In the near future, this will change the way we interact with our surroundings, with many advantages for the various stakeholders involved in any indoor business.
Andrea Bottino is an assistant professor at the Polytechnic of Turin, Italy. His current main research interests include virtual and augmented reality, computer graphics, computer vision, and human-computer interaction. He has also carried out important research in the field of computational geometry. Bottino's most recent works deal with the development of automatic computer tools for planning the outcomes of plastic surgery and with virtual heritage, which combines ICT technologies and cultural heritage. Contact him at firstname.lastname@example.org.
Giovanni Malnati is an assistant professor at the Polytechnic of Turin, Italy. His current main research interests are in software and network technologies for mobile and pervasive systems, vehicular network applications, indoor positioning systems, and multimedia technologies supporting e-learning environments. Malnati has actively participated in several European and national research projects, as well as in technology transfer activities with private companies. He has coauthored several patents in the fields of indoor positioning and remote file system access. Contact him at email@example.com.
Paolo Montuschi is a professor at the Polytechnic of Turin, Italy. His research interests are in computer arithmetic, computer graphics, computer architectures, and electronic publications. Currently, he is associate editor-in-chief of IEEE Transactions on Computers, a steering committee member of IEEE Transactions on Emerging Topics in Computing, and an advisory board member for Computing Now. Montuschi also serves on the IEEE Computer Society Board of Governors (2012–2013), and as chair of the Computer Society's 2013 magazine operations committee. Contact him at firstname.lastname@example.org.