Home » Aviation » The U.S. Navy’s Secret Counter-Stealth Weapon Could Be Hiding in Plain Sight


The U.S. Navy’s Secret Counter-Stealth Weapon Could Be Hiding in Plain Sight

An E-2D lands on the aircraft carrier USS Dwight D. Eisenhower (CVN-69). US Navy Photo

An E-2D lands on the aircraft carrier USS Dwight D. Eisenhower (CVN-69). US Navy Photo

The Northrop Grumman E-2D Advanced Hawkeye maybe the U.S. Navy’s secret weapon against the emerging threat of enemy fifth-generation stealth fighters and cruise missiles.

The key to that capability is the aircraft’s powerful UHF-band hybrid mechanical/electronically-scanned AN/APY-9 radar built by Lockheed Martin. Both friend and foe alike have touted UHF radars as an effective countermeasure to stealth technology.

One 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 omni-directional 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.

“You can’t be everywhere at once on a fighter-sized aircraft,” one source told USNI News earlier in the year.

An E-2D Hawkeye outside the hangar at Naval Air Station Patuxent River on March 26, 2014. US NAvy Photo

An E-2D Hawkeye outside the hangar at Naval Air Station Patuxent River on March 26, 2014. US NAvy Photo

However, as Westra and many other sources point out, UHF and VHF-band radars have historically had some major drawbacks. “Poor resolution in angle and range, however, 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.
The Navy would not directly address the issue, but service officials did say the APY-9 provides a massive increase in performance over the E-2C Hawkeye 2000’s radar.

“The E-2D APY-9 radar provides a significantly enhanced airborne early warning and situational awareness capability against all air targets including threat aircraft and cruise missiles,” said Naval Air Systems Command spokesman Rob Koon in an emailed statement to USNI News.

“The modern technology of the APY-9 radar provides a substantial improvement in performance over the E-2C’s APS-145 radar whose heritage dates back to the 1970s.”

But the Navy openly talks about the E-2D’s role as the central node of its Naval Integrated Fire Control-Counter Air (NIFC-CA) (pronounced: nifk-kah) construct to defeat enemy air and missile threats—Rear Adm. Mike Manazir, the Navy’s director of air warfare, described the concept in detail to USNI News last December.

Under the NIFC-CA ‘From the Air’ (FTA) construct, the APY-9 radar can 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.

Additionally, the APY-9 also acts as a sensor to guide 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. And thus far, all live-fire NIFC-CA missile shots have been successful.

The first increment of NIFC-CA is set to be fielded later this year when the first E-2D squadron, VAW-125, is set to declare initial operating capability in October 2014. NIFC-CA will be declared operational concurrently with that squadron.

The APY-9 is a unique design in many respects, NAVAIR and Northrop brag that the radar is a “two-generation leap” over the APS-145 in an information booklet the service has been distributing. While externally the radar appears to be no different than the purely mechanically-scanned AN/APS-145—also built by Lockheed Martin–internally it is an another matter entirely.

While the APY-9 does rotate inside the E-2D’s dish-shaped radome to achieve 360-degree coverage, the crew of the aircraft can control the antenna rotation speed to focus on an area of interest according to NAVAIR. Further, the 18-channel passive phased-array ADS-18 antenna has the ability to steer its radar beam electronically. It also incorporates an electronically-scanned identification friend or foe system.

The transmitter and receiver hardware are located inside the aircraft’s fuselage and connect to the antenna via high power radiofrequency transmission lines and a high power radiofrequency rotary coupler. Thus, it is not an active electronically scanned array radar.

The APY-9 has three distinct radar modes, Advanced Airborne Early Warning Surveillance, Enhanced Sector Scan, and Enhanced Tracking Sector.

Advanced Airborne Early Warning Surveillance is the normal operating mode for the radar to provide uniform 360-degree, simultaneous air and surface coverage with long-range detection of low radar cross-section targets. The antenna rotates 360 degrees every ten seconds or so when it is operating in this primarily mechanically scanned mode.

The Enhanced Sector Scan mode merges traditional mechanical scanning with steerable electronic scanning to leverage the benefits of both technologies while simultaneously mitigating the shortcomings of either methodology. The antenna rotates mechanically, but the operator can select a specific sector where the rotation of the antenna is slowed to focus on an area.

Enhanced Tracking Sector is a pure electronically scanned mode, where the antenna is geographically stabilized or following a particular target. This mode provides enhanced detection and tracking in a selected sector by stopping the antenna and scanning purely electronically. This mode is particularly useful against low-observable targets due to its rapid track updates.

The APY-9 has a range of at least 300 nautical miles and seems to be limited only by the performance of the E-2D airframe–which normally operates at 25,000ft.

The Navy ultimately hopes to buy a total of 75 E-2D with the last examples entering the fleet in the 2020s.

