Japan is set to acquire 4 E-2D Advanced Hawk Eyes

These advanced Hawk Eyes are being purchased specifically to counter Chinese stealth J-20 and J-31
http://nationalinterest.org/blog/the-bu ... j-31-14016

These advanced Hawk Eyes are being purchased specifically to counter Chinese stealth J-20 and J-31
http://nationalinterest.org/blog/the-bu ... j-31-14016

Author Dave Majumdar uses the sale of four Northrop Grumman E-2D Advanced Hawkeye aircraft to Japan as an opportunity to repeat himself and make the same claims that the Lockheed Martin AN/APY-9 UHF-band radar is a stealth killer.

"The U.S. Navy’s Secret Counter-Stealth Weapon Could Be Hiding in Plain Sight"
By: Dave Majumdar
June 9, 2014 9:14 AM

Source:
http://news.usni.org/2014/06/09/u-s-nav ... lain-sight

Discussion of the previous article:

viewtopic.php?p=272799#p272799

These advanced Hawk Eyes are being purchased specifically to counter Chinese stealth J-20 and J-31
http://nationalinterest.org/blog/the-bu ... j-31-14016

Japan is set to acquire four Northrop Grumman E-2D Advanced Hawkeyes airborne early warning aircraft that would nullify the threat of Chinese stealth fighters and afford it a potent missile defense capability. The new aircraft is equipped with a powerful hybrid mechanical/electronically scanned UHF-band radar that will be able to tie into the U.S. Navy’s state-of-the-art Naval Integrated Fire Control—Counter Air (NIFC-CA) battle network.

Japan’s purchase of the E-2D is significant because the capabilities of those two key features. The E-2D’s Lockheed Martin AN/APY-9 UHF-band radar is the central feature of the Advanced Hawkeye. Both friend and foe alike have touted UHF radars as an effective countermeasure to stealth technology. One early public example of that is a paper prepared by Arend Westra that appeared in the National Defense University’s Joint Forces Quarterly academic journal in the 4th quarter issue of 2009. “It is the physics of longer wavelength and resonance that enables VHF and UHF radar to detect stealth aircraft,” Westra wrote in his article titled Radar vs. Stealth.

UHF-band radars operate at frequencies between 300MHz and 1GHz, which results in wavelengths that are between 10 centimeters and one meter long. Typically, due to the physical characteristics of fighter-sized stealth aircraft, they must be optimized to defeat higher frequencies in the Ka, Ku, X, C and parts of the S-bands.

There is a resonance effect that occurs when a feature on an aircraft—such as a tail-fin tip— is less than eight times the size of a particular frequency wavelength. That omnidirectional resonance effect produces a “step change” in an aircraft’s radar cross-section. Effectively what that means is that small stealth aircraft that do not have the size or weight allowances for two feet or more of radar absorbent material coatings on every surface are forced to make trades as to which frequency bands they are optimized for.

That would include aircraft like the Chengdu J-20, Shenyang J-31, Sukhoi PAK-FA and indeed the United States’ own Lockheed Martin F-22 Raptor and tri-service F-35 Joint Strike Fighter. Only very large stealth aircraft without protruding empennage surfaces — like the Northrop Grumman B-2 Spirit or the forthcoming Long Range Strike-Bomber — can meet the requirement for geometrical optics regime scattering. Effectively, that means the E-2D’s AN/APY-9 radar can see stealth aircraft like the J-20 or J-31.

Pentagon and industry officials concede that low-frequency radars operating in the VHF and UHF bands can detect and even track low-observable aircraft—that’s just physics. But conventional wisdom has always held that such systems cannot generate a “weapons quality” track—or in other words, are unable to guide a missile onto a target. “Poor resolution in angle and range, however, has historically prevented these radars from providing accurate targeting and fire control,” Westra wrote.

However, electronic scanning and new signal processing techniques have mitigated those shortcomings to an extent. And there are other techniques in development, such as linking multiple low-frequency radars via high-speed datalinks, which might enable those radars to generate weapons quality tracks. But industry officials say those technologies are not ready for prime time.

Yet, the U.S. Navy and Lockheed may have already solved the problem. The service openly talks about the E-2D’s role as the central node of its NIFC-CA battle network to defeat enemy air and missile threats. Indeed, Rear Adm. Mike Manazir, the Navy’s director of air warfare, described the concept in detail to myself and my good friend Sam LaGrone at the U.S. Naval Institute just before Christmas in 2013.

