Geosynchronous Satellites

1Geosynchronous Satellites

1. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering Satellite Communication Bangla Tutorial

2. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering 5.Advantages and Disadvantages of Geosynchronous Satellites 1.Geosynchronous Satellites 2.Geosynchronous Satellites Orbital Velocity 3.Round-Trip Time Delay of Geosynchronous Satellites 4.Clarke Orbit

3. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering 1.Geosynchronous Satellites A geosynchronous orbit is a high Earth orbit that allows satellites to match Earth's rotation. Located at 22,236 miles (35,786 kilometers) above Earth's equator, this position is a valuable spot for monitoring weather, communications and surveillance Geosynchronous satellite is placed in the geosynchronous orbit with an orbital period matching the Earth's rotation period. These satellites take 24 hours to complete one rotation around the earth. 

4. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering 2.Geosynchronous Satellites Orbital Velocity The circumference (C) of a geosynchronous orbit is C= 2π(42,164 km) =264,790 km Therefore, the velocity (v) of a geosynchronous satellite is v= =11.033km/ hr or v ≈ 6840 mph  

5. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering 3.Round-Trip Time Delay of Geosynchronous Satellites The round-trip propagation delay between a satellite and an earth station located directly below it is t= = =238 ms  

6. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering 4.Clarke Orbit A geosynchronous earth orbit is sometimes referred to as the Clarke orbit or Clarke belt, after Arthur C. Clarke, who first suggested its existence in 1945 and proposed its use for communications satellites. Clarke was an engineer, a scientist, and a science fiction author who wrote several books including 2001: A Space Odyssey.

7. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering The advantages of geosynchronous satellites are as follows: Geosynchronous satellites remain almost stationary in respect to a given earth station. Consequently, expensive tracking equipment is not required at the earth stations. 2. Geosynchronous satellites are available to all earth stations within their shadow 100% of the time. The shadow of a satellite includes all the earth stations that have a line-of- sight path to it and lie within the radiation pattern of the satellite’s antennas. 3. There is no need to switch from one geosynchronous satellite to another as they orbit overhead. Consequently, there are no transmission breaks due to switching times. 4. The effects of Doppler shift are negligible The advantages of geosynchronous satellites

8. AL-AMIN Jatiya Kabi Kazi Nazrul Islam University Department of Electrical & Electronic Engineering The disadvantages of geosynchronous satellites are as follows: Geosynchronous satellites require sophisticated and heavy propulsion devices onboard to keep them in a fixed orbit. High-altitude geosynchronous satellites introduce much longer propagation delays. The round-trip propagation delay between two earth stations through a geosynchronous satellite is between 500 ms and 600 ms. Geosynchronous satellites require higher transmit powers and more sensitive receivers because of the longer distances and greater path losses. High-precision spacemanship is required to place a geosynchronous satellite into orbit and to keep it there