by Sam Ralpala GPS handheld devices are one of the most awesome technological innovations in the modern age. They vary in size, weight and features, but they are used for one main purpose: to calculate ground position and velocity. This is done through GPS receivers that intercept signals from the earth-orbiting satellites. In a nutshell, GPS (Global Positioning System) navigation system tracks exactly where a person or object is located. Devices that use GPS technology receive data from num