Title: Pros and Cons of the Global Positioning System for O
1Pros and Cons of the Global Positioning System
for OM10 years Later
- Research, Products and Usage for the Blind and
Visually Impaired.
2L. Jeffrey Fitterman, Ed.S., ATPAT Consultant
- Florida Instructional Materials Center f/t
Visually Impaired
- 4210 West Bay Villa Avenue, Room 26
- Tampa, Florida 33611-1206
- 813-837-7830 voice
- 813-837-7979 fax
- http//www.fimcvi.org
- jfitterman_at_fimcvi.org
- Micro-Enabling Resources, Inc. (MERI)
- 13176 North Dale Mabry Highway
- Suite 135
- Tampa, Florida 33618-2406
- 813-244-7499 or 3198 voice
- meri_at_tampabay.rr.com
3Purpose
- In an effort to improve the orientation and
mobility skills of the Blind and Visually
Impaired (after 10 years of using Global Position
Systems), I am revisiting the journey to bring
educators research on the selection, acquisition,
implementation, and use of GPS technological
developments.
4Presentation
- This presentation is not meant to be an in-depth
explanation of GPS research, products and usage,
but a means of disseminating thought provoking
information on a topic of importance to those
individuals that experience orientation and
mobility challenges in their daily lives.
L. Jeffrey Fitterman, Ed.S., ATP
5Overview
- History of the Global Positioning System (GPS)
- How GPS works
- Types of GPS receivers
- Applications and Uses of GPS
- Implications for OM usage
- Past research and development
- Off-the-shelf product usage
- Overall advantages and disadvantages
- Applied Research
- Educational activities using GPS technology
- Conclusion
- Where do we go from here?
6What is GPS?
- Electronic navigational system based on the use
of high orbiting satellites to find your relative
position on the Earths land, water or sky.
7HistorySatellite-Based Systems
- 1957 Sputnik
- Measuring Doppler Shift in the frequency of
satellites bleep, bleep
- 1960s SatNav Navy Navigation Satellite System
- Measuring the Doppler Shift in the frequency of
satellites radio wave of four to five satellites
nested. Intermittent coverage
- 1970 Radio Determination Satellite Systems
(RDSS)
- Loran-C continuous position-fixing but lacked
worldwide coverage
8HistorySatellite-Based Systems
- 1973 Navigational Satellite Timing And Ranging
Global Positioning System (NavStart GPS)
- Consists of 24 satellites in six orbital planes
- 98 probability of having 21 or more satellites
operational at one time
- Continuous position fixing with a minimum of 5
satellites in view to users world wide
9How GPS Works
- System Characteristics
- Control Segment
- Provides and updates the information on satellite
position that is transmitted as part of the
satellites message
- Space Segment
- Consists of a constellation of 24 satellites
positioned in six synchronic orbital planes
- User Segment
- Consists of all areas in which GPS signals are
used to determine navigation and time
information
10How GPS Works
11How GPS Works
- GPS determines the range at a specific time by
measuring how long it takes a radio signal to
reach a receiver from the satellite
- Signal transfer time is achieved by synchronizing
the satellites and GPS receivers.
- By measuring the time difference in receiving the
satellites code, distance from the satellite can
be computed to establish Line Of Position (LOP)
12How GPS Works
13How GPS Works
- To get a two dimensional fix, another LOP is
calculated from a second satellite
- Where the LOPs cross is your relative position
- To resolve the time element
- A third satellite is needed to determine a two
dimensional fix
- A fourth satellite is necessary for a three
dimensional fix
14How GPS Works
- Time is of the Essence
- Distance Speed x Time
- Known Radio waves travel at the speed of light
- Known Speed is a known constant (186,000
miles/second)
- Variable transmission time of a
satellite-generated radio signal
- The difference (Time) between the receiver and
satellite generated code
15How GPS Works
- Finding the LOP of 3 separate satellites will
give you a 2 dimensional look at your position.
LOP3
1. Satellites are at an altitude of 20,180 km.
2. Satellite orbits are 60 degrees between each
of 6 orbital plane. 3. At least 5 satellites visi
ble to user at any given time.
