Indoor Frontier

We spend most of our lives indoors, yet the GPS services that serve us so well outdoors are blind when they can’t see the sky. Fortunately, the indoor/outdoor location gap is closing. Leaps in indoor positioning accuracy provided by a large number of competing technologies, along with the already booming availability of indoor maps, point to a new frontier of indoor location based services. Given the promise of market value, we can anticipate a convergence to a smaller set of indoor location technologies.  


Many technologies have been proven for determining indoor location and orientation, but no single one has yet emerged to dominate and lock in the mass market of mobile devices. We are still at an early stage in the market characterized by intense competition among technology companies that are duplicating efforts at great expense (The Economist), e.g, the current Skyhook v. Google cases.

While we can expect a market shake-out and convergence to a smaller set of technologies, it’s clear that indoor positioning will not mimic the tidy world of outdoor, augmented GPS. Indoor position results sufficient to meet the requirements of commercial applications will almost certainly require real-time fusion of several technologies. The Khronos Consortium's StreamInput API work points the way toward using multiple sensors on a mobile device to determine indoor position more accurate than that provided by any single technology. One dark horse may be dead reckoning using microelectromechanical systems (MEMS) based gyros funded by DARPA. Several alliances are advancing standards and industry cooperation aimed at convergence of indoor positioning technologies: In-location Alliance, OMA, Small Cell Forum, and the OGC.

So who will map the great indoors? Indoor maps emerged rapidly in 2009 through the efforts of start-ups such as Point Inside and Micello, and later giant NAVTEQ. Indoor maps and indoor location quality are now becoming a selling point for commercial real estate. Micello recently announced it has mapped 15,000 indoor venues.  Ed Parsons says Google Maps Indoors combines a WiFi map along with floor plans that the facility provides, and they have a goal of “ultimately, a 2-3 meter accuracy.” Another OGC member - aisle411 - is powering over 9,500 indoor retail maps in an eBay app with store profile pages from dozens of big-name retailers, including Walgreens and Home Depot.  

These commercial advances are leading to indoor applications with higher precision and availability, e.g., for emergency response. The FCC recently hosted a workshop on a Communications Security, Reliability and Interoperability Council (CSRIC) test bed for improving indoor location accuracy.

For indoor positions the GPS coordinate reference system based on latitude and longitude will need to be extended or supplanted. 2-dimensional maps are sufficient for some applications, but more robust applications will require 3D and richer information content. OGC's IndoorGML provides such a multilayered space model. The topographic space model encodes the building’s structure which serves as the basis for route planning. A second model for sensors and transmitter spatial presence enables the encoding of data that merges radio footprints with the building spaces. Some applications will require other functionality such as provenance tracking, metadata and gathering of user-provided Point of Interest data. These are all spatial processing functions for which the OGC provides a locus of expertise and a pathway to interoperability with a very wide world of spatial software.

In the Netherlands, a working group associated with Geonovum and the Dutch 3D cadastre is attempting to align the OGC City Geography Markup Language (CItyGML) Application Domain Extension (ADE) GeoBIM standard and the Industry Foundation Classes (IFC) BIM (Building Information Model) standard maintained by buildingSMART International. Such activities will enable semantically rich precision mapping of indoor spaces and support policy-based access for an unimaginable number of applications. To glimpse this future check out Sisi Zlatanova's webinar on 3D Indoor Modeling for Navigation.

Convergence to a smaller set of indoor map encodings will benefit all in the commercial and consumer markets. A shared language for communicating indoor location and location-related information will open up the market. Who among the leading vendors will step forward to offer their indoor map encoding as an open OGC standard, just as Google contributed KML to the OGC to provide an open API (application programming interface) for map browsing?  

• More information and references in this Evernote site.

• Overview of this blog series on geospatial trends

• Next Week's topic:  Cartographers of the future

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