NAVI-LIGHT: GPS 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

Definitions Backtrack GPS Time-to-first-fix Embedded System 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

Technical Description NAVI-LIGHT is an embedded system based, innovative flashlight used for navigation Primary function is to record the user’s 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

Technical Description Records the user’s 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

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

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

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

Assumptions Vector 2X digital compass has a 2-degree accuracy and must measure the Earth’s 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

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 user’s exact distance would yield more accurate results in backtracking mode

System Design Vector 2X Digital Compass DATA 8 Software for backtracking and GPS mode control SBC1190 Embedded System +5V to GPS Antenna GPS Module TTL to RS232

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

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

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

Operational Flow Chart button not pressed return to run mode

Backtracking Flow Chart if heading has changed if button is not pressed Return to Main if button is pressed

GPS Flow Chart if button is not pressed Return to Main if button is pressed

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