Directed energy takes an unexpected turn and surfaces as a handy antimissile device that can be built into aircraft, ship and ground-based radars

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2 ELECTRONIC WARFARE Raytheon s MP-RTIP radar uses thousands of T/R modules installed on arrays up to 21 ft. long. It will be able to disable or confuse cruise missiles with spikes of energy. AESA s high average power, there are also bandwidth benefits and the ability to utilize flexible waveforms. They can also be used for jamming, a term now encompassing weapons effects on enemy electronics from the right combination of power, waveform, frequency and pulse length. Possible AESA techniques for attacking another radar could include burning through the target radar s antenna side-lobes, filter sidelobes, or other known features of the target system. Radar specialists suggest it is reasonable to suppose this capability is Directed energy takes an unexpected turn and surfaces as a handy antimissile device that can be built into aircraft, ship and ground-based radars DAVID A. FULGHUM/WASHINGTON and DOUGLAS BARRIE/LONDON Radar is emerging as one of the key weapons nearly all of them still shrouded by secrecy in the Pentagon s growing arsenal of nonexplosive devices. Knowledge that radar can produce violent effects on electronic systems is not new. More than 20 years ago, bomber aircraft radars were capable of generating enough concentrated noise jamming to burn out the valve amps (tube amplifiers) in fighters attempting an interception. The emergence over the last few years of the active electronically scanned array (AESA) radar, and its ability to provide high average power for appreciable times, makes such electronically destructive devices all the more attractive and effective. The weapons-effect utility of the AESA will provide a useful adjunct to other nonkinetic not relying on explosives or impact weapons research being done in the U.S. and in Europe. The intent is to develop an arsenal of weaponry that limits, or perhaps eliminates, collateral damage and unintended casualties, a particular concern with civilians in countries that coalition forces are trying to aid. Arrays designed for carriage by aircraft appear to be focused on cruise missiles and self-defense against anti-radiation, home-on-jam and air-to-air missiles. The radars seem particularly effective against the latter categories because energy available to focus on the approaching missile increases as an inverse square as distance decreases. With large ground- or sea-based AESA-type arrays, the targets are to include ballistic missile warheads, supersonic sea-skimming missiles or shoulderfired surface-to-air missiles that threaten airport operations. Some of the airborne AESA radars, designed for X-band frequencies, use thousands of small transmitters/receivers, each a couple of inches square, that allow the array to conduct many tasks simultaneously. Those include detection of small, even stealthy targets, tracking and communications. Along with the already available to some fielded systems. The AESA transmitters can also be focused on other targets to deliver bursts of X-band radio frequency energy into the vulnerable electronics of missiles the current focus or enemy aircraft and helicopters or computer systems. Under such assault, computers become confused and missiles lose interest in their targets. MOREOVER, THE AESA radar is related to high-power microwave (HPM) just beginning to emerge as missile defense systems. The primary difference is that AESA radars produce a sustained pulse for microseconds over a limited frequency range to create an effect while HPM produces a one-pico-sec. pulse of much greater power over gigahertz of frequencies, says a long-time Pentagon radar specialist. A laser beam, by comparison, would have to be held on the target for several seconds. Some industry specialists say such descriptions oversimplify the technology because both AESA radars and HPM can produce a variety of pulse lengths and bandwidths. They contend the only dif- 2 AVIATION WEEK & SPACE TECHNOLOGY/SEPTEMBER 5,

