PC2: SATCOM and Footprints Flashcards

1
Q

Identify

Utilizes microwave frequencies to exchange voice, data, and video information by either wired or wireless methods

A

Terrestrial Communication

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2
Q

Identify

Employs satellites and Earth ground stations to exchange voice, data, and video information

A

Satellite Communication (SATCOM)

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3
Q

What are the SATCOM Advantages?

A
  • Mobility/Flexibility
  • Beyond Line-of-Sight (LOS)
  • Coverage
  • Cost effective
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4
Q

What are the SATCOM Disadvantages?

A
  • Congestion of frequencies
  • Interference
  • Propagation
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5
Q

What are the SATCOM Applications?

A
  • Radio and TV broadcasting
  • Internet Applications
  • Commercial Communications
  • Military Communications
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6
Q

What is the SATCOM Process?

A
  1. An uplink is established (Earth to satellite)
  2. The satellite amplifies the incoming signal and changes the frequency
  3. Downlink commence (satellite to Earth)
  4. The ground equipment receives the signal
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7
Q

What are the two One-Way Communications?

A
  • Broadcast
  • Multicast
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8
Q

What is the Two-Way Communication?

A

Point-to-Point

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9
Q

What are the 3 SATCOM Segments?

A
  • Ground/User
  • Space
  • Link
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10
Q

Identify

Consist of the ground facilities and antennas required to control the satellite (TT& C) and all terminals

SATCOM Segment

A

Ground/User

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11
Q

Identify

Consist of military and commercial satellites in orbit

SATCOM Segment

A

Space

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12
Q

Identify

Connects the ground and space segment together through the electromagnetic spectrum

SATCOM Segment

A

Link

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13
Q

What are the 3 Earth Station Components?

A
  • Outdoor Unit (ODU)
  • Indoor Unit (IDU)
  • Inter Facility Link (IFL)
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14
Q

Identify

Components or subsystems installed in an outdoor location

Earth Station Component

A

Outdoor Unit (ODU)

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15
Q

Identify

Components or subsystems installed in an indoor location or weatherproof shelter

Earth Station Component

A

Indoor Unit (IDU)

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16
Q

Identify

Cable system to connect an ODU and IDU

Earth Station Component

A

Inter Facility Link (IFL)

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17
Q

Give an example of an Outdoor Unit (ODU)

A
  • Antenna and antenna base
  • Feed horn
  • Filters
  • Low Noise Block (LNB)
  • Block Up Converter (BUC)
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18
Q

Give an example of an Indoor Unit (IDU)

A
  • Modems
  • Satellite Receivers
  • Tracking Devices
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19
Q

Give an example of an Inter Facility Link (IFL)

A
  • RF Signals
  • Monitor and Control (M&C)
  • Power
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20
Q

What are the 3 SATCOM Terminal Types?

A
  • Fixed
  • Transportable
  • Mobile
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21
Q

Identify

In-place

SATCOM Terminal Type

A

Fixed

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22
Q

Identify

Designed to be movable, but once on location remain fixed

SATCOM Terminal Type

A

Transportable

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23
Q

Identify

Land, maritime, aerospace, etc.

SATCOM Terminal Type

A

Mobile

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24
Q

Identify

A circuit which increases the strength of the signal it receives and retransmit it

A

Microwave Repeater

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25
Q

What are multiple channels called?

A

Transponders

They provide bandwidth and power over designated radio frequencies.

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26
Q

“How much we have”

“refers to data capacity of a channel. It is defined as the potential of data which can be transferred in specific period of time”

A

Bandwidth

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27
Q

“How much we actually transmitted”

“refers to measurement of data transferred in a specific time period. It is also termed as effective data rate or payload rate”

A

Throughput

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28
Q

Identify

Any data rate less than 64 kbps

Data Rate Considerations

A

Low Data Rate (LDR)

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29
Q

Identify

Any data rate between 64 kbps and 1536 kbps

Data Rate Considerations

A

Medium Data Rate (MDR)

30
Q

Identify

Any data equal to or greater than 1536 kbps

Data Rate Considerations

A

High Data Rate (HDR)

