Google Map Research Paper

How Google Maps Work arkokoley December 2014

1

Introduction

Location Tracking is one of the most famous and most frequently used feature of Google Maps. Location services are also one of Google’s most controversial and most discussed features. How Google does it, is a matter of great interest.

Google Maps uses a multi layered structure of data services to locate a user device. At a very general level, Google’s servers use to the device’s unique IP address to find the approximate location of the user. Further fine tuning of location is achieved using a combination of Cell Phone Triangulation, GPS and Wifi Triangulation.

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Locating a Device

Assessing the location of a device requires Google’s server to use several methods at various level of

Therefore, the knowledge of the location of the base station implies the cell phone is nearby.

It relies on various means of multilateration of the signal from cell sites serving a mobile phone. This includes comparing the relative signal strength from multiple antenna towers to get a geographical position of a phone through various techniques like time difference of arrival (TDOA) or En- hanced Observed Time Difference (E-OTD).

This implies accurate location in typically urban locations where mobile traffic and density of antenna towers (base stations) is sufficiently high. In such places, one can achieve a precision of down to 50 meters. Rural and desolate regions will therefore determine locations less precisely because of spotty coverage and insuffient antenna density.

Precision of upto 50 metres, although pretty decent, might not be of help when it comes to situations like navigation and cases where one requires precision to the metre. In such cases, GPS is helpful.

2.3

Global Positioning System

Global Positioning System (GPS) is a worldwide radio-navigation system formed from the constellation of 24 satellites and their ground stations.

2GPS provides special satellite signals, which are processed by a