Comm 33: Satellite Communication

Question 1

SATCOM Overview
Space
Control
User
Crosslink
Throughput
Worldwide coverage
Global Coverage

Answer 1

Space:

• Satellites (most important components)
• Transponders: a unit in a satellite that receives an uplink signal, converts its frequency, amplifies it and retransmits it to the ground. (10-60 transponders in a comms sat)

Control:
- Service providers

User:

• Limited availability
• Restricted access

Crosslink:
- Inter-satellite communication

Throughput:
- Measurement of volume of user data carried by the channel during a specified time period. Expressed in bits or packets per second

Worldwide Coverage:
- Earth coverage south of 70N and north of 70S

Global Coverage:
- Earth coverage including the poles

Question 2

Network Types
Commercial SATCOM:
Military SATCOM:
Satellite Phone:
UHF SATCOM:
Broadband SATCOM:

Answer 2

Commercial SATCOM:

• TV
• Telephone
• Radio
• Broadband Data

Military SATCOM:

• UHF
• Broadband Data

Satellite Phone:

• Mobile phones that connects to satellites
• Voice, short messaging and low-bandwidth internet access
• No encryption

UHF SATCOM:

• UHF relay communication using GEO satellites for BLOS reach
• Half-duplex encrypted voice (Strategic network CAOC, tactical operations in remote areas)
• Full duplex Data (Demand Assigned Multiple Access DAMA)

Broadband SATCOM:

• SHF/EHF wideband and high throughput IP streaming communication using GEO satellites for BLOS reach
• Code Division Multiple Access capable of more than 45 mbps data rate
• Common Data Link (UAV and ISR)
• Network Access (Internet, DWAN/CSNI, Video conference, VoIP)

Question 3

Iridium SATCOM

Answer 3

• LEO satellite constellation
  
  • 66 satellites (originally 77)
  • 780 km altitude
  • sun-synchronous
  • 6 planes of 11 satellites each
• Crosslink Comms
  
  • less gateway required
• Control Centre
  
  • Boeing
• User Terminals
  
  • Motorola

Question 4

MILSTAR SATCOM

Answer 4

• GEO satellite constellation
  
  • 5 Satellites (2 Block I, 3 Block II)
• Communications
  
  • Voice (mobile)
  • UHF Voice
  • Low/medium data rate
  • Teletype
  • Fax
• Control Centres
  
  • Schriever AFB
  • Los Angeles AFB
• AEHF program

Question 5

INMARSAT

Answer 5

• GEO Satellites constellation
  
  • 10 satellites
  • 4 regions
  • 3 types of coverage (global beam, regional spot beam, narrow spot beam)
• Communication
  
  • Voice (mobile)
  • Broadband (high data rate up to 60 mbps)
  • Secure for sensitive operations
• Control Centre
  
  • London, UK

Question 6

Wideband Global SATCOM

Answer 6

• GEO Satellite constellation
  
  • Military dedicated (boeing)
  • Planned for 10 satellites (Canada will provide #9)
  • 4 operational satellites
• Communications
  
  • Broadband data (4.8 Gbps)
  • Multiple applications
  • Ability to connect X band users to Ka band users
• Control Centre
  
  • Schriever AFB
  • Peterson AFB

Question 7

Operating Procedures for SATCOM
Satellite Phone:

Commercial Providers:

UHF SATCOM:

Answer 7

Satellite Phone:
- International Calling
- Iridium
- 001 (204)833 2500/ +1(204)833 2500
- 011 8816 789 12345 (‘+’ = 00)
- INMARSAT
Commercial Providers:
-Security issues (no encryption, geo-location)
- No guarantee of service (ECM, foreign control, $)
- Shared capability (enemy/friendly)
UHF SATCOM:
- Half-duplex voice
- Full duplex DAMA
- 2 frequencies per channel (Uplink Tx, downlink Rx)
- Latency issues