Client-Server Based LBS Architecture: A Novel Positioning Module for Improved Positioning Performance

Positioning Technologies Background

Generally, the positioning technologies are divided into two major categories. The first one is described as network-based which involves different types of implementations such as mobile network positioning, in which mobile signals and the network infrastructure are used to locate the mobile device utilising several methods such as Angle of Arrival (AoA), Time of Arrival (ToA) and Enhanced Observed Time Difference (E-OTD). Also, this category includes wireless local network (Wi-Fi) and Radio Frequency Identification (RFID) based positioning, these methods are mainly used for position determination in local scales and indoor environments (Esmond, 2007). However, the network based positioning techniques are still not widely implemented as stand alone solutions because of its accuracy limitations. In addition, network operators still are not considering that LBS applications are typically to be utilised by all mobile phone users.

The second main category is known as satellite-based positioning, in which satellite signals are received by handheld receivers and used to position the mobile device based on a triangulation process of three or more different signals. This technology is known as the Global Navigation Satellite Systems (GNSS) such as GPS which has been widely utilised for a variety of air, land and sea applications. GPS is considered as the cornerstone of positioning in LBS applications because of its simplicity of use, inexpensive implementation, and global availability (Filjar, 2003). However, the positioning performance provided by a single frequency GPS receiver has proved to be insufficient for some precision and accuracy demanding applications (Kaplan & Hegarty, 2006).