1. Senior Project – Computer Engineering – 2006
Handheld Campus Tour Guide
Michael Boyer
Advisor: Professor John Spinelli
Overview
System Design
The goal of this project was to design and build an automated handheld tour guide system for the Union College campus. The purpose of the system is to provide prospective students with an informative and enjoyable campus visit at times when student-guided tours are not available.
The system provides the user with a continuously updated visual representation of his or her current location on a campus map. As the user approaches a building, the system also displays the building’s name. The user can then press a button to learn more about the building, including its history and present use.
The main technological challenge associated with the project is localization, the process of determining the user’s location. For the proper operation of this system, the localization process needs to occur in three dimensions, in real time, and both indoors and outdoors. For outdoor localization, the system uses the well-established Global Positioning System (GPS). For indoor localization, the system uses a recently developed localization process based on signals transmitted by GSM cell phone towers.
The GPS and GSM Trackers generate updated position estimates at set intervals
GPS
Tracker
Position Estimate
(Latitude/Longitude)
GSM
Tracker
Position
Converter
Position Estimate
(Pixel Location)
Position Estimate
(Pixel Location)
Tracker
GSM Localization
Current Position Estimate
Display System
The GSM Localization algorithm is based on a training process. Before system deployment, GSM signal strength measurements are taken in the area of interest using the training application shown to the left. Clicking on the map queries the GSM modem, which returns the signal strengths of all nearby cell towers. The set of signal strength readings and the point at which they were taken constitute a measurement. All of the measurements are stored in the training set.
If there are no nearby buildings,
simply indicate the position
Otherwise, indicate the position
and the nearest building
Outdoors
When the system wants to determine the user’s location, it once again takes a measurement of GSM signal strengths.
Button
Pressed
Indoors
The distance (in signal space) between the current measurement and each measurement in the training set is then calculated.
The four closest measurements are selected and their positions averaged to generate a position estimate.