ABSTRACT The presented information server concept, developed at VTT, is a user-centred and task oriented client-server approach for solving informational needs of special user groups. This paper describes application of the concept for producing an unbroken trip chain for the visually impaired. The goal of the study was to build a navigational aid for the visually impaired using commercial passenger information and personal navigation services without laborious and expensive changes in the current infrastructure. Visually impaired persons do not have any specific information needs. Information needed either exists but is not accessible, or would be useful for all passengers. Passenger information systems should be equipped with a standard XML interface, which is accessible via Internet. This would make it easier to serve special user groups, whose means to reach the information is different

Koskinen Sami

Virtanen Ari

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1 
INFORMATION SERVER CONCEPT for SPECIAL 
USER GROUPS 
Virtanen Ari  
Research scientist, VTT Industrial Systems 
P.O.Box 1302 , Fin-33101 Tampere, Finland 
tel: +358 3 3163609 ,email: ari.virtanen@vtt.fi 
 
Koskinen Sami 
Research scientist, VTT Industrial Systems 
P.O.Box 1302, Fin-33101 Tampere, Finland 
tel: +358 3 3163636, email: sami.koskinen@vtt.fi 
ABSTRACT 
The presented information server concept, developed at VTT, is a user-centred and task 
oriented client-server approach for solving informational needs of special user groups. This 
paper describes application of the concept for producing an unbroken trip chain for the 
visually impaired. The goal of the study was to build a navigational aid for the visually 
impaired using commercial passenger information and personal navigation services without 
laborious and expensive changes in the current infrastructure.  
Visually impaired persons do not have any specific information needs. Information needed 
either exists but is not accessible, or would be useful for all passengers. Passenger information 
systems should be equipped with a standard XML interface, which is accessible via Internet. 
This would make it easier to serve special user groups, whose means to reach the information is 
different. 
INTRODUCTION 
Generic travelling difficulties for the visually impaired are localisation and environment 
perception, selecting and maintaining correct heading, and detecting obstacles above waist and 
unexpected road works. 
There have been numerous research projects about creating electronic travel aids (ETA) for 
visually impaired persons. These projects usually have concentrated on solving one specific 
problem. The result has been usually technically simple device, which may be difficult to use. 
Because the visually impaired have several problems, they would have to acquire a 
wheelbarrow to take with all these devices to carry off everyday life. 
Development of travelling aids based on positioning has a long history, the use of GPS has been 
researched since the late 80’s and since then there have been many research projects like Mobic 
[1], Drishti [2] and Brunel Navigation System for The Blind [3], and commercial products like 
Sendero Groups BrailleNote GPS [4] and VisuAide's Trekker [5] addressing GPS based ETA 
for the visually impaired. Navigation systems have usually worked well in small-scale 
implementations, but a large-scale implementation will be extremely expensive (especially with 
beacon based navigation systems). Percentage of visually impaired persons of the whole 
population is less than 1.5 % in developed countries; therefore large investments to the 
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infrastructure are not reasonable. Still, visually impaired persons have equal rights to achieve 
the same services as all other citizens. Despite intensive research and development, electronic 
travelling aids for the visually impaired have not yet become common. This indicates that the 
problems at hand are not easy to solve.  
The most important guidance aids for the visually impaired are still the white cane and guide 
dog. Electronic travelling aids should be considered as supplementary equipment. What we 
need is a travelling aid that produces a small amount of navigational information and does not 
disturb other information perceived from the environment. Further, the evaluation of the device 
should be based on the benefits it produces not the amount of information it generates. 
NOPPA ARCHITECTURE 
VTT's Information server concept aims to utilise commercial services and devices for 
improving public transport accessibility with creating access to passenger information with a 
personal mobile device rather than building physical infrastructure.  
Research and development of the concept was done in a research project NOPPA (Navigation 
and guidance for the visually impaired) [6], which started at June 2002 and ends of the year 
2004. Project pilots a personal navigation system for the visually impaired, which produces a 
unbroken trip chain for the visually impaired. 
The most important building blocks of the system are mobile Internet, mobile phones and 
personal navigation systems and services. For unbroken trip chain for the visually impaired 
there are requirements for continuous, general use positioning techniques, continuous (Internet) 
access to passenger information and availability of map data accurate enough for users' needs. 
For example there aren't generally maps available, which would include pavement information 
or information about large public premises either. Door-to-door guidance would require map 
data including entrances and continuous guidance would even require indoor maps and indoor 
positioning, which are generally unavailable.  
Design goals of the NOPPA -guidance system were: 
 Easy and fast to use 
 Flexibility 
 Affordable to the user 
 Access to public transportation and passenger information systems   
 Applicable both indoors and outdoors 
 Integration of products and services for personal navigation  
 Modular, easy to update, easy to add functions 
 Speech user interface. 
To fulfil these requirements, we created an architecture presented in Figure 1. Because of low 
processing capacity of the mobile terminal and a low bandwidth wireless data connection, most 
of the work is done in the Information server. Data flow between mobile client and Information 
server is minimized, which keeps the communication costs low and shortens response time. 
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LOCAL
INFORMATION
POSITIONING
BLUETOOTH
INFORMATION SERVER
INTERNET
GPRS
GUIDANCE
SPEECH 
RECOGNISER
GPS
NEWS
PASSENGER
INFORMATION
ROUTE PLANNERS
INFORMATION
MANAGEMENT
WLAN
SPEAKER
MICROPHONE
COMMAND
INTERPRETER
PERSONAL
INFORMATION AND
SETTINGS
REALTIME
INFORMATION
WEATHER
GSM
SMS
SERVICE
INTEGRATION
OBSTACLE
DETECTION
 
