Navy Details New Super Hornet CapabilitiesAviation Week and Space Technology
http://www.aviationweek.com/aw/search/a ... 2607p2.xmlFeb 25, 2007
By David A. Fulghum
The U.S. Navy's "Advanced Super Hornet" will tie together an electronic attack system with a powerful new radar that would allow the aircraft to find, deceive and, perhaps, disable sophisticated, radar-guided air-to-air, surface-to-air and cruise missiles. Moreover, it could do so at ranges greater than that of new U.S. air-to-air and air-to-ground weapons.
Silence about these key features of the Super Hornet's advanced radar and integrated sensor package is being broken by U.S. Navy and aerospace industry officials just as the President's budget faces scrutiny by Congress. Supporters of the design say it will give the Block II Boeing-built Navy aircraft a fifth-generation capability similar to that of the F-22 Raptor and F-35 Joint Strike Fighter. The Hornet's electronic attack capability could become even more sophisticated with additional modifications, says Capt. Donald Gaddis, F/A-18E/F Super Hornet program manager.
Radar-guided, air-to-air missiles that worry U.S. planners are the Chinese PL-12, which is on the brink of entering service; the Russian R-77 (AA-12 Adder); the R-27R/ER (AA-10 Alamo) family, and possibly the AA-10's R-27P/EP passive receiver variants. In the world of antiship cruise missiles, the Russians have developed RF-seeker-based antiship systems that include the Novator 3M-54 (SS-N-27) family and NPO Mashinostroenia 3M-55 (SS-NX-26), which is also the basis of the Russo-Indian Brahmos. The YJ-63 is a Chinese antiship cruise missile; Iran has the RAAD, and North Korea has a system in development known as KN-01 in U.S. intelligence circles.
Many Navy and industry planners hope that the merits of the F/A-18E/F's advanced systems, which can detect, identify and attack new classes of very small targets, will help it survive any congressional predilection to trim upgrades that are crucial to the program. Moreover, the Super Hornet equipped with a fifth-generation radar and integrated sensor suite is expected to be a tough competitor for international fighter sales. The advanced package has already resulted in a likely sale of 24 aircraft to Australia and is being pitched for large fighter buys planned by Japan and India.
The newest version of the Boeing Super Hornet, equipped with an advanced, Raytheon-built APG-79 active electronically scanned array (AESA) radar, can spot small targets--even stealthy cruise missiles--at ranges great enough to allow an effective defense. Navy officials are loath to talk with any detail about the metrics of electronic attacks and admit only to "extremely significant tactical ranges" for EA effects against air-to-air and surface-to-air radars, Gaddis says. However, other Pentagon and aerospace industry officials say that while air-to-air missiles are struggling to reach the 60-100-mi.-range mark, some sophisticated electronic attack effects can reach well beyond that.
"That's at least 100 mi.," says a long-time Pentagon radar specialist. "
There are different forms of electronic attack, and they include putting false targets or altered ranges, speeds and positions of real targets into the enemy's radars. Those are effects that require less power than jamming and therefore are effective at longer ranges."
An industry official with insight into AESA development says that the ability to affect a foe is limited by the enemy radar's range because the signal has to be captured, manipulated and returned. Therefore, long-range ground-based radars and even AWACS radars could be electronically attacked at ranges well over 100 mi. For air-to-air and surface-to-air missiles, the techniques would be the same but the effective ranges would be shorter.
The U.S. Navy's first AESA-equipped squadron has been developing combat procedures as the unit works up to its first deployment. VFA-213, flying all two-seat F/A-18F models, already has been through training cycles at NAS Fallon, Calif.'s "Strike U."
The Navy's concept of operations is to use combinations of EA-18 Growler electronic attack and the advanced Block 2 F/A-18E/F strike aircraft to offer self-protection, almost instantaneous location and identification of targets, and a variety of forms of electronic and conventional missile attack. That entity will be part of the advanced air wing in the Carrier Strike Group of 2024.
The U.S. Air Force is considering a similar approach--subtle effects versus brute power--in its next attempt at fielding a long-range, standoff jammer to protect its stealth aircraft fleet (AW&ST Jan. 22, p. 47) It's expected that advanced electronic warfare operations, including communications and network invasion and exploitation, may eventually be part of the Air Force's and Navy's capability. However, that's some years off and subject to budget realities.
Critics from within the electronic warfare community are concerned that jamming capabilities in fighter-size AESA radars have been over-sold on two counts. First, they contend that the radar's frequency band is small, so the target it affects would be limited. Second, concerns have been voiced that liquid cooling of the arrays isn't sufficient for creating a sustained, high-power jamming signal for more than a second without damaging the radar.
"The F-22's radar is already up against its duty cycle [sustained emission] limits with just finding targets," says a senior Air Force official. However, industry officials with knowledge of the Northrop Grumman radar say overheating problems with early versions of the sensor have been overcome with redesign of transmitter/receiver modules.
Critical for development of the "next generation," or Block II, Super Hornet and the ability to keep it militarily relevant as a "first day of the war" warplane beyond 2024 are a number of items in the President's budget now before the U.S. Congress, Gaddis says.
Three years of warfighting analyses by the Navy have produced a system of updates called "The Flight Plan," he says. Segments include upgrading the aircraft with a distributed targeting processor, integrating the sensors, and improving communication links for network-centric operations.