3 ference between AESA radars and HPM systems are the waveforms and RF power levels. Both systems use the same electronics technologies and those electronics are optimized for the performance needed to achieve the desired radar or HPM effect. That goal is often to confuse or damage enemy electronics. These capabilities aren t openly discussed. Moreover, those with knowledge of the technology offer many caveats. It s not wise to characterize all AESA radars as potential weapons, says an aerospace industry expert in advanced radars. Most radars are for defensive purposes only. Also, one does not need an AESA to turn a radar into a weapon. It can be done with other technologies. High power is required, but beyond that, it s mostly a software issue. more efficient and reliable since their RF and low-noise amplifiers are near the radiators so that very little energy is lost. The beam is produced by ganging the effects of thousands of lower-wattage T/R modules. There are lots of similarities between ground-based HPM systems and AESA radars including the T/R modules. In fact, ground-based HPM is becoming affordable because the proliferations of AESA radars has driven the price of modules down. HPM and AESA radar are not much different, said the radar specialist. However, HPM is not trying to be a radar. It s much simpler to concentrate the beam into a peak power pulse [since it s not busy detecting, tracking and identifying targets]. The instantaneous power Wide bandwidth is needed in order to find a vulnerable frequency for the target, he says. Purpose-built HPM systems would be better in this than most AESAs. THE NEWLY EMERGING HPM [devices] come in different flavors, says a second industry specialist. It can make it uncomfortable for a human being to be in the beam by relying on high average power to heat the skin. Another is used to confuse or burn out missile seekers. The level of peak and/or average power depends on the specific technique being used to counter the threat. In general, high peak power is not unique to HPM [devices], he says. Radars also use high peak power in long-range search modes, and AESA [arrays] are used for both. The discriminators are the waveform properties and techniques, which include power, duty cycle, pulse length, etc., to counter the various threats, not the technology that goes into the AESA itself. AESA [arrays] support HPM, radar, communications and electronic warfare applications. What makes them unique are the properties of the waveforms that are transmitted. There are AESAs fielded that operate at HF frequencies (re-locatable over the horizon radar) to millimeter waves (communications and other radar applications). The transmitter/receiver (T/R) modules for these devices can range from several feet to less that 1 4-in. square. Moreover, many frequencies beyond X- band can be exploited to produce weapons effects. AESA radars on fighter aircraft aren t particularly suited to create weapons effects on missiles because of limited antenna size, power and field of view, a senior U.S. Air Force official says. And, while weapons effects from radars are interesting, There s no requirement yet for the capability, at least on smaller aircraft, he says. The military s primary concern for now is high-resolution radar with moving target and synthetic aperture capabilities. While it s easier to plug the energyhungry system into city electrical power grids as ground-based systems or the Navy s next generation of electric-propulsion ships such as DD(X), the capability is also quickly moving into airborne systems. A weapons capability exists in a handful of F-15Cs modified with the APG- 63(V)2 radars for cruise missile defense and the latest production F/A-18E/Fs. It will soon be part of the F/A-22 and B- 2 as part of their radar upgrades, and AESA is also to equip the F-35 Joint Strike Fighter. HPM is eventually to be part of the Joint Unmanned Combat Air System payload, and the huge 4 X 21-ft. MP-RTIP AESA radar array is to fly on the E-10. An AESA array is also to be carried by the British Astor. As to weapons effects, the AESA radar offers the best way to generate high, sustained power where countermeasures demand average power, the radar specialist says. However, weapons effects or countermeasures will vary depending on the target s sensitivities. Very high peak power, short duration pulse may be the best method for attacking enemy electronics. In that case, the attack might better and more cheaply be delivered by an HPM weapon. An AESA is best used where it can use its radar function to locate the target and focus its energy. It can then rapidly move to other targets and select how long it wants to dwell on each. The radar s weapons effect is measured in watts/sq. cm. AESA arrays are it creates can burn out missile front ends [including focal planes and imagers]. BY COMPARISON, AESA radar uses more elaborate wave forms that focus on detection, he says. They put more sustained energy onto enemy missiles and burn out the low noise amplifiers and receivers in a seeker. Other specialists caution this generalization isn t necessarily always true. While HPM produces higher peak power, AESA often generates greater average power. That produces different operational and targeting strategies. For example, Raytheon s airport protection system uses infrared sensors to find the target and determine where to focus its beam. It also produces effects at longer range, possibly as much as 100 mi., because it produces powerful pulses of energy. AESA radar has the built-in ability to find and track a target, so it can be held on the target for the necessary additional microseconds needed to create its weapons effect. Some HPM pulses are designed to be very broadband, covering many gigahertz of frequencies, so they are more likely to find any opening or vulnerability in a target, the radar specialist says. AESA radar has a narrower frequency range, but it uses its radar capability to identify a target, search a library for its vulnerable frequencies and then tailor the signal for the specific target. c AVIATION WEEK & SPACE TECHNOLOGY/SEPTEMBER 5,

