X Band Satellite Communication

Last updated

X band or SHF Satellite Communication is widely used by military forces for beyond line of sight communications. X band is used because it provides a compromise between the characteristics of different frequency bands which is particularly suited to the needs of military users. The characteristics include interference and rain resilience, terminal size, data rates, remote coverage and whether it is reserved for governmental use.

Contents

Characteristics of the SHF frequency band

Frequency

x Band Satellite Communication operates in the part of the X band or Super High Frequency (SHF) spectrum which is designated by the International Telecommunication Union (ITU) for satellite communication, which is those frequencies in the range 7.25 GHz to 7.75 GHz (Earth to Space) and 7.9 GHz to 8.4 GHz (Space to Earth). [1] The ITU Frequency allocation defines the primary use of this spectrum as Fixed satellite service (FSS) and a portion to Mobile Satellite Services (MSS), primarily used for ship based satellite communications. UK Frequency Allocation Table (UK FAT) [2] along with other NATO countries and some other countries’ (but not all) national frequency allocations tables, have an additional note detailing the primary allocation for government use. It is important to note that the allocation of these frequencies and services is for government use and not, as commonly stated, military use. The ITU and the UK Ofcom considers military use as just one part of government use.

Rain resilience

X band is below those frequencies which are severely affected by Rain Fade, therefore X band provides extremely good rain resilience unlike higher frequencies such as Ku or Ka which are also used for satellite communication. This allows extremely high link availability, in some cases as high as 99.9%

>4° separation between satellites

X band satellites typically have at least 4° separation between satellites, therefore there is less chance of adjacent satellite interference (ASI) and higher power density carriers allowed. [3]

Terminal size v data rates

As with any satellite communication link, the data rate that can be achieved with a terminal is dependent on the gain of the parabolic antenna. Antenna gain increases with the square of the ratio of aperture width to wavelength. Therefore, for a fixed antenna size the gain, and hence the achievable data rate increases with frequency. Thus X band provides data rates which are much higher than can be achieved with UHF, L band, or C band. The achievable data rates will approach those achievable with Ku band, the exact values will depend on other link parameters (satellite power, link margin, modulation scheme, etc.).

Therefore, X band provides a good compromise between terminal size and data rates while maintaining resilience to rain fade. Data rates of 10 Mbit/s are achievable to a 45 cm antenna without interfering with adjacent satellites. [2]

Remote and maritime coverage

X band spot beams typically have a diameter of 1000 km or more. This is the result of the frequency and the size of Parabolic antenna which can be accommodated inside satellite launch vehicles. This means that a single beam is able to be steered to cover an entire region of interest. X band satellites also have an earth cover or global beam providing coverage of the entire planet that is visible from the satellite. This is in contrast to satellites in commercial bands which typically provide fixed beams for areas of high density of users. Therefore, X band satellites are able to support users in remote areas with little or no infrastructure and in mid ocean away from land and shipping lanes.

Characteristics of SHF Satcom systems

SHF Satcom systems often possess features designed to meet the needs of military users and to counter threats to the system. Features include

Components of SHF Satcom systems

Like other Satellite Communications systems, X band satellite communication systems comprise the following segments:

Satellite communication systems operating at X band

Skynet

The Skynet fleet of satellites are owned and operated by Airbus Defence & Space who hold a long term concession for beyond line of sight communications with the UK MOD. The fleet includes four high performance Skynet 5 satellites with 160W TWTAs providing up to 8W/MHz and an active receive antenna capable of creating multiple uplink beam patterns. The Skynet fleet also includes older Skynet 4 satellites which are beyond their original design life and in inclined orbits, these orbits enable them to provide communications to arctic and Antarctic regions. In addition to SHF capacity the Skynet satellites also have UHF capacity. [4]

Wideband Global SATCOM system (WGS)

The WGS system is a constellation of military communications satellites procured by the U.S. Air Force MILSATCOM Systems Directorate at Los Angeles Air Force Base (AFB). Each WGS satellite provides capacity in both the X and Ka frequency bands. Each WGS satellite is digitally channelized and transponded. [5] International partners participating on the program are Australia, Canada, Denmark, Luxembourg, The Netherlands and New Zealand. [6]

XTAR-EUR

The XTAR-EUR satellite is owned and operated by XTAR LLC and Hisdesat. It was launched in February 2005 and is positioned at 29 degrees east. XTAR-EUR has 100W, 72 MHz transponders [7]

Spainsat

SpainSat is owned by Hisdesat. SpainSat was launched in March 2006 and is positioned at 29 degrees west. Spainsat has an X-Band payload with 100W, 72 MHz transponders. It also has Ka band capacity. [8]

Sicral

SICRAL (Sistema Italiano per Comunicazioni Riservate ed Allarmi) is Italy’s satellite system for military communications. The SICRAL 1 satellite was launched in 2001 and the SICRAL 1B satellite was launched in 2009. [9]

Syracuse

Syracuse III (système de radiocommunications utilisant un satellite) is the military satellite communication system of the French ministry of Defence. Syracuse 3A was launched in 2005 and Syracuse 3B was launched in 2006. [10]

Anik G1

Anik G1 was launched in April 2013, and includes a 3-transponder, global-beam X-band payload, operating from 107.3°W. [11]

DC-MS Series 2

DC-MS Series 2 consists of 2 triple-transponder global-beam X-band payload, operated by Delta Communications. DC-MS Series 2 was launched in January 2014.

