Most of today’s Location Based Services (LBS) provide information based solely on a users’ location, not taking into account context knowledge about the user’s current situation and needs. This often results in low-quality and inappropriate information to the user. Hence, in order to provide user-oriented services, an improvement of the response-quality of information requests is required. Knowledge about the coordinates of places where the user regularly stays in her life combined with semantics about such places can provide valuable knowledge for LBS. Zhou et al.

There are many different types of technologies employed in calculating the location of handsets in wireless networks with various levels of success and accuracy. Assisted-GPS (A-GPS) is a positioning technology that is presently used for locating handsets in wireless networks and is gaining traction in the market. An A-GPS server provides assistance data to the handset in order for it to have a low Time to First Fix (TTFF), weak signal acquisition and optimize handset battery use. A-GPS is used as a location technology in isolation or hybridized with other positioning technologies that provide range-like measurements.

They went up a hill to fetch a pail of water. Jack fell down and broke his bone and Jill came tumbling after… And now they need medical attention and must locate a medical center soon. How far is the nearest hospital? How do they get there from the accursed hill? What is their current location? They need location-based services (LBS). “What is LBS?” asks Jill….

THE land-sea interface is one of the most complex areas of management in the world consisting of both the marine and terrestrial environments. The coastal zone is also home to an increasing number of activities, rights and interests. Population along the coastline is continuously increasing, bringing about new pressures on the fragile eco-system of the coastal zone. This has brought with it an increased need to more effectively and efficiently manage this area to meet the economic, environmental and social outcomes of sustainable development.

In particular the comfortable and mobile access to the internet were here the driving factors. Access points can nowadays be found in our daily environment, e.g. in many office buildings, public spaces and in urban areas. Parallel to this development there is meanwhile substantial interest in offering the user information which refers to the current location of the user (so-called Location Based Services LBS). Such Location Based Services, however, will be accepted by the user only if the cost performance ratio is satisfactory. If existing infrastructure such as WiFi without additional hardware installation can be used for location determination, then the realization costs are small and the service can be offered under attractive conditions. Several systems are nowadays available for location determination using WiFi signals. Their major application is the location determination of persons and objects inside buildings.

Location based services (LBS) are a rapidly growing field of wireless data services that can be accessed through a mobile phone equipped with a GNSS receiver. Some of the services are intended for outdoor use while others are suited for use in urban and indoor areas. It is therefore likely that subscribers will expect these services to be available throughout the coverage area of the mobile telephone network…

There are numerous types of GPS receivers in the current international marketplace, ranging from inexpensive, low accuracy handheld devices to expensive, high precision geodetic equipment. By and large, low–cost GPS receivers (whether sold as a plug– in hardware device or as a complete navigation and positioning receiver) have almost assumed mass market status in the consumer electronics industry. Recent advances in micro and wireless technology, reductions in consumer costs, and the apparent growth of the Location Based Services (LBS) industry have somewhat fuelled the need for mobile (information communications and technology) consumers to become “location aware”.

Recently mobile location based services (LBS) are provided via a mobile terminal such as a personal digital assistant (PDA), a cellular phone and so on. The location method that searches where the mobile terminal of a user is accurately is a key factor for providing convenient and useful LBS. The most well known method associated with positioning system is GPS. The signal of GPS satellites can be always acquired outdoors and this system provides comparatively accurate location information. However, there are difficulties in applying GPS directly to indoor positioning because of the weakness of signal. And the positioning using the mobile communication signal between a base station and a cellular phone does not provide adequate accuracy due to some technical limitations of communication systems when applied to navigation. In addition, severe multipaths are present in an indoor environment. So a new wireless communication technology is required for indoor positioning to achieve a better and appropriate accuracy. Wireless local area network (LAN) has been installed in a number of indoor areas such as office, terminal, campus, and park with interests in mobile Internet. Therefore, it is expected that a wireless LAN signal would be easily acquired for indoor positioning. Various positioning measurements like time of arrival (TOA), time difference of arrival (TDOA), and received signal strength may be employed for indoor positioning. Employing TOA or TDOA measurements requires a time synchronization between a transmitter and a receiver. But, a time synchronization between a transmitter and a receiver is very difficult if not impossible in a wireless LAN. Therefore, it is more appropriate to use signal strength for indoor positioning with a wireless LAN.

In the aftermath of the terrorist attacks on New York and Washington, finding people and bodies in the rubble was of utmost importance. This task was directed at finding location bearing devices incorporated in commonplace instruments such as mobile phones, personal digital assistants (PDAs) and electronic pagers. By polling these devices electronically using a system of triangulation points it was thought that persons and bodies could be found. Polling is simply sending electronic impulses to receivers to ascertain where these devices are located. However, and sadly, such devices have a limited range and may have no effect if buried in more than a meter of rubble. Also, some such devices incorporate global positioning systems (GPS) and these require access to the sky and to the constellation of satellites orbiting the Earth. Even the sniffer dogs gave up this mammoth task.