31
Q

Identify

Provides 8.192 Mbps

Data Rate Considerations

A

Extreme Data Rate (XDR)

32
Q

Identify

A beam which covers a wide area such as the entire continental US (CONUS)

A

Wide Beam

33
Q

Identify

SATCOM terminology to describe the targeting of radio signals from a satellite at a specific point on the earth surface (the use of multiple narrow beams with a focused coverage of a small area)

A

Spot Beams

34
Q

Multi Beam Antenna (MBA)

A
  • Power to each beam is adjustable
  • Have a single aperture (the entire footprint is denied)
35
Q

Identify

  • Reduced transmission delay
  • Reduced launch cost
  • Reduced path loss
  • Lower power
  • Great for mobile cellular services
A

Low Earth Orbit (LEO) Advantages

36
Q

Identify

  • Short visibility from any point on earth (15-20 min.)
  • Ground stations Tracking required
  • Inter-satellite handoffs
  • Potentially large constellations
  • Radiation effects on solar cell and electronics lifetime (Van Allen belt)
  • Need to compensate for Doppler shift
  • Atmospheric drag effects
A

Low Earth Orbit (LEO) Disadvantages

37
Q

Identify

  • Visibility for longer periods than LEO (2-8 hrs.)
  • Larger coverage area than LEO
  • Wider foot print than LEO
  • Fewer satellites than LEO
A

Medium Earth Orbit (MEO) Advantages

38
Q

Identify

  • Transmission delay more than LEO
  • More transmitting power than LEO
  • Exposed to space debris and atmospheric drag
  • Weaker signal than LEO
A

Medium Earth Orbit (MEO) Disadvantages

39
Q

Identify

  • Global view (three satellites)
  • No ground station tracking required
  • No-Inter satellite handoff
  • Almost no Doppler shift
  • 24 hours view of a particular area
A

Geo-synchronous/Geo-stationary Earth Orbit (GEO) Advantages

40
Q

Identify

  • Poor Coverage at high latitudes (cannot see latitudes > 77˚)
  • Heavily regulated by the ITU
  • High transmission latencies
  • Weak received signal
A

Geo-synchronous/Geo-stationary Earth Orbit (GEO) Disadvantages

41
Q

What orbit is the most commonly used in SATCOM?

A

GEO

42
Q

What orbit is used for special applications where coverage of high latitude locations is required?

A

Highly-Elliptical Orbit (HEO)

43
Q

Identify

A ground station that relays data to/from the satellite to the local area network

SATCOM Link Segment

A

Satellite Gateway

It houses the antennas and equipment to convert RF signals to an Internet Protocol (IP) signal for terrestrial connectivity.

Also referred to as a teleport or hub.

44
Q

Identify

Basic strategy used to get a signal around the Earth via satellite

SATCOM Configuration

A

Bent Pipe

Also known as M-Hop

45
Q

Identify

Anti-jam, survivable technique used to get a signal around the Earth via satellite

SATCOM Configuration

A

Crosslinks

46
Q

Identify

  • Mobile applications
  • Employs variety of ground equipment

SATCOM Frequencies

A

L-Band (1-2 GHz)

47
Q

Identify

  • Lower transmission power over wide geographical area
  • Requires larger ground equipment (Antenna 1.8 M)
  • Better on adverse weather on the ground

SATCOM Frequencies

A

C-Band (4-8 GHz)

48
Q

Identify

  • Mainly Military applications
  • Employs variety of ground equipment
  • Less crowded frequency
  • Less affected by adverse weather

SATCOM Frequencies

A

X-Band (8-12 GHz)

49
Q

Identify

  • Higher transmission power over a small geographical area
  • Uses smaller ground equipment (Antennas 0.8-0.9m)
  • Affected by snow and rain

SATCOM Frequencies

A

Ku-band (12-18 GHz)

50
Q

Identify

  • Higher transmission power than Ku
  • High bandwidth services (such as high-speed internet, video conferencing and multimedia applications)
  • Antenna sizes 60 cm-1.2m
  • Affected by snow and rain

SATCOM Frequencies

A

Ka-band (26-40 GHz)

51
Q

Which SATCOM frequency is used for mobility?

