Navigating at the Speed of Satellites
Figure 1. The Roentgen Satellite (ROSAT) is an Earth-Orbiting X-ray Observatory.Copyright http://heasarc.gsfc.nasa.gov/docs/xte/xte_1st.html
For thousands of years, navigators have looked to the sky for direction. Today, celestial navigation has simply switched from using natural objects to human-created satellites. A constellation of satellites, called the Global Positioning System, and hand-held receivers allow for very accurate navigation. In this lesson, students investigate the fundamental concepts of GPS technology — trilateration and using the speed of light to calculate distances.
Creating GPS required contributions from many engineering disciplines. Mechanical engineers created GPS equipment able to perform reliably in the unique environment of space. Electrical engineers designed computers, circuit boards, power systems and wiring. Aerospace engineers determined the satellite arrangement around the Earth and designed their orbits. Software engineers wrote computer programs so that the satellites operate on their own and transmit useful data to Earth receivers.
After this lesson, students should be able to:
- Understand the basic concepts that make GPS work: that distance is determined by knowing the time it takes a signal to travel from a satellite to a receiver.
- Analyze error and its effect on real-world problems
- Understand early navigation technologies and how advancements in technology have improved our ability to navigate
- Recognize that GPS required contributions from many engineering disciplines