Title Page
Info Page
Strider Picture
Abstract
Acknowledgments
Table of Contents
List of Figures
List of Tables
Glossary
Chapter 1: Introduction
1.1 Prolog
1.2 Motivation
1.3 The Needs of the Visually Impaired
1.4 Technical Overview
1.5 Master Objectives
1.6 Layout
Chapter 2: Background Research
2.1 Historical Overview
2.1.1Navigational System for the Visually Impaired –Fourth-Year Project
2.1.2 Feasibility Study for Sextant
2.1.3 Atlas Speaks and Strider
2.1.4 Inertial Guidance System
2.2 Related Subject-matter
Chapter 3: Atlas Speaks
3.1 Layout of Atlas Speaks
3.1.1 Map Area
3.1.2 Message Window
3.2 Features of Atlas Speaks
3.2.1 Language Independence
3.2.2 Setting Explore Position
3.2.2.1 Specific Address
3.2.2.2 Destination
3.2.2.3 Point of Interest
3.2.3 Destinations
3.2.4 Routes
3.2.4.1 New Route
3.2.4.2 Find Route
3.2.4.3 Edit Route
3.2.4.4 Reverse Route
3.2.4.5 Route Status Window
3.2.5 Points of Interest
3.2.5.1 Nearest and Alphabetical Points of Interest
3.2.6 Voice Settings
3.2.7 Speech-Queuing
3.2.7.1 Example of the Functions called for the "Where amI"message
3.2.7.2 Speech-Queuing Features Continued
3.2.8 Atlas Options
3.2.8.1 Reset S/W Pedometer
3.2.8.2 Units and Measures
3.2.8.3 Serendipity
3.2.8.4 Key Announcements
3.3 Summary
Chapter 4: Strider
4.1 Layout of Strider
4.1.1 Map Window
4.1.2 Strider Message Window
4.1.2.1 GPS Status Window
4.1.2.2 Satellites Tracked Window
4.1.2.3 GPS Time Window
4.1.2.4 GPS Accuracy Window
4.1.2.5 Heading Window
4.1.2.6 Speed Window
4.1.2.7 Latitude and Longitude Window (Expert Mode)
4.1.2.8 Altitude Window (Expert Mode)
4.1.2.9 Satellite Information Window (Expert Mode)
4.1.2.10 Additional Information Window
4.2 Features of Strider
4.2.1 Automatic Route-Recording
4.2.2 Route-Following
4.2.3 Strider Settings
4.3 Strider Interface
4.3.1 GPS Specific DLL
4.3.1.1 Strider requests its position from the GPS receiver.
4.3.1.2 Strider requests current time from the GPS receiver.
4.4 Summary
Chapter 5: GPS, DGPS, and Backup Systems
5.1 GPS Failures
5.1.1 PDOP (Position Dilution of Precision) [6] [7]
5.1.2 Multipath Error
5.1.3 Line-of-Sight
5.2 DGPS increased accuracy
5.3 Position Accuracy
5.4 Possible Backup Systems
5.4.1 Measuring Distance Travelled using accelerometers
5.4.1.1 Pendulous Accelerometers
5.4.1.2 Pendulous Integrating Gyroscope Accelerometer
5.4.1.3 Liquid Level Accelerometer
5.4.1.4 Force-Rebalance Accelerometer
5.4.1.5 Variable Capacitance Accelerometers
5.4.1.6 Force Balanced Capacitance Accelerometer
5.4.1.7 Problems with Accelerometers
5.4.2 Measuring distance travelled by AccelerationThresholdSwitches
5.4.3 Measuring distance travelled through other means
5.4.3.1 Odometer Wheel
5.4.3.2 Shoe sensors
5.4.3.3 Pedometer
5.4.4 Determining Heading
5.4.4.1 Fluxgate Compass
5.4.4.2 Polarized Light [9e]
5.4.4.3 Dinsmore Digital Compass
5.4.4.4 Vector 2X Compass
5.5 Personal Dead Reckoning Module[13]
5.6 Alternative Navigation System
Chapter 6: Alternative Navigation System
6.1 Overview
6.1.1 Pedometer
6.1.2 Compass
6.1.3 Computer Connection
6.1.3.1 Switching Circuit (MUX)
6.1.4 Motorola HC705-K Microcontroller
6.1.4.1 Reasons for the Discontinuance of theHC705-KMicrocontroller
6.2 Motorola HC705-J Microcontroller
6.2.1 Internal Clock
6.3 Programming the HC705-J Microcontroller
6.3.1 Program Design
6.3.2 Debouncing the Pedometer
6.3.2.1 Waiting for Fifteen Consecutive 5volt Levels
6.3.2.2 Using an Interrupt Timer and Monitoring the IRQ Line
6.3.3 Obtaining the Direction of Travel
6.3.3.1 Slave Mode of Operation
6.3.3.2 Calibrating the Compass
6.3.3.3 Clocking in and Storing the Compass Direction
6.3.4 Sending Data to the Computer
6.4 Computer Interface
6.4.1 Problems that Occurred
6.5 Summary
Chapter 7: Testing the Alternative Navigation System
7.1 Testing around a City Block
7.2 Testing Pedometer Accuracy
7.3 Testing ANS Indoors
7.4 Performance around Bridges
7.5 Summary
Chapter 8: Conclusions
8.1 Summary
8.1.1 Results
8.2 Claims of Originality
8.3 Benefits
8.4 Future Improvements
Appendix A: Popular Press Articles about this Project
Appendix B: Available Atlas Speak Functions
Appendix C: Speech-Queuing Interface Prototypes
Appendix D: Available Strider Functions
Appendix E: Keypad Keys
Appendix F: GPS Receiver's DLL Interface Prototypes
Appendix G: OEM 4000 Technical Specifications [16]
Appendix H: Lassen SK8 Technical Specifications [17]
Appendix I: Vector 2X Compass Specifications [12]
Appendix J: Assembly Language for the ANS
Appendix K: Pseudocode for Pedometer and Timer
Appendix L: Pseudocode for Calibration of the Compass
Appendix M: Pseudocode for Obtaining a Direction
Appendix N: Pseudocode for Transmitting Data to the Computer
Appendix O: Pseudocode for the Windows Test Program
References