Mobile Intelligence

10.6 LOCATION SERVICES

As stated in previous sections, location services are offered via the LP2U reference point and are realized by the T2LP reference point, which incorporates mechanisms for achieving positioning transparency and the operations of position management. Both functions are based on the architecture depicted in Figure 10.8 and are explained in this section.

The core element of the T2LP reference point is a positioning daemon executed at the mobile device of a target. The positioning daemon sits on top of the implementations of one or several positioning technologies and publishes location data either to local front ends or to the remote location server maintained by the location provider. The interface to local front ends is necessary for realizing all kinds of self-referencing LBSs, where the user's own location is used to request location-based content. If a dedicated client application is used, it receives location data from the positioning daemon over a set of well-defined APIs. In order to access location data through a local Web or WAP browser, the positioning daemon can also be configured to act as a local proxy and thus appears as a kind of Web service that can be interlinked with Web pages or scripts loaded into the browser. However, in the following, the focus is on publishing location data to a remote location server, which is described in the following subsections.

Figure 10.7 Example of an LBS front end.

Figure 10.8 Architecture for publishing location ...