Under the NIFC-CA ‘From the Air’ (FTA) construct, the APY-9 radar would act as a sensor to cue Raytheon AIM-120 AMRAAM air-to-air missiles for Boeing F/A-18E/F Super Hornets fighters via the Link-16 datalink. Moreover, the APY-9 would also act as a sensor to guide Raytheon Standard SM-6 missiles launched from Aegis cruisers and destroyers against targets located beyond the ships’ SPY-1 radars’ horizon via the Cooperative Engagement Capability datalink under the NIFC-CA ‘From the Sea’ (FTS) construct. In fact, the Navy has demonstrated live-fire NIFC-CA missile shots using the E-2D’s radar to guide SM-6 missiles against over-the-horizon shots—which by definition means the APY-9 is generating a weapons quality track.

For Japan, it is the E-2D’s ability to facilitate over-the-horizon missile shots against supersonic anti-ship missiles, stealthy low-level cruise missiles and theatre ballistic missiles that are of great interest given the growing threat from China and North Korea. The ability to nullify China’s investment in the Chengdu J-20 and J-31 is likely just an added bonus—especially if Japan upgrades its F-15 Eagles and other fighters to take advantage of NIFC-CA.

Indeed, there is a possibility Japan plans to do just that. According to a recent Sept. 25, 2015, story that appeared in the Yomiuri Shimbun—which is the ruling Liberal Democratic Party’s favored news outlet—Japan is building two Aegis destroyers installed with NIFC-CA. “The Defense Ministry will introduce NIFC-CA capable E-2D airborne early warning aircraft and also plans to install the latest information-sharing system that supports NIFC-CA on two Aegis ships now being built,” the Yomiuri Shimbun reported.

https://news.usni.org/2014/06/09/u-s-na ... lain-sight

Article is written by Dave Majumdar but he does quote a paper prepared by Arend Westra that appeared in the National Defense University’s Joint Forces Quarterly academic journal in the 4th quarter issue of 2009.

UHF and VHF-band radars have historically had some major drawbacks. “Poor resolution in angle and range, has historically prevented these radars from providing accurate targeting and fire control,” Westra wrote.

Northrop Grumman and Lockheed Martin appear to have overcome the traditional limitations of UHF-band radars in the APY-9 by applying a combination of advanced electronic scanning capability together with enormous digital computing power in the form of space/time adaptive processing.

I actually take this as a good thing.

Basement dwellers have often said that the US has too much faith in Stealth which is only useful in the Ka, Ku, X, C and parts of the S-bands. But they are useless in the UHF and VHF bands.

The Typical counter is, of course, UHF and VHF cannot be used to guide missiles anyway.
But they believe that China and Russia are close to developing UHF and VHF systems that are capable of weapons guidance.

They claim that the US does not use these lower frequencies at all believing that it will be impossible to turn them into systems capable of targeting stealth fighters. This is the reason why 5th gens are allegedly so successful in exercises. It's because adversary forces keep using radars that 5th gens are optimized for.

Turns out, the US navy is way ahead of them already. And the fact that they are unwavering in their faith in the F-35C means that it is effective even against the best "counter-stealth" radar available, the AN/APY-9

I am sure with enough computing power and technology we can make UHF and VHF radar bands more accurate and less susceptible to clutter but in the end we're dealing with the laws of physics.

UHF band may not be enough to counter stealth.
According to the book written by (Djordje Anicic), Deputy Commander of the famous 3 rocket divisions (3rd PVO) who shot down F-117 in Serbia
http://www.lektire.me/prepricano/djordj ... -smena_945

Suddenly on the observation radar, I see the target on azimuth 195, 23 kilometers away. The next circle on the observation radar clearly indicates that the plane is approaching us. I say: "Dani, this is going to us!" Days opened his eyes, looked at the screen, and uninterestedly followed the situation. The reflection approached us. The plane was at 14-15 km, when Dani ordered: "Azimuth 210, search!" As an assistant to the shooting man, I ordered that moment: "Antenna!" The commander of the battery began to point the guiding officer on the azimuth and the meat corner to the target - left, left: stop !, right, up, up: stop! - antenna. He switched on the radiation of the observation radar. That's when the cats and the mouse started playing. Who will be faster and more skilful. The guiding officer, turning three wheels at the same time, tries to find the target. We run for more than ten seconds in an unsuccessful search for the target. Ordering: "Stop Searching - Equivalent!" After a few moments, Dani again orders the new search azimuth 230, and I am the moment of radiation. Adrenaline is in the air. This road manager manages to see the target on his two screens, but in no way can he cover it with a cross-section of horizontal and vertical markers. The dots just shrink - it has to push them out, cover the goal in the cross-section of the two markers. At the moment when the target is in the cross-section of the marker, they can begin to be monitored by manual tracking operators - by plane F1 and F2 on their pointers. Then conditions were created for the guidance officer to monitor the goal by distance, and manual tracking operators to run launched missiles at the target that is in the cross-section of the marker. The goal is to run and maneuver. Again the radiation time is too long and I order: "Stop searching - equivalent!" After a few seconds, we try the same procedure, the third time on the azimuth 240. Very soon, after a few seconds, the guidance officer finds the target and reports that the goal is to maneuver. The dashboards of the guards are shaking, the operators are losing it. The radiation time was long and dark when I wanted to order: "Stop searching - equivalent", the monitor of the monitor, Dragan Matić, cried out, "Give it! Give it, I have it!"