Figure 1. Architecture of the NOPPA guidance system. 
INFORMATION SERVER 
The Information Server in the architecture is an interpreter between the user and information 
systems. It collects, filters and integrates information from different sources and delivers only 
the results to the user. For the visually impaired speech user interface is a natural choice. If the 
users are deaf, user interface based on text and visual information is used instead. 
The server constructs a route plan, which is transferred to the terminal. Terminal is responsible 
for route following and guidance functions. It however reports its coordinates periodically to the 
server which could follow the progress of the journey and possible changes and disturbances 
concerning the rest of the journey. Real time information plays an important role through the 
unbroken trip chain [7]. 
Route following and guidance is done in the terminal, because these are time critical functions 
and because of unreliable wireless connection. Although GPRS connection is often considered 
continuous, in practise it is not. Implementation of guidance in the terminal makes it available 
even when the connection to the server is temporarily off. 
THE PROTOTYPE 
The prototype of the terminal is built on a commercial mobile phone. The system carries out 
following characteristics 
 Speech user interface (Finnish)  
 Route planner (commuter and intercity traffic both bus and train) 
 Access to bus and train real time information 
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 Guidance and route following during a trip 
 Personal stop announcements in-vehicle 
 Roadwork information 
 Airport departures (domestic flights), real time information 
 News, watch, local weather, memo  
 GSM phone and SMS services 
 GPS, GSM positioning, pedometer, compass 
 Bluetooth, GPRS (WLAN) connectivity 
 Indoor navigation system based on Bluetooth or WLAN positioning  
 Own recorded walking routes with location based comments 
User evaluation tests are planned for autumn 2004. In the tests the value of the information 
provided is under evaluation not usability of the device.  
 
Figure 2. Noppa prototype terminal. 
VISUALLY IMPAIRED PERSONS AND UNBROKEN TRIP 
CHAIN 
If we examine problems a visually impaired person meets when using public transport, we 
recognize the following list (depends slightly of the transportation mean): 
trip planning, finding a stop/station, finding an entrance to the station, navigating inside the 
station, finding the right platform and waiting place, knowing when the right vehicle arrives, 
finding a vehicle entrance, payment, finding a seat, depart on right stop, navigating inside the 
station, finding the exit of the station and finding the destination. 
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Most of these tasks are trivial for the sighted, but very difficult for the visually impaired. There 
are cases when a blind person has spent several hours on the bus stop, because he couldn't 
recognise arrival of the right vehicle. 
Nevertheless, in our studies we couldn't find any specific information needs for the visually 
impaired. Information needed is either available for the sighted, existing but not accessible, or 
would be useful for all passengers. However, the means for a visually impaired person to reach 
the information is different. This is an important factor to take into account when new passenger 
information services are designed. 
To produce unbroken trip chain for visually impaired, we have to switch seamlessly between 
different modes of operation during the trip (see Figure 3). This requires that system must be 
context aware to recognise transition points and change automatically its mode of operation 
accordingly. 
 
