Introduction
The MQ-1C Gray Eagle has two options for operating BLOS: Air Data
Relay (ADT) and Satellite Communications (SATCOM). SATCOM is the primary BLOS capability while ADT
is a backup system in case SATCOM is not available for some reason. SATCOM requires minimal extra equipment while
ADT requires a considerably larger footprint.
There are some human factors considerations while operating in BLOS
especially when using the SATCOM mode.
Finally we will look at some possible commercial applications for BLOS
operations with either the Gray Eagle or other systems similar in size and capability.
SATCOM
Satellite communications is the primary BLOS capability for the
MQ-1C Gray Eagle as well as other UAS of similar size and capability,
especially aircraft in the Predator family.
SATCOM uses orbiting military and commercial satellites to provide data
link capability for the UAS BLOS and the Ground Control Station (GCS) can be located
anywhere in the world, many times thousands of miles from the operational
aircraft and theater.
SATCOM operation requires a different GDT which is called a
Satellite Ground Data Terminal (SGDT) and a larger air data terminal dish
antenna to conduct these operations. The
SGDT is much larger and more complex than the LOS GDT but requires very little
extra consideration by the operator. No
extra personnel is required for SATCOM operations and handover to SATCOM
operations is relatively simple. After
the UAS is launched using the LOS GDT the aircraft will climb to operational
altitude and prepare for SATCOM handover.
The aircraft has two ADTs and modem assemblies. They are the modem
assembly (MA) and the satellite modem assembly (SMA). The MA is used for LOS operations only and
the SMA can be used for both LOS and BLOS operations. The LOS GDT will communicate with the MA
while the SMA is used to gain data link with the required satellite(s). When data link is established with the
satellites LOS data link is turned off and the aircraft can then conduct SATCOM
BLOS operations.
Air Data Relay
The ADT is used as a backup BLOS system in case SATCOM operations
are not available. ADR operations use
only LOS equipment and antennas for its BLOS operations. This operation requires a considerable amount
of additional equipment and crew. ADR
basically takes double the equipment of normal LOS operations including two
aircraft. ADR operations consist of one aircraft
acting as a Data Relay aircraft for a second mission aircraft. Two GCSs are also required, a launch and
recovery (LRE) GCS and a mission GCS. The
launch and recovery GCS will launch the relay aircraft (RAC) and hand it off
the mission GCS. The mission GCS then puts the RAC into a loiter at a
predetermined point and prepares to receive the mission aircraft (MAC). The LRE GCS then hands off the MAC to the
mission GCS who then uses the two ADTs on the RAC to monitor and control the
RAC while controlling the MAC through the RAC.
This in theory doubles the range of the MAC and is limited only to the
operational range of the aircraft and its ability to complete the mission and
have enough fuel to return to base and land.
LOS datalink is only limited to LOS capability and with the RAC at max
operational altitude of 25,000’ MSL this as stated earlier will limit the MAC aircraft
to its ability to return to base and land.
Human Factors Issues
The human factors issues that can arise from these operations is
that there will be a time delay in commands given to the aircraft because of
the greater distances and extra components (satellites, RAC, etc.). For ADR operations the time delay should be
minimal while the SATCOM delay can be significant enough to impact payload and
weapons operation. While useable in SATCOM
payload and weapons operations require a high level of experience and expertise
with certain limitations. SATCOM delay
can be as long as 6 seconds from the time a command is sent until the aircraft receives
it and responds.
Commercial Applications
There are many commercial applications that could benefit from the
use of BLOS capability in a UAS but it will most likely be restricted to only
the largest corporations and local governments due to the large increase in
operational cost and equipment footprint.
Because BLOS equipment is considerably more expensive and complex and
satellite time can cost in excess of $10,000 an hour there will probably be
limited commercial use of BLOS operations.
Some applications that could benefit from BLOS UAS operations
would be infrastructure monitoring in remote areas including over water
missions, wildlife monitoring in remote areas and over water, and other
extended range and time research missions.
References
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