Device Location
Devices may not necessarily need a built-in location-providing method. For example, devices implementing the Location API may require an accessory that implements a location method. Such an accessory may be a GPS receiver with a Bluetooth connection or a GPS receiver in a functional cover. The accuracy of the location information depends on the location-providing method. Some devices implementing the Location API may obtain location information from the mobile phone network stations. Local short-range positioning beacons can also be used to obtain the location information. In addition, some devices may support a hybrid approach called assisted-GPS (A-GPS), in which GPS and the network are used to provide the location. The figure below demonstrates the positioning of a device by using the network's mobile stations and/or satellites.
In general, location data from GPS receivers is more accurate than network-based data. In a downtown area GPS receivers may suffer from "canyon effects," where satellite visibility is intermittent. That may cause service breaks on MIDlets using the Location API. Depending on the location-providing method, the use may or may not be free. The API includes the possibility to define certain criteria for which location-providing method should be used. The decision whether to pay for the service can be made using the criteria.