Once the AESA radar's operational evaluation is officially ended, the only other system needing op eval will be the ALE-55 fiber-optic towed decoy. Other systems are completed and in full-rate production, including the ALQ-214 jammer, ALE-47 chaff/flare dispenser and the advanced crew station in the cockpit's decoupled back seat. The weapon systems officer has the mission of maintaining situational awareness in the battlespace with user-friendly controls for the aircraft's advanced displays and sensors. The next step for the Super Hornet program is to integrate those systems and make the collected sensor information available to those in the battlespace through a common operational tactical picture.
"For example, our ALR-67(v)3 radar warning receiver is going to be delivered with a digitally cued receiver," Gaddis says. "We'll be able to pick up some different waveforms that we've not been able to capture before." Industry specialists say that means finding combinations of frequencies and pulse structures that allow identification of specific radar and aircraft threats.
"More importantly, we're going to marry the digitally cued receiver to single-ship geolocation algorithms [for precision location] and specific emitter ID algorithms with the AESA radar," says Gaddis.
Also, the radar warning receiver and ALQ-214 jammers will be integrated to produce "high-gain electronic attack and high-gain electronic surveillance measures," he adds. "We would use them as a survivability upgrade against advanced air-to-air and a certain spectrum of the surface-to-air threat.
"
We're going to create a high-speed data bus so that [electronic attack] techniques generated by the ALQ-214 will be sent through the AESA radar with much more power and effect," Gaddis says. "
Rather than wait for a threat to develop some electronic countermeasure, we plan to attack him [at long range] through the radar."
The associated long-range, high-resolution electronic surveillance capability of the Super Hornet is making it popular with the intelligence community. The real-time data make the aircraft important for updating the electronic order of battle--what's emitting and from where.
"It's going to duplicate what the radars on the F-22 and F-35 can do in integrating and analyzing what's happening in the battlespace," Gaddis says. "It's all tied to advanced architectures and mission computers, open architecture principles, high-order software languages and the way you integrate all these sensors that give you a fifth-generation capability."
Cruise missile defense with conventional weapons is a primary task of the Block II Super Hornet. "That is one of our assigned mission areas, and AESA does that very well," Gaddis says.
Part of the secret of the radar's ability to spot small targets and track them is a combination of power (for range and discrimination) and processing speeds that permit better ways of using radar information[/b]. Early radar designs could use a variety of waveforms with high, medium and low pulse-repetition frequencies. High PRF offers unambiguous, nose-on speed resolution and clutter rejection; medium PRF gives good low-speed resolution but low detection range, and low PRF provides unambiguous target ranges but poor clutter rejection.
"If you're looking for cruise missiles, often you have to pick them out of clutter, at low altitude and often at high speed," says an Air Force pilot with AESA radar experience. "With mechanically scanned radars, you would have to take six sweeps looking in high PRF, six in medium and six in low to cover different target sets. With an AESA radar, you can assign different parts of the radar to do each function so you don't have any gaps in your surveillance. If PRFs are suitably chosen, targets within a span of interest can be kept continuously in the clear."
Changing PRF radically affects both the radar's signal processing requirement and its performance. But a high-speed processor can simultaneously extract the best information from each category of PRF observations.
Operators of each aircraft type (F-22, F-35, F-15C, F/A-18E/F and EA-18G) with AESA radars are so far independently developing their tactics, techniques and procedures (TTPs) for how to fight cruise missiles.
"I would describe that as still in its nascent stages," Gaddis says. "If you ask about interoperability between those platforms, I think that's under development and will be driven by the combatant commanders. There's an acute realization that [joint interoperability TTPs] are absolutely required."
There's also a lag in developing new missile variants and warheads to cope with both subsonic and supersonic cruise and sea-skimming missiles.
"We have a very powerful radar that can detect cruise missiles," Gaddis says. "Now we need a missile to kill them. There are programs in the Amraam portfolio for taking out that target set."
Air Force researchers at Eglin AFB, Fla., and Raytheon engineers are working on the AIM-120C-6, which has a warhead specialized for head-on attack of small, slow-flying targets; the AIM-120C-7 that adds the ability to anticipate a cruise missile's flight path for a more efficient intercept, and the AIM-120D with longer range and the ability to maneuver vigorously at the end of its flight (AW&ST Feb. 12, p. 24).
Gaddis, who flew F-14s carrying the Phoenix long-range, air-to-air missile, helped develop tactics for shooting down air-to-surface cruise missiles.
"Some flew very high and very fast," he says. "If [your aircraft's nose] wasn't within 10 degrees of the [cruise] missile, Phoenix wasn't going to catch up. Now we have a different target set--Mach 3--but the principle is the same. You've got to be right on the [cruise missile's] nose if you're going to shoot down something like that."
Significant reductions can be made in the time it takes to locate and strike a target. Navy officials plan to install a precision targeting-like workstation on the F/A-18E/F called the distributed targeting processor. It will take an AESA-generated synthetic aperture radar map, compare it with an onboard SAR map that has every pixel geo-registered, then match the two images to generate a mensurated target coordinate and transfer it to a GPS-guided weapon, an anti-radiation missile or to direct an electronic attack.
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