23-05-2012, 11:31 AM
Foundations of Location Based Services
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Introduction
Mobile phones and the Internet have revolutionized the communication and with it the lifestyle of people.
An increasing number of mobile phones and Personal Digital Assistants (PDA) allow people to access
the Internet where ever they are and when ever they want. From the Internet they can obtain on one
hand information on events (cinema, concerts, parties) and on the other hand information on places (city
maps, restaurants, museums, hospitals).
Let us consider the example that somebody wants to take a dinner in a restaurant and is therefore searching
a restaurant in the Internet. A useful approach to prevent that one gets as search result every restaurant
web-page on the world one could restrict the search by adding further search criteria. A good choice
is the city where the mobile user is (position), the actual time (evening) or a special type of restaurant
(Chinese or Greek).
Such kind of restaurant search with respect to position and time can be done by use of a Location Based
Service (LBS). Thus, one can define that:
LBS Definition 1:
LBSs are information services accessible with mobile devices through the mobile network and
utilizing the ability to make use of the location of the mobile device. (Virrantaus et al. 2001)
A similar definition for LBS is given by the international OpenGeospatial Consortium (OGC, 2005):
LBS Definition 2:
A wireless-IP service that uses geographic information to serve a mobile user. Any application
service that exploits the position of a mobile terminal.
These definitions describe LBS as an intersection of three technologies (see Figure 2). It is created from
New Information and Communication Technologies (NICTS) such as the mobile telecommunication
system and hand held devices, from Internet and from Geographic Information Systems (GIS) with spatial
databases (Shiode et al. 2004).
From a historical point of view location based information are not a new thing which came up with the
invention of mobile phones. Espinoza et al. (2001) emphasize that position specific information is also
transported on one hand in a person-to person communication by post-it notes and graffiti. On the other
hand methods to locally inform a mass-audience are posters (e.g. of concerts in the town) or simply traffic
signs, which submit navigational information. These communication forms are usually one way communications.
LBS give the possibility of a two way
communication and interaction. Therefore the user
tells the service provider his actual context like the
kind of information he needs, his preferences and his
position. This helps the provider of such location
services to deliver information tailored to the user
needs.
In the following four chapters we will try to answer
the mayor questions which may appear if somebody
likes to know what Location Based Services are:
• What are Location Based Services?
• How is it useful?
• What is special about it?
• How does it work?
Figure 2. LBS as an intersection of technologies (Brimicombe
2002).
What are Location Based Services?
In the following sub sections some major characteristics and definitions on LBS will be given. We will
discuss the relation between GIS and LBS and give some Keywords which are useful to describe the LBS
Technology. Later the basic LBS components are introduced shortly. Finally we will explain what a Push
and a Pull Service is.
The relation of GIS and LBS
the Introduction shows that GIS and LBS have some particular similarities. Such common
features are the handling of data with positional reference and spatial analysis functions (LBS-services)
which give answers to questions like:
• “Where am I”,
• “What is near by?” or
• “How can I go to?”.
But LBS and GIS have different origins and different user groups as described by Virrantaus et al.
(2001). They analyse that Geographic Information Systems have been developed during several decades
on the basis of professional geographic data applications. Whereas LBS were born quite recently by the
evolution of public mobile services. With respect to user groups, GIS can be seen as traditional “professional”
systems intended for experienced users with wide collection of functionality. Furthermore GISystems
require extensive computing resources. In contrast, the LBS are developed as limited services
for large non-professional user groups. Such LBS applications operating with the restrictions of mobile
computing environment like low computational power, small displays or battery run time of the mobile
device.
Nota bene: If you don't know what Geographic Information Systems (GIS) are, have a look on this GIS
e-learning Project www.GITTA.info
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.
[attachment=22816]
Introduction
Mobile phones and the Internet have revolutionized the communication and with it the lifestyle of people.
An increasing number of mobile phones and Personal Digital Assistants (PDA) allow people to access
the Internet where ever they are and when ever they want. From the Internet they can obtain on one
hand information on events (cinema, concerts, parties) and on the other hand information on places (city
maps, restaurants, museums, hospitals).
Let us consider the example that somebody wants to take a dinner in a restaurant and is therefore searching
a restaurant in the Internet. A useful approach to prevent that one gets as search result every restaurant
web-page on the world one could restrict the search by adding further search criteria. A good choice
is the city where the mobile user is (position), the actual time (evening) or a special type of restaurant
(Chinese or Greek).
Such kind of restaurant search with respect to position and time can be done by use of a Location Based
Service (LBS). Thus, one can define that:
LBS Definition 1:
LBSs are information services accessible with mobile devices through the mobile network and
utilizing the ability to make use of the location of the mobile device. (Virrantaus et al. 2001)
A similar definition for LBS is given by the international OpenGeospatial Consortium (OGC, 2005):
LBS Definition 2:
A wireless-IP service that uses geographic information to serve a mobile user. Any application
service that exploits the position of a mobile terminal.
These definitions describe LBS as an intersection of three technologies (see Figure 2). It is created from
New Information and Communication Technologies (NICTS) such as the mobile telecommunication
system and hand held devices, from Internet and from Geographic Information Systems (GIS) with spatial
databases (Shiode et al. 2004).
From a historical point of view location based information are not a new thing which came up with the
invention of mobile phones. Espinoza et al. (2001) emphasize that position specific information is also
transported on one hand in a person-to person communication by post-it notes and graffiti. On the other
hand methods to locally inform a mass-audience are posters (e.g. of concerts in the town) or simply traffic
signs, which submit navigational information. These communication forms are usually one way communications.
LBS give the possibility of a two way
communication and interaction. Therefore the user
tells the service provider his actual context like the
kind of information he needs, his preferences and his
position. This helps the provider of such location
services to deliver information tailored to the user
needs.
In the following four chapters we will try to answer
the mayor questions which may appear if somebody
likes to know what Location Based Services are:
• What are Location Based Services?
• How is it useful?
• What is special about it?
• How does it work?
Figure 2. LBS as an intersection of technologies (Brimicombe
2002).
What are Location Based Services?
In the following sub sections some major characteristics and definitions on LBS will be given. We will
discuss the relation between GIS and LBS and give some Keywords which are useful to describe the LBS
Technology. Later the basic LBS components are introduced shortly. Finally we will explain what a Push
and a Pull Service is.
The relation of GIS and LBS
the Introduction shows that GIS and LBS have some particular similarities. Such common
features are the handling of data with positional reference and spatial analysis functions (LBS-services)
which give answers to questions like:
• “Where am I”,
• “What is near by?” or
• “How can I go to?”.
But LBS and GIS have different origins and different user groups as described by Virrantaus et al.
(2001). They analyse that Geographic Information Systems have been developed during several decades
on the basis of professional geographic data applications. Whereas LBS were born quite recently by the
evolution of public mobile services. With respect to user groups, GIS can be seen as traditional “professional”
systems intended for experienced users with wide collection of functionality. Furthermore GISystems
require extensive computing resources. In contrast, the LBS are developed as limited services
for large non-professional user groups. Such LBS applications operating with the restrictions of mobile
computing environment like low computational power, small displays or battery run time of the mobile
device.
Nota bene: If you don't know what Geographic Information Systems (GIS) are, have a look on this GIS
e-learning Project www.GITTA.info
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.