Global Positioning System (GPS): As we know GPS is widely used as a navigation system, not only in transportation systems, it can also be found in mobile phones and many other electronic devices. How it works: The GPS is satellite-based navigation system made up of a network of 24 satellites placed in orbit around the earth by the U.S. Department of Defense.Each satellite has a precise orbit and circle the earth twice a day. GPS receivers receive data from these satellites and use triangulation to calculate the position of the receiver and show it on the devices electronic map. The receivers found in vehicles can record the position of the vehicle continuously and therefore calculate the speed of the vehicle and position. Data Collected: Instantaneous speed, average running speed, distance traveled and travel time. Advantages: Inexpensive,easy to install and operate and works under all weather and lighting conditions. Disadvantages: Receivers provide only vehicle specific data, where data must be gathered from all vehicles in the traffic stream and also GPS signals can be obstructed by tall buildings and trees.
Posted on: Sat, 09 Nov 2013 18:16:36 +0000