I was just doing some research on the Raptor when I found
this:
October 2000
©SIGNAL Magazine 2000
Simulator Sharpens Raptor's Claws
System measures fighter's electronic defenses against variety of
real-world threats.
By Henry S. Kenyon
A powerful computer that generates thousands of radar signals is
being used to test the electronic warfare suite on the F-22 Raptor.
The device pushes the aircraft's countermeasure package to the
breaking point, allowing engineers to locate, analyze and repair
faults in the system prior to installation.
The Raptor, the U.S. Air Force's next-generation fighter, is
designed to dominate all emerging aircraft threats well into the
21st century. An important feature of the F-22 is its advanced
electronic warfare (EW) suite, the AN/ALR-94. Cutting-edge
technology allows the fighter to detect, analyze, evaluate and
react to the most current EW threats fielded by potential
adversaries.
The aircraft will enter service at a time when there are no major
global political blocs with their complementary families of
equipment, radar and jamming systems. Even the poorest developing
nations can access a variety of sophisticated weaponry from either
the West or the former communist bloc. This mixed radar environment
complicates the work of the EW system designer because radars
formerly identified as friendly could be operated by potential
aggressors. Over its expected operational life of 40 or more years,
the Raptor's EW package will have to protect the aircraft under
constantly shifting threat conditions.
According to John J. Sciuto, chairman, president and chief
executive officer of Comptek Research Incorporated, Buffalo, New
York, his company has been involved with every phase of the
AN/ALR-94 since its initial concept and validation phase in 1996.
He believes it is the most sophisticated airborne EW system ever
developed for an attack aircraft.
It was during the development process that Comptek designers
realized how much power the computer would need to generate all of
the scenarios and the signals of threat emitters to adequately test
the system.
"When you test one of these systems, you try to take it to the
point where you saturate or break it," Sciuto explains. It took
almost three years to deliver the project because of the complexity
of the system involved, he adds.
The testing device, called the advanced dynamic radio frequency
simulator (ADRS), is used on F-22 EW systems before they are
installed in the aircraft. It is built around a supercomputer-class
processing engine that contains nearly 40 gigabytes of high-speed
memory, integrated to provide a total processing capability of more
than 500,000 million instructions per second. This capability
allows ADRS to generate the signals of more than 2,000 radar
emitters simultaneously. Built from commercial off-the-shelf
components, the simulator can be easily upgraded and maintained to
meet changing threat profiles. Sciuto claims that ADRS is one of
the 10 most powerful computers on the planet.
ADRS features a built-in scenario-generation capability that allows
end-users to program in a variety of simulations. This is coupled
with an up-to-date threat library provided by the U.S. government
that contains data on every known radar signal currently in use.
The scenarios consist of a variety of signals selected from the
threat library that are fed into an F-22's EW system. The simulator
then measures how the system processed the scenario and the EW
signals. ADRS can also analyze the effectiveness of specific
functions within the aircraft's countermeasures suite. Sciuto notes
that the overall complexity of the EW system required a more
complicated testing and measurement capability.
In the testing and development phase, the fighter's EW system is
tested to saturation--a point where there is too much data coming
in to be analyzed. Once that level is identified, the goal is to
modify and repair the weakness before the system is put into
production, he says.
Comptek has built three simulators to support the F-22 program. Two
were delivered to Lockheed Martin and a third is being installed
for the Air Force in its electronic combat test laboratory at
Edwards Air Force Base in California. This particular simulator
will be modified to test the Raptor's EW suite as well as those on
several other aircraft, Sciuto notes. ADRS also could be used to
test the Joint Strike Fighter's (JSF's) countermeasures suite.
However, because the JSF has a different mission than the F-22, its
EW system will also differ. Barring potential modifications to the
hardware, any dissimilarity between systems should be minor enough
to require only software changes in the simulator, he
predicts.
Sciuto asserts that there is an art to writing computer code for EW
suites. Designers must understand the environment in which the
system will operate. For example, shipboard units must deal with
radar reflections off the water and onboard interference from the
constant operation of the ship's own radars and communications
gear. When a countermeasures system is being developed for an
aircraft, the designers must understand the airborne environment.
For example, radar and EW systems developed for aircraft operating
at low altitudes have to cope with problems such as ground clutter,
which is not a requirement in high-altitude platforms.
Sciuto maintains that advanced EW systems testing capabilities did
not exist 15 years ago and that countermeasures suites built before
then were made without the benefit of current measurement and
analysis techniques. He notes that there have been complaints from
within the EW systems development community that EW packages are
not performing correctly. But this problem would not be identified
if the technology did not already exist to test and look for
deficiencies. "These systems are invaluable. Even if it costs $20
million to build a simulator to test the F-22, it's worth every
cent and more to make sure the thing is in fact doing what it's
[specified] out to do," he says.
The added complexity of ADRS is necessary because the EW threat
environment that the F-22 will operate in is considerably more
complicated than the bipolar Cold War world. Unlike previous
decades, where systems operated against a specific suite of Soviet
designed radars and jammers, the current global situation can pit
sets of potentially friendly equipment against each other. During
the Cold War, EW and threat library design was much simpler, Sciuto
says. However, now it is possible to encounter a hostile F-4
Phantom of U.S. manufacture that is equipped with an APQ-72 radar.
In the past, a system would identify the F-4's APQ-72 as being
friendly and move on to the next threat, he explains.
"Today you can't do that," Sciuto observes. "Now you have to be
able to actually distinguish a friendly F-4 from a potentially
hostile one because the bad guys have the same equipment. It really
has complicated the EW world immensely, and therefore it equally
complicates the simulator business."
Modern countermeasures systems must be able to identify differences
in similar systems that might distinguish friend from foe. One
example is the distinction between properly and improperly tuned
radar systems. The United States and most developed world military
organizations keep all of their equipment in top operating form at
all times. This is not a common practice in some parts of the
world.
"One of the discriminating factors when dealing with Third World
countries is that they do not do that [tune their radars]. For
example, the pulse train coming from a French-made Mirage jet
operated by a Third World nation will not look the same. If that
same radar was on a U.S. platform, those peaks would be sharper,
clearer and spaced correctly," Sciuto observes.
Once these differences are understood, EW systems can be programmed
to discern them and other similar triggers. Sciuto believes two
lessons were learned from the Gulf War: Though developing nations
may have access to the best equipment available, they often do not
train their personnel on how to use it at peak efficiency, and
those systems also are not maintained at maximum operating ability,
he says.
The nations that supply arms and equipment to much of the world are
also continually upgrading and developing new radars that are less
susceptible to jamming. The French, Israelis, Germans and British
have been very active in developing new, more sophisticated
systems, Sciuto notes.
Intelligence also plays a role in good EW capabilities. When the
U.S. military deploys into a potential threat area, the units are
provided with the latest information on the enemy's order of
battle, including the electronic order of battle. Sciuto explains
that current EW systems are designed with online and offline
libraries of signal data. However, when a force moves into a
specific theater of operation, its online threat library is
reprogrammed to minimize the time lost from sorting through the
library. "While the system has a vast capability, it is condensed
to the specific theater of operation," he says.
As the F-22 program grows, Sciuto believes there may be a
possibility for selling the ADRS overseas. While Comptek has never
sold anything as complex as the F-22 EW simulator internationally,
it has sold many other types of EW testing systems to Germany,
France, the United Kingdom, Australia, Singapore, Taiwan and Japan.
Although these countries buy the systems, the threat libraries are
not included in the sale. Only the software is provided so users
can enter their own threat data, he notes.
Comptek has recently become a subsidiary of the Northrop Grumman
company. Additional information on Comptek Research Incorporated is
available on the World Wide Web at http://www.comptek.com .
Some of Comptek's EW simulating equipment were sold to Singapore!
This may not sound like much, but it confirms many articles I have
read that puts Singapore as one of the few countries in Asia (along
with Japan, South Korea, Austrialia) with an EW equipment potential
within this decade.
