Developing Android Applications with Adobe AIR

Locating a Device Using Global Positioning System and Network/WiFi Technology

The Android platform uses both GPS and network/WiFi to locate a device. There is no direct way to specify a unique location source, but a workaround is to only add the relevant permission, fine or coarse as defined earlier, in the manifest file.

Using GPS

GPS is a manmade navigation system. Satellites in space constantly broadcast messages with their ephemeris, or position in the sky, and the time. Your mobile device, as a GPS receiver, uses the messages received to determine the distance to each satellite by measuring the transit time of the message. Using triangulation, the device is able to determine its own position as latitude and longitude or on a map. Other information derived from this is direction and speed, calculated from changes in position. Visit the TomTom site for a simple explanation and good graphics on how GPS works (http://www.tomtom.com/howdoesitwork/page.php?ID=8&CID=2&Language=1).

GPS is the most accurate positioning technology, and it provides the most frequent updates. However, it is not always available, particularly indoors. It also consumes the most battery power.

Position acquisition is often not very accurate initially, but it improves over time. The GPS sensor can take several minutes to get a proper position from satellites. Do not make your application full screen so that the status bar is hidden from the user so that they cannot see network activity and signal strength. If ...