Information Technology Reference
In-Depth Information
Chapter 6
Abstract
Positioning is a featuring topic of pervasive computing and context-aware
services providing. Positioning plays a relevant role in coupling what to do
and context factors such as who, where and when. Other factors typically
deal with semantics and allow a system to arrange those services someone
may expect in a given reality. Positioning can contribute to better instantiate
a context by providing time and space information. Time information is often
simple to get; on the contrary, the position of people who need to be provided
with context-aware services is unpredictable and more difficult to detect
because of the use of wireless communication. In this chapter we will give
an overview of most used positioning methods, along with some existing
implementations.
1
Introduction
Position-based services are becoming a relevant topic in context-aware
applications. Location awareness is a basic requirement for new applications
on mobile devices, as in the case of advertisement systems in large stores [1]
and guidance systems in museums [2] with handheld devices which are only
feasible with an accurate position estimation of the mobile terminal. There
are many existing indoor and outdoor positioning systems which use different
technologies and algorithms for positioning.
The first step to accomplish the positioning task is the distance estimation
between a mobile device to be positioned (mobile device) and a number of
