Braille Monitor February 2006
GPS Technology for the Blind, A Product Evaluation
by the NFB’s Access Technology Staff
From the Editor: Global Positioning Systems are more and more common in our technology-laden world. It is a measure of the progress that the blind community has made that we now have three accessible systems to choose among. In the following article the staff of the International Braille and Technology Center of the NFB Jernigan Institute (IBTC) briefly explain GPS technology and evaluate the three current systems. This is what they say:
Global Positioning System (GPS) technology is a valuable asset to the United States military, aiding soldiers in determining their positions in combat. Commercial and private boaters use GPS technology to track their coordinates while they are out on the ocean or big lakes. Many automobiles are now equipped with GPS systems. A driver can get turn-by-turn directions to any destination nationwide. Furthermore, if an individual calls 911 from a GPS-ready cellular phone, emergency personnel can easily locate the caller.
In all of the situations mentioned above, GPS technology proves useful. With the advancement of GPS technology blind people can also use many GPS-ready devices as travel aids. Currently blind consumers can choose from three GPS products: the Trekker produced by HumanWare, a portable GPS system that connects to a personal data assistant; a GPS system from the Sendaro Group for HumanWare’s BrailleNote portable notetaker; and a GPS system for PAC Mate produced by Freedom Scientific. When using these GPS-ready products, a blind person can preplan travel routes without leaving the house. With GPS a traveler can explore the surrounding area by searching for a specific business or other point of interest. Whatever means of travel is used—car, bus, train, or shoe leather—blind travelers can be reasonably well informed.
Unfortunately, as with all technology, there are a few drawbacks. As advanced as GPS technology is, a traveler must realize that no machinery can function 100 percent of the time. In order for a GPS system to provide accurate information to a traveler, it must be able to receive a signal from a minimum of four satellites. Inclement weather or tall buildings can interfere with signal reception. Another disadvantage of GPS is its dependence on battery power. Even though using a battery enables a GPS system to have portability, a battery can fail without warning. All three of the GPS-ready products mentioned above use digital commercial mapping from a third party, and maps become obsolete if not updated periodically. A GPS receiver cannot inform a blind traveler of a drop-off on the sidewalk or a rise in elevation; therefore a blind pedestrian will not be able to use GPS to determine ordinary obstacles that may lie ahead or let him or her know when it is safe to cross the street at a busy intersection.
GPS technology has other disadvantages worth mentioning. The largest drawback is that the system does not work everywhere blind people want to travel. The GPS signal is sent as a low-powered radio signal from 20,000 kilometers (12,400 miles) out in space. By the time the signal passes through free space, the stratosphere, ionosphere, and the troposphere, not much power is left to carry the signal to the user. It is said that by the time the signal reaches a user its power is equivalent to that of two Christmas tree light bulbs mounted on the satellite seen by a watcher standing on the surface of the Earth. The signal strength transmitted to today’s GPS receivers is not enough to penetrate all useful locations.
A GPS signal cannot penetrate many of the ordinary objects around us. It cannot pass through dense materials such as stone, concrete, metal, dirt, or thick trees. This can be bothersome, since most travel is not done in large open spaces but indoors or on city streets. Another barrier for the GPS signal is water. While it seems implausible that water would impede the GPS signal for a person walking down a street, most of the human body is made of water. So our own presence causes signal blockage. When a system is mounted on a person, the antenna is usually mounted on the shoulder. A person’s head, which is full of water, will block the signal. Fortunately for us, it is only blocking about half of the sky so some satellites can still be reached and used to navigate. Impractical but effective, the best place to put a GPS antenna is on the head.
A GPS receiver actually provides very limited data. Its primary function is to relay three elements: position, velocity, and time (PVT). These three elements are the building blocks of basic navigation. The GPS receiver does nothing more than make constant PVT calculations.
Navigation software also
uses maps to pinpoint a person in the context of surrounding geographical references.
