SSPI Satellite Network Design & Operations 5

Question 1

What is the significance of the 'threshold' in satellite receiver design?

Accepted Answer

The minimum C/N or Eb/N0 below which demodulator performance degrades rapidly

Answer

Below the receiver threshold, bit error rates increase dramatically, causing the link to become unreliable even with small additional degradations.

Question 2

In a satellite network employing MF-TDMA, what does the 'MF' prefix signify?

Accepted Answer

Multiple Frequency — carriers are spread across several frequencies to increase total system capacity

Answer

MF-TDMA combines multiple frequency carriers with time division, allowing scalable capacity allocation across both frequency and time dimensions.

Question 3

Which phenomenon causes a satellite's apparent position to oscillate in a figure-eight pattern over the course of a year?

Accepted Answer

Analemma effect due to combined inclination and eccentricity drift

Answer

The analemma is caused by residual inclination and eccentricity of a nominally geostationary satellite, causing apparent north-south and east-west drift.

Question 4

What type of satellite orbit is best suited for continuous coverage of polar regions that GEO satellites cannot serve?

Accepted Answer

Molniya orbit

Answer

Molniya orbits (highly elliptical, 63.4° inclination) spend most of their time over high latitudes, providing extended coverage of polar regions.

Question 5

What is the primary function of Doppler compensation in a LEO satellite terminal?

Accepted Answer

To correct for the frequency shift caused by the satellite's high orbital velocity relative to the ground station

Answer

LEO satellites move at ~7.5 km/s, causing significant Doppler shifts that must be pre-compensated to maintain accurate carrier frequency at the receiver.

(SSPI) Society of Satellite Professionals International Certification Practice Test

(SSPI) Society of Satellite Professionals International Certification Practice Test

SSPI Satellite Network Design & Operations 5