4 ELECTRONIC WARFARE Zap, It s Here Jumper confirms scope of new arsenal of explosive-less weapons being built and tested that can take their AESA arrays and not only receive with them, but turn around and jam with them, Jumper says. He confirms that the Air Force has used the term jamming to encompass, but not directly acknowledge, the ability of the AESA-type radars to focus the power of hundreds or thousands of small transmitter/receivers with enough accuracy to confuse the electronic guidance or damage electrical components of enemy missiles or aircraft radars. an attack is virtually impossible without forewarning. The target set for nonkinetic weapons could also include facilities that manufacture nuclear, biological or chemical weapons; the weapons, once they are filled, or the missiles or aircraft that carry them. At the other end of the spectrum are weapons such as shoulder-fired missiles targeted against airliners. Jumper also acknowledged the relationship between AESA radars and the first high-power microwave (HPM) weapons that are just emerging from development as a defense against surfaceto-air missiles. There s a lot of similarity, he says. One missile specialist notes that microwave weapons operate at much higher power than tactical radars and produce the most damage in enemy electronic systems. Nevertheless, electronic attack is viable with tactical [fighter-sized] RAYTHEON ILLUSTRATION In addition to radar weapons, the Air Force will add high-power microwave devices to its nonkinetic arsenal. Raytheon s Vigilant Eagle is a ground-based airfield defense system designed to shoot down shoulder-fired missiles. DAVID A. FULGHUM/WASHINGTON The U.S. Air Force s top commander has confirmed the service s development of a technologically diverse arsenal of nonkinetic devices that, without relying on explosives or impact, can produce destructive weapons effects on virtually any enemy system that relies on electronics. High in this emerging array are new radars that can be used as weapons. They are fulfilling the U.S. Air Force s desire for offensive tools that can find enemy threats, accurately identify them and immediately strike. Also among these 21st century foils some in operational use, others in test or development are high-power microwave devices for damaging or confusing enemy electronics; for example, those in surface-to-air missiles. There are also systems for the invasion of communication networks such as integrated air defense systems with which U.S. operators can take control, or passively gather intelligence. Other weapons exist for computer network attack (operated by the Air Intelligence Agency) and reactive electronic attack that is being prepared for the B-52 s standoff jamming capability and will later migrate to smaller tactical aircraft and UAVs. Absolutely, that s exactly right, said Gen. John Jumper, Air Force chief of staff, when these weapons were itemized during his last interview with AW&ST before retiring. It all fits in. While he is circumspect about exact details of weapons capabilities, he did acknowledge the ability of new active electronically scanned array (AESA) radars and, more particularly, future designs to inflict damage on enemy electronic systems. Once a planned series of radar upgrades are completed, if there is contested airspace because of surface-toair missiles, you have systems up there Unlike classic electronic noise jamming, it s fairly destructive, Jumper confirms. He also referred to the ability of larger AESA arrays to disable cruise missiles. In the theater, probably [you could use airborne AESA radars] because the places where the cruise missiles go are where you are, with orbits of defending aircraft, Jumper says. There s potential there to take advantage of nonkinetics. The problem becomes tougher for homeland defense because the nation s borders are so long, and placing aircraft in the right position for AESA radars by transmitting RF noise into enemy threat receivers, he says. There s also a glimmering space-based radars could additionally offer weapons effects, but treaty limitations and costs are expected to keep them tightly confined to the research world. With space-based radar, you have some [potential] capability for sure, Jumper says. But, I m not saying, let s call it a space-based radar, but it s really a microwave [weapon]. We re far from knowing [its true weapons potential]. Moreover, while there s a great payoff [for space-based radar], it s so darned expensive. c 4 AVIATION WEEK & SPACE TECHNOLOGY/SEPTEMBER 5,

