Blind World Magazine

GPS devices earn the confidence of blind users.

The Boston Globe.
Thursday, March 16, 2006.

By Erica Noonan, Globe Staff.

WATERTOWN -- When Brian Charlson walks out his front door, he's guided by satellites hovering 11,000 miles above Earth.

In an instant, a tiny Global Positioning System receiver he carries in a pocket can pinpoint where he is and offer step-by-step directions verbally or via a Braille display.

Charlson, who is 50, lost his vision at age 11 in a household accident. Thanks to a GPS system he bought in January, he is navigating the streets he's walked for decades in a whole new way.

Instead of painstakingly memorizing routes, he just types in a street address. If he's hungry, he calls up a list of nearby restaurants and chooses on a whim.

The lightweight laptop, which he slings over his shoulder, contains software locating schools, ATMs, stores, cafes, and just about any other possible destination.

''It's not that I couldn't go to these places before," said Charlson, vice president for computer training services at the Carroll Center for the Blind in Newton.

''But now I don't have to concentrate on counting cross streets when I walk. If I get disoriented, I don't have to ask someone passing by.

''There's a lot I have learned about my own neighborhood, places I have walked by for years but never knew were there."

The blind community is among the latest beneficiaries of GPS technology, which was developed by the military in the 1970s and has become popular with pilots, hikers, boaters, bicyclists, and motorists. The network relies on two dozen satellites orbiting the Earth that beam low-power radio signals to determine a user's latitude and longitude and other location information. It provides directions measured in feet, yards, or meters.

Each GPS device for the blind comes with its own street-mapping software, designed with safe walking routes in mind, which most companies update annually. Users can also add their favorite destinations and share customized maps.

Charlson's laptop, a PAC Mate manufactured by Freedom Scientific of St. Petersburg, Fla., also allows him to do the previously unthinkable: Head out for a stroll in a random direction with only his guide dog, Keegan, for company. His software features a ''breadcrumb" function, which can automatically record his position every 10 seconds and plan a route back home.

He has used his GPS system on several cross-country business trips. It guided him on a tour of Capitol Hill. It even allowed him to walk alone to a wine shop near a friend's house in Alexandria, Va.

''It does make everything we do better, " said Joe Lazzaro, director of assistive technology for the state Commission for the Blind. ''Blind people have been mobile for a long time and would continue to be without GPS, but this is a lot nicer, and offers more sureness and a greater comfort level."

Lazzaro said he uses his GPS to direct taxi drivers and track his own progress through downtown rush hour while commuting aboard the MBTA's shuttle for disabled customers, The Ride.

With the GPS droning in the background, he knows when to pack up his work and prepare to step off. ''It lets me have a lot more familiarity with what's around me, when I used to wind up asking other people."

GPS would have come in handy two years ago, when Lazzaro walked out of a Green Line station and stumbled into a deserted, fenced-off area covered in two feet of snow. He eventually found a way out, but GPS would have made the detour a lot less frightening. ''It offers tremendous freedom," he said. ''Turn it on, and it will tell you where you are."

It's not known how many of the state's 35,000 blind residents have GPS devices, but industry pioneers say the market for the blind is still extraordinarily tiny -- probably fewer than 5,000 specialty units sold nationwide.

Only about 2 percent of blind people who already use adaptive technology -- such as talking computers and personal digital assistants -- use GPS, estimated Mike May, founder of the Sendero Group, based in Davis, Calif., which in 2000 became the first to market GPS systems for the blind. May said his company has sold 1,500 BrailleNote, PDA-style GPS devices.

The main obsticle is cost. A stripped-down GPS for sighted people sells for less than $100, but the least expensive devices for the blind are nearly $2,000.

Sophisticated systems like Charlson's that come with Braille display keyboards cost more than $6,000.

Advocates for the blind say most potential users can't pay that much, noting that many visually impaired people are unemployed or elderly and living on Social Security.

The potential benefits for blind people of all ages, however, are enormous. Children as young as 6 are using Sendero devices, May said. The Carroll Center soon will launch a program to teach blind schoolchildren to use GPS. Lazzaro said the state commission can afford to subsidize about a dozen GPS setups per year for people who meet special work or educational guidelines.

May and others in the industry hope that government agencies that subsidize assistive technology will soon cover GPS equipment. ''I think we've turned the corner in the past year and it's being recognized as a tool that's necessary for life," he said.

Technological advances, such as providing GPS via cellphone, are expected to bring the cost down dramatically, but not for another few years, May said.

Bob Hachey, 45, of Waltham, has been using a PAC Mate-type system since December. He said he particularly appreciated it when his office was moved and he was breaking in a new guide dog.

''I was able to confirm where I was and negotiate some strange street crossings that confused the dog," Hachey said.

Without the GPS, he said, ''I might have had to call someone on my cell to ask questions along the way." Hachey is a caseworker for MAB Community Services, a nonprofit agency that helps blind seniors. He makes frequent house calls and finds that he can better direct drivers in unfamiliar neighborhoods. The device also helps him direct his wife when she drives him around town.

GPS will not replace the white canes that some blind people use for navigation, or the traditional German shepherd guide dog. Sidewalk obstacles, errant drivers, and low-hanging branches are hazards far too small and temporary for any GPS system to detect.

Nor is the technology perfect. The location-plotting system can be off by up to 100 feet, and it is only as good as its mapping software, which may not include every point of interest or updated to account for new construction or road changes.

The limits of GPS became amusingly clear to Charlson during a business trip to Jacksonville, Fla. He led a group of six blind friends to a barbecue restaurant at an outdoor market near their hotel. But when they walked through the doors at the GPS-specified address, they found themselves standing in a Hooters franchise.

Everyone had a good laugh, and Charlson quickly deduced that the restaurant they wanted was one flight up -- on the second floor of the same building. ''The women in the group gave me a hard time about that for days."

The ABCs of GPS.

The nation's Global Positioning System, or GPS, was developed by the US government in the 1970s for military use.

The system relies on radio signal transmissions from 24 satellites orbiting the Earth twice daily some 11,000 miles high. The satellites, which measure about 17 feet across, run on solar power and have rocket boosters to keep them from veering off course.

Using four to eight of these satellites at any particular time, GPS uses a complex triangulation calculation-- measuring the speed of the radio waves from each satellite -- to pinpoint within 50 feet the position of anyone holding a GPS receiver.

Once the receiver has determined a user's latitude, longitude, and altitude, the unit can calculate other useful information like speed and distance to any destination in feet, yards, meters. By combining GPS technology with detailed street and city mapping software, a user can plot just about any journey on foot or by vehicle.v

GPS works anywhere in the world, 24 hours a day, under nearly all atmospheric conditions, although a clear day without tall buildings or mountains nearby is optimal for accuracy.


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