Location Based Services

Introduction:
Location-based services (LBS) are the most popular services at present and in the
future world. LBS provide added value by enabling many services like resource
tracking, navigation, emergency services, public safety, weather, I-Phone
applications, etc.

Location-based Services or LBS are any services use spatial data that are
available to anyone, anywhere, anytime on any mobile-based device. This
project deals with the design delivery and testing of location-based service
components using Java technologies.

Location-based services, or LBS in short, refer to the services provided by

mobile operators based on location, including user’s current location and

location of a target. In fact, knowledge of user’s location can enable or enhance
different applications, such as fleet management, object tracking and routing. For
example, application may provide you information corresponding to your current
location. However, LBS can be released to ordinary users until all known issues
have been solved, including privacy. This chapter would give the overview of
location-based services, including the classification, architecture, service
requirement and platform standardization.
The evolution of LBS features

Early LBS was reactive, self-referencing, single-target, and content-oriented. This

started to change with the maturation of low-power positioning technology (such
as assisted GPS), LBS middleware technology, and 3G mobile networks.

Operators and other providers started offering services for fleet management and
for tracking children and pets—these were the first examples of cross-referencing
LBSs. Initial versions of these services were based on Cell-ID positioning using
triangulation techniques, which suffered from low accuracy and were soon
replaced by GPS.

With the emergence of GPS-capable mobiles, users started to write small

applications passing location data to a central server to make their location
available to other users. Soon, these early initiatives turned into professional
businesses that created a broad range of proactive and multitarget services—such
as for mobile gaming, marketing, and health. These developments were
accompanied by Web 2.0: location became another context item exchanged
between the members of a social network, which was the origin
Figure . The evolution of location-based services. A timeline from the E911
mandate to current LBSs (the red arrows represent predictions).

for location sharing, a basic function of many of today’s multitarget LBSs.

Problem Statement
The main task is to design and implement an application, which should be able to
provide an information exchange system on the basis of location and time. As
opposed to ordinary gathering of information, in this application it is the interplay
between the user’s profile and events governed by time and place, which will
initiate the services. To use a simple description, it is the information that will find
the right user at the right time instead of the person needing to search through
information relevant in the current situation. In short; application should be able to
answer the following questions:

 Where is the user located now?

 How to notify its users with some special information on reaching at that
site.
 How to make information exchange time bound?

For us the development of information services for individuals particularly about

getting locations alone were not enough. Rather, the aim should be to satisfy the
needs of users more precisely at least” right location” and” right on time”.
Positioning Technologies for Mobile Systems
The most important issue before going to develop a location based service
application it is to decide which positioning technology is better and suit to get the
location of mobile device. In this chapter the different positioning technologies,
their advantages and disadvantages will be discussed. After going through the
advantages and disadvantages of different positioning technologies it will be
decided which technology best suits for this application development.

Many location determination technologies have been employed to find out the
location of a mobile device. The positioning technology is used to deal with the
physical position of the mobile device. Depending on the position of mobile
device, the positioning technologies can be further grouped as

 Outdoor positioning technology

 Indoor positioning technology

There is no single method or technology that can operate effectively in all type of
environments (e.g., indoor and open terrain) with sufficient accuracy. These
technologies employed various media such as optical, acoustic or radio frequency
(RF) and each has advantages in certain situations.

Outdoor positioning technology is based on the Global Positioning System

(GPS). The GPS is satellite-based technology and is most widely used radio
frequency system, providing global out door coverage. Since the satellite signals
 used in the GPS are prevented from entering by construction materials of the
building, so the indoor positioning technology use another approach.

Indoor positioning technology is based on wireless LAN (IEEE 802.11b standard).

Wireless geolocation positioning system can be classified into the following two
types .

 Network based geolocation

 Handset based geolocation

In Network based geolocation, fixed stations receive signal from the mobile
station and send information to a central station where the mobile station’s location
is computed. “It is referred to as Network based because the mobile network, in
conjunction with network based position determination equipment is used to
position the mobile device” .

In Handset based geolocation, a mobile station receives signals from the fixed
stations and computes its own location. “It is referred to as Handset based because
the handset itself is the primary means of positioning the user, although the
network can be used to provide assistance in acquiring the mobile device and/or
making position estimate determinations based on measurement data and handset
based position determination algorithm”.
Types of Location-Based Services
There are numerous of location-sensitive applications that people may
think of. In technical view, all location-based services can be classified as two
types, namely pull-based and push-based. These two types based on client-
server model, where clients may be wireless computing devices or mobile
phones, while servers refer to network operators or service providers.