5 DEFENSE ADVANCED RESEARCH PROJECTS AGENCY Unmanned Energy Many future directed-energy weapons will be carried by unmanned aircraft DAVID A. FULGHUM/WASHINGTON The Pentagon s accelerating push to field nonkinetic weaponry will bring with it a concomitant demand for more unmanned aircraft. The reasons for that choice are the options provided by removing aircrews from the aircraft, both for their protection from the effects of the weapons they carry which will rely on large electronic pulses and protection from air defenses that must be penetrated for a successful mission. When using short-range, directed-energy devices, effective ranges can be as little as a kilometer. High-power microwave [HPM weapons] on an aircraft is an engineering challenge, particularly when you have a person in it, says a senior Pentagon official. It s a lot easier to shield electronics [needed to control the aircraft] than it is to shield a body. Also, the closer I can get to the target, the more precise I can be [with an energy beam], the less power I need and the wider range of effects I can achieve. As planned by the Pentagon, there will be a series of increasingly sophisticated and more powerful weapons that range from electronic jamming to weapons effects from active electronically scanned array (AESA) radars and escalating to their most destructive level with high-power microwave bursts. Ultimately, military planners want to have the whole continuum at their disposal during a conflict. At the upper end I can fry the [target s electronics], the Pentagon official says. I can kill it and take it down hard. But, in many cases, that s not what I want to do. I believe the Defense Dept. wants flexibility to operate over that entire range dynamically. You may operate at the low end [creating disruption, injecting false targets or mining intelligence] for a while and then decide to kill the thing. THE AIR FORCE S directed-energy road map is classified, but an Army master plan names a primary goal of intercepting and bringing under electronic attack advanced communications signals being used by adversarial command and control networks. These digital communications signals will be disrupted, denied, and/or modified to render the communications system ineffective and unreliable. Long-term goals include the ability to surgically attack specific users [through] nonobtrusive means while maintaining the overall integrity of the target communications network. The Army also describes the use of high-power microwave or RF-directed energy to cause temporary upsets in electronics or permanent destruction due to burnout or electrical overload. As modern systems and their components become ever more reliant on sophisticated electronics, they also become more vulnerable to DE radiation. Northrop Grumman s X-47B is being sized to carry a combination radar sensor and weapon that can fry enemy electronics. There will also be a playbook of tactics that develop around the directedenergy weapons that will include the ability to find, chart and manipulate enemy networks. If I can find one node, stimulate it and bring up the network, I then know where everything is, the official says. Then I can selectively do other things to the remaining nodes. But I probably still want access to the [enemy] network, so I don t want to kill my gateway into communication or data streams. Directed energy will also be closely associated with information warfare. The Air Force s Suter series of experiments at Nellis AFB, Nev., demonstrated the ability to get inside an integrated air defense network, see what the enemy radars could see, and ultimately take control of the network if needed. Other capabilities allow packages of algorithms to be slipped in to enemy networks. There already have been demonstrations of AESA radars being able to disrupt and jam enemy electronics and of prototype HPM systems to shoot down a variety of shoulder-fired surface-to-air missiles. To get to the level that you can destroy an offensive [enemy] capability, you re probably talking years, the Pentagon official says. But there s a lot of capability below that that will be delivered a lot sooner. I think by 2010 we will be doing demonstrations of capabilities with nontraditional weapons with very interesting capabilities. Obviously the first high-end capabilities will be on big platforms such as the E-10 multi-sensor command-andcontrol aircraft, he says. However, there will be some interesting stuff below radar effects that is not exclusively information operations. There are some disruptive capabilities down there [that could fit into unmanned aircraft]. I don t have to have a big, honking AESA array to achieve some of these effects. It s not as robust [an effect] as having an AESA, but today all the AESAs are on manned tactical aircraft and there are AVIATION WEEK & SPACE TECHNOLOGY/SEPTEMBER 5,

