M.Sc. (Semester IV) (CBCS) Examination Nov/Dec-2018
Electronics Science
SATELLITE COMMUNICATION
Time: 2½ Hours Max. Marks: 70
Instructions: Q.1 and Q.2 are compulsory
Answer any three questions from Q.3 to Q.7.
All questions carry equal marks.
Use of nonprogrammable calculator is allowed.
Q.1 Select the most correct alternative. 14
orbit is closed to the surface of the earth.
LEO MEO
GEO None of these
Square of an orbital period is directly proportional to
the distance between surface of the earth and a satellite.
the square of distance between earth station and a satellite.
eccentricity of an orbit
the cube of an orbital radius
Eccentricity of an ellipse is
Zero One
Between zero and one ∞
A VSAT earth station receiver system uses antenna.
patch gregorian
array horn
Azimuthal angle is AZ 180 if earth station is in northern hemisphere
with satellite to of the earth station.
south west south east
north west north east
Each satellite carries transponders.
two eight
four none of the above
The change in received frequency and transmitted frequency is
range variation transit outage
doppler shift effect orbital perturbation
Which of the following is an orbital element satellite?
semi-major axis argument of perigee
time of perigee all of the above
EIRP is the product of and
time and distance frequency and power
gain and power area and efficiency
10) developed an analog DBS-TV service in US.
Primestar Echostar
SDARS Globalstar
11) A westerly directed orbit of satellite is
prograde critical mode
retrograde stand-alone mode
12) The frequency band of DBS TV in ITU Region-1 is
10.7 12.75 GHz 1.22-1.27 GHz
11.7-12.2 GHz 2.34-2.34 GHz
13) constellation provides location and time information in all
weather conditions.
Teledesic Iridium
GPS Skybridge
14) Geo satellite are more costlier because,
greater altitude greater weight
lower altitude apogee point distance
Q.2 Answer the following.
State Keplers laws of planetary motion. 05
Explain the downlink design. 05
What is sun transit outage? 04
Q.3 Explain the terms centrifugal and centripetal forces with regard to satellite
in an orbit. Derive an expression of orbital period.
10
Orbital period of satellite is once per sidereal day of 23h 56min 4.09s.
Calculate the orbital radius of a satellite.
04
Q.4 Explain AOCS subsystem with a suitable sketch. 10
What are the types of redundancy? 04
Q.5 Explain the basic transmission theory and hence derive an expression for
a power received by a real antenna with a physical receiving area
and effective aperture area Explain what are link equation and path
loss?
10
A satellite at a distance of 40000 km from a point on the earth's surface,
radiates a power of 10W from an antenna with a gain of 17dB in the
direction of the observer. Find the flux density at the receiving point, and
the power received by an antenna at this point with an effective area of
10m2
.
04
Q.6 What is VSAT? Explain the different VSAT network architectures. 10
Write a note on sun synchronous orbit. 04
Q.7 Explain what is meant by GPS. Describe various segments of GPS. 10
Write a note on satellite radio broadcasting. 04