| Location-Aware Computing |
by Sanjay Deshmukh and John David Miller (Dec. 3, 2003)
Overview: Location Everywhere
Many of the devices we use every day for convenience are affected by location. And yet, our cell phones, laptops, PDAs, and even our cars have virtually no idea of where they are or what's nearby. If you get on an airplane in Portland and get off the airplane in Boston, chances are that your high-tech devices won't even know that you've switched time zones! But that is about to change.
In Intel Software Research and Technology Labs, engineering teams are working to make location-aware a reality. That is, Intel devices will know where they are, know what objects and places are nearby, and be able to communicate with other devices and servers over new, standardized protocols, such that location becomes a new data type in our applications and on the Internet and World Wide Web.
At the same time Intel is developing more devices with an ability to sense their location, Intel is also raising the bar on the breadth and depth of location applications. Today, virtually all first-generation location applications are variants on the "thing-finder" theme: find a restaurant, find a building, etc. Even the navigation systems in cars are really "thing-finders."
These technologies are just the first steps on a longer journey: to bring a broader array of device types, and a broader array of applications beyond "thing-finder" and make them location-aware.
New Users and New Uses
The Global Positioning System (GPS) is perhaps the most familiar technology that uses location-aware computing. Two dozen satellites, orbiting 11,000 miles above the Earth, help car drivers and hikers find their way virtually anywhere on the globe. In fact, using GPS has also become an integral part of a game -- a treasure hunting sport called "geo-caching."
But beyond the novelty, what uses for location-awareness will we think of when it becomes part of our everyday computing environment? What location applications will emerge when we can determine our location anywhere -- indoors as well as outdoors (Footnote 1) -- and when location applications and content become the domain of the Internet, instead of proprietary cellular networks? How much easier will life be when mobile devices know where they (and each other) are, and automatically do the right thing for that location?
The features that most people would expect from a location-aware device include: - Automatically reconfiguring itself, such that it always (1) uses the right network settings (for firewall proxies and VPN), and (2) prints on the right printer (i.e., use the home printer when at home, the work printer when at work)
- Making it secure, only allowing access from designated physical locations
- Help to find it if it is misplaced, or stolen
- Enabling the ability to easily share papers and presentations with everyone else in a room, without having to email it or set up a folder on a common server
But why stop there? Additional features that work in combination with a computer's existing time-awareness capability would also enhance location-awareness. Features such as: - Reminders that tell you when to leave for your appointments, knowing how long it will take to get there
- An accurate calendar function that shows the free/busy time on your calendar, allowing for the travel time between where you're scheduled to be and a new appointment as it's being made
- An ability to recognize patterns in your daily, unscheduled travel between home and work and proactively fetch the current traffic info before it's time for you to leave and recommend the fastest route
All of these capabilities are just the beginning. It's worth considering that notebook computers are not used for the same things, nor are they used in the same way as cell phones or PDAs. Therefore, while it's reasonable to expect that there may be areas of overlap, each category of device has its own idea of an application for location; one size does not fit all. This thinking extends to other potentially "location-enabled" devices, too, such as desktop PCs and servers.
Fortunately, from a technological perspective, there is overlap, and quite a lot of it. Network connectivity over an IP connection, for example, bridges data islands and breaks down proprietary "walled gardens." Open, Internet-style standards level the playing field, help new technologies quickly gain critical mass by avoiding market fragmentation, and deter duplication of effort. This is definitely true for location-aware computing, where isolated pockets have existed for years, but is now looking to become mainstream across the entire spectrum of devices.
Indoors: The New Location for Location
Some of the biggest and most exciting changes in the world of location-aware computing are by bringing location-awareness indoors. Geo-spatial Information Systems (GIS) is a comparatively mature industry -- and cartographers have been making maps for centuries. With so much data readily available and many practical applications, it's no surprise that online maps are among the most popular applications on the World Wide Web. And it's no wonder that when most people think of location-aware computing, they immediately think of GPS.
Unfortunately, none of this applies indoors. Like the early days of globe-charting, indoor maps are by-and-large nonexistent or proprietary. Some of the challenges, then, for making location knowable indoors as well as out include: - Location-sensing technologies other than GPS
- Access to indoor map data via strong and verifiable security measures.
- Indoor coordinate spaces. While latitude/longitude/altitude (LLA) is suitable for describing points on the globe, it isn't the most natural or descriptive for describing points indoors. In the short run, we have to make do using LLA, but its long-term successor is likely to be a hybrid format that describes both locales well (Footnote 2).
Location Sensing Technologies
For all practical purposes, GPS is useless indoors. Its satellites can't be seen indoors and a GPS fix requires a clear view of at least three satellites. Even if you could see the satellites, the accuracy of GPS, while much better than cellular phone network location technologies like Cell ID or Enhanced Observed Time Difference (E-OTD), isn't sufficient for many indoor applications. We need something else.