6 ELECTRONIC WARFARE limitations to how close they can get. There are also problems to solve. The number of technological breakthroughs needed to make the systems a success depend on where in the effects continuum a design needs to work. On the high end, there are some technology breakthroughs that need to happen power generation, shielding, integration, better high-energy arrays and new methods to direct fairly high pulses through a small [antenna] array without destroying it, the official says. But at the low end of the spectrum [the problems are concerned with] integration of the technology on the platforms and the [development of] concept of operations that allows effective use. The Army master plan also called for the development of high-gain, broadband antennas, silicon carbide hardening devices to prevent fratricide and and use Boeing s X-45C has been eyed since its inception to carry future airborne highpower microwave weapons and jamming missiles to blind and confuse air defenses. of chaos theory research results to achieve greater control of RF-DE weapon sources. The last refers to the long-term problem of focusing directedenergy beams accurately for best effects. Other analysts agree that the use of nonkinetic weapons will demand coordination with other aircraft to protect the penetrating UAVs. It will also mean blocking out big areas of airspace so that friendly aircraft aren t damaged by the side effects of directed-energy weapons. Predictions are that by 2010, the Pentagon will have demonstrated capabilities on UAVs that solve most of the Defense Dept. s issues involving sharing airspace with manned and unmanned aircraft. Anything that produces a big spike of energy could potentially interfere with the operation of an aircraft, the official says. We re going to have to find solutions that allow us to operate in a pretty dirty environment, in some cases one that we re creating ourselves. A part of the solution will be the development of very focused, niche aircraft systems. The Defense Dept. is not going to build 2,000-3,000 unmanned aircraft of any one kind, the official says. That excludes production of smaller UAVs where production has already reached 250 per month for some designs. My sense is that the first Joint Unmanned Combat Air System [J- DEFENSE ADVANCED RESEARCH PROJECTS AGENCY UCAS] vehicles that the military builds and they won t buy a lot, probably will be focused on a couple of missions, he says. And they will rely on other systems [jamming and decoys] to get them close. You might imagine they will have an AESA [array for weapons effect] on them, but the array will be fairly small because they want to keep the [radar] signature levels low. So to have an effect, I have to get relatively close. Based on the information researchers derive from the J-UCAS demonstration program, acquisition decisions will be made. A key element is an unmanned, stealthy platform that can get in close to threats. c Bomber Jam B-52 standoff jammer selection nears, and Northrop Grumman steps up first to talk DAVID A. FULGHUM/WASHINGTON Another piece of the Pentagon formula for electronic attack is falling into place as the U.S. Air Force gets back into the tactical jamming world and the Navy begins to phase out its expeditionary EA-6B squadrons. The Air Force is planning an Oct. 11 selection of the contractor to lead development of B-52 modifications that would make it capable of long-range electronic jamming and the management of a large number of electronic attack weapons distributed across the battlefield in other aircraft. The proposed USAF arsenal is to include unmanned aircraft, decoys, computer attack, new radars that can jam or disable enemy electronics and although few will discuss them two new tools: One is the ability to tap into enemy communication networks and even take control of them; the other is high-power microwave (HPM) weapons that disable enemy electronics with large spikes of energy. Northrop Grumman officials won t discuss the effective distance of the B-52 s jamming except to say it allows the bomber Northrop Grumman s mockup shows the EW officer s station in a B-52 modified as a standoff jammer. 6 AVIATION WEEK & SPACE TECHNOLOGY/SEPTEMBER 5,

