Comparison Between LEO, MEO, and GEO
Comparison Between LEO, MEO, and GEO: The basic difference Between LEO, MEO, and GEO is based on the distance from the earth to the satellite. But before the differences between LEO, MEO, and GEO, we discuss some basics about them.
Non-Geostationary Orbit Satellite Systems
Satellites can be categorized depending on their altitude above the earth’s surface, these are
- Geostationary Earth Orbit (GEO)
- Medium Earth Orbit (MEO)
- Low Earth Orbit (LEO)
The GEO satellite altitude is of around 36,000 km, MEO satellites altitude is in the range of 10,000 to 15,000 km. and LEO satellites are confined between 500 to 1500 km. MEO and LEO satellites are referred to as Non-Geostationary Orbit (NGSO) satellites.
Geostationary Earth Orbit (GEO)
GEO is also called geosynchronous (or synchronous) orbits, which have 23 h, 56 min., 4.091s, or 24 hours period of revolution but are inclined with respect to the equator. Orbits that are below a mean altitude of about 35,784 km have periods of revolution shorter than 24 hours and hence are termed as non-GEO.
GEO satellite has the ability to provide coverage of an entire hemisphere at one time. Satellites are designed to last only about 15 years in orbit, because of the practical inability to service a satellite in GEO and replenish consumables (Fuel, battery cells, and degraded and failed components).
Medium Earth Orbit (MEO)
An MEO satellite is in orbit somewhere between 8,000 km and 18,000 km above the earth’s surface. MEO satellites are similar to LEO satellites in functionality. The MEO satellites are visible for much longer periods of time than LEO satellites, usually between 2 to 8 hours. MEO satellites have a larger coverage area than LEO satellites.
Low Earth Orbit (LEO)
LEO satellites are much closer to the earth than GEO satellites, ranging from 500 to 1,500 km above the surface. LEO satellites don’t stay in a fixed position relative to the surface and are only visible for 15 to 20 minutes each pass. A network of LEO satellites is necessary for LEO satellites to be useful.
Comparison Between LEO, MEO, and GEO
| Parameter | LEO | MEO | GEO |
| Distance from earth | 100 miles to 300 miles | 6000 miles to 12,000 miles | 19,000 miles to 25,000 miles |
| Rotation period | 1.5 hours | 5 to 12 hours | 24 hours |
| Numbers of satellites required | 30 to 60 | 10 to 20 | 3 to 6 |
| Life time | 5 years | 10 to 15 years | 10 to 15 years |
| Launching cost | Low cost for each satellite | Moderate cost for each satellite | High cost for each satellite |
| Coverage area | Small, therefore hundreds of ground stations are required | Large area, therefore less number of ground stations are required | Much large area, therefore small number of ground stations are required |
| Line of sight time | 0.5 hours | 2 to 4 hours | 24 hours |
| Ellipse interval | Frequency day-night cycle. Satellite remains in darkness 30% of time | Infrequent day-night cycle. Satellite remains in darkness 2% of time | Infrequent day-night cycle. Satellite remains in darkness 1-2% of time |
| Elevation angle variation | Rapidly varying elevation angle | Slowly varying elevation angle | No variation in elevation angle |
| Tracking | Slow speed tracking | Slow speed tracking | Tracking is not required |
| Travelling speed | 17,500 mph | 10,000 mph | 6,879 mph |
| Application | Weather forecasting | Communication and navigation purpose | Telephony, data/TV distribution,mobile communication, broadcasting |
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