Handheld Wireless GPS
Tracking Device
Senior Design
EEL 4914C : UWF, Fall 2006
Team
Doug Cumbie
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Developed GPS Module and Wireless Transceiver Module.
Assisted in development of LCD software interface.
Jonathon Bean
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Developed User-Interface Module, Power Supply Module,
and assisted with LCD software/hardware interface. PCB
Design and assembly.
Faculty Mentor: Dr. Thomas Gilbar
Abstract
The enhanced awareness that Global Positioning Systems (GPS)
provide has revolutionized the way we interact with our
surroundings. Many industries today, primarily in aviation,
depend upon the latitude, longitude, and altitude information
that GPS provides. Commercially, GPS has become increasing
popular for use in vehicles and handheld units. An
enhancement to a GPS device would allow for the ability to not
only track your own position, but the position of other remote
devices. By utilizing wireless communication technology, the
position information obtained from a GPS may be relayed to
other devices for tracking and increased awareness of other
remote units.
Introduction
Main Goal: Develop a GPS Device with the added feature of
remote position tracking/sharing.
Intended Users: Various user groups
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Hikers
Military
Disaster Relief – Rescue workers
Limitations
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GPS requirement for outdoor, sky-visible condition
Limited range of wireless transceiver
Design Requirements
Main Design Objectives
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Provide geographical present position information
Provide ability to transmit present position information to a remote
unit either automatically or on-command
Provide ability to receive a remote unit’s position information
Present a graphical presentation of remote unit’s position relative to
self position
Provide a predefined-message sending capability
Present all information on a graphical liquid crystal display (LCD)
Provide a minimal user-interface for simple use
Package components in a compact case
Design Requirements cont…
Constraints
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Time
Product Selection and Cost
Standards
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NMEA 0183 Interface Standard for GPS Data Retrieval
UART for Module Communications
FCC Approved Radio Transmission
End Product Description
The Handheld Wireless GPS Tracking Device is a product that
provides the user with the ability to obtain one’s geographical
position in the form of latitude, longitude, and altitude and
wirelessly share this data with another similar device. The
battery-powered device is packaged in a compact case for easy
operation and portable use. The user interface consists of a
graphical display and four buttons used for paging through
various informative screens. The graphic LCD provides
information to the user that consists of current present position,
numeric position of the remote unit, graphical position of the
remote unit, and a message sending/receiving capability. The
device utilizes a wireless transceiver that is capable of
transmitting the user’s position information up to 14 miles lineof-sight. The Handheld Wireless GPS Tracking Device is useful
for many scenarios that require knowledge of another person or
group’s location.
Technical Approach
Modularized Design
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Microprocessor Module
GPS Receiver Module
Wireless Transceiver Module
User Interface Module
 LCD and Pushbuttons Interface
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Power Supply Module
System Software Modules
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Main
GPS
Radio
LCD
Component Parts Breakdown
Microprocessor Module
Runs Main Loop
Initializes all Modules
UART Parsing
Button Handling
LCD Refresh
LCD Screen Transitions
User Message Sending
GPS Receiver Module
Initializes GPS Receiver
NMEA Parser
Updates Present Position Structure (Latitude,
Longitude, Altitude, Heading, and Speed)
Slant Range and Bearing to Remote Device
Calculations
Formats Position Message for Sending
Radio Software Module
Initializes Wireless Transceiver
Sends Message Data
Receives Message Data
 Parses Received Position or User Messages
 Stores Parsed Position Data in Remote Position
Structure
Message Structure Format: Comma-Delimited ASCII
Packets
User Interface Module
Pushbutton Interface
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Power Switch: Double-Pole Double-Throw
Four User Pushbuttons
User Interface Module cont…
LCD Interface
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Initializes MOD5213 Queued Serial Peripheral Interface
(QSPI)
Initializes LCD Device
Provides Software API for Character Writing and Graphical
Drawing to the Display
Format 48x84 pixel display into 6 row x 14 column character
map
User Interface Module cont…
User Interface Module cont…
Graphical Tracking
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“X” represents remote unit
position relative to self
User’s heading is referenced
toward top of screen, remote
unit is referenced from user’s
heading.
2 Miles Wide by 0.878 Miles
High Maximum Distance (1 mile
= 20.5 pixels)
Range (miles) and Bearing
(degrees)
Power Supply Module
Two DC Voltage Supplies
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3.3VDC Regulated for MOD5213 and LCD
5.0VDC Regulated for GPS and Radio Modem
Double-Pole Double-Throw used for Power
Switch
Transient Suppression Circuits for Protection
Battery Life (max calculated):
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20.697 hrs for 3.3V Supply
9.69 hrs for 5.0V Supply
Approximately 9 hour overall battery lifetime
Full System Schematic
Power Supply Schematic
Printed Circuit Board Design
Printed Circuit Board Assembly
Testing Approach
Validate each individual module
independently for proper operation
Full System Tests
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Validate all modules operate as expected
Radio transmission between units
GPS Position Fix
LCD Updates
Pushbutton Events
Budget
Final Product Results Handheld Wireless GPS Tracking Device
Compact Case Design with Simple User Interface
GPS Position Information
Remote Device Position Tracking
Predefined Message Sending/Receiving