Location Based Services will play a key role in the future development of the Galileo market, as they represent the ultimate synergy between wireless communication networks, Geographic Information Systems and positioning technologies in order to deliver to the mass market a wide variety of new services.
This chapter begins with a general description and definition of LBS. A categorization and the different application types of LBS takes place later on. An overview (state of the art) of available positioning techniques (network based and satellite based) is also included in order to present a clearer view of related technologies and availability for capturing the position of terminals. The chapter concludes with a market analysis and market trends of the LBS that reveal the importance as well as the business perspectives for developing innovative applications that exploit mobile terminal position.

LBS Definition

Location Based Services or LBS are business and consumer services, which give users a set of services starting from the geographic location of the client. By these services users or machines are offered possibilities to find/locate other persons, machines, vehicles, resources and also location-sensitive services, as well as to track their own location. The request for location can originate in the client himself or in another entity such as application provider or network operator. In any case, whenever location is requested the customer has to give permission for the location request.
Location Based Services can automatically be triggered when the client is at a specific location, e.g. geographical areas subjected to different billing systems. Alternatively it can originate in the client himself in order to satisfy location-based requests e.g. information needs; finding points of interest, checking traffic conditions, finding other people, vehicles, resources, services or machines and emergency requests.
The main services of LBS categories include Emergency and Safety, Tracking and Monitoring, Information and Navigation, (e.g. In-Vehicle navigation service), (e.g. Fleet Management service), Trigger services (e.g. location advertising), etc.
Moreover, LBS can be generated by any given Location Determination Technology (LDT), such as Cell-ID, A-GPS, and EOTD, etc. These technologies usually require modifications in either the networks or smart devices (mobile phones), and in some in both. LBS can thus be seen as convergence of New Information & Communication Technologies (NICTs) such as mobile telecommunications system, location aware technologies and handheld devices with the Internet, GIS and spatial database as illustrate in Figure 23.

Finally, in the area of potential future directions, it is evident that location based services will not necessarily be a service category in itself, but rather an added feature to existing services. The formation of LBS will be changed as the market matures and new technologies and more sophisticated demands will be generated from the consumers and operators.

LBS classification

Location based Services can be classified according to various categorisations. One is by their class of application: trigger services, tracking & monitoring, location-based information and assistance services. A second is those that are requested by users once their location is determined, and those that are triggered automatically once a certain condition is met (e.g. a boundary is crossed). We might consider the former set to be “pull” services and the latter to “push” services [10]. A third is by the market segments (b2b, b2c, c2c, c2b, g2c, etc.).

4.3. LBS Application types

A first classification scheme based on different application types of location-based services is discussed in this section. We have four main families or categories or types of applications regarding to location-based services, which are: Trigger services, Location-based information services, Tracking and Monitoring services and Assistance Services.

Trigger Services
Location Based Services can be described as “applications, which re-act according to a geographic trigger”. A Geographic trigger might be the input of a Town name, Zip code or Street into a web page, the position of a mobile phone user or the precise position of your car as you are driving home from the office. Any location-based service can define so called ‘triggers’ to automatically alert the users of service when predefined conditions are met. Two main services of this category/family are: Location billing and automated advertising services.

4.3.2. Location-based information services
Location-based information access, where an agent takes advantage of location information to access resources within suitable locality constraints (e.g. Point Of Interests such as tourist sites). Also, where data – are searched and accessed on the basis of their content rather than on the basis of nodes network addresses or location. General location-based information applications are: navigation, routing and other proximity services.

Tracking & Monitoring services

The objective of tracking in sensor networks is to construct a distributed indexing structure that enables queries to determine the location of a user that has the appropriate device. Moreover, Tracking & Monitoring services consist of detecting and monitoring locations of real-world objects (e.g. cultural asstes), possibly using several types of sensing such as acoustic, seismic, electromagnetic, etc. Numerous applications of tracking are currently in use; for example, air traffic control, fleet tracking, habitat monitoring, automatic vehicle location, etc.

Assistance services

Assistance service is the solution, which provides the call centre with a spatial user interface, in order to enable operators to pinpoint the exact location of callers seeking assistance from service providers. Assistance services including legal advice, tax, investment, vehicle breakdown, household services, accommodation, claims, map services, travel assist and medical emergency evacuation. For instance, regulatory agencies are forcing carriers to accurately position wireless emergency calls (E-911 in the United States), which is one of the most common assistance services.

Location techniques overview
The LBS techniques developed so far, are characterized by a trade off between the accuracy they can achieve and the cost they require in order to be employed in a commercial network. The dilemma of the industry is closely related with this trade-off:

(a) Investment on LBS technology: LBS applications are not expected to be “killer applications” and their commercial success will take time. Therefore, the associated investment should be adjusted, if possible, to the actual market demand and growth.

(b) LBS Accuracy as a factor of commercial success: On the other hand, using LBS technologies, which require low investment leads, to low accuracy levels which significantly constraints the range of applications that can be provided and consequently limits the expected market growth.

