APRS
APRS : Automatic Position Reporting System is a modern component where a device such as Global Positioning System is fitted to a wireless transmitting device such that the location of the device is constantly monitored without human intervention. Modern Amateur (Ham) Radio Trans-Receiver are fitted with APRS so that a digital longitude, latitude, altitude and speed (if travelling) is constantly transmitted if the equipment is kept on - so the person need not keep giving his location. This is a very useful device for Search & Rescue - Tracking