GLOBAL POSITIONING SYSTEM
Appendix A: Bibliography
1. Trying to figure out where you are and where you're going to is probably one of man's oldest pastimes. Navigation and positioning are crucial to so many activities and throughout the years the task of navigating and positioning was tried being simplified with all kinds of technologies but most of them have had some disadvantage. In 1974 the U.S. Air Force developed a satellite-based navigation system which cost them $12 billion and provides highly accurate navigation information to military forces around the world. The system is called the Global Positioning System (GPS) but is formally known as the NAVSTAR (Navigation Satellite Timing and Ranging) Global Positioning System. In addition, Russia maintains a constellation called GLONASS (Global Navigation Satellite System), while the European Union is developing its own version of GPS known as Galileo.
2. The Navstar GPS system is a worldwide space-based radio navigation system that sends and receives specially coded satellite radio signals. A GPS receiver acquires these signals and processes them, enabling the receiver to compute accurate, three-dimensional position, velocity and time, 24 hours a day, in any weather conditions anywhere in the world for free. The Navstar GPS system consists of three major segments: the space segment, the control segment, and the user segment. The space segment is made up of a network of 24 satellites placed into six orbital planes, requiring a minimum of four satellites in each to operate. These 24 GPS satellites orbit the earth twice a day in a specific pattern. They travel at approximately 7000 miles per hour at about 12000 miles above the earth’s surface. These satellites are spaced so that a GPS receiver anywhere in the world can receive signals from at least four of them. The GPS satellites are powered by solar energy. When the satellite is in the earth’s shadow and solar energy is unavailable,...