Pull-based LBS describes the action that client (or client application)
actively asks server for location so that it can further deal with the returned
information to achieve certain goals. Positioning is a simple example of pull-
based LBS. Users would continuously request for where they are in the map
so that they can go for a specific places. Another example is the restaurant
finder which people can find the nearest restaurant around them. Pull-based
service often involves object tracking.

Push-based LBS works in the opposite way: server side would locate the
position of client device through wireless connection so that server (or server
application) may use this piece of information to perform some tasks. On typical
example is the advertisement from mobile operator.
LBS Components

If the user wants to use a location based service different infrastructure

elements are necessary. In Figure
3 the five (4+1) basic components and their
connections are shown:

• Mobile Devices: A tool for the user to request the needed information.
The results can be given by speech, using pictures, text and so on.
Possible devices are PDA's, Mobile Phones, Laptops,but the device
can also be a navigation unit of car or a toll box for road pricing in a
truck.

• Communication Network: The second component is the mobile

network which transfers the user data and service request from the
mobile terminal to the service provider and then the requested
information back to the user.

• Positioning Component: For the processing of a service usually the

user position has to be determined. The user position can be obtained
either by using the mobile communication network or by using the
Global Positioning System (GPS). Further possibilities to determine
the position are WLAN stations, active badges or radio beacons. The
latter positioning methods can especially used for indoor navigation
like in a museum. If the position is not determined automatically it
can be also specified manually by the user.
 • Service and Application Provider: The service provider offers a
number of different services to the user and is responsible for the
service request processing. Such services offer the calculation of the
position, finding a route, searching yellow pages with respect to
position or searching specific information on objects of user interest
(e.g. a bird in wild life park) and so forth.

• Data and Content Provider: Service providers will usually not store
and maintain all the in- formation which can be requested by users.

Figure . The basic components of LBS: User, Communication Network,

Positioning, Service Provider and Content Provider.

Therefore geographic base data and location information data will be

usually requested from the maintaining authority (e.g. mapping
agencies) or business and industry partners
(e.g. yellow pages, traffic companies)
For a more detailed discussion on the components see Section 4 “How
does it work” and subsequent sections.

Categories of Location Service Applications

There exist a broad range of different location based services. The first figure
in Table 2a gives an over- view on the main categories of LBS applications.
This listing does not claim to be complete and is certainly growing over
time. For some application fields, namely navigation, information,
advertising & billing and games & leisure, additionally information on the
positional accuracy needs, the environment and the service.

LBS Architecture

A location-based service is a service based on the geographical position of a

mobile handheld device
(a) Mobile handheld devices, which are small computers that can be held in
one hand.
For most cases, they are smart phones.
(b) Positioning system, which is a navigation satellite system that
provides location and time information to anyone with a receiver.
(c) Mobile and wireless networks, which relay the query and location
information from devices to service providers and send the results from
the providers to devices.
(d) Service providers, which provide the location-based services.
(e) Geographical data providers, which are databases storing a huge
amount of geographical data
Figure : A System Structure of Generic Location-Based Services.

Location-Based Applications
In business or user perspective, location-based applications can be
classified as different types in terms of their use. The below shows several fields
on which LBS is applicable.

Emergency: The initial motivation of location-based services is to locate

victim’s position on emergency call in the United States. Originally, terminals
of emergency centre could only show the corresponding address of home or
office lines. However, there was no such support on mobile phone calls. Mobile
phone positioning was highly demanded.
Information-Oriented: Like the location-sensitive advertising example stated
in the “pull-based service” model, client location data is useful for network
operators and content providers to deliver suitable information, such as weather
of that district, surrounding traffic condition.

Navigation: Navigation is just positioning service with guidance to subscribers

what way they should go. One typical example is driving navigation system
which provides support to ordinary drivers. With very high accuracy, positioning
devices, such as Global Positioning System (GPS), could be used on military and
war.

Billing Service: Applications under this field are often adopted by service
providers or resource owners. They provide some kinds of service, like car
parking or public transport, where charges are different at different locations.
Keeping track of user location within duration of service allows automatic
calculation the overall charges. Such billing service is usually a pull-based one.

Games and Entertainment: Location information can be inserted into game

logic, giving game developers high opportunities to design innovative games,
especially multi-player games. Virtual game, where factors of reality are put
into the virtual game world, may also be realized, including treasure hunt and
role-playing game (RPG).
Others: Besides the above, LBS could be used for the various purposes. For
administrative issues, managers may want to know where their employees are.
People can also keep track of their valuable belongings, such as vehicle and
jewelry box, by putting location-sensitive devices on them. Besides, LBS also
helps network operators themselves in terms of cell planning and network
optimization. They can know the distribution and usage of their customers so that
they can change the base station deployment and tune the configuration, like
output signal strength, in a cost-effective way.