![What does GPS stand for ? & What does GIS stand for ? ,[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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How gps works
- 1. How Does GPS Work?
- 6. How Does GPS Work?
- 9. Example X Y Z
- 10. 3-D Trilateration 1 Satellite 2 Satellites
- 11. 3 Satellites
- 13. Example
- 14. Map Page Compass Page
- 15. Trip Page Satellites Page
- 16. Thank You For Listening
Editor's Notes
- GPS stands for Global Positioning System. It made up of a network of 24 satellites placed into orbit. It works anywhere in the world, 24 hours a day, in all weather conditions, and on land, air or sea. The best part is that it is FREE to use! GIS is a computer system for storing, analyzing and displaying information related to positions on the Earth's surface
- GPS satellite weighs approximately 1 Ton . It is powered by solar energy and it has backup batteries for emergencies. these Satellites are orbiting 20 000 km above the Earth high in the sky. Each satellite circles the Earth twice a day.
- When GPS satellite circles the earth, it transmits radio signal to the earth. Each signal is encoded with information used to determine the receiver’s location. The signal transmission includes the time the signal was sent and the satellite’s location in space. This signal travels at the speed of light. Receivers on earth receive this signal. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position by using a process called trilateration. Once the user's position has been determined, it’s possible to calculate other information, such as speed, trip distance, distance to destination, sunrise and sunset time and more.
- GPS uses a process called trilateration to determine a precise location. Trilateration is the process of measuring the distance from at least three satellites to determine a location on earth. Three satellites calculate a 2D position while four or more satellites calculate a 3D position. 2D positions consist of latitude and longitude measurements. 3D position contains both latitude and longitude in addition to altitude measurements. The differences between these two is that a 2D position can track movement, while a 3D position can calculate speed, bearing, trip distance, distance to destination, sunrise/sunset, etc.
- You have no idea where you are. You ask someone and he say you are 250 Km from X. Someone else says you are 350 Km from Y. Another person tells you that you are 150 Km from Z. Now, if you give this information to a person who know where is X, Y and Z then he will know where you are.
- . One satellite can determine a receiver’s position somewhere on a sphere. Two satellites narrow the position down to a circle where the two spheres intersect. Three satellites locate the position to one of two points at the intersection of all three spheres. The second point is automatically ruled out because it is located somewhere in space.
- The compass page show the direction you. In order for this to work, you must be moving! The Map page show you where you are.
- The satellite page show you the sky view (the view if you were looking straight up). the blue circles are satellites that have acquired a signal. The trip page contains your travel information.