Figure 3. Unbroken trip chain and different operation modes. 
TRIP PLANNING 
All planning is based on commercial journey planners. Helsinki metropolitan area (Helsinki, 
Vantaa, Espoo and Kauniainen) is covered by one planner [8], which covers local bus, tram, 
metro and local train traffic. A speech user interface for the journey planner was constructed in 
the server. Speech recognition software is speaker independent and requires street names from 
these cities to accomplish recognition. List of 10 000 street names is acquired from the journey 
planner and automatically compiled to recogniser grammar.  
Positioning makes route planning easier, because the current address can be searched with 
reverse geocoding. Often used target addresses can be saved to a list, but if the start or target 
address is unknown, terminal asks for an address. Voice response is recorded and transferred to 
the server for recognition. Recognition result is then transferred back to the terminal for 
certifying. All personal parameters like walking speed are also transferred to the server. When 
we have all the information needed for route planning, the server generates a route request and 
sends it to the journey planner. 
6 
Route plan is based on journey planner's response. It is augmented with road work information, 
Point of interest (POI) -information and Area of interest (AOI) -information. Road works on the 
route are gathered from WINKKI-database from Helsinki Public Works Department. User 
listens the route plan and if he/she considers it acceptable, the next step is to start route 
guidance. 
 
Figure 4. Example route planned by Helsinki metropolitan area journey planner [8]. 
PEDESTRIAN NAVIGATION 
In pedestrian mode we have to navigate using mostly the same map data than in car navigation. 
Map data used in navigation systems today is collected for car navigation purposes. The map 
usually includes only street centre line, street name and class, no pavement information. 
Example of this can be seen in Figure 4, where walking route is marked (on) with blue dashed 
line. This is not adequate for pedestrians, because pedestrians use pavements, zebra crossings 
and footpaths. Required accuracy of the maps would be about 2-5 meters and routing should 
include pavements, zebra crossings and traffic lights. Result information should include 
coordinates and form points of the route. 
Map quality is an important factor in navigation, because navigation systems can't recognize 
map errors without environment perception sensors. Correct route is more essential for the blind 
persons, because they can't see if the route proposed by the navigator is dangerous or unusable.  
Positioning errors are easier, because for example GPS receiver delivers error estimate. 
Therefore, although we can't correct the error, we can warn the user of the operation defect. 
Navigation systems must always take into account that the maps are not accurate and have 
errors and positioning accuracy varies sporadically.  
Guidance methods change according to possible inaccuracies in positioning. If the positioning 
accuracy is 1 m, you can give guidance to a target, which is for example 10 meters away, but 
not if the positioning accuracy is 100 m. Guidance in the case of low positioning accuracy is 
telling the big picture of the route and resembles asking for another person for guidance. 
7 
PUBLIC TRANSPORT TERMINALS 
Stations and terminals are usually indoor environments, where satellite positioning is 
unavailable. There are several possible technologies available for indoor positioning, but none 
of these methods has the same standard position than GPS has for outdoors. Moreover we must 
be able to utilize the positioning with our terminal device. The most promising candidates for 
indoor positioning are wireless LAN and Bluetooth based systems [9], but positioning methods 
are still at early stages and not commonly accepted. Both of them need also infrastructure 
investments, but these investments concern all passengers. Cell phone based positioning is too 
coarse for navigation purposes. Cell ID based systems give usually coordinates that are not 
inside building's area but the coordinates of closest GSM antenna.  
Besides of no feasible indoor positioning, lack of standardized indoor maps or data models is 
the second barrier for indoor navigation. Often there already exists a suitable guide map of the 
area or building. This is the case with museums, fairgrounds and airports for example. These 
maps need to be modified into navigational form, where it is possible to plan simple routes and 
