BLOS
Operations
Scott
E. Leishman
ASCI
638- Human Factors in Unmanned Aero Sys
Assignment
4.6
Embry-Riddle
Aeronautical University-Worldwide
December
15, 2016
Introduction
For
the purpose of this assignment I am reviewing the Global Hawk Unmanned Aircraft
System (UAS). The Global Hawk is used as a High-altitude, Long-Endurance (HALE)
UAS. It was designed to be a persistent reconnaissance UAS for use at the Joint
Force command. This was a program initiative enacted by the Defense Airborne Reconnaissance
Office (DARO) (Pike, n.d.). The Global Hawk is equipped with a variety of
sensors and amongst those sensors the following are included: an
electro-optical sensor (EO), an infrared sensor (IR), and a synthetic aperture
radar (SAR) vision system. These systems can be operated either line-of-sight
(LOS) via a radio data link, or they can be operated via Ku-band satellite
communication (SATCOM) data link for command, control, and communication
purposes(C3)(Pike,n.d.) during beyond-line-of-sight (BLOS) operations. When using BLOS, via the Ku-Band SATCOM, this
C3 link is able to provide a 50-megabit per second connection, which allows a
throughput of several million gigabytes (Gb) of video and imagery during a
continuous operation( this UAS is capable of a 24 hour operation due to its
endurance). Along with having an outstanding ability to record data, this
airframe can carry upwards of 3,000lbs. of interchangeable payload and can
reach altitudes of well over 60,000 feet.
Satellite
Communication
The
SATCOM over Ku-Band data link is typically used whenever the UAS is expected to
operate BLOS. It does this because of
how SATCOMS are leveraged. SATCOM uses low-earth polar along with
geo-stationary orbits to establish various air/ground telecommunications. The
ground infrastructure provides controls for position of a satellite and monitor
the health of the usable satellite (Duncan, 2015). The primary providers of aviation
communications via satellite are Inmarsat and iridium. Iridium utilizes an
immense network of 66 cross-linked satellites (with seven of them being
backups), and this network covers the majority of the Polar Regions, airways,
as well as Earth’s Oceans (Duncan Aviation, 2016). The orbit for this satellite
network circumvents the globe once every 100 minutes, with at altitude that is
nearly 485 miles above Earth’s surface. In doing so this network provides
uninterrupted voice communications throughout the world (Duncan Aviation, 2016).
Comparatively, Iridium is the private sector leader and is the primary consumer
telecommunication provider, by proxy Inmarsat is more of a legacy system of
international satellite service providers. What Inmarsat proves is data rate
transfers upwards of 432 kilo bytes per second (kbps) over a network of 11
multi-use satellites, not to include those areas designated in Polar Regions (Duncan
Aviation, 2016). Inmarsat is the more desirable satellite infrastructure for
Government and Civil Authorities due to its compatibility and compliance with
International Civil Aviation Organization (ICAO) standards. Inmarsat becomes
more desirable because it meets future needs of an integrated global traffic
management system, also referred to as the Aeronautical Telecommunications
Network (ATN) (Duncan Aviation, 2016). Inmarsat’s infrastructure is built in a
manner to support information transfer between aircraft operators, service
providers, passenger’s onboard large and commercial commuter aircraft and, air
traffic providers (Duncan Aviation, 2016).
Global Hawk Infrastructure
Because
the Global Hawk operates autonomously, use of a ground-based infrastructure
eliminates the need for a lot of aircrew to gather information, surveillance,
and reconnaissance (ISR) information when comparing it to other aircraft
(Northrop Grumman, 2012). In doing this, this platform enables more time in the
ground control station (GCS) that other manned aircraft systems (Northrop
Grumman, 2012). The Global Hawk
personnel handle the command, control, aircraft management, and sensors
operations from a Mission Control Element (MCE) (Northrop Grumman, 2012). This
is a shelter where communication to the vehicle, mission planning, and imagery
quality control take place. The systems within the MCE are operated similarly
to those of a manned system. The processes for supply, management systems,
maintenance, and equipment/components are the same for manned aircraft with the
exception being manuals, which are electronic with visual illustrations, and
maintenance manuals come preloaded on a ruggedized laptop that is utilized when
troubleshooting and ordering parts for the Global Hawk (Northrop Grumman,
2012).
