GEO vs MEO vs LEO Satellites: Key Characteristics and NTN Design Implications
Different satellites possess different characteristics, and these characteristics have significant implications for Non-Terrestrial Network (NTN) system design, supported applications, and services. The three widely used satellite types—Geostationary Earth Orbit (GEO), Medium Earth Orbit (MEO), and Low Earth Orbit (LEO)—differ significantly in terms of altitude, velocity, orbital period, propagation delay, coverage area, path loss, and deployment requirements.
Understanding these differences is essential when designing and deploying satellite-based NTN systems.
1. Satellite Altitude
One of the most important differences between GEO, MEO, and LEO satellites is their orbital altitude.
GEO satellites: approximately 35,786 km above the Earth's surface.
MEO satellites: approximately 7,000 to 25,000 km.
LEO satellites: approximately 300 to 1,500 km.
GEO satellites operate at a much higher altitude than both MEO and LEO satellites. LEO satellites are positioned closest to Earth, while MEO satellites occupy the intermediate range.
The altitude of a satellite directly influences several NTN characteristics, including:
Propagation delay
Path loss
Coverage area
Satellite mobility
Beam design
Gateway requirements
Supported applications and services
2. Satellite Movement and Doppler Shift
A GEO satellite appears to remain stationary relative to a fixed observer on Earth's surface. In contrast, MEO and LEO satellites appear to move across the sky relative to a fixed observer.
This relative movement between the satellite and the user device creates a Doppler shift in the received signal.
The velocity of MEO and LEO satellites is significantly higher than the typical velocity of user devices communicating with them. Therefore, satellite movement becomes an important factor in NTN radio and system design.
An LEO satellite travels at approximately:
7.78 km/s
Approximately 28,000 km/hour
An MEO satellite travels at approximately:
3.83 km/s
Approximately 13,800 km/hour
The difference in satellite velocity means that LEO and MEO NTN systems must account for significant relative movement between the satellite and the user equipment.
3. Orbital Period
The orbital period also differs considerably among satellite types.
For an MEO satellite, the orbital period generally ranges from approximately 6 to 12 hours, whereas an LEO satellite completes an orbit in approximately 90 minutes.
Therefore, LEO satellites move around the Earth very rapidly compared with GEO satellites, while MEO satellites have intermediate orbital characteristics.
These differences in orbital period and movement have direct implications for:
Mobility management
Handover procedures
Beam management
Tracking
Timing
Frequency synchronization
NTN system operations
4. Satellite Beam Types
Satellite altitude and movement also influence the type of beam used by an NTN system.
Generally:
GEO satellites utilize Earth-fixed beams.
MEO and LEO satellites utilize quasi-Earth-fixed beams or Earth-moving beams.
Because a GEO satellite appears stationary relative to the Earth's surface, maintaining an Earth-fixed coverage pattern is comparatively straightforward.
MEO and LEO satellites, however, continuously move relative to Earth. Their beams therefore require different management approaches.
The detailed characteristics of Earth-fixed, quasi-Earth-fixed, and Earth-moving beams are important considerations in NTN system design.
5. Propagation Delay
The propagation delay between a user device and a satellite is strongly influenced by the satellite's altitude.
Because GEO satellites are located much farther from Earth than MEO and LEO satellites, GEO-based NTN systems experience significantly higher propagation delays.
Typical one-way propagation delays are approximately:
Satellite Type | Approximate One-Way Propagation Delay |
GEO | ~119.3 ms |
MEO | ~23.3–83.3 ms |
LEO | ~1–5 ms |
The much larger distance between a GEO satellite and a user device therefore results in significantly greater propagation delay.
This delay is an important consideration when selecting NTN technologies and applications. Services that require low latency may benefit more from LEO-based systems, while GEO systems are more appropriate for applications that can tolerate higher delays.
6. Propagation Path Loss in NTN
Another major consideration is propagation path loss.
Terrestrial Networks (TNs) typically have considerable clutter and obstruction between the transmitter and receiver. Buildings, trees, terrain, and other objects can create a Non-Line-of-Sight (NLOS) propagation environment.
This can result in significant signal attenuation.
For example, the path loss exponent used to characterize distance-based path loss in a terrestrial environment can be relatively high, such as:
n ≈ 3.5
In contrast, the propagation path between a user device and an NTN platform tends to be more Line-of-Sight (LOS).
Under free-space propagation conditions, the path loss exponent is approximately:
n = 2
Therefore, from the perspective of the propagation environment, NTN can provide a more benign radio environment than a typical terrestrial network.
However, this does not mean that NTN always experiences lower overall path loss.
The transmitter and receiver in an NTN system are separated by a much larger distance than in a terrestrial network. This very large distance can produce substantial path loss.
7. GEO, MEO, and LEO Path Loss Comparison
The satellite's altitude has a direct impact on path loss.
A GEO satellite-based NTN generally experiences the largest path loss because of its extremely high altitude.
The path loss decreases as satellite altitude decreases:
GEO → highest path loss
MEO → lower path loss
LEO → lowest path loss
Thus, among these three satellite types, LEO satellites generally provide the most favorable link budget from a distance perspective.
However, link design must consider many other factors, including antenna characteristics, frequency, atmospheric effects, transmit power, satellite payload, and beam configuration.
8. Coverage Area
Satellite altitude also has a major influence on coverage area.
Because LEO satellites are much closer to Earth than GEO satellites, an individual LEO satellite covers a relatively smaller geographical area.