search location based data. 
For public transport terminals and similar areas we use Area of Interest (AOI) information. 
These are detailed descriptions of target locations. Proximity of the AOI is detected from 
position coordinates. In NOPPA project, orientation and mobility specialists made speech 
descriptions of two railway stations for the visually impaired. Visually impaired listen the 
description and produce a mental map of the terminal.  
Terminals have acoustic announcement systems. Information is not available for example deaf 
persons. Usually announcements are generated by automatic systems, where information is 
already in text form. Also this information should be made available through suitable public 
interface. Then it would be possible to serve for example minor language groups as well as 
disabled persons. 
PERSONAL ANNOUNCEMENTS 
Personal announcements are possible to produce trough a navigation system in a station and in a 
vehicle. There are cases where for unknown reasons, that acoustic announcement system is 
turned off in a station or in a vehicle. Also there are some user groups that cannot hear or 
understand acoustic announcements at all.  
The main idea of the personal announcements is to pick up only those announcements that have 
meaning for the passenger.  
In a vehicle it is possible to produce personal stop announcements. From the route plan we 
know names, passing times and coordinates of the start and end stops and all stops between 
them.  GPS positioning is usually available in a bus and our tests show that method works quite 
nicely. Another way to produce personal announcements is to request the vehicles position from 
an operator's real time tracking system, if available. 
8 
CONCLUSIONS 
Our prototype fulfils the requirements we set at the beginning of the project. The main goal was 
to show that a guidance system for the visually impaired person is possible to build without 
laborious and expensive changes in the current infrastructure. This is possible with utilising 
common Internet services for passenger information and personal navigation. 
Passenger information systems should be equipped with a standard Internet interface (XML). 
Through this interface it would be possible to deliver static information (timetables), real time 
information and disturbance information in such way that it is accessible to the special user 
groups. These interfaces are needed for example when developing mobile applications for all 
passengers.  
Development of public transport route planners should be focused on pedestrian use, because 
pedestrians use public transport. Required accuracy of the maps would be about 2-5 meters and 
routing should include pavements, crosswalks and traffic lights. Result information should 
include coordinates and form points of the route. 
ACKNOWLEDGEMENT 
NOPPA-project is part of Ministry of Transport and Communications Finland's HEILI 
Passenger information programme [10], which aims to improve the accessibility of public 
transport information.  
REFERENCES 
                                                          
[1] Gill, J., Mobility of Blind and Elderly People Interacting with Computers. 
http://www.tiresias.org/reports/mobicf.htm. (27.2.2004) 
[2] Garaj, V., "The Brunel Navigation System for Blind: Determination of the Appropriate Position 
to Mount the External GPS Antenna on the User's Body", In Proceedings of the U.S. Institute of 
Navigation - GPS 2001 Technical Meeting, Salt Lake City, Utah, USA.  
[3]  A. Helal, S. Moore, and B. Ramachandran, "Drishti: An Integrated Navigation System for 
Visually Impaired and Disabled," Proceedings of the 5th International Symposium on Wearable 
Computer, October 2001, Zurich, Switzerland  
[4] http://www.senderogroup.com (27.2.2004) 
[5]  http://www.visuaide.com  (27.2.2004) 
[6]  http://www.vtt.fi/tuo/53/projektit/noppa/noppaeng.htm 
[7]  Koskinen Sami & Virtanen Ari. Public transport real time information in Personal navigation 
systems for special user groups. In Proceedings of 11th World Congress on ITS. 18 - 24 October 
2004,  Nagoya, Aichi, Japan. 
[8]  http://www.reittiopas.fi (27.6.2204) 
[9] Virtanen Ari & Koskinen Sami, Towards Seamless Navigation. In proceedings of the 
MobileVenue'04. 27-28.5.2004 Athens, Greece. 6 p.  
[10] Ministry of Traffic and Communications Finland, Passenger information programme - HEILI. 
http://www.heili.info 


INFORMATION SERVER CONCEPT for SPECIAL USER GROUPS

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INFORMATION SERVER CONCEPT for SPECIAL USER GROUPS

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