He energically turned his wheel, trying to bring the reflection from the target to the center of the screen. He succeeded. The tracking operators managed to hit the target with a cross - cross-section of two markers and thus provide the conditions for launching the missile. Another tracking operator, Dejan Tiosavljević, reports that the goal is to have a large reflecting surface. That moment, I say to Daniel: "Take care that it's not bait to screw us." My thoughts on war experiences from Iraq passed through my mind when the united forces put up angular reflectors on unmanned aircraft and thereby increased the reflective surface. The Iraqi combat crew thought it was a real plane and began radiating a Nishan radar. At that moment, airborne hunters captured the radar-nišan location and then eliminated the missile from anti-aircraft missiles from the ambush. The guiding officer, Muminović, reports - the station follows the target, the target on arrival, a distance of 13 kilometers. At the same time, operators report - by F1 I follow the target, following F2 I follow the goal. Dani commanded: "Object Destroy, Method T / T Launch!"

According to the book, P-15 (operate in UHF band) detected F-117 from 23 km, SNR-125 (operate in X-band) detected F-117 at distance less than 14 km.
P-15 claimed to have range = 150 km, assumming this is detection range is against target with RCS = 10 m2, this radar will detect target will RCS of -30 dBsm (0.001m2) from 14 km and it will detect target with RCS = -20dBsm (0.01m2) from 26 km, P-15 detect the F-117 from 23 km, therfore in UHF band -20 dBsm > F-117 RCS > -30 dBsm


SNR-125 can detect target with RCS = 10m2 from 80 nm (148 km), according to radar equation, 10 times reduction in RCS will decrease detection range down to 56%, so a target with RCS = 0.001 m2 will be detected at 7.87 nm (or 14.5 km), F-117 was tracked and detect at distance less than 14 km so F-117 rcs in X-band is less than 0.001m2.

I am sure with enough computing power and technology we can make UHF and VHF radar bands more accurate and less susceptible to clutter but in the end we're dealing with the laws of physics.

I'm making a distinction below, using "US5th-gens", simply because it's quite unrealistic to think the first operational LO jet gen from China (or anywhere else, for that matter) will be directly comparable in multi-band low-observability terms. These will still be chalk and cheese.

With regard to this subject you're also dealing with scale limitations.

An AEW&C aircraft is illuminating from one (mobile) location, with limited electrons, and limited payload scale, and is still quite radar footprint limited. Plus it is not creating weapon quality tracks, it is creating sensor cues for the AMRAAM-derived terminal sensor on the SM6 (to try and produce its own weapon track).

Does this same sensor family currently work well against US5th-gens when they are plainly visible?

No.

And do full-sized fighter radars readily lock-up US5ths, when they're plainly visible to the pilot?

No (but an advanced IRST may have changed this situation now).

So this UHF AEW&C approach is a very useful fighter and terminal-seaker cueing tech, against 4th-gens--but logically, it is not such against US5th-gens.

Such 'over-the-horizon' cueing of fighter sensors is not new. JORN already does the the same thing, and over a whole vast threat-axis region, not just on the scale of a moving AEW&C footprint and effective sensitivity radius.

The innate scale problems are overcome via using even longer waves, VHF/HF bands, fixing antennas well inland, and emitting millions of watts into a region, making these watts steerable, and focus-able, landing where you want them, plus overlapping the separate respective array footprints to thus use continent-wide triangulation to generate fighter-cueing and sensor-cueing accurate (not precise) 2D location quality spacial-resolution within the 'first-bounce' region in the highest threat-axis of approach region (the late-1990s initial-operational tracking radius was out to ~3,000km deep with ~1.6 million watt output).

The thing this approach doesn't supply is direct altitude data (AEW&C does, hence E-7A) but that also can be indirectly derived/estimated from the observed flight-track data, like the logged climb speed and climb time, the top of climb cruise speed and its ∆ during flight, etc. So the probable ID of the type and nationality can be narrowed-down from where the track has originated (airbase and the types based there) and its flight profile plus associated ATC comms, flight-plans lodged (or rather, not) plus COMMS, ELINT, etc.

Hence an active interest in hypersonic missile development by Australia as a hypersonic SAM plus JORN and other sensors may be an effective combo for countering cruise-missile carrying aircraft early, at long ranges, thus freeing up the strikefighters to strike, instead of intercepting or in wasting time on unnecessary BVR ding-dongs.

