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Pros and Cons of the Global Positioning System for O

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Title: Pros and Cons of the Global Positioning System for O


1
Pros and Cons of the Global Positioning System
for OM10 years Later
  • Research, Products and Usage for the Blind and
    Visually Impaired.

2
L. 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

3
Purpose
  • 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.

4
Presentation
  • 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
5
Overview
  • 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?

6
What 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.

7
HistorySatellite-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

8
HistorySatellite-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

9
How 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

10
How GPS Works
11
How 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)

12
How GPS Works
  • Line of Position (LOP)

13
How 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

14
How 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

15
How 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
16
GPS 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.

17
GPS Accuracy
  • Errors in accuracy
  • Control Segment produced
  • Less expensive clock in receiver
  • Atmospheric conditions
  • Physical Obstructions

18
GPS 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.

19
GPS 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.

20
GPS 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

21
Types 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.

22
Types of GPS Receivers
  • Sequential Receivers (most are obsolete)
  • Starved power single channel
  • Single channel slow sequence
  • Two channel slow sequence
  • Single channel fast sequence

23
Types 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)

24
General 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?)

25
General Applications and Uses of GPS
  • Position Functions (Where are you?)
  • Latitude and Longitude
  • Present position
  • Warning area
  • Waypoint arrival

26
General 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

27
General Applications and Uses of GPS
  • Steering Functions (How do we get there? )
  • Course to steer
  • Course corrections
  • Graphical displays

28
Land Applications andUses of GPS
  • Pedestrian navigation
  • Vehicular navigation

29
Land Applications and Uses of GPS
  • Pedestrian navigation
  • From point to point
  • Hiking
  • Walking
  • Locating current point
  • Point on city map
  • Waypoint

30
Land 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

31
ResearchImplications for OM Usage
  • MoBic
  • Drishti
  • Brunel Navigation System for the Blind
  • NOPPA
  • BrailleNote GPS
  • Trekker
  • Trinetra

32
ResearchImplications 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.

33
ResearchImplications 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.

34
ResearchImplications 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.

35
ResearchImplications 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.

36
ResearchImplications 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.

37
ResearchImplications 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.

38
ResearchImplications 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/

39
ResearchImplications 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.

40
ResearchImplications 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.

41
Advantages 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

42
Disadvantages of GPS Navigation
  • Variable accuracy
  • Obstructed reception
  • Physically conspicuous
  • Auditory discrimination
  • Cost and maintenance
  • Power supply issues

43
Off-the-Shelf Hardware
Factory Adapted for the Blind
User Adapted f/t Blind
44
Off-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
45
Off-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!
46
Off-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
47
Where 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

48
Review 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?

49
OM 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

50
OM 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.

51
OM 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

52
OM 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.

53
The 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)
55
GPS 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
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