7 to operate beyond the range of surfaceto-air missiles. That means at least 100 mi. and undoubtedly farther, since proposed SAM systems have ranges of up to 250 mi. Competitors for the $235-million, twoyear pre-development phase are Northrop Grumman and the Boeing/BAE Systems team. However, if the Air Force modifies the first 16 B-52s and buys 12 electronic attack systems, the contract would be worth $2 billion. If the entire fleet of 76 B-52s is modified, the value would escalate to $3 billion. Northrop Grumman is the first to lay out its vision of the B-52 SOJ concept and its place in a larger electronic warfare battle management network. Two ft. pods will fit on the stations that now carry wingtip fuel pods. Each pod will have active electronically scanned arrays (AESA) facing outboard. The concept of operations would have one array actively scanning the enemy and emitting pulses of jamming energy while the other, on the opposite side of the aircraft, passively monitors friendly forces to provide situational awareness of their positions and electronic activity. The emitter arrays have not been completely defined, but Northrop Grumman officials say they are consulting with major suppliers such as Raytheon and ITT, as well as its own Electronic Systems division. However, it is known that each pod will be equipped for preemptive (against known targets) and selective-reactive electronic attack (against unexpected or pop-up threats). The arrays more than 100 in. in length (although that may change) would operate in multiple X and Y frequency bands, say company officials. Against a sophisticated enemy, the system would be focused, at least initially, on analyzing and disabling integrated air defenses. Against a guerrilla or terrorist threat, the emphasis would likely involve jamming and analyses of communications. USAF S B-52 SOJ request for proposals asked the lead systems integrator candidates to provide more extensive battle management to control a distributed, nonkinetic weapons capability as a likely future spiral to the program. So Northrop Grumman researchers are offering their airborne electronic attack mission management processing (AMMP) system as the basic building block for control of the electronic attack network. AMMP is already functioning in the laboratory. It processes reports to analyze communications networks. In addition, there are programs being developed to let intelligence specialists get inside enemy networks to monitor them, and some work is being done on slipping algorithms into networks that can help open them up to intelligence exploitation such as information mining. Other extensions of this network will be supplied by the parallel development of the EA-18G Growler, which will supplement and eventually replace the EA- 6B; and the Joint Unmanned Combat Aircraft Systems (J-UCAS), which will be stealthy and long range for carrying onboard jammers close to targets. Or if the site is too heavily defended, the B- 52 can fire Miniature Air-Launched Decoys with small jammers into the target while standing out of air defense range. J-UCAS also is being considered The B-52 SOJ is to carry two ft. wingtip pods packed with transmit/receive modules that can jam enemy electronics at ranges of more than 100 mi. from various nodes, analyzes effects on enemy systems, and assigns additional electronic attacks. The larger electronic attack network also includes the EA-6B Prowler with its new ICAP III selective-reactive electronic attack. It is expected to deploy to Iraq for the first time in early 2006 with the Navy s VAQ-139 from NAS Whidbey Island, Wash. While military personnel will not discuss the mission, the system is aimed at jamming highly sophisticated radars (used by other countries in the region) and radios used by insurgents, and at collecting electronic data that can be used for payloads that include AESA radar or high-power microwave weapons. These are envisioned as the next generation of nonkinetic weapons that can damage and confuse electronic systems, including computers and virtually anything dependent on electronics. Yet another electronic weapon is airborne computer-network attack: That s the ability to insert packages of algorithms into enemy computers to conduct a range of activities from intelligence gathering to destruction of the network s software. The early operational capability of the B-52 SOJ is to be available by 2012, as the EA-6B expeditionary units are phasing out. Initial operational capability, with a full electronic attack arsenal including selective-reactive jamming, is to follow in c Posted from Aviation Week, September 5, 2005, copyright by The McGraw-Hill Companies, Inc. with all rights reserved. This reprint implies no endorsement, either tacit or expressed, of any company, product, service or investment opportunity. # Managed by Reprint Management Services, To request a quote online, visit