Given the current thermal sensors also seem to struggle WVR against US5th-gens, the other scale problem to providing useful missile-cueing against an actual VLO US5th-gen, is the need for a high-gain active (passive?) UHF/VHF sensor, on the terminal missile's nose. Good luck with that, plus it would be fairly easy to jam it, off-board, via EA support aircraft (hence EA-18G off-board standoff support).

IMO, UHF/VHF over-the-horizon defeat of tactical VLO is a long way off if you want to cue and then home a weapon on to them--indirectly and remotely.

Direct non-remote observation with multi-spectral missile seakers at much shorter (traditional kill) wavelengths plus the necessity of advanced datalinks are what might actually be effective (i.e. BVR) ... and then there are the directed-energy options coming that can be added to secure the direct-detection fight also ... which then presents a real problem for the AEW&C, if say 12 F-35As focused their energy on it simultaneously (even from long range from high altitude).

IMO, the real value of a well-developed UHF (AEW&C) and VHF/HF (OTHR) indirect fighter and weapon cueing is that it can positively slaughter any 4th-gen dominated legacy force. A good reason to divest 4th-gens as 5th-gens are built (USN?).

Which is an issue that will mostly not be one for a US-alligned joint force, as many Western-European and South and East-Asian airforces will have an initial US5th-gen capabiliity soon. It may however be a growing problem for airforces like Germany, and cash-strapped Eastern-European airforces which have not invested in US5th-gens as yet. Hence the need for forward F-35 deployments, with EA support to provide a re-enforced deterrent.

No cigar.

It is possible possibility that Đorđe Aničić was inside P-18 cabin instead of P-15
https://www.in4s.net/obaranje-f-117a-pr ... /?lang=lat

The fact that the F-117A was downgraded from the third attempt is unquestionable. The first and second attempts to find the target in the air by the Nishan radar were unsuccessful. Sitting in the PRG view point toward the P-18 observation radar at one time on the azimuth 195, I notice three targets, 23 kilometers away. The next circle on the observation radar clearly indicates that the plane is approaching us. I follow him in the next round of the distance is 18 km. The operator of the observation radar P-18, Ljubenkovic's guide through the GGS (voice-of-speech) reports that we have a goal. Obviously we are following the same situation in the air.

DSCA announcement on 9 more E2Ds for Japan.

http://www.dsca.mil/major-arms-sales/ja ... aircraft-0

A lot of speculation and very little facts.....

Japan cleared to buy nine additional E-2Ds

https://www.flightglobal.com/news/artic ... ds-451809/

The US government has cleared Tokyo to obtain nine additional Northrop Grumman E-2D Advanced Hawkeye airborne early warning & control (AEW&C) aircraft.

The US State Department announced the potential deal in Defense Security Cooperation Agency (DSCA) statement. This means that Tokyo could eventually obtain up to 13 E-2Ds, as it already has firm orders four examples of the type.

The DSCA says the nine aircraft contract could be worth up to $3.1 billion. Tokyo tends to order one aircraft per annum.

Should Tokyo buy the full allotment of E-2Ds, it could replace its aging fleet of E-2Cs on a one-for-one basis. Previously, however, officials have said that the new aircraft will augment rather than replace the legacy E-2Cs.

Flight Fleets Analyzer shows that the Japan Air Self Defense Force operates 13 E-2Cs, aged between 25 to 36 years old.

In addition to the nine aircraft, the package includes 28 Rolls-Royce T56-A-427A engines (18 installed and 10 spares), ten Lockheed Martin APY-9 radars (nine installed and one spare), plus an array of equipment, support, and training.

Japanese E-2Ds have several modifications compared with those operated by the US Navy. Given that the type will operate from land bases, and not aircraft carriers, it is modified to carry extra fuel in a “wet wing”, providing endurance of 8h, compared with 5h for the US E-2Ds. Those aircraft rely on air-to-air refueling to boost their endurance.

In addition to the 13 E-2Cs, Japan has four E-767s serving in the AEW&C mission. The average age of these aircraft is 22.7 years.

The sole operator of the E-2D is the US Navy, which has 31 examples. It has firm orders for an additional 24, and letters of intent for another 24.

E-2 has always (operational for well over 50 years) used UHF frequency band and nothing in that changed with E-2D. Sure E-2D has by far the most capable radar and other systems of all E-2s, but frequency band remained the same. UHF band was chosen because the operating environment is mostly over water. UHF is by nature less affected by sea clutter and bad weather than higher frequency bands. It's also easier for signal processing given the limited volume inside E-2. It was accurate enough to give early warning for carrier groups and later variants/upgrades have improved performance significantly with advanced signal processing etc.

Sure UHF frequency also helps against VLO targets but so does the advanced signal processing used in E-2D. Of course VLO targets will still be seen much closer than non-stealthy targets. I'm sure Japanese air force likes all the advances in performance. These include radar, ESM, communications, EW and even cockpit and engine. All help in getting more performance against potential adversaries.