MEO satellites provide larger coverage than LEO satellites, while GEO satellites can provide extremely large coverage areas.
For LEO and MEO systems, the largest dimension of an elliptical beam can typically range from approximately 100 to 1,000 km, depending on the system configuration.
Hundreds or even thousands of LEO satellites may be required for global coverage.
In comparison, approximately six MEO satellites or three GEO satellites can provide coverage of the entire Earth under the simplified coverage assumptions described for these systems.
9. LEO Satellite Constellations
The requirement for many LEO satellites has led to the development of large satellite constellations.
For example:
OneWeb's planned LEO satellite system has been described as consisting of more than 600 LEO satellites.
Starlink has applied for authorization to deploy more than 40,000 LEO satellites.
Large LEO constellations make it possible to provide continuous and wide-area coverage while taking advantage of the lower altitude and lower propagation delay of LEO satellites.
LEO satellites can also provide suitable radio coverage in polar regions, making them particularly useful for extending connectivity to areas that are difficult to serve through conventional terrestrial infrastructure.
10. Earth Gateways and NTN Connectivity
Satellites use Earth gateways to connect user devices to terrestrial networks and services such as the Internet.
The number of gateways required depends on several factors, including:
Satellite beam coverage
Satellite altitude
Satellite mobility
Network architecture
Traffic requirements
Because GEO satellites provide very large coverage areas and remain effectively stationary relative to Earth, fewer Earth gateways may be sufficient for a GEO-based NTN.
In contrast, LEO satellites have smaller coverage areas and move rapidly relative to Earth. Therefore, an LEO-based NTN generally requires a larger number of Earth gateways to support network connectivity and traffic requirements.
11. Satellite Type and Supported Services
Different satellite orbits are suitable for different types of applications.
GEO Satellites
GEO satellites are generally suitable for:
Relatively low-rate services
Delay-tolerant applications
Large-area coverage
Broadcast-type services
Their major advantage is extremely wide coverage from a small number of satellites.
However, their high altitude results in significant propagation delay and path loss.
MEO Satellites
MEO satellites provide an intermediate solution between GEO and LEO.
They can support:
Medium-rate services
Medium-latency applications
Larger coverage than LEO
Lower latency than GEO
LEO Satellites
LEO satellites are generally suitable for:
Relatively higher-rate services
Low-latency applications
Broadband connectivity
Wide-area connectivity using large constellations
Their low altitude provides lower propagation delay and lower path loss compared with GEO and MEO systems.
12. LEO Satellite Lifetime
LEO satellites typically have a shorter operational lifetime than GEO satellites.
For example, an LEO satellite may have a lifespan of approximately five years, although the actual lifetime depends on the satellite design, orbit, mission requirements, and operating environment.
One reason for the shorter lifespan is the harsher environmental conditions experienced in LEO, including:
Radiation
Atmospheric drag
Orbital environmental effects
Despite the shorter lifespan, LEO satellites offer important advantages in terms of manufacturing and deployment.
13. Smaller and Cost-Efficient LEO Satellites
LEO satellites can be relatively small and lightweight.
An LEO satellite's dimensions may be less than one meter, while nanosatellites can have dimensions of only a few dozen centimeters.
Their smaller size and lower mass can contribute to reduced manufacturing and deployment costs.
Another important advantage is that multiple LEO satellites can be launched during a single launch mission using a larger rocket.
Furthermore, LEO satellites do not require the same high launch energy needed to place satellites into much higher orbits.
As a result, the launch and deployment cost of LEO satellite systems can be reduced.
14. Overall Comparison of GEO, MEO, and LEO
Characteristic | GEO | MEO | LEO |
Altitude | ~35,786 km | ~7,000–25,000 km | ~300–1,500 km |
Relative Movement | Appears stationary | Moving | Moving rapidly |
Approx. Velocity | Very low relative to Earth | ~3.83 km/s | ~7.78 km/s |
Orbital Period | ~24 hours | ~6–12 hours | ~90 minutes |
One-Way Delay | ~119.3 ms | ~23.3–83.3 ms | ~1–5 ms |
Path Loss | Highest | Medium | Lowest |
Coverage per Satellite | Very large | Large | Smaller |
Beam Type | Earth-fixed | Quasi-Earth-fixed / Earth-moving | Quasi-Earth-fixed / Earth-moving |
Typical Service | Low-rate, delay-tolerant | Medium-rate, medium-latency | Higher-rate, low-latency |
Number Required for Global Coverage | Very few | Several | Hundreds/thousands |
Satellite Size | Generally larger | Intermediate | Small/lightweight possible |
Conclusion
GEO, MEO, and LEO satellites have fundamentally different characteristics, and these differences strongly influence the design and operation of Non-Terrestrial Networks.
GEO satellites provide extremely large coverage areas and require relatively few satellites, but their high altitude creates significant propagation delay and path loss.
MEO satellites provide an intermediate solution, offering a balance between coverage, latency, and path loss.
LEO satellites operate much closer to Earth, providing lower propagation delay and lower path loss. However, their smaller coverage areas and high orbital velocity require large constellations, sophisticated mobility management, and appropriate gateway infrastructure.
Therefore, there is no single satellite orbit that is ideal for every NTN application. The selection between GEO, MEO, and LEO depends on factors such as coverage requirements, latency, data rate, path loss, mobility, satellite cost, gateway infrastructure, and the target application or service.
Understanding these orbital characteristics is essential for engineers and telecom professionals working with modern 5G NTN and future 6G integrated terrestrial–non-terrestrial networks.
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