Unfortunately maps are not always accurate. Changes frequently occur to structures,
streets, curbs, and objects on the ground. Where no mailbox was on the corner
yesterday, one appears today. This type of information is not updated in the
map database. The piece of lumber that fell off a truck onto the crosswalk a
few minutes ago will not be in the database either. It would not make sense
to add it since, one hopes, it will be gone in a few hours. Thus a GPS system
cannot guarantee safety for a blind traveler; only good mobility training and
independent traveling skill can. However, no doubt anyone with good basic travel
skills can benefit from the advancement of GPS technology.
Since GPS technology is useful to just about any traveler, engineers and scientists constantly try to advance this technology. For example, a project currently underway will map not just roads, but also the centerline of each road, the curbs, and much more, to an accuracy of less than ten centimeters (four inches). This will greatly improve the accuracy of GPS. While completion of this project is several years away, it will certainly arrive.
In Fairfax County, Virginia, updated mapping has already been implemented using high accuracy GPS receivers in a few places. They have created a GIS (Geographic Information System) map not only of every road, but also of every manhole cover, storm drain, road sign, telephone or power pole, fire hydrant, walkway, sidewalk crack, and much more. Think of how useful it would be to a blind traveler to know that not only is a telephone pole just ahead on the right, but there could be a large crack in the sidewalk that may not have been repaired yet.
During GPS demonstrations and testing conducted at our annual National Federation of the Blind conventions, we have observed great interest in GPS technology. More and more mobile computing/communication devices such as cellular phones are equipped with GPS receivers for the general public. As more blind people travel for business and leisure, the use of GPS among the blind community will increase too. Blind people need to be educated about which devices are accessible. What follows is a product evaluation by the staff of the International Braille and Technology Center for the Blind of the GPS technology for the blind which is currently available for purchase in the United States.
A Review of Trekker Bluetooth, Version 2.7
Trekker software, Version 2.7, is supplied by HumanWare, Inc., as a stand-alone system on a PDA (personal data assistant). HumanWare supplies a PDA compatible with this software. Maestro software can be added to create a full-functioning talking PDA. In this review we concern ourselves with the Trekker option only.
The recently released Trekker Version 2.7 is more compact than its predecessor. It has a PDA with a tactile keyboard, a RoyalTek Bluetooth wireless GPS receiver, an external speaker, and a strap to attach the receiver speaker and PDA. The system includes a power splitter enabling the charging of the batteries in the PDA, speaker, and GPS simultaneously. Each unit contains its own rechargeable battery, so no extra power pack is necessary. A cradle is provided to download and install software and can be used to charge the battery in the PDA. Because the Trekker incorporates Bluetooth wireless technology, no cable is required from the GPS receiver to the PDA. This is convenient because there are fewer cables to attach and get in the way. The GPS receiver and speaker are handheld devices and come with carrying cases. The PDA is portable and lightweight and has its own carrying case. All of the units may be worn on the strap or on a person’s clothing or belt. Using the external speaker requires a cable.
The traveler can wear the strap over the shoulder or around the neck. It is also possible to attach the small units to clothing without using the strap. The system includes the traveler’s choice of one regional map, which is installed on a digital storage card. For an additional cost more regional maps may be purchased. Currently only one map may be installed at a time.
One basic function is obtaining one’s position with the GPS and then tracking streets and points of interest as one walks along a route. Trekker automatically provides pedestrian route details including whether the street is a two-, three-, four-way (or more) intersection with cross streets on either side. When traveling in a vehicle, the traveler may select “motorized route,” which provides less detailed information, so it is easier to keep up with the rate of travel. In motorized mode the Trekker will announce highway exits and intersections. The free mode is useful in parking lots, on large campuses, and on waterways. In this mode points of interest are announced along with direction heading and other useful information. “Browsing online” allows the traveler to explore nearby streets using the arrow keys on the keyboard to move along a route. “Browsing off line” is available to research points of interest and streets in an area or explore a route before using it. “Points of interest” are provided from the maps, or the traveler can create his or her own points and even record a short message describing the point. Points of interest are organized by categories such as restaurants, shopping centers, recreation, and so on. Routes may be created, saved, and deleted.