In the context of the above rationale, methods that increase the accuracy of LBS techniques without requiring significant investment in both the terminal and the network side are of crucial importance from the commercial viewpoint.

The existing positioning methods can be divided into three main categories: (a) network based, (b) handset based and (c) hybrid technologies. In this section we briefly present the most well known positioning techniques highlighting issues related to accuracy and the implementation costs. LBS techniques typically rely on communication between known reference points (e.g., Base Stations or satellites) and the target object (e.g., mobile terminal), that should be located. The following methods (with many variations) have been proposed for cellular mobile systems so far [2][3]:

Cell ID and Timing Advance Technique (CGI+TA): The Cell Global Identity (CGI) identifies the cell in which the mobile terminal is located. The TA parameter is an estimate of the distance (in increments of 550m in GSM [4][5]) from the mobile terminal to the base station. The resulting accuracy varies with the cell size. CGI alone can be used for terminal positioning, however with lower accuracy. CGI+TA technique has no requirements concerning extra software or hardware to the mobile device.

Cell ID and Received Power measurement technique (CGI++): This technique exploits the received power (Rx) levels (the terminal measures) from the neighbouring and the serving base stations. Based on the Rx levels, an estimation of the distances between the mobile terminal and the base stations is feasible by using a propagation model (e.g., Hata model [6]). Then by applying methods like triangulation the terminal position can be derived. This method requires no additional software or hardware.

Uplink Time Of Arrival technique (UL-TOA): UL-TOA is based on measuring the TOA of a signal (a burst training sequence) from a terminal to three or more base stations. UL-TOA requires no terminal modification, while it requires Location Measurement Units (LMU) to be installed at certain base stations. The network combines the LMU measurements and provides the terminal location. The LMUs’ geographical coordinates and the timing offset between the LMUs should be known.

Angle Of Arrival technique (AOA): AOA requires the installation of directional antennas or antenna arrays. The terminal position is determined based on triangulation. The intersection of two directional lines, each formed by a radial from a base station, define a unique position for the terminal. At minimum the AOA of two base stations should be measured. Line-of-sight is essential for accurate terminal position estimation.
Enhanced – Observed Time Difference technique (E-OTD): E-OTD is based on the measured OTD between bursts arrivals for base stations pairs based on additional software at the terminal. As base stations are not synchronized, the network must measure the Relative Time Difference (RTD). For accurate triangulation, OTD and RTD measurements are needed for at least three distinct pairs of geographically separated base stations. The terminal location can be calculated by the network or the terminal.

WLAN: WLAN positioning software is already commercially available, which makes it the best candidate for indoor positioning, when devices are equipped with WLAN hardware. Companies such as Ekahau claim that they can locate users of WLAN within 1m, given that the user can “see” 5-7 access points. The accuracy drops to 3m when 3-5 access points are within range. These types of system work by a combination of using the propagation delay of signals from different access points and using a triangulation method. Other parameters may be added to increase the accuracy, and the system is prone to degradation from interference of other similar frequency devices. A major issue with these or other existing WLAN based positioning systems, however, is that there are no standards, meaning that all solutions are vendor-specific.
GPS (Global Position System) technique: GPS is a time-based method where the terminal, has a chipset and an antenna that receives signals of the GPS satellite constellation. The terminal calculates its position based on the difference in time it takes for each of the satellites’ signals to reach the terminal. This method has very high accuracy outdoors, but is complicated in indoor environment or in certain urban areas because the GPS needs direct contact with the GPS satellites to function.
Assisted GPS (A-GPS) technique: A-GPS is based on GPS and the mobile network (eg., GSM) which provides assistant information to the terminal (e.g., Differential GPS corrections). This leads to shorter Time to First Fix and lower terminal battery consumption (as the terminal no longer needs to search for and decode the signals from each available satellite). A-GPS can be either terminal or network based depending on where the terminal position is being calculated.
EGNOS: EGNOS is intended to be a precursor to Galileo. It is a system of satellites and ground stations designed to increase the accuracy of the current GPS and GLONASS. Consisting of three geostationary satellites and a network of ground stations, EGNOS will achieve its aim by transmitting a signal containing information on the reliability and accuracy of the positioning signals sent out by the Global Positioning System (GPS) and the Global Orbiting Navigation Satellite System (GLONASS). It will allow users in Europe and beyond to determine their position to within 5m compared with about 20m at present.
Galileo: The Galileo positioning system is a proposed satellite navigation system, to be built by the European union as an alternative to the US military-controlled GPS and the Russian GLONASS. The system should be operational by 2008. It is based on the emission from satellites of signals indicating the time extremely precisely. This enables any individual to determine his or her position or the location of any moving or stationary object (e.g. a vehicle, a ship, or a herd of cattle, etc.) to within one metre thanks to a small cheap individual receiver.