In satellite communications, which statements are true for a geostationary satellite used by communication systems?

Introduction / Context:
Geostationary Earth Orbit (GEO) satellites are the backbone of many broadcast and telecommunications services. Their unique orbital characteristics allow ground antennas to point at a fixed position in the sky, simplifying deployment and maintenance. Knowing the defining properties of GEO satellites is essential for understanding coverage, latency, and link budgeting.

Given Data / Assumptions:

• The term ‘‘geostationary’’ refers to a satellite that appears motionless to a ground observer.
• We consider standard GEO altitude and orbital plane characteristics.
• We are not discussing Medium Earth Orbit (MEO) or Low Earth Orbit (LEO) constellations.

Concept / Approach:
A geostationary satellite orbits at approximately 35,786 km above mean sea level in the equatorial plane. It has an orbital period equal to the Earth’s rotational period (sidereal day). Because it orbits in the same direction as Earth’s rotation and at the correct altitude and inclination (0 degrees), it maintains a constant position relative to the Earth’s surface.

Step-by-Step Solution:

Verification / Alternative check:
Observe fixed satellite TV dishes: they are not motorized because GEO satellites remain in a fixed sky position. Coverage maps also show GEO satellites centered above the equator with footprints spanning large regions.

Why Other Options Are Wrong:

• Picking any single statement ignores other equally true properties.
• ‘‘None of the above’’ is incorrect since each statement reflects GEO fundamentals.

Common Pitfalls:
Confusing ‘‘geosynchronous’’ with ‘‘geostationary’’: geosynchronous matches Earth’s period but may have inclination or eccentricity, causing figure-8 ground tracks. Geostationary is the special case with zero inclination and circular orbit over the equator.

Final Answer:
All of the above