Deploying Indoor WLAN Positioning Systems

Most of us are familiar with Global Positioning System (GPS)
products that help us navigate while driving, hiking, boating,
and flying. GPS uses a combination of orbiting satellites to determine position
coordinates. This works great in most outdoor areas, but the satellite signals
are not strong enough to penetrate inside most indoor environments. As a result,
a new strain of indoor positioning technologies that make use of 802.11 wireless
LANs is beginning to appear on the market.

Awesome Applications

The idea of combining positioning information with wireless LAN applications
has always been interesting to me. A central server can monitor the coordinates
of wireless tags and users and feed position information to various types of
application software. Warehouse location systems make it faster to find items
and hospitals can track the location of doctors and nurses to dispatch the right
person who’s closest to an emergency.

The usage of location-aware systems over wireless LANs, however, is now moving
toward the consumer market. For example, the ability to track children is extremely
valuable. Imagine being in a theme park and your toddler wanders off without
your knowledge. With a location system, you can easily find them among a large
crowd. Through the use of a concealed wireless tracking tag, this type of system
can aid tremendously if someone takes a child without permission.

The use of location-aware applications in retail environments is pretty exciting.
You can deploy this type of system in a shopping mall or large retail store
and implement electronic flyers and advertisements. The system takes into consideration
the physical location of shoppers within the facility and customizes content

For example, users can receive an electronic directory and advertisement flyer
on their wireless PDA after entering the mall. The directory would include a
map of the facility that identifies the person’s exact position on the map.
As the shopper clicks on a store, restroom, or ATM machine in the directory,
the map indicates directions that take them to the desired selection. If your
spouse or shopping friend is carrying a wireless device, then you can also keep
track of each other’s whereabouts.

To take this further, retailers can push sales information out to shoppers
that come within range of the store. If the user selects one of the advertisements,
their PDA can lead them to the applicable merchandise. Of course, this can result
in electronic competition. For example, you can be shopping for tools in one
store, and a competing store can pop up an advertisement for a better deal in
an attempt to steal the business.

These are all pretty thrilling applications for a gadget guy like me. Anything
that beeps and displays stuff captures my interests. The problem with expanding
this market, though, is that most people just want to shop traditionally, which
is why Internet-based shopping has yet to overtake a trip to the mall.

Proprietary Technologies

Indoor positioning requires the deployment of specialized equipment that integrates
with a wireless LAN. Vendors are not too open about discussing how their products
determine the user’s position, but they likely monitor propagation delays among
the wireless nodes (access points and users) to triangulate and calculate relative
position. An issue with these systems, however, is that there are no standards.
All solutions are vendor-specific.

For example, Ekahau offers the Ekahau Positioning Engine (EPE)
that locates laptops or PDA devices within 1 meter (3.5 feet) in less than a
second. EPE is a software-only solution based on Java 2 that runs on Windows
NT/2000/XP, WinCE 3.0 and Pocket PC 2002. An Ekahau Manager application records
site data and tracks devices, with the ability to show a floor plan that displays
the location of each wireless nodes.

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