Satellite communications Question bank

QUESTION BANK

                     UNIT – I SATELLITE ORBITS

PART - A

1.  Define Satellite Communication.

2.  What is Satellite?

3.  State Kepler’s first law.

4.  State Kepler’s second law.

5.  State Kepler’s third law.

6.  Define apogee and perigee.

7.  What is line of apsides?

8.  Define ascending node and descending node.

9.  Define Inclination.

10.  Define mean anomaly and true anomaly.

11.  Mention the apogee and perigee height.

12.  What is meant by azimuth angle and look angles?

13.  Give the 3 different types of applications with respect to satellite systems.

14.  Mention the 3 regions to allocate the frequency for satellite services.

15.  Give the types of satellite services.

16.  What is mean by DOMSAT, INTELSAT, SARSAT?

17.  Define polar-orbiting satellites.

18.  Give the advantage of geostationary orbit.

19.  Write short notes on station keeping.

20.  What are the geostationary satellites?

21.  What is sun transit outage?

PART-B

1. a) Explain about frequency allocations for satellite services. (10)

(b) Explain about U.S Domsats. (6)

2. Discuss briefly the development of INTELSAT starting from the 1960s through the present. (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)

 1. Explain in detail the geocentric-equatorial coordinate system which is based on the earth’s equatorial plane. (16)

2. Explain in detail about topocentric-horizon coordinate system which is based on the

observer’s horizon plane. (16)

7. Explain in detail about various measure of time. (16

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. Write short notes on station keeping.

7. What is meant by Pitch angle?

8. What is an propellant?

9. What is an Yaw and zero ‘g’?

10.            Describe the spin stabilized satellites.

11.            What is meant by frequency reuse?

12.            What is meant by spot beam antenna?

13.            What is meant by momentum wheel stabilization?

14.            What is polarization interleaving?

15.            Define S/N ratio.

16.            What is noise weighting?

17.            What is noise power spectral density?

18.            What is an inter modulation noise?

19.            What is an antenna loss?

20.            Define sky noise.

21.            Define noise factor.

22.            What is TWTA?

23.            What is an OMT?

PART-B

1. Explain in detail about antenna look angles and the polar mount antenna. (16)

2. Explain about Earth eclipse of satellite and sun transit outage. (16)

3. Explain about launching orbits. (16)

4. Explain what is meant by satellite attitude and briefly describe two forms of attitude Control . (16)

5. Draw the block diagram of TT&C and explain its blocks. (16)

6. Describe briefly the most common type of high-power amplifying device used aboard a communication satellite. (16)

7. Explain about wideband receiver and advanced Tiros-N spacecraft. (16)

8. Describe briefly the antenna subsystem and Anik-E. (16)

9. Explain in detail about thermal control and Morelos. (16)

UNIT – III SATELLITE ACCESS

PART-A

1. What is a single mode of operation?

2. What are the methods of multiple access techniques?

3. What is an CDMA?

4. What is SCPC?

5. What is a thin route service?

6. What is an important feature of Intelsat SCPC system?

7. What is an TDMA? What are the advantages?

8. What is preamble?

9. Define guard time.

10.            What is meant by decoding quenching?

11.            What is meant by direct closed loop feedback?

12.            What is meant by feedback closed loop control?

13.            Define frame efficiency.

14.            What is meant by digital speech interpolation?

15.            What is meant by telephone load activity factor?

16.            What are the types of digital speech interpolation?

17.            What is meant by freeze out?

18.            What is DSI?

19.            What are the advantages of SPEC method over DSI method?

20.            Define satellite switched TDMA?

21.            What is SS / TDMA?

22.            What is processing gain?

23.            What is burst code word?

24.            What is meant by burst position acquisition?

25.            What is an single access?

26.            What is an multiple access technique?

27.            What is meant by frequency reuse?

28.            What is meant by space division multiple access?

29.            What is an error detecting code?

30.            What are the limitations of FDMA-satellite access?

31.            Write about pre-assigned TDMA satellite access.

32.            Write about demand assigned TDMA satellite access.

PART-B

1. Explain with an example the type of traffic route where single access is used. (16)

2. Explain in detail about FDMA and show how this differs from FDM. (16)

3. Explain in detail the operation of a preassigned SCPC network. (16)

4. Explain in detail the operation of the spade system of demand assignment. What is the function of the common signaling channel? (16)

