NAVI-LIGHT: GPS based Embedded System for Backtracking in Unfamiliar Environments

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NAVI-LIGHTGPS based Embedded System for
Backtracking in Unfamiliar Environments

• Ashray Solanki, Antony Pollail, Lovlish Gupta
• Undergraduate Students,
• Computer Engineering
• Advisor Alex Doboli, Assistant Professor
• Electrical and Computer Engineering Department

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Definitions

• Backtrack
• To go back over the course by which one has come
• GPS
• Global Positioning System (GPS) is a world-wide
  radio-navigation system formed from a
  constellation of 24 satellites and their ground
  stations
• Time-to-first-fix
• Amount of time it takes the GPS receiver to start
  producing solutions
• Embedded System
• A complete computer on a smaller scale which
  contains a microprocessor, memory, I/O ports and
  sensors

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Technical Description

• NAVI-LIGHT is an embedded system based,
  innovative flashlight used for navigation
• Primary function is to
• record the users starting point
• trace the path taken
• display the path back to the user
• NAVI-LIGHT is a compact portable device that can
  be easily controlled

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Technical Description

• Records the users path by choosing between a GPS
  receiver or digital compass based on the
  availability of a GPS signal
• Implements a software controlled backtracking
  system for situations in which a GPS module would
  be ineffective

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Operating Environment

• NAVI-LIGHT is designed to operate under normal
  weather conditions
• Operating temperature is between 0 Celsius and
  60 Celsius
• Storing temperature is between -40 Celsius and
  70 Celsius

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Design Requirements

• Main objective of the design is a navigational
  tool that displays the path taken by the user
• Primary objective combines the design with the
  integration of a compass sensor, a GPS module and
  embedded system
• Secondary objective involves software programming
  and debugging to interface the components
  together

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Approach and Design

• Design and develop a system level diagram of the
  components necessary for implementing the
  navigational flashlight
• Components were chosen to be of low power
  consumption and minimal size allowing them to be
  embedded in a portable flashlight

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Assumptions

• Vector 2X digital compass has a 2-degree accuracy
  and must measure the Earths field in the plane
  which is level
• The M12 Oncore GPS receiver has a cold
  time-to-first-fix of no greater than 60 seconds
  and a positioning accuracy of less than 25 meters

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Assumptions

• Assumed that the user will operate the GPS
  receiver outdoors and obtain a signal from at
  least three satellites
• Implementing a velocity sensor to measure the
  users exact distance would yield more accurate
  results in backtracking mode

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System Design
Software for backtracking and GPS mode control
to GPS Antenna
GPS Module
TTL to RS232
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SBC1190 Embedded System

• Ready-to-run embedded PC
• 128K RAM, 256K flash
• Small PC/104 format and expansion
• Two RS232/RS485 COM ports
• 24 TTL-compatible I/O Lines
• 5V - only operation

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Vector 2X Digital Compass

• Complete compass module
• Easily integrates with embedded systems
• Small in size
• High accuracy
• Ease of calibration
• Low power consumption
• Low cost

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M12 Oncore GPS Receiver

• Ready for software and systems integration
• Small in size
• Low cost
• Quick implementation
• Low power consumption
• Fast time-to-first-fix

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Operational Flow Chart
button not pressed
return to run mode
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Backtracking Flow Chart
Return to Main if button is pressed
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GPS Flow Chart
if button is not pressed
Return to Main if button is pressed
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Status and Future Plans

• Present
• - Interfacing components of design
• - Coding software for backtracking and GPS
• Future Plans
• - Implement a velocity sensor to calculate
  distance traveled with a given degree
  parameter
• - Implement a battery pack to make the
• NAVI-LIGHT portable