your wrong. gps needs satelites. First of all i dont see air balloons in the sky so it must be satelittes. Also it cant be towers. sprint doesnt get service in India when you use your phone there. Maybe becuase towers dont go that far. Explain how one phone company can have their phones work all around the world (satellite phones) when all other companies cant. Dont tell me its the siganl becuase those companies engineers would know that and just change the type of signal. you can explain satellite technology.