LOP1
LOP2
16GPS Accuracy
- The GPS system
- has been turned over to the Public Domain and all
military cryptology has been removed to allow a
Precise Positioning System (PPS).
- Positioning now gives us a range with a decrease
margin of error from 100 meters to 0-3 meters.
17GPS Accuracy
- Errors in accuracy
- Control Segment produced
- Less expensive clock in receiver
- Atmospheric conditions
- Physical Obstructions
18GPS Accuracy
- WAAS-Wide Area Augmentation System
- a system of satellites and ground stations that
provide GPS signal corrections, giving position
accuracy up to five times better. A WAAS-capable
receiver can give you a position accuracy of
better than three meters, 95 percent of the time.
You don't have to purchase additional receiving
equipment or pay service fees to use WAAS.
19GPS Accuracy
- How WAAS Works
- Ground reference stations monitor GPS satellite
data, and master stations collect data from the
reference stations and create a GPS correction
message accounting for GPS satellite orbit and
clock drift plus signal delays caused by the
atmosphere. The corrected differential message
is then broadcast through geo-stationary
satellites (satellites with a fixed position over
the equator). Any WAAS-enabled GPS receiver can
read the signal.
20GPS Receivers Functions
- Receivers
- Acquire or lock onto the satellites
- Make measurements or determine how far away the
satellite is from the receiver
- Read the satellites navigational message
21Types of GPS Receivers
- Sequential (Slow Lock Increased Error)
- Acquire and move through a set of satellites with
a single channel to solve for position.
- Simultaneous/Parallel (12 channels)
- Acquire and solve each individual satellites
data using parallel channels, each of which is
dedicated to a single satellite.
22Types of GPS Receivers
- Sequential Receivers (most are obsolete)
- Starved power single channel
- Single channel slow sequence
- Two channel slow sequence
- Single channel fast sequence
23Types of GPS Receivers
- Multiple/Parallel Receivers
- Independent Channels (4 to 12)
- Instantaneous position
- Constant velocity data
- High accuracy
- Require less signal strength
- Better performance to acquire satellites and
begin navigation (Time to First Fix - TTFF)
24General Applications and Uses of GPS
- Everyday Uses can be water, land, or air
- Position Functions (Where are you?)
- Dead Reckoning Functions (Where do we want to
go?)
- Steering Functions (How do we get there?)
25General Applications and Uses of GPS
- Position Functions (Where are you?)
- Latitude and Longitude
- Present position
- Warning area
- Waypoint arrival
26General Applications and Uses of GPS
- Dead Reckoning Functions (Where do we want to
go?)
- Course over ground
- Speed over ground
- Distance traveled
- Distance to waypoint
- Elapsed time
- Estimated time of arrival
- Sensory and Physical Landmarks
27General Applications and Uses of GPS
- Steering Functions (How do we get there? )
- Course to steer
- Course corrections
- Graphical displays
28Land Applications andUses of GPS
- Pedestrian navigation
- Vehicular navigation
29Land Applications and Uses of GPS
- Pedestrian navigation
- From point to point
- Hiking
- Walking
- Locating current point
- Point on city map
- Waypoint
30Land Applications and Uses of GPS
- Vehicular navigation
- From point to point
- Bicycling and skating
- Automobile
- Sailing and boating
- Locating current point
- Point on city map
- Waypoint
31ResearchImplications for OM Usage
- MoBic
- Drishti
- Brunel Navigation System for the Blind
- NOPPA
- BrailleNote GPS
- Trekker
- Trinetra
32ResearchImplications for OM Usage
- MoBIC
- MoBIC means Mobility of Blind and Elderly people
Interacting with Computers, which was carried out
from 1994 to 1996 supported by the Commission of
the European Union. It was developing a route
planning system which is designed to allow a
blind person access to information from many
sources such as bus and train timetables as well
as electronic maps of the locality. The planning
system helps blind people to study and plan their
routes in advance, indoors. - With the addition of devices to give the precise
current position and orientation of the blind
pedestrian, the system could then be used
outdoors. The outdoor positioning system is based
on signals and satellites which give the
longitude and latitude to within a meter the
computer converts this data to a position on an
electronic map of locality. The output from the
system is in the form of spoken messages. Add
additional GPS/DGPS capabilities for current
position and orientation of pedestrians.