Today, it is 802.11 and Wi-Fi, the very same Wi-Fi that's already in your Intel Centrino Mobile Technology notebook computer and XScale PDA. That's the good news. The bad news is that Wi-Fi as it currently stands doesn't have any inherent location-sensing capability. But engineers have already devised a way to use the Wi-Fi signal as a sort of radio frequency (RF) lighthouse, and thus as a mechanism for computing location.
While the data connectivity features of 802.11 have shaped up nicely (manifesting as a progression of alphabet-suffixed versions: 802.11a, 802.11b, . . .) there has been no such standardization on location features in Wi-Fi.
The benefit of using Wi-Fi for indoor location is that it takes advantage of radio technology, instead of adding an additional, location-specific radio (Footnote 3). But, in order for Wi-Fi location to become as entrenched as Wi-Fi data, some consensus will be necessary between workgroups defining the access point and the mobile device as well as between the application and the device's networking card. This is true for Wi-Fi, Bluetooth, RFID, and other related technologies.
But Wi-Fi is not the only solution for indoor location tracking. Other technologies, notably RFID, can provide proximity information that can both establish the location and the surroundings. Used together, RFID and Wi-Fi complement each other: Wi-Fi establishes location to within a few meters and RFID establishes a particular object or spot within the range of a few centimeters.
Using Beacons and Proximity Tags
A mobile device requires assistance in order to use the RF signals it sees as location beacons or as proximity tags. Specifically, it needs to know where these beacons are themselves located and what tags are attached. Short of embedding that information into the signal, the best way to do it is to simply look up the beacon or tags station identifier (such as a Wi-Fi access point's bssid) in a database that has this information: - Device periodically scans to see what RF signals are in the area
- Device looks up the station IDs in a database (possibly local, possibly on a server or group of servers that can be accessed as a Web service).
- Armed with the database info, the device can make use of the signal characteristics of the observed access points to calculate its own location or proximity information from the RFID tags to make logical inferences about where it is and what is nearby.
This simple technique extends to virtually any observable radio signal: GPS, Wi-Fi, Bluetooth, RFID, Cell ID, UWB, FM radio, DTV, and others. If the device has the data cached locally, or can get to a database or a Web service with the data cached, then it can determine its location.
Although proprietary protocols are available for several of these technologies; Intel is working with standards bodies on defining and promoting a single, extensible, open, IP-based, Internet-style version, complete with a simple reference implementation that will location-enable any device with an IP connection.
Summary
Location-aware computing brings with it many possibilities that will make mobile devices even more effective and convenient both at work and in the home. With this technology we're moving away from proprietary, closed location systems to the Internet where your location is just another piece of data. But by using this data, applications can provide richer, more productive, and more rewarding user experiences.
More Info
For more information on location-aware computing, visit Intel's Location-Aware Computing website.
This site has a collection of white papers and articles that will help you understand how this technology will help you and your business.
Footnotes - By itself, GPS is only effective with a clear line-of-sight to at least three (and preferably four) satellites. Thus, it is typically of no use indoors or even in an "urban canyon" of buildings.
- We suspect that this coordinate scheme should also provide for both publicly- and privately-understandable address components, similar to network names (e.g., how to get to www.intel.com is publicly known, but any component after the first slash is translated internally), which would allow scalable route-building via levels of agency encoded within the address.
- Additional radios add additional cost, take up additional space, and consume additional power.
About the authors:
 Sanjay Deshmukh is a standards architect in Intel's Corporate Technology Group (CTG). Deshmukh is currently focused on location-based services and is Intel's delegate to the Open Mobile Alliance (OMA) and the Java Community Process (JCP) location work groups. Prior to joining Intel, Deshmukh was at Motorola and Raynet. He has 13 years of experience in the research and development of wire-line and wireless telecommunications systems with expertise in network management and cellular standards, architecture, systems engineering, and software development across 2G and 3G cellular networks. Deshmukh has M.S.E.E. and M.S.C.S. degrees from the University of Illinois, Chicago and B.S. degrees in computer science and math sciences from Oregon State University. He holds a U.S. and an international patent and several patent disclosures.
 John David Miller co-leads the location-aware computing initiative for Intel's Systems Technology Lab in CTG. Prior to joining Intel Architecture Labs in 1995, Miller was the founder and CEO of Harmonic Software, Inc. He is the author of the book, An Open Look at UNIX, and has over a dozen patents in information visualization, data broadcasting, personalized information filtering, 3D user interfaces, and mobile/wireless devices.
Copyright © Intel Corporation 2003. All rights reserved. Reproduced by DeviceForge.com with permission. This article was originally published in Intel's Technology@Intel Magazine.
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