SATELLITE COMMUNICATIONS UNIT WISE Important Questions Answers :-
UNIT – I SATELLITE ORBITS
PART – A
2. State Kepler’s three laws.
4. Define apogee and perigee.
5. What is line of apsides?
6. Define ascending node and descending node.
9. Define mean anomaly and true anomaly.
10. A satellite is orbiting in the equatorial plane with a period from perigee to perigee
of 12 hours. Given that the eccentricity is 0.002, calculate the semi-major axis.
Assume earth radius aE = 6378 km.
11. What is meant by azimuth angle and look angles?
12. What is station keeping?
13. Mention the apogee and perigee height.
14. What is sub-satellite point? What is its significance?
15. List out the orbital parameters.
16. What is orbital perturbations?
17. Define Limits of visibility.
18. What is a polar antenna?
19. Give the advantage of geostationary orbit.
20. What is sun transit outage?
1. (a) What are the orbital elements? Explain them. (10)
(b) Discuss about the orbital perturbation. (6)
2. What are look angles? Explain how they are determined? (16)
3. What is meant by polar orbiting? Explain in detail. (16)
4. State Kepler’s three laws of planetary motion. Illustrate in each case their relevance
to artificial satellites orbiting the earth. (16)
5. i) Explain about Geo-stationary & near Geo-stationary orbits. (8)
ii) Determine the limits of visibility for an earth station situated at mean sea level, at
latitude 48.42o
elevation of 5o
6. i) Explain the significance of station keeping. (8)
ii) Discuss about launching orbits. (8)
7. Explain how satellite position are estimated using Sub-satellite points. (16)
8. (a) Explain about frequency allocations for satellite services. (10)
(b) Explain about U.S Domsats. (6)
9. Explain in detail the geocentric-equatorial coordinate system which is based on the
earth’s equatorial plane. (16)
10. Discuss briefly the development of INTELSAT starting from the 1960s through the
present. (16)
north and longitude 89.26o west. Assume a minimum angle of
. (8)
UNIT – II SPACE SEGMENT AND LINK DESIGN
PART-A
1. Give the two segments of basic satellite communication.
2. Write short notes on attitude control system.
3. What is declination?
4. What is meant by payload?
5. What is meant by transponder?
6. Define EIRP.
7. What is meant by Pitch angle?
8. What is propellant?
9. Describe the spin stabilized satellites.
10. What is meant by frequency reuse?
11. What is meant by spot beam antenna?
12. What is meant by momentum wheel stabilization?
13. What is polarization interleaving?
14. Define S/N ratio.
15. What is noise weighting?
16. What is noise power spectral density?
17. What is an inter modulation noise?
18. What is an antenna loss?
19. Define sky noise.
20. Define noise factor.
PART-B
1. Explain satellite attitude and briefly describe two forms of attitude Control. (16)
2. Draw the block diagram of TT&C and explain its blocks. (16)
3. Describe briefly the most common type of high-power amplifying device used aboard
a communication satellite. (16)