33ResearchImplications for OM Usage
- Drishti
- is a wireless pedestrian navigation system. It
integrates several technologies including
wearable computers, voice recognition and
synthesis, wireless networks, Geographic
information system (GIS) and GPS. It augments
contextual information to the visually impaired
and computed optimized routes based on user
preference, temporal constraints (e.g. traffic
congestion), and dynamic obstacles (e.g. ongoing
ground work, road blockade for special events). - constantly guides the blind user to navigate
based on static and dynamic data. Environmental
conditions and landmark information queries from
a spatial database along their route are provided
on the fly through detailed explanatory voice
cues. The system also provides capability for the
user to add intelligence, as perceived by the
blind user, to the central server hosting the
spatial database.
34ResearchImplications for OM Usage
- Brunel navigation system for the blind
- Prof. W. Balachandran is the pioneer and the head
of GPS research group at Brunel University. He
and his research team are pursuing research on
navigation system for blind and visually impaired
people. The system is based on the integration of
state of the art current technologies, including
high-accuracy GPS positioning, GIS, electronic
compass and wireless digital video transmission
(remote vision) facility with an accuracy of
34m. It provides an automated guidance using the
information from daily updated digital map
datasets e.g. roadworks. If required the remote
guidance of visually impaired pedestrians by a
sighted human guide using the information from
the digital map and from the remote video image
provides flexibility. - The difficulties encountered includes the
availability of up to date information and what
information to offer including the navigation
protocol. Levels of functionality have been
created to tailor the information to the users
requirements.
35ResearchImplications for OM Usage
- NOPPA
- navigation and guidance system was designed to
offer public transport passenger and route
information using GPS technology for the visually
impaired. This was a three-year (20022004)
project in VTT Industrial Systems in Finland. The
system provides an unbroken trip chain for a
pedestrian using buses, commuter trains and trams
in three neighbor cities area. It is based on an
information server concept, which has
user-centered and task oriented approach for
solving information needs of special needs
groups. - information Server is an interpreter between the
user and Internet information systems. It
collects, filters and integrates information from
different sources and delivers results to the
user. The server handles speech recognition and
functions requiring either heavy calculations or
data transfer. The data transfer between the
server and the client is minimized. The user
terminal holds speech synthesis and most of route
guidance. - currently able to offer basic route planning and
navigation services in Finland. In practice, the
limits are map data can have outdated information
or inaccuracies, positioning can be unavailable
or inaccurate, or wireless data transmission is
not always available.
36ResearchImplications for OM Usage
- BrailleNote GP
- device is developed by Sendero Group, LLC, and
Pulse Data International, now called Humanware,
in 2002. It is like a combination of a personal
digital assistant, Map-quest software and a
mechanical voice. - With a receiver about the size of a small cell
phone, the BrailleNote GPS utilizes the GPS
network to pinpoint a travelers position on
earth and nearby points of interest. The personal
computers receive radio signals from satellites
to chart the location of users and direct them to
their destination with recorded voice commands.
The system uses satellites to triangulate the
carriers position, much like a ship finding its
location at sea. - Visually impaired people can encode points of
interest such as local restaurants or any other
location, into the computers database.
Afterward, they can punch keys on the units
keyboard to direct themselves to a specific point
of interest.
37ResearchImplications for OM Usage
- Victor Trekker
- designed and manufactured by Canada-based company
VisuAid, was launched on March 2003. It is a
personal digital assistant (PDA) application
operating on a Pocket PC, adapted for the blind
and visually impaired with talking menus, talking
maps and GPS information. Fully portable (weight
600g), it offered features enabling a blind
person to determine position, create routes and
receive information on navigating to a
destination. It also provided search functions
for an exhaustive database of point of interests,
such as restaurants, hotels, etc. - It is fully upgradeable, so it can expand to
accommodate new hardware platforms and more
detailed geographic information.