5. Describe the general operating principles of a TDMA network. Show how the transmission bit rate is related to the input bit rate. (16)

6. Explain the need for reference burst and preamble and postamble in a TDMA System . (16)

7. Explain in detail about network synchronization with neat sketch. (16)

8. Define and explain the terms carrier recovery, bit-time recovery, traffic data, frame efficiency and channel capacity. (16)

9. Explain in detail about speech interpolation and prediction. (16)

10.            Explain in detail about satellite switched TDMA. (16)

11.            Describe briefly about on board signal processing for FDMA/TDM operation. (16)

12.            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)

13.            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

PART-A

1. Define earth segment.

2. Give the difference between KU-band and the C-band receive only systems.

3. What is mean by ODU and IDU.

4. Explain about MATV system.

5. Write about CATV system.

6. Define S/N ratio.

7. What is noise weighting?

8. What is an EIRP?

9. What is noise power spectral density?

10.            What is an inter modulation noise?

11.            What is an antenna loss?

12.            Define noise factor.

13.            A satellite downlink at 12 GHz operates with a transmit power of 6 W and an antenna gain of 48.2 dB. Calculate the EIRP in dBW.

14.            The range between a ground station and a satellite is 42000 km. Calculate the free space loss a frequency of 6 GHz.

15.            An antenna has a noise temperature of 35 K and it is matched into a receiver which has a noise temperature of 100 K. Calculate the noise power density and the noise power for a BW of 36 MHz.

16.            Define Saturation flux density.

17.            Write the equations of losses for clear sky conditions.

18.            What are the types of antenna losses?

19.            Define sky noise.

20.            What is an Apsorptive n/w?

PART-B

1. With the aid of a block schematic, briefly describe the functioning of the receive only home TV systems. (16)

2. Describe and compare the MATV and CATV systems. (16)

3. With the relevant expression explain in detail about transmission losses. (16)

4. Explain the classifications of system noise temperature. (16)

5. Explain uplink satellite circuit. (16)

6. Explain downlink satellite circuit. (16)

7. Describe briefly about the rains effects. (16)

8. Explain about inter-satellite link. (16)

UNIT – V SATELLITE APPLICATIONS

PART-A

1. Give the 3 different types of applications with respect to satellite systems.

2. Mention the 3 regions to allocate the frequency for satellite services.

3. Give the types of satellite services.

4. What is mean by DOMSAT, INTELSAT, SARSAT?

5. What are the applications of Radarsat?

6. What is ECEF?

7. What is dilution of precision?

8. What is PDOP?

8. What is DBS?

9. Give the frequency range of US DBS systems with high power satellites.

10.            Give the frequency range of US DBS systems with medium power satellites.

11.            What is DTH?

12.            Write about bit rates for digital television.

13.            Give the satellite mobile services.

14.            What is GCC and GEC?

15.            What is INMARSAT?

16.            List out the regions covered by INMARSAT.

17.            What is INSAT?

18.            List out the INSAT series.

19.            What is GSM?

20.            What is GPRS?

21.            Define DAB.

22.            What is DVB?

23.            What is GRAMSAT?

PART-B

1. Describe briefly the video compression process used in MPEG-2. (16)

2. Explain about indoor and outdoor unit of home receiver. (16)

3. Explain about frequencies and polarization, transponder capacity and bit rates for digital television. (16)

4. Explain in detail about satellite mobile services. (16)

5. Describe the operation of typical VSAT system. State briefly where VSAT systems and find widest applications. (16)

6. Describe the main features of Radarsat. Explain what is meant by dawn to dusk orbit and why the Radarsat follows such on orbit. (16)

7.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?

8. Describe the main features and services offered by the orbcomm satellite system.

How do these services offered by geostationary satellites and terrestrial cellular systems?