The keyboard is arranged with a set of Braille keys at the top. Arrow keys are arranged in a cross pattern for navigation, and function keys are located along each edge. A handy help mode can be entered at any time to learn the function of any key. Entering Braille is slightly different because dots are entered one at a time and each letter is verified with the press of a button. While this sounds cumbersome, after a bit of practice the user can enter the Braille quickly. The system allows for the entry of contracted (Grade Two) or uncontracted (Grade One) Braille.
Trekker uses Eloquence for speech, which is quite clear when using the external speaker. Using ear buds is not recommended because, though it may enhance speech quality, it may also interfere with safe travel. Trekker is currently a speech-only output system. It has user settings for speech rate, volume, and the other usual speech options to suit individual needs.
We find Trekker easy to use with some practice. We like the description of street intersections noting three-, four-, or more way crossings and whether the street changes name or is only on the right or left side of the intersection. The menu system is familiar to those used to Windows menus on a PC. The key describer mode is easy to use, and many functions may be toggled on and off by holding down keys. Hot key functions are available for common tasks.
Improvements we recommend for future versions would be the ability to load more than one map at a time, which the company is working on; adding more Bluetooth GPS receiver support; and adding the ability to print and email created routes. According to HumanWare the list of supported receivers is growing. For those who want a speech access GPS solution, Trekker may be the right choice.
To purchase Trekker, visit the HumanWare Web site at <www.humanware.com> for the name of a distributor in your area, or call HumanWare toll-free at (800) 722-3393.
A Review of PAC Mate GPS
The PAC Mate GPS system
is comprised of three components: a Bluetooth GPS receiver; Destinator, GPS
software that can also be installed on conventional PDAs used by sighted travelers;
and StreetTalk, proprietary nonvisual interface software. All are sold by Freedom
The GPS receiver and Destinator software can be purchased from a mainstream commercial supplier, but only Freedom Scientific and its dealers sell StreetTalk. If preferred, the buyer may purchase the entire package from Freedom Scientific, including all maps for the United States and Canada. A socket Bluetooth card is required for the GPS receiver and the PAC Mate to communicate. In either case the buyer must install the separate components in this order: Bluetooth drivers, Destinator, StreetTalk, then maps. We recommend that maps be installed on a compact flash card to be inserted in the PAC Mate. In order to activate Destinator and StreetTalk, a user will need access to the Internet.
Basic features of the PAC Mate GPS are the ability to create a route from one address to another as well as create a route from the current position of the traveler to an address or point of interest. One unique feature of this system is that the route created can be emailed, printed, or embossed. The GPS can operate in two modes—navigation mode and planner mode. Navigation mode is used when the GPS receiver is tracking satellites. Planner mode is used when a traveler wishes to create a route or find points of interest when the GPS isn’t available.
When the GPS receiver is tracking satellites, speech output can alert the traveler when to make turns along the created route. The PAC Mate will give directions such as “turn left” or “turn right.” The only time cardinal directions are given is when the journey begins.
Currently the traveler cannot create a pedestrian route in the same way that one can with the Trekker and BrailleNote GPS. Strictly speaking, the PAC Mate GPS program can create vehicular routes only. Moreover, only one region of the United States maps can be running at one time. Therefore a user can’t create a continuous route from New York to California because they are in different regions. When the GPS is tracking satellites, it can determine speed, direction, distance traveled, distance left to travel, latitude, longitude, and altitude. When the GPS receiver isn’t tracking satellites, the user can create routes, but the PAC Mate GPS will not report which streets are in the area, not even cross streets along the way. The GPS will say, “Turn right at Baker Street,” or, “Turn left at University Avenue,” but nothing else. A route can be created only from an origin to a destination. Once the route is created, it can’t be reversed. The user must manually create another route in reverse order.
