Day 2: Transponder & TT&C

Question 1

A communication path or ‘channel’ rather than a specific piece of equipment

Answer 1

Transponder

Question 2

What are the primary functions of transponders?

Answer 2

• Amplifying the received input signal
• Translates the frequency of the input signal to avoid the interference between the transmitted and received signals

Question 3

Regenerative / On-Board XPDR adds what compared to transparent/bent pipe?

Answer 3

FEC/signal correction

Question 4

Advantages of Regenerative / On-board XPDR

Answer 4

• Better link quality
• Harder to jam
• Direct connection between terminals

Question 5

Path management for specified communication signals

Answer 5

Channelizing

Question 6

Channelizing Techniques

Answer 6

• Fan in
• Fan out

Question 7

Digital signal processor that routes between any uplink subchannel to any downlink subchannel

Answer 7

Digital channelizer

Question 8

Transmission path from a satellite to Earth stations

Answer 8

Downlink footprint

Question 9

Transmission path from an Earth station (ground-based transmitter) to a satellite

Answer 9

Uplink footprint

Question 10

A location is within the uplink footprint means it’s in the downlink footprint

Answer 10

False

Question 11

Large footprint - covers 1/3 of earth

Answer 11

Earth Coverage Beam Advantage

Question 12

Does not cover polar regions

Answer 12

Earth Coverage Beam Disadvantage

Question 13

Easy to place a jammer in the footprint

Answer 13

Earth Coverage Beam Disadvantage

Question 14

More resistant to jamming since individual elements can be switched on/off

Answer 14

Multi Beam Arrays

Question 15

Cannot follow mobile forces

Answer 15

Fixed Spot Beams

Question 16

Can follow mobile forces and shape to geographical location

Answer 16

Steerable Spot Beams

Question 17

Much more complex design, more costly

Answer 17

Phased Array

Question 18

Information conveyed by satellite subsystem to the TT&C subsystem (e.g. resources, health, altitude, mode, payload data, etc.) where it is then encoded and transmitted to a user in space for ground segment

Answer 18

Telemetry

Question 19

A one-way process (downlink only)

Answer 19

Telemetry

Question 20

Used by satellite operators to precisely determine a satellites orbit

Answer 20

Tracking

Question 21

Two-way ranging from ground station common

Answer 21

Tracking

Question 22

Permits the satellite to be reconfigured in response to RF signals that are sent from the ground

Answer 22

Command