Aerospace & Defense Technology - December 2022 - 27

Tech Briefs
Advanced Airborne Defensive Laser for Incorporation on
Strike Fighter Aircraft
A technical and operational analysis of an airborne " hard-kill " Ytterbium fiber laser-based anti-missile
system for use on strike fighters.
Naval Postgraduate School, Monterey, California
S
hort-range missiles pose a
significant threat to U.S.
strike fighters. These missiles are
usually small and highly mobile
and can be carried on light vehicles
and by individual people.
Although these missiles do not
have a long range, the unpredictability
of their launch sites
increases their lethality. Also
contributing to their lethality
are the methods of homing in
on their targets. Most are passive
methods, such as infrared.
Unlike active radar homing,
these missiles provide no warning
to the aircraft that it is being tracked
until the missile has been launched.
The varieties of homing methods for
these missiles can also provide problems
for aircraft countermeasure systems. Each
type of homing method requires a different
type of countermeasure. All current
airborne countermeasure systems rely on
" soft-kill " methods of protection involving
confusion or distraction of the homing
system. These systems work differently
for different homing methods and must
be constantly upgraded to protect against
ever more complex targeting systems.
A " hard-kill " Advanced Airborne
Defensive Laser (AADL) system could
use a high-energy laser to either destroy
an incoming missile or cause enough
physical damage to prevent the missile
from intercepting its target. The AADL
will be an external pod mounted on a
strike fighter and will be almost entirely
autonomous. The system will detect
missile launch, track targets, and eliminate
them. It will use built-in systems
for power generation, target tracking,
and laser transmission.
The concept of operations (CONOPS)
of the system begins with detecting
missile launch. The system detects the
missile and automatically begins tracking
it and plotting a firing solution.
Simultaneously, the mission computSingle
Missile Fired at Host Aircraft.
er of the AADL uses the host aircraft's
communication systems to alert the
pilot and friendly forces to the threat.
Once a firing solution has been determined
and the laser transmitter moved
into position, the incoming missile is
fired upon and neutralized. This action
is taken without input from the pilot as
any delay from human reaction time
can cause disaster.
After the threat is neutralized, the
pilot and friendly forces are once again
notified. If there are further incoming
missiles, the highest priority threat is
targeted and engaged. A set of requirements
describing the actions necessitated
by the CONOPS in further detail was
also developed. Based on these requirements,
a functional architecture was
created. This architecture breaks those
requirements down into a hierarchy of
functions and allows, in combination
with the physical architecture, creation
of an allocated architecture. This physical
architecture is a generalized relationship
of components based on research
into existing systems analogous to the
subsystems of the AADL. Following this,
an allocated architecture was developed,
showing that every function is
accomplished by a component.
Research was then conducted into
currently existing technology that
Aerospace & Defense Technology, December 2022
mobilityengineeringtech.com
could be used to develop design
alternatives for the AADL. These
alternatives consisted of technology
for the power supply,
laser transmission, and targeting
subsystems. These specific subsystems
were analyzed because
these were the main subsystems
whose functions could not be
accomplished by technology
commonly used by the U.S. military.
These technologies were
analyzed for cost, effect on flight
performance, technology risk,
and functional performance.
Because of the immature nature
of these technologies, the cost could not
always be established. Where that information
was not available, information
on construction materials and methods
was used to provide a comparative cost
between alternatives.
Effect on flight performance was
established by comparing the weights
and speed limits of the alternatives.
Technology risk was based on the Technology
Risk Level standards established
by the Department of Defense. Finally,
the functional performance was assessed
through the use of computer simulations.
These simulations use a program
named ExtendSim to model the positions
and velocities of the aircraft and
incoming missiles. This information was
then passed to a physics-based highenergy
laser modelling program called
HELEEOS to determine the amount of
time needed to neutralize the missile.
This work was performed by Stephen
Cannon, Timothy Kaniss, Nathan Lautzenheiser,
Cesar Rios, Greyson Siegel,
Jeremy Smith, and Eric Wright for the
Naval Postgraduate School. For more
information, download the Technical
Support Package (free white paper)
at mobilityengineeringtech.com/tsp
under the Lasers & Photonics category.
NPS-0026
27

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Aerospace & Defense Technology - December 2022

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