NATO SATCOM Post-2000

The NATO X Band satellite system consists of a NATO owned ground segment with capacity leased from a consortium formed by the British, French and Italian governments. [12]

See also

Related Research Articles

The Ku band is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under", because it is the lower part of the original NATO K band, which was split into three bands because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz, (1.35 cm) which made the center unusable for long range transmission. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521–2002.

<span class="mw-page-title-main">Skynet (satellite)</span> Communications satellite

Skynet is a family of military communications satellites, now operated by Babcock International on behalf of the United Kingdom's Ministry of Defence (MoD). They provide strategic and tactical communication services to the branches of the British Armed Forces, the British intelligence agencies, some UK government departments and agencies, and to allied governments. Since 2015 when Skynet coverage was extended eastward, and in conjunction with an Anik G1 satellite module over America, Skynet offers near global coverage.

Super high frequency (SHF) is the ITU designation for radio frequencies (RF) in the range between 3 and 30 gigahertz (GHz). This band of frequencies is also known as the centimetre band or centimetre wave as the wavelengths range from one to ten centimetres. These frequencies fall within the microwave band, so radio waves with these frequencies are called microwaves. The small wavelength of microwaves allows them to be directed in narrow beams by aperture antennas such as parabolic dishes and horn antennas, so they are used for point-to-point communication and data links and for radar. This frequency range is used for most radar transmitters, wireless LANs, satellite communication, microwave radio relay links, satellite phones, and numerous short range terrestrial data links. They are also used for heating in industrial microwave heating, medical diathermy, microwave hyperthermy to treat cancer, and to cook food in microwave ovens.

The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0–11.2 GHz. In radar engineering, the frequency range is specified by the Institute of Electrical and Electronics Engineers (IEEE) as 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks.

<span class="mw-page-title-main">Milstar</span> Constellation of American military satellites

Milstar is a constellation of military communications satellites in geosynchronous orbit, which are operated by the United States Space Force, and provide secure and jam-resistant worldwide communications to meet the requirements of the Armed Forces of the United States. Six spacecraft were launched between 1994 and 2003, of which only five were operational after launch; the third launch failed, both damaging the satellite and leaving it in an unusable orbit.

<span class="mw-page-title-main">Defense Satellite Communications System</span> Defense satellite communications project

The Defense Satellite Communications System (DSCS) is a United States Space Force satellite constellation that provides the United States with military communications to support globally distributed military users. Beginning in 2007, DSCS began being replaced by the Wideband Global SATCOM system. A total of 14 DSCS-III satellites were launched between the early 1980s and 2003. Two satellites were launched aboard the Space Shuttle Atlantis in 1985 during the STS-51-J flight. As of 14 September 2021, six DSCS-III satellites were still operational. DSCS operations are currently run by the 4th Space Operations Squadron out of Schriever Space Force Base.

<span class="mw-page-title-main">Wideband Global SATCOM</span> Defense satellite communications project

The Wideband Global SATCOM system (WGS) is a high capacity United States Space Force satellite communications system planned for use in partnership by the United States Department of Defense (DoD), Canadian Department of National Defence (DND) and the Australian Department of Defence. The system is composed of the Space Segment satellites, the Terminal Segment users and the Control Segment operators.

<span class="mw-page-title-main">Advanced Extremely High Frequency</span> Series of American military satellites

Advanced Extremely High Frequency (AEHF) is a constellation of communications satellites operated by the United States Space Force. They are used to relay secure communications for the United States Armed Forces, the British Armed Forces, the Canadian Armed Forces, the Netherlands Armed Forces and the Australian Defence Force. The system consists of six satellites in geostationary orbits. The final satellite was launched on 26 March 2020. AEHF is backward compatible with, and replaces, the older Milstar system and will operate at 44 GHz uplink and 20 GHz downlink. The AEHF system is a joint service communications system that provides survivable, global, secure, protected, and jam-resistant communications for high-priority military ground, sea and air assets.

<span class="mw-page-title-main">USA-195</span> United States Space Force military communications satellite constellation

USA-195, or Wideband Global SATCOM 1 (WGS-1) is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2007, it was the first WGS satellite to reach orbit. It is stationed at a longitude of 174.8° East.

XTAR, LLC is a commercial satellite operator exclusively providing services in the X band frequency range, which is the communications cornerstone of today's military, diplomatic, humanitarian and emergency disaster response operations. A privately owned and operated company, XTAR supports the critical satellite communications needs of governments around the world through its two X-band payloads. The XTAR satellites were designed and built by private financing. Loral Space & Communications, Inc. owns the majority share. XTAR is headquartered in Ashburn, VA.