When using GPS for PAC Mate, the traveler needs to initiate only the StreetTalk program. When the program is launched, Destinator is running in the background. StreetTalk has four menus. They are routes, favorites, toggle modes, and utilities. In the routes menu, the traveler can find out where he or she currently is by accessing the “where am I” option, and, if the system is tracking satellites, the traveler can query the system for cross street information. A route can be created from origin or current location or point of interest to destination. The destination may also be a point of interest. If desired, a traveler can retrieve a saved route.
StreetTalk has an interesting
feature called a breadcrumb route. This means that electronic breadcrumbs will
be dropped the first time the traveler explores a route, and the next time the
traveler wants to go to the same place, the traveler can reuse the breadcrumb
A traveler has the option of using a current GPS location or a specific address to create a point of interest and can later delete it. Another useful feature allows the traveler to give the new point of interest a name using his or her own voice. If desired, as the traveler moves, StreetTalk will announce upcoming points of interest automatically. The distance can be set to announce the points of interest when the traveler is a certain number of feet away. If the point of interest is not found, the distance can be expanded to search for it.
Improvements we would recommend for future upgrades are the ability to create pedestrian routes and the capability for a traveler to preview walking a route. This should include information on cross streets and points of interest in the same way as the other two GPS systems provide.
To purchase the PAC Mate GPS system, visit the Freedom Scientific Web site at <www.freedomscientific.com> or call (800) 444-4443.
A Review of BrailleNote GPS
Sendero Group is the manufacturer of the GPS application used in the entire BrailleNote family of products. The Bluetooth GPS receiver will work only with BrailleNote Bluetooth-compatible products such as BrailleNote PK and the BrailleNote MPower, while a regular GPS receiver will work with the BrailleNote Classic. The BrailleNote GPS software package includes a GPS receiver, eight CDs with maps of the United States, and a one-gigabyte compact flash card. This card contains the GPS software with ample room left over to install multiple maps. Sendero also provides an MP3 tutorial to introduce a buyer to the various features of the GPS application. BrailleNote GPS is the only GPS application that allows the buyer to install and pre-load multiple maps in multiple regions. BrailleNote GPS also provides a context-sensitive help menu which is already familiar to BrailleNote users.
In the BrailleNote GPS Version 3.3, a traveler can create, store, and delete both vehicle and pedestrian routes. A reverse route feature is also available. A traveler can choose to have every cross street on the route announced or just the turning points.
The heading mode (also known as travel direction) can be set according to the individual’s preference. The traveler may choose headings using clock-face navigation or the standard right or left. BrailleNote GPS offers both GPS mode for tracking while traveling and a virtual mode for route planning when no GPS signal is detected.
If a traveler is unfamiliar with a city or town, the street name mode can be set to short or long to enhance understanding of the route. For example, if one travels on I-695, when the street name mode is set to short, I-695 is the only information spoken. But if a traveler wants to inquire whether I-695 is the Baltimore Beltway, the street name mode should be set to long.
A traveler can search for the nearest points of interest while traveling or search for them in virtual mode while planning a route. The points of interest are arranged in categories such as restaurants, hospitals, or hotels. A traveler can jump quickly from one point of interest to another. When desired, a traveler can obtain the address and other detailed information about a particular point of interest with a single keystroke. A traveler can set a desired point of interest as a destination and create a route to it from the current location. While moving, the GPS system reports speed status, latitude and longitude, altitude, and directions. A look-around mode can be turned on so that the system will announce every point of interest and cross street on the route. With the BrailleNote GPS, a traveler can add a new waypoint or create a new point of interest when needed.
Of the three systems we
examined, the Sendero Group product offers the greatest flexibility in features
and ease of use. Currently the GPS system cannot print or emboss a created route.
We hope that this feature will be implemented in a future version. For pricing
details on the BrailleNote GPS, visit the Sendero Group Web site at <www.senderogroup.com>
or phone (530) 757-6800.
For additional product evaluation details on any of these three GPS devices, contact the NFB’s Access Technology staff at <firstname.lastname@example.org>, or call (410) 659-9314, extension 5, for the technology answer line (during business hours, 8 a.m. to 5 p.m. Eastern Time).