  • Marcd30319

    The Northrop Grumman E-2D Advanced Hawkeye maybe the U.S. Navy’s secret weapon against the emerging threat of enemy fifth-generation stealth fighters and cruise missiles.

    Need a space between “may” and “be” in you opening sentence unless you are deploying stealth verbs.

  • Matthew

    If I understand correctly, the US should scrap everything that isn’t made by Northrop Grumman…? You earned your paycheck from Northrop with this article…..

  • Jack Aaron Howell

    CEC is not a data link. It is another way for CEC-equipped ships to identify contacts. Also, the SM-6 isn’t scheduled to enter service until 2018.

  • Secundius

    Only if you can keep the Israeli’s from trying to sell the PHALCON, Airborne Early Warning System from the ChiCom’s.

    • R’ Yitzchak M

      A reeally…?? You are fairly persistent on your agenda
      of Israeli “selling out”? ISRAELI TECHNOLOGY..to? China? or was it
      India? Now lets be honest for a bit.. Out of 18 Terrorsists that killed 3,000
      BRIGHTEST and the best economic and BUSINESS MINDS in the US and the planet as
      well they truly hurt a very backbone and a nerve center of the capitalist
      economy TRADE and FREE ENTERPRISE were the victims of THE Saudi Arabia out of
      18 murderers FIFTEEN WERE SAUDIS.. A
      prince who actually financed 2 PROOVEN
      or there was seem to be some data to support involvement with the other 4
      murdering thugs. Or shall we be more politically correct (not to offend
      Saudis?) and let say: “those Saudi “Martars”.??” Does that works for
      you? Well this “character” got captured to be soon after released by
      the INTERVENTION of the US State
      Department making that TERRORISTSS master a “Diplomatic” Entity of
      sort.. ONLY TO PLEASE SAUDI FAMILY) Irrespective of the US LAWS, CONSTITUTION
      and RESPECT of the LIVES LOS. The “prince” DID NOT have Diplomatic Immunity and
      NOTHING could made this kreep IMUNE
      because he lost “diplomatic status 6 months earlier.. because Someone
      finally sane enough decided that Saudi were making the MOCKERY out of
      Diplomatic status and Immunity for every relative of Saudi Family he was
      “Diplomatically’ IMUNE so FINNALY someone SANE enough decided that going farce
      must end, and it did end.. at least to the letter of the “law” which
      is of course in reality totally irrelevant to the bureaucrat who know better
      than to be limited – bothered by the justice, truth, or general interests of
      American people. Which is TOTALY optional in any case. Because American people
      according to the bureaucrats are “stupid” and would not understand? And well as
      an act of our “friendship” to the Saudi OLIGARCHS who really DO share
      the very same “values” as our own State Department bureaucrats who have nothing
      but the utter contempt on the American PEOPLE? Ask any American which had
      “pleasure” to work or to serve there. How Americans were treated
      there by Saudis and how much help they got from THEIR State Department? Swiss
      care about their citizens, Canadians as well, German? But American.. yes they
      have few “shiny” examples that Saudi respect and love like Bechtel? GE? Boeing?
      But to the rest..? Our Soldiers? Osama
      Bin Laden quite “eloquently” voiced that sentiment in “American INFIDELS
      defiled the Saudi Soil by stepping on it..” (in order to SAVE THEIR TUCHAS
      risking their lives) and he was ticked off on all Americans like ANY RACIST-NAZI
      would. And for only THAT tainy “little reason” American had to pay
      the ultimate price.. H O W I N S A N E
      and worped world is that? Check the “moral fiber” of ISIS thugdom and you can CLEARLY RECOGNISE macabre
      philosophy that prevails – GROWING there. Our boys are “infidels” (that came there to save their tuchas? Was
      that the same policy Germans made against the Jews then and the Arabs having
      against the Jews.. hm? ALL OF US??? ALL
      OTHER “INFIDELS” T O D A Y? How about Kurds? Shia? and of COURSE
      CHRISTINAS.. now why I went on this tangent? It is simple US Sold to Saudis
      FIVE E-3 Sentyry receently they just got modified to the block 40/45 (go and
      check it out it is substantial upgrade) Whole NATO in Europe has 5 of those..
      of course not yet updated. About but not yet. Now Saudi Arabia is in constant
      war against the very existence of Israel either by direct war or a war of
      attrition trough financing the “local assassins” to do their dirty job of
      killing girls in their bat mitzvah, children in kinder gardens, or Pizzerias. to do their dirty work for them “who pays he
      chooses the music?” Only for stepping on the JEWISH holly land. BECAUSE once
      Muslim conquer the land and have their graves there this land could NEVER BE
      ABANDONED it has to be re-conquered with the “holly jihad” Sorry we DISSAGREE
      as strongly as we can. And Israel “selling” out American people.. N E W E R
      EVER.. We would never ask Americans to release MURDERERERS of American people
      as a gesture to please the ENEMIES of American people Israel HAS TO just to be
      considered as a “friendly” by the US State Department? Israel would never ask American
      people to secede 1/3 of their land to Mexico just for “consideration for the
      negotiations (Obama is doing that without Israeli blessing anyways..just be
      cause RADICALS and bureaucrats know what is best for US on the long run?? At
      least he acts like he knows.. Israel had to give to Arab terrorist organization
      that killed thousand of Jewish C I V I L I A N S just a gesture that a Jewish
      lives are worth nothing. Thus rewarding MURDERERS to keep killing Jews because
      they will get all of it.. why? Are the PLOtniks so good friends to the American
      people? Killing hundreds of Americans? Celebrating just two block of Trade Centers
      giving candies and hysterically screening lololololololo you know the “melody”
      while Americans were burning alive and jumping from the buildings.. EVERY JEW
      HAD THEIR HEARTS REAPED TO PIECES, EVERY JEW FELT THE PAIN AND AGGONY THOSE
      PEOPLE WENT THROU EVERY JEW know and feel it our parents told us what they went
      trough and we taught no one could ever understand that until we saw that.in
      front of our very eyes. Israel is nor will ever betray American people ever.
      For betrayal you look ELESWARE.. pleeeezzz

