Electronic Threats Fall Prey to Fast Moving Simulation Laboratory

June 1999
By David A. Brown

Facility develops electronic scenarios that closely duplicate battlefield, evaluating defensive systems against known and new dangers.

As a first point in the United States’ electronic combat test process, researchers strive to re-create electronic warfare accurately to challenge the effectiveness of hardware against hostile threats. A major link in this process is the U.S. Air Force Electronic Warfare Evaluation Simulator in Fort Worth, Texas, which can evaluate defensive systems against most known threats and can respond quickly to newly discovered threats.

The Air Force Electronic Warfare Evaluation Simulator, or AFEWES, is one of the only places that offers a high fidelity, real-time test ability as well as provides complex background signal environments, clutter, fully dynamic maneuvering target engagements and operation interaction. The AFEWES concept tests the actual hardware of a system, not just its theoretical or calculated performance.

Today, in addition to a growing electronic warfare challenge, the laboratory is also wary of possible budgetary restrictions and political pressure that could affect its future capability. The money to carry out combat missions in Yugoslavia and Iraq could come in part from cutting back research and development funds—what some officials are calling an infrastructure tax—to make up for the cost of actual combat.

Congressional staff workers so far are not terribly worried about the lack of funds to keep AFEWES running. A house armed services committee staff member predicts the administration will cut the operations and maintenance funding to pay for combat costs before it goes after research and development facilities.

A second fear of AFEWES supporters is that political pressure will force the laboratory to move to a site near other U.S. Air Force test facilities at Edwards Air Force Base, California. An unseen problem exists here, according to one long-time research and development engineer. “There is a lot of in-the-mind capability within AFEWES, but much of it is not documented. It is transmitted to new researchers in the course of working with older colleagues. And a lot of those older colleagues will retire rather than move to another site, taking their knowledge and expertise with them.”

Moving the facility, or consolidating it with an existing research and development organization, is worrisome, but not likely for the next several years. “At the last round of base closure studies, they looked at AFEWES and found it efficient and economical, and I would hope they would find the same situation in any future study,” a staff worker in the office of Representative Kay Granger, (R-TX) says. The AFEWES facility lies within Representative Granger’s district.

AFEWES became operational 41 years ago for the sole purpose of testing the electronic countermeasures system on the Convair B-58 Hustler supersonic bomber. The Air Force took over the laboratory in the early 1960s. Currently, a staff of 65 test personnel and a seven-person Air Force management and supervisory staff operate the facility. The 412th Test Wing at Edwards Air Force Base administers the laboratory, which supports not only U.S. needs, but also the needs of many U.S. allies who frequently use AFEWES to evaluate their own electronic warfare designs and concepts.

Many of the electronic countermeasure devices that U.S. aircraft use today are developed versions of, or evolved from, the electronic countermeasure systems developed with AFEWES participation for the Vietnam conflict.  Engineers developed these devices by using some of the more than 30 threat signal generators. These are not simulations but real equipment that has been acquired and placed at AFEWES, such as an SA-6 emitter.

In addition to simulating a variety of threats, AFEWES can do so in a realistic battle environment using its radio frequency/millimeter wave length and infrared/electro-optical/ultraviolet environmental simulators. 

Housed in a 42,000-square-foot secure facility, AFEWES is a hardware-in-the-loop test laboratory that develops and operates a range of high fidelity radio frequency and infrared threat simulators. These simulators are sufficiently accurate to permit the developers of electronic combat systems to test their devices in a controlled, ground-based environment with great fidelity.

AFEWES can provide test scenarios that closely duplicate a real electronic battlefield. A large part of this capability comes from the facility’s multiple emitter generator, an open-loop radio millimeter wavelength simulator that can evaluate such things as radar warning receivers or power-managed electromagnetic countermeasure systems.

Using this system, analysts can perform a realistic simulation of a specific theater, with a dense radio frequency signal environment containing a variety of hostile, friendly and neutral signals, just as the military would encounter in real combat.

The multiple emitter generator has 73 instantaneous emitters built-in, and time multiplexing allows expansion to more than 200 emitters. Such features as terrain masking of some emitters and the capability of being integrated with an external manned flight simulation cockpit provide highly realistic evaluations.

AFEWES can simulate hostile signals that range from the Russian Back Track to the Yo Yo and so-called neutral signals that include the French-developed Crotale, the British Fox Hunter and the German Super Fledermaus. The laboratory can represent virtually all U.S.-developed signals, right up to the AN/APG-66 in the F-16.

In addition to its electronic simulation capability, AFEWES has two independent infrared test laboratories that can work independently, in conjunction with each other, or with one of the radio frequency simulation systems at AFEWES to provide a multispectral simulation.

The facility consists of two buildings. The older of the two, called the north laboratory, has been in operation since 1965. The south laboratory joined it in 1992. The Air Force added the south building to keep up with the rapidly developing infrared countermeasures technologies. While the north and south laboratories are similar in layout, the newer south laboratory can evaluate passive missile warning systems as well as infrared countermeasures systems. The laboratories are closed-loop systems that can be used to develop specific countermeasures systems, such as flares and jammers.

Both laboratories use a free-space, folded optical path transmission system. This system can present target signature, infrared countermeasures and flare effects at their true wavelengths to infrared seekers mounted on a dynamic flight table to simulate dynamic flight conditions accurately. These air-to-air seeker simulations can be linked directly to airborne interceptor radar simulations for a more realistic battlefield scenario.