The
Global Hawk runs effectively because of how LOS and BLOS control work with each
other and allow the aircraft to operate virtually anywhere around the world.
BLOS operations become crucial for this UAS because of the primary missions the
Global hawk serves. Using BLOS enables the aircraft to have long range
surveillance, and gives the platform the ability to operate overseas, while the
operators are stateside. BLOS operations are carried out similar to the
Predator drone, which uses several repeaters to establish communications
between relay points (Brown, 2015).
These repeaters can either be active or passive. When considering what
each is, we consider passive repeaters to include components which are land
based, essentially those that do not require supplied power to relay a signal
to the next receiver in the communication chain (Brown, 2015). These repeaters
work particularly well in remote areas where landmass obstructions and
mountainous terrain often exist. Comparatively, an active repeater is one that
would include a transmitter and receiver that would bounce a received signal to
the next link via a LOS signal chain, but can also be amplified to relay
signals, data and can be transmitted continuously by changing the frequency
streams of satellite data-links when using Ku-band. BLOS systems that operate via a bounced
signal utilizing multiple repeaters can have a tendency to be distorted over
time and distance (Brown, 2015). This creates a signal that is not only
distorted, but can also become slower as it passes through each of the
repeaters in that infrastructure (Brown, 2015).
For this reason the Global Hawk is at greater risk of errors and
corruption and can lead to delays with that system which would make manual
control of this platform exceptionally risky. For that reason, lost-link
scenarios within LOS become easier to fix, because there are less communication
components at play (Brown, 2015).
Conclusion
A very distinct disadvantage for this platform is similar
to other platforms in that it can create problems when handing the UAS from one
GCS to another. The potential delay leads to possible anomalies in not only
aircraft settings but configuration as well. This false positive is a huge
human factors concern, as it can be misleading. An operator may have a read out
of a different altitude or heading when the aircraft is being turned over to
another GCS, but the UAS has performed that step moments ago and is now at a
lower altitude or a different heading, leading to poor situational awareness.
These delays at BLOS essentially eliminate any possible positive control in
manual operation, and leaves the aircraft susceptible to a mishap or an incident.
Although the Global Hawk has an abundance of advantages
and use in private applications, much of the regulatory framework in place
limits operations within the National Airspace System due to lost link concerns
BLOS. When the platform is able to meet regulatory framework and the Federal
Aviation Administration can provide guidance, these platforms can lend a hand
in many different applications. Anything from search and rescue missions, to 3D
mapping of terrain and cities ("Unmanned Aerial Vehicle Systems
Association Commercial Applications", 2016).
References
Brown, J. (2015). Beyond Line of Sight (BLOS)
and the MQ9 Reaper. Droning on and on. Retrieved from
http://www.droningonandon.com/blog/beyond-line-of-sight-and-the-mq9-reaper
Duncan Aviation,. (2016). What Is
Satcom? | Straight Talk About Satcom & HSD. Archive.da.aero.
Retrieved 15 December 2016, from
http://archive.da.aero/straighttalk/satcom/what_is_satcom.php
Northrop Grumman,. (2012). Q-4
Enterprise. Global Hawk Capabilities Brochure. Retrieved 15
December 2016, from
http://www.northropgrumman.com/Capabilities/GlobalHawk/Documents/Brochure_Q4_HALE_Enterprise.pdf
Pike, J. Global Hawk (Tier II+ HAE UAV). Fas.org.
Retrieved 15 December 2016, from
https://fas.org/irp/program/collect/global_hawk.htm
Unmanned Aerial Vehicle Systems Association
Commercial Applications.
(2016). Uavs.org. Retrieved 15 December 2016, from
https://www.uavs.org/commercial