- Trekker and Maestro, which is the first
off-the-shelf accessible PDA based on Windows
Mobile Pocket PC, are integrated and available in
May 2005.
38ResearchImplications for OM Usage
- Trinetra
- The project aims to develop cost-effective,
independence-enhancing technologies to benefit
blind people. One such system addresses
accessibility concerns of blind people using
public transportation systems. Using GPS
receivers and staggered Infrared sensors,
information is relayed to a centralized fleet
management server via a cellular modem. Blind
people, using common text-to-speech enabled cell
phones can query estimated time of arrival,
locality, and current bus capacity using a web
browser. - Trinetra, spearheaded by Professor Priya
Narasimhan, is an ongoing project at the
Electrical and Computer Engineering department of
Carnegie Mellon University. Additional research
topics include item-level UPC and RFID
identification while grocery shopping and indoor
navigation in retail settings. Additional
information can be found here http//www.ece.cmu.
edu/trinetra/
39ResearchImplications for OM Usage
- GPS research
- Research considerations for the User
- Travel planning and orientation during travel.
- Need more detailed information before travel.
- Have to rely on less perceptual information from
the environment during travel.
- More information on useful landmarks
(dead-reckoning).
- Information on head height obstacles.
- Suitable places to cross streets.
- Headphones may block environmental sounds.
- Device should be inconspicuous.
40ResearchImplications for OM Usage
- GPS research
- Research considerations for the OM Specialist
- Increase independence and quality of life.
- Increase independence through sensory,
navigational, and mobility skills.
- Should be easy to integrate into existing
training programs.
- Should be used as an enhancement to training.
- OM specialists need adequate training in the
implementation and integration of GPS devices
before they were expected to teach users.
41Advantages of GPS Navigation
- Assistive Technology enhancement for orientation
mobility
- Source of real-time information for navigation
- User can manipulate navigational information
- Navigational information is sequential
- Add individual routes and dead reckoning
information
- Can be used overseas in other countries
42Disadvantages of GPS Navigation
- Variable accuracy
- Obstructed reception
- Physically conspicuous
- Auditory discrimination
- Cost and maintenance
- Power supply issues
43Off-the-Shelf Hardware
Factory Adapted for the Blind
User Adapted f/t Blind
44Off-the-Shelf Software
PacMate StreetTalk GPS
Maestro
Braille Note GPS
- calculate the distance and directions to an
address/intersection
- find out the relative location of hundreds of
Points of Interest
- create routes for either walking or riding in a
vehicle
- information on speed, direction, and your altitude
Blue Tooth GPS Receivers
45Off-the-Shelf Software
Not Adapted f/t Blind
RouteBuddy The Premium Mac OSX GPS mapping softwa
re title that all Mac GPS Users have been waiting
for... USA or North America
Streets Trips includes Pocket Streets for your
Pocket PC and SmartPhones - WM5 Support!
iGuidance navigation software for Windows Pock
et PC. USA CANADA (DVD)with WM5 Support!
46Off-the-Shelf Software
Not Adapted f/t Blind
Street Atlas Adds 150 million phone address lis
tings linked to the maps. Import and
geo-locate your own data. PLUS all the features
of Street Atlas USA
Fugawi atlas of the continental USA for the home
computer with included software for GPS and PDA
47Where Do We Go From Here?
- GPS devices will become
- more accurate
- quicker TTFF
- better resolution and larger displays
- Better quality voices on smaller units
- less costly
- more compact
- longer and more reliable battery life
48Review and Applications
- Our Turn.
- Who will benefit from this technology?
- What type of technology should I consider?
- Where do I go to obtain assistance regarding this
technology?
- When should this technology be used?
- Why should this technology be considered?
- How will you use this new technology?