<span class="mw-page-title-main">USA-233</span> United States Space Force military communications satellite constellation

USA-233, or Wideband Global SATCOM 4 (WGS-4) is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM program, launched in 2012. The fourth Wideband Global SATCOM satellite, it is the first WGS Block II satellite to be launched. It is stationed at 88.5° East in geostationary orbit.

<span class="mw-page-title-main">USA-243</span> United States Space Force military communications satellite constellation

USA-243, also known as WGS-5, is a United States military communications satellite. It was the fifth satellite to be launched as part of the Wideband Global SATCOM program and the second Block II satellite.

<span class="mw-page-title-main">USA-204</span> United States Space Force military communications satellite constellation

USA-204, or Wideband Global SATCOM 2 (WGS-2) is a United States military communications satellite which is operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2009, it was the second WGS satellite to reach orbit, and operates in geostationary orbit at a longitude of 60° East.

<span class="mw-page-title-main">USA-211</span> United States Space Force military communications satellite constellation

USA 211, or Wideband Global SATCOM 3 is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2009, it was the third WGS satellite, and final Block I satellite, to reach orbit. It was originally stationed in geostationary orbit at 12° West.

<span class="mw-page-title-main">USA-244</span> United States Space Force military communications satellite constellation

USA-244, or Wideband Global SATCOM 6 (WGS-6) is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2013, it was the sixth WGS satellite to reach orbit. It is stationed at a longitude of 135° West, in geostationary orbit. WGS-6 was procured by the Australian Defence Force for the U.S. Air Force, in exchange for participation in the programme.

<span class="mw-page-title-main">USA-263</span> United States Space Force military communications satellite constellation

USA-263, or Wideband Global SATCOM 7 (WGS-7) is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2015, it was the seventh WGS satellite to reach orbit. It is stationed at a longitude of 135° West, in geostationary orbit. WGS-7 was procured by the United States Air Force.

<span class="mw-page-title-main">USA-272</span> United States Space Force military communications satellite constellation

USA 272, or Wideband Global SATCOM 8 is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched Delta IV in 2016, it was the eighth WGS satellite to reach (target) orbit. It is stationed at a longitude of 135° West, 149°E i=0° in geostationary orbit. WGS F8 was procured by the United States Air Force.

<span class="mw-page-title-main">USA-275</span> United States Space Force military communications satellite constellation

USA-275, or Wideband Global SATCOM 9 (WGS-9) is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2017, it was the ninth WGS satellite to reach orbit. It is stationed at a longitude of 135° West, in geostationary orbit. WGS-9 was procured by the United States Air Force.

<span class="mw-page-title-main">USA-291</span> United States Space Force military communications satellite constellation

USA-291, or Wideband Global SATCOM 10 (WGS-10) is a United States military communications satellite operated by the United States Air Force as part of the Wideband Global SATCOM programme. Launched in 2019, it was the tenth WGS satellite to reach orbit. It is in geostationary orbit. WGS-10 was procured by the United States Air Force.

<span class="mw-page-title-main">WGS-11+</span> United States Space Force military communications satellite constellation

Wideband Global SATCOM 11+, is a United States military communications satellite to be operated by the United States Space Force as part of the Wideband Global SATCOM Program. Scheduled for 2024, it is the eleventh WGS satellite and is expected to be in geostationary orbit. WGS 11+ was acquired by the United States Air Force.

References

  1. ↑ "ITU Radio Regulations 2012" (PDF). Archived from the original (PDF) on 28 July 2017. Retrieved 18 June 2014.
  2. 1 2 National Frequency Planning Group on behalf of the Committee on UK Spectrum Strategy. "United Kingdom Frequency Allocation Table Issue 17" (PDF). www.ofcom.org.uk. Retrieved 19 June 2014.
  3. ↑ "Commercial X-Band: The Technical + Operational Advantages" . Retrieved 18 June 2014.
  4. ↑ "Skynet Data Sheet" (PDF). Retrieved 18 June 2014.
  5. ↑ "Boeing WGS Factsheet". Archived from the original on June 13, 2014. Retrieved 18 June 2014.
  6. ↑ "Los Angeles Airforce Base WGS Factsheet". Archived from the original on March 25, 2014. Retrieved 18 June 2014.
  7. ↑ "XTAR-EUR Data sheet" (PDF). Retrieved 18 June 2014.
  8. ↑ "Spainsat data sheet" . Retrieved 18 June 2014.
  9. ↑ "Italian MOD announcement of Sicral 1B launch (Lancio del Satellite SICRAL 1B)" . Retrieved 18 June 2014.
  10. ↑ "Syracuse III". Archived from the original on March 6, 2014. Retrieved 18 June 2014.
  11. ↑ "Anik G1 Datasheet" (PDF). Retrieved 18 June 2014.
  12. ↑ "SATCOM Post-2000" . Retrieved 18 June 2014.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.