All about GPS Satellite
Satellites are behind this miracle of modern times.
There is a satellite based navigation system which is knowns as GPS (Global Positioning System). It provides time and location-based information to a GPS receiver, located anywhere on or near the Earth’s surface. GPS works in all weather conditions, provided there is an uninterrupted line of sight communication with 4 or more GPS satellites.
The Global Positioning System (GPS) is a technological marvel made possible by a group of satellites orbiting the Earth. It transmits precise signals, allowing the GPS receiver to calculate and display accurate location, speed, and time information to the user. GPS is owned by the U.S.
By capturing signals from satellites, GPS receivers are able to use the mathematical principle of tripartite to indicate your location. Additionally to stored the data of road maps, point of interest, and more, GPS receivers are capable of converting location, speed, and time information into a useful display format.
Invention and development of GPS
GPS was originally created as a military application by the United States Department of Defense (DoD). The system has been active since the early 1980s but began to be useful to ordinary citizens in the late 1990s, supporting it with the advent of consumer devices. Consumer GPS has become a multi-billion dollar industry with a wide range of products, services and Internet-based utilities. As with most technology, its development continues; Although it is a true modern miracle, engineers understand its limitations and work continuously to overcome them.
How GPS Satellite Works:
- Initially when GPS was developed for military use, there were 24 GPS satellites orbiting the Earth every 12 hours at altitudes of 20 to 180 km.
- The 4 GPS satellites were located in each of the 6 orbits with a 60 ° orientation between each other. These orbital planes do not rotate in relation to any star.
- Later, the number of satellites was increased to 32 to improve location accuracy.
- The flight calculation periods are used to identify every GPS receiver.
- The higher the number of satellites in sight of the GPS receiver, the higher the accuracy in determining the receiver’s position.
At any given time, there are at least 4 GPS satellites in sight of a receiver on Earth. Each of these GPS satellites sends information to its current time GPS receiver at a fixed regular instant of time. This information is transmitted to the receiver as a signal that is then intercepted by the receiver device. These signals are radio signals that travel with the speed of light. The distance between the GPS receiver and the satellite is calculated by finding the difference between the time sent from the GPS satellite and the time the GPS receiver receives the signal.
Once the receiver receives signals from at least three satellites, the receiver then indicates its location using a tripartite process. A GPS requires at least 3 satellites to calculate the 2-D position (latitude and longitude on a map). In this case, the GPS receiver assumes that it is located on the mean sea level. However, the receiver needs at least 4 satellites to find the 3-D position (latitude, longitude and altitude).
- GPS works accurately in all weather conditions, around the clock, and around the world.
- There is no membership fee to use the GPS signal.
- GPS receivers are typically accurate to within 15 meters, and newer models that use the Wide Area Augmentation System (WAAS) signal are accurate to within three meters.
- Through dense forests, walls of mountains, skyscrapers, bridges, buildings, etc., GPS signals can be blocked, allowing difficult or impossible GPS navigation.
- Similarly, indoor and underground locations, GPS does not work well.
- Radio interference and the coverage of solar storm may cause gaps to satellite maintenance.
Facts about GPS:
- Two frequencies, used by Military GPS, while only one frequency civilian uses by civilians GPS. This increases accuracy. Dual-frequency GPS devices are available to citizens, but their cost and size make them impractical.
- The US government is engaged in a continuous, multi-dollar-dollar reform and modernization program.
- American taxpayers fund the world’s GPS services, mostly through the Department of Defense. The 2017 budget was about $ 900 million.
- An American joint civilian / military body oversees space-based positioning, the National Executive Committee for Navigation, and Timing, GPS. The US Air Force maintains and operates it.
- As of 2017, 24 GPS satellites orbit the Earth.
- GPS devices are essential for suitability and services that we carry every day, such as cell phones, clocks, computers, weather forecasting, energy distribution, navigation and emergency / disaster response.
- Banking, building and shipping industries to financial markets, agriculture and so on are dependent on GPS accuracy.
- GPS is important for national security. All new military equipment is equipped with GPS.
- GPS informs the world’s air, sea and road transport systems.