    • R’ Yitzchak M

      I am prety sure that Israelis would put their shoulders to the alliance a lot more when needed than you will ever will. You are persistent on this .. but let examine reality check how many discoveries Israeli shared with US and how many of those went to the Israeli enemies? Israel have quite decent homegrown electronic solutions and vis a vis alliences Israel did not requre from US to give 1/3 of America to its enemies as US State Department asked ISrael to give. No friend would ask you to commit a NATIONAL SUICIDE to “please” terrorists aand mortal enemies of Israel. Israel did not condition its friendship to US with the blackmail of ani KIND. US State Department DOES as a matter of continuous policy AGAINST the ISrael. In overall such “friendship” is terminal to the very existance of Israel.

      • Secundius

        @ R’ Yitzchak M.

        When I was in School, they taught me that you Multiply a “Positive” number with a “Negative” number, it “Equals” a “Negative” number and the same hold’s true when you “Divide” the same way. So, now your trying to “Quantify” the problem by saying, when an “Proton” comes into contact with an “Anti-Proton”, they “Cancel” each other OUT. You can’t just “Nullify” a “Negative” action by doing a “Positive” action. Histories, roads are paved with “Good” actions, that go very “Bad”, at the end of the road. In other words, Israel, by doing two “Good” deeds, can “Erase” one really “Bad” deed.

        Unfortunately, Israel keeps repeating it’s “Bad” deeds, over and over and over, again. Explain to me why the ChiCom’s are allowed to have an operating secret PLAN Naval Base in Haifa, Israel.

        • R’ Yitzchak M

          Secundius please do me a favor go in any half decent university library and pull the data on Sino tech cooperation with the West I BET YOU you will have at least one sleepless night.. 3 stage missile separation sequencing, (US GAVE THEM AS A GIFT.. as a matter of “space cooperation..bla bla blabbb.. oh dreck” Italians gave them the precise TARGET positioning on reentry procedures again for the “space cooperation”? Chinese BARGED into the Los Alamos almost run over our soldier an NOOOOTHING State Departmant told them not to do that and “diplomatic” immunity yada.. yada.. that’s it. No one Chinese spy had any jail time while only Jewish spy who gave the pictures to the Israel “government” at the time that US knew where the Scudds are and chose to do nothing about it. Schultz and Caspar Weinberger (both Bechtel C.E.O.’s) choose to terrorize Israelis into the submission toward the “peace plan” with PLO giving them 1/3 of Israel. Now that is a kind of Jewish “folklore” that goes around, and also that the reason why Jonathan Pollard is the longest sitting spy in US history is a promise Caspar gave to the Saudi family.. or Bibi would be “embarrassed” by the information of his culpability in this TERRORIST plot. So given prospective that no “FRIEND” would ask his FRIEND to commit a national SUICIDE to please his enemies.. giving Sinai did Israel got a peace it did NOT? It got a TRUCE? AWAR with Egypt started over Gaza strip, because Egyptian Military Intelligence created PLO with Arafat as its head of operation, Israeli knew that is a war of attrition that Egyptians are waging against the Israel. Israel warn them of ensuing consequences. Egypt “just” wanted an UTTER DESTRUCTION OF JEWS and that was just a process of “bleeding” the enemy.. Now Carter demanded of Israel as a “gesture” of course to give the Sinai, Bechtel (with the help of the US State Department) demanded the secession of Judea and Samaria creating the ultimate “Gaza Strip” a polygon that will bleed Israel out of existence.. No enemies of Israel ever