I am completely new to Android and I have the following questions: 1) Do Android phones have a built-in GPS receiver? 2) What happens to Android phones when GPS signals are not available? How is location data collected then? 3) In what format is location data stored in Android phones? 4) Is it possible to write a Java application which takes the GPS data and the location data when GPS signals are not available and integrate the two types of data...also, the application should transmit the data over GSM/GPRS network!