4. Explain about uplink satellite circuits. (16)
5. Explain the system noise and Interference in detail. (16)
6. Explain Thermal control and Propulsion in detail. (16)
7. Discuss the effects of rain in satellite propagation. (16)
8. Discuss the satellite downlink analysis. (16)
9. Explain Link budget and E/N calculation. (16)
10. Explain the propagation characteristics and frequency considerations. (16)
UNIT – III SATELLITE ACCESS
PART-A
1. What is CDMA?
2. What is multiple access technique?
3. What is SCPC?
4. What is preamble?
5. Define guard time.
6. What is meant by decoding quenching?
7. Define frame efficiency.
8. What is meant by digital speech interpolation?
9. Define satellite switched TDMA?
10. What is processing gain?
11. What is meant by burst position acquisition?
12. What is burst code word?
13. What is meant by frequency reuse?
14. What are the advantages of SPEC method over DSI method?
15. What are the limitations of FDMA-satellite access?
16. Write about pre-assigned & demand-assigned TDMA satellite access.
17. Define satellite switched TDMA?
18. What is TDMA? What are the advantages?
19. What are the types of digital speech interpolation?
20. What is meant by space division multiple access?
PART-B
1. Explain in detail the operation of a pre-assigned SCPC network. (16)
2. Explain in detail the operation of the spade system of demand assignment. What is
the function of the common signaling channel? (16)
3. Explain the need for reference burst and preamble and post-amble in a TDMA
System. (16)
4. Explain in detail about speech interpolation and prediction. (16)
5. Explain in detail about satellite switched TDMA. (16)
6. Describe in your own words how signal acquisition and tracking are achieved in a
DS/SS system. And also derive the expression for maximal sequence. (16)
7. Define and explain the terms carrier recovery, bit-time recovery, traffic data,
frame efficiency and channel capacity. (16)
8. Describe briefly about on board signal processing for FDMA/TDM operation.
9. Describe the general operating principles of a TDMA network. Show how the
transmission bit rate is related to the input bit rate. (16)
10. Explain the principle behind spectrum spreading and dispreading and how this is
used to minimize interference in a CDMA system. Also determine the throughput
efficiency of the system. (16)
UNIT – IV EARTH SEGMENT
1. Define earth segment.
2. Give the difference between KU-band and the C-band receive only systems.
3. What is Polarization interleaving?
4. What is MATV system?
5. Write about CATV system.
6. Discuss about Low noise block.
7. Draw the home receiver IDU block diagram.
8. What is the use of VSSB in conventional TV?
9. Write the EIRP equation.
10. What type of modulation technique used in Earth station receiver unit?
11. What is the need for demultiplexer in Home receiver indoor unit?
12. What is HPA?
13. What is the need for diplexer?
14. How the tracking is achieved?
15. What is Antenna mounting?
16. List out the types of Antenna mounting.
17. Write the basic requirements of an earth station antenna.
18. What is LHCP and RHCP?
19. What is TVRO?
20. Compare MATV & CATV.
1. With the aid of a block schematic, briefly describe the functioning of the Receive only
home TV systems. (16)
2. Describe MATV systems in detail (16)
3. Explain CATV systems with suitable diagrams. (16)
4. Explain about the Test Equipment Measurements on G/T & C/No. (16)
5. Compare MATV and CATV with valid points. (16)
6. Explain Terrestrial interface with appropriate diagrams. (16)
7. Explain about indoor and outdoor unit of home receiver. (16)
8. Discuss Earth station technology with relevant diagrams. (16)
9. Discuss EIRP & Antenna Gain measurement details. (16)
10. Explain the Antenna systems in detail. (16)
UNIT – V SATELLITE APPLICATIONS
PART-A
1. What is mean by DOMSAT, INTELSAT, SARSAT?
2. What are the applications of Radarsat?
3. What is dilution of precision?
4. What is PDOP?
5. What is DBS?
6. Give the frequency range of US DBS systems with high power satellites.
7. Give the frequency range of US DBS systems with medium power satellites.
8. What is DTH?
9. Write about bit rates for digital television.
10. Give the satellite mobile services.
11. What is GCC and GEC?
12. What is INMARSAT?
13. List out the regions covered by INMARSAT.
14. What is INSAT?
15. List out the INSAT series.
16. What is GSM?
17. What is GPRS?
18. Define DAB.
19. What is DVB?
20. What is GRAMSAT?
PART-B
1. Describe briefly the video compression process used in MPEG-2. (16)
2. Explain about frequencies and polarization, transponder capacity and bit rates for
digital television. (16)
3. Explain in detail about satellite mobile services. (16)
4. Describe the operation of typical VSAT system. State briefly where VSAT systems
and find widest applications. (16)
5. Explain why a minimum of four satellites are visible at an earth location utilizing the
GPS system for position determination. What does the term dilution of precision
refer to? (16)
6. What is meant by DTH? What are the design issues to be considered for launching
DTH system? (16)
7. Discuss in detail about Global positioning system. (16)
8. Write brief notes on the advantages and disadvantages of using satellites in LEOs,
MEOs and GEOs for mobile satellite communications. (16)
9. Explain DBS in detail with necessary diagrams. (16)
10. Discuss about the satellite navigational systems. (16)