49OM GPS Research
- Accessible GPS Reorientation and Target Location
Among Users with Visual Impairments Journal of
Visual Impaired and Blind, 2006.
- Abstract This article presents the results of
two single-subject experiments that were designed
to determine consumers' ability to use a
BrailleNote GPS. The participants decreased their
mean orientation time from 6 minutes to 45
seconds and increased their target- location
efficiency fourfold with BGPS than without BGPS.
Additional results and implications for the field
are presented. - Braillenote GPS Making the World Accessible for
the Blind and Visually Impaired
- Traveler
- Melanie White, COMS,
- Global Positioning Satellite technology is having
a very positive benefit for many visually
- impaired travelers. In this session participants
will learn the sequence of skills for the GPS
- and have a chance to see videos of these skills
in use. They will also receive resources for
- lessoning planning. http//www.tsbvi.edu/Outreach/
handouts/jun07/index.htm
50OM GPS Research
- Florida State University/College of Education
Mapping the Campus for Students Who are Blind
- Abstract The outcome of the project is to map
the FSU campus with Points of Interest that
- Would allow a blind student to navigate the
campus with no or very little assistance.
- Bruce Alsup from OSET will serve as the overall
project manager. This project envisions the FSU
- summer intern graduate students using equipment
provided by VisuAide and Freedom Scientific.
- The student teachers will first map the FSU
campus and then work with newly arriving
- Undergraduate students as part of their campus
Orientation and Mobility (OM) training.
Training
- for the student teachers will be provided by a
team from OSET, FS, and VisuAide Bruce Alsup,
- Jeff Bazer, and Louis Duchene respectively.
Training will be provided to undergraduate
students by
- the student teacher interns and OSET. FSU
Department of Education will provide an on-site
project
- supervisor, presumably Kathryn O'Farrell.
- Timeline Preparation and intern training,
April-May 15 2004 Customize mapping of FSU
campus,
- May-June 2004 and Undergraduate student OM,
June-July 2004
- Desired Outcomes Accessibility for OM on the
FSU Campus will be dramatically increased.
- Newly arriving undergraduate students will be
able to navigate the FSU campus independently.
- Graduate student interns will gain invaluable
experience and training for using technology
devises
- coupled with OM techniques.
51OM GPS Activities
- Street Orientation/Verification (POI)
- Setting Point of Interests
- Restaurants, meeting location, schools, street
intersection, etc.
- Planned Trip POI
- Highway intersections, hotels, restaurants,
origin/destination
- Pedestrian and Public Transportation Verification
(POI)
- Bus
- stops, transfers, riding time
- Taxi
- verify distance, directions, route, and POI
- Special Transport
- verify direction, POI, route
52OM GPS Activities
- Educational/Instructional and Supervised
Activities - GeoCaching
-
- Traditional Cache
- "If you take an item, leave an item, and write in
the logbook."
- Multi-Cache
- A multi-cache ("multiple") involves two or more
locations
- Letterbox Hybrid
- A letterbox is another form of treasure hunting
using clues instead of coordinates
- Event Cache
- Litter (trash out), charity walks related to
finding multiple cache locations
- Mega-Event Cache
- 500 or more people
- Mystery or puzzle caches
- involve word puzzles. You first need to solve to
determine the coordinates for a locations.
- GPS Adventures Maze Exhibit
- traveling educational exhibits designed to teach
people of all ages about navigation, GPS
technology and geocaching.
- Virtual Cache
- Finding a location from coordinates and sharing
information about your visit
- Outside locations such as Sporting field,
gardens, swimming pool, fish pond, etc.
53The Rest Is Up To You!
- The presentation was not meant to be a
complete compendium of information and
activities. It was meant to be a starting point
for the inclusion of the Global Positioning
System Technology into your Orientation and
Mobility Program for clients and students.
54(No Transcript)
55GPS Presentation Materials
- You may obtain a copy of this presentation by
going to the following link and selecting GPS Ten
Years Later. The presentation will be in 3
formats (PowerPoint Show, PDF, and RTF Text) - http//www.fimcvi.org/index_files.cfm?category17