Both the infrared and radio frequency laboratories at AFEWES provide vector components throughout the complete simulated engagement necessary to permit research engineers to see the true position and attitude for both the target and the threat missile. This allows easy computation of such vital data as probability of kill or survival, reduction in lethality and other means of measuring the effectiveness of the defensive system.

The AFEWES complex includes five test management centers to allow test directors the widest possible control over each test and to ensure that the greatest amount of information is received rapidly from the test. Each test management center has eight digital strip chart recorders. Each strip chart recorder has four channels, five video monitors, two video recorders, and a high-density optical data recorder that can capture more than 100 instrumentation signals in a digital format.

To achieve the ultimate in testing electronic warfare and infrared defensive systems in a real-world environment, the threat simulation at AFEWES can be electronically tied to any manned flight simulator cockpit operating in a domed dynamic visual simulator. A pilot in the cockpit of the visual simulator can see the realistic flash of a missile launch and then decide whether to evade it by maneuver only, by electronic or infrared countermeasures only, or by a combination. This type of interactive testing provides the best means to evaluate the overall ability of the aircraft to evade attacks by radar or infrared guided missiles or guns.

To obtain the most from the facilities installed at AFEWES, the laboratory links electronically to other research facilities in the United States and Europe, including digital computer models, system integration laboratories, hardware-in-the-loop laboratories, installed system test facilities, and open air ranges. Among the other facilities that link to AFEWES are those at Patuxent River, Maryland, and Spangdahlem, Germany.

Within this environment, electronic warfare systems operating at the proper frequencies or wavelengths in real time can fight simulated engagements. These engagements can include the effects of hostile operators acting within the loop and affecting the actual progression of the test.

The AFEWES facility is sufficiently flexible to permit tests involving advanced concepts through actual fielded hardware to be conducted against surface-to-air and air-to-air missiles, antiaircraft artillery and airborne interceptors.

If actual equipment is not available, such as on some newly discovered threats, accurate simulations are provided and updated as data become available.

Among the threats that the AFEWES test chambers can reproduce are Russian-built surface-to-air missiles from the SA-2B up through the SA-18, Redeye and Stinger Basic; air-to-air missiles from the AA-6 through the AA-11, the AIM-9L and -9M.

The laboratory also has the airborne radar interceptor systems of such Russian-built combat aircraft as the MiG-21, -25, -29, -31 and Su-27; antiaircraft artillery such as the Russian ZSU-23-4 and RPK-1; and such widely used radars as Long Track and Wild Card.

The reconfigurable airborne interceptor closed-loop simulation is typical of the variety of simulations that AFEWES can perform. The facility can conduct this simulation either in a radio frequency or an infrared-only mode or in a radio frequency/infrared multispectral configuration.

The simulation facility can portray a range of potential threat aircraft, such as the Su-27, MiG-29 or MiG-31, along with their associated airborne radars, cockpit control and displays, kinematically correct airframe simulations, and real frequency or wavelength simulations of both radar and infrared guided air-to-air missiles.

Also present are digital simulations of such likely battlefield emitters as infrared search/track radars; laser range finders; identification friend or foe signals; command, control and communications link transmissions; and various other weapons.

An open-loop jammer technique simulator is available for evaluating radio frequency electronic countermeasures concepts or techniques when the actual hardware is not available. This simulator can project a range of radar techniques, including track-while-scan, range deception, Doppler, conical scan and monopulse systems.

Researchers can use the AFEWES facility to evaluate and develop concepts or provide data on the potential benefits of upgrades to existing systems, and they have used the simulator to represent cooperative jamming by multiple aircraft, even when only one electronic combat system is available for test.


Laboratory Called to Action Solves Real-Time Problems on Battlefield

When U.S. Air Force Capt. Scott O’Grady’s F-16 was shot down over Bosnia in 1995 by a Russian-made missile fired by the Yugoslav army, his parachute had hardly deployed before a rapid call went out to the Air Force Electronic Warfare Evaluation Simulator in Fort Worth, Texas.

“What went wrong?” the Air Force mission controllers asked.

With United States and other North Atlantic Treaty Organization aircraft flying daily combat patrols over the breakaway Yugoslav province, there was suddenly an urgent need to know how the enemy missile was able to penetrate the aircraft’s electronics countermeasures system.

While Capt. O’Grady was dodging Serbian patrols, the Air Force Electronic Warfare Evaluation Simulator (AFEWES) was determining what the aircraft manufacturers and operators needed to know to correct the F-16’s radar warning system properly, Lt. Col. Linda Palmer, USAF, former AFEWES director, relates.

The radar warning system on the F-16 was put into the dynamic situation of the battle area in the AFEWES laboratory, and the laboratory transmitted the same signals that Capt. O’Grady and his wingman actually saw.

By putting the F-16s into a situation with the same electronic order of battle, AFEWES technicians were able to fly the aircraft in the same situation that had existed in Bosnia. They programmed the radar warning receivers the same way those on the lost F-16 had been programmed, so AFEWES researchers were able to confidently say that this is what the radar warning receivers actually saw.

Air Force approval for the study was given on the Friday after Capt. O’Grady was shot down, and by the following Monday at noon—three days later—the laboratory was supplying useful data to operational Air Force units, Col. Palmer relates. While the Air Force has not made public the exact data provided, the fact that no other F-16s have been lost in the area is significant.

Incidents such as this have made AFEWES famous for its quick reaction time in providing data to meet short-term requirements. But it is not just the rapidity with which the laboratory can solve problems that the armed services face. It is the complexity of the problems and the degree to which they involve the newest technology, both U.S. and foreign, that have made AFEWES a byword among weapons developers and users    .