A

UHF

52
Q

Which SATCOM frequency provides high data rate?

A

SHF

53
Q

Which SATCOM frequency is used for nuclear survivability?

A

EHF

54
Q

Identify

Uses ground equipment at set locations to receive and transmit satellite signals

SATCOM Services

A

Fixed Satellite Services (FSS)

Supports:
* Majority of domestic and international services
* International internet connectivity
* Private business networks

55
Q

Identify

Uses a variety of transportable receiver and transmitter equipment to provide communications services for land mobile, maritime, and aeronautical users

SATCOM Services

A

Mobile Satellite Services (MSS)

56
Q

Identify

Offers high transmission power for reception using very small ground equipment

SATCOM Services

A

Broadcast Satellite Services (BSS)

BSS is best known for direct-to-consumer TV and broadband application.

57
Q

Identify

Military dedicated Satellite Communications

SATCOM Services

A

Military (MILSATCOM)

Communications Types:
* Narrowband Communications
* Wideband Communications
* Protected Communications

58
Q

Identify

Supports worldwide tactical communications, including in-route contingency communications, in-theater communications, intelligence broadcast, and range extension for combat net radios

SATCOM Services

A

Narrowband Communications

  • UHF Follow-On (UFO)
  • Mobile User Objective System (MUOS)

Operates in the UHF band and commercial L and S bands

59
Q

Identify

Support high data rate communications for the execution of C2, crisis management and intelligence data transfer

SATCOM Services

A
  • Defense Satellite Communications System (DSCS)
  • Wideband Global Satellite (WGS)
  • Non-classified Internet Protocol Network (NIPRNET)
  • SECRET Internet Protocol Network (SIPRNET)
  • Joint Worldwide Intelligence Communications Systems (JWICS)
  • Video teleconferencing (to deployed forces)

Operates in C, Ku, K, Ka, S, and X bands

60
Q

Jam-resistant communications at the strategic, operational, and tactical level

A

Protected Communications

  • Military Strategic and Tactical Relay (MILSTAR)
  • Advanced Extremely High Frequency (AEHF)
  • Enhanced Polar System (EPS)

Operates in EHF (downlink) and EHF (uplink) band

61
Q

Identify

Can be defined as the time it takes for a signal to travel up to a satellite and back down to a receiving station

SATCOM Limitations & Vulnerabilities

A

Transmission Delays

Note: Real-time communications prefer shorter the transmission delays

62
Q

Identify

  • Due to the gravitational pull of the Sun and Moon
  • Largest perturbation concern
  • Most demanding on satellite’s fuel reserves

SATCOM Limitations & Vulnerabilities

A

North-South Perturbations

63
Q

Identify

  • Due to Earth’s triaxiality
  • Affects satellite’s velocity and altitude

SATCOM Limitations & Vulnerabilities

A

East-West Perturbations

64
Q

Identify

Satellite lateral errors can be as much as ± 3˚ at the end of life

SATCOM Limitations & Vulnerabilities

A

Satellite Positioning

65
Q

Identify

There are two solar eclipses (Vernal and Autumnal Equinoxes) for about 6 weeks each year

SATCOM Limitations & Vulnerabilities

A

Solar Outages

Satellites are in the Earth’s shadow for a few minutes to as much as 65 minutes on the day of the equinox

66
Q

Identify

What happens when the satellite eclipses the Sun?

SATCOM Limitations & Vulnerabilities

A

Becomes exposed to background noise build up

67
Q

Identify

This interferes with nearby satellites

SATCOM Limitations & Vulnerabilities

A

Side lobe Radiation Problem

Note: Antenna shapes are often skewed to lower the side lobes

68
Q

Identify

Not all satellites are located above the Earth station. At lower elevation angles signals traverse more atmosphere, thus the overall what is increased?

A

Slant Range

69
Q

What is the most common adverse effect on signal transmissions?

A

Rain Fade

70
Q

What must you have to burn through adverse weather?

A

Power to spare

71
Q

Satellite communications system that can be setup with a two-way ground station connected to a dish antenna that points to or tracks a particular satellite

A

Very Small Aperture Terminal (VSAT)