Geostationary satellites are located exactly above the earth’s equator and revolve around the earth in a circular orbit. Its revolving speed and direction (west to east) is exactly same as that of the earth, which makes it look stationary from the earth’s surface. The exact altitude of these satellites above the equator is approximately 36,000 Kilometers (22369 Miles). The phrase geostationary evolves from the fact that this kind of a satellite looks practically stationary in the sky as observed by a person on the earth’s surface. The orbital path of a geostationary satellite is called the Clarke Belt, in honor of Arthur C. Clarke.
A geostationary satellite can be contacted via a directional antenna, typically a little antenna dish, targeted at the location in the sky where the satellite seems to float. These dish antennas can permanently be put in one place and are low-priced compared to tracking antennas. One geostationary satellite can cover approximately 40 percent of the earth's surface area. Three such geostationary satellites, each separated by 120 degrees of longitude, can offer coverage of the complete earth surface area, with the omission of little circular areas situated at the north and south geographic poles. The typical service life expectancy of a geostationary satellite is ten to fifteen years.
Advantages/Disadvantages of Geostationary Satellites
These satellites are placed at high altitude allowing them to inspect the entire earth’s surface area except for small regions at the south and north geographic poles, which significantly helps in meteorological studies. Use of highly directional dish antennas can reduce signal interventions from earth-based sources and from other satellites too
The orbital sector is a really thin loop in the plane of the equator; hence a very small number of satellites can be maintained within this sector without mutual conflicts and collisions. The precise hovering location of a geostationary satellite fluctuates a little over each 24-hour period loop. This fluctuation happens due to the gravitational interference among the satellite, the earth, the sun, the moon, and other planets. Radio signals take roughly 1/4th of a second for a two-way trip to the satellite, resulting in a small but major signal wait. This wait raises the trouble of interactive communication like telephonic conversation.
Application of Geostationary Satellites
Geostationary satellites have modernized and transformed worldwide communications, television broadcasting, meteorological and weather forecasting. It also has a number of significant defense and intelligence applications.
