OTHER SOFTWARE PROGRAMS 12 GLOBAL POSITIONING SYSTEM (GPS) Answer these questions. a. What different experiences/activities you have/do in your daily routine do you think hide a computer? b. Do you use any technology at school or at home for learning? bearing: rilevamento to broadcast: trasmettere compass: bussola dashboard: cruscotto to ensure: assicurare ice sheet: ghiacciaio continentale on the move: in movimento whereabouts: posizione windshield: parabrezza My GPS asked me how much I loved it. I replied: Well, I d be lost without you. The Global Positioning System (GPS) is made up by approximately 30 well-spaced satellites in orbit around the Earth. The satellites make it possible for people with ground receivers to pinpoint their geographical location. The location accuracy varies, according to the equipment, from 10 to 100 metres. However, with militaryapproved equipment, the approximation can be reduced to 1 metre. The owner and operator of the GPS system is the US Department of Defense, but the system is made available for general use around the world. 21 GPS satellites and three spare satellites are in orbit at 10,600 miles above the Triangulation Earth. They are spaced in such a way as to ensure that, from any point on Earth, four satellites will be above the horizon. Each satellite contains a computer, an atomic clock and a radio. With an understanding of its own orbit and the help of the clock, the satellite continually broadcasts its changing position in time. Moreover, each satellite checks its own sense of time and position with a ground station once a day and makes any minor corrections that may be necessary. Any GPS receiver on the ground contains a computer that triangulates its own position by getting bearings from three of the four satellites. The result of this triangulation is provided in the form of a geographic position expressed in longitude and latitude. If the receivers are also equipped with a display screen that shows maps, e.g. a smartphone or tablet, the position can be shown on a map. If a fourth satellite can be received, the receiver can also figure out the altitude as well as the geographical position. In case of movement, the receiver can also calculate the speed and direction and give estimated times of arrival at a specified destination. The main uses of GPS are in science. It provides data that has never been available before, as regards both quantity and accuracy. At the moment, it is being used to measure the movement of the arctic ice sheets, the Earth s tectonic plates, and volcanic activity. However, as the cost has become relatively low, almost anyone can own a GPS receiver. Mobile GPS technology in smartphones enables the end users to receive navigating instructions via a global positioning system process called trilateration. A built-in GPS receiver communicates with an array of satellites which provides navigation instructions. Technologically advanced smartphones can identify individual streets and places on maps and provide narrated tracking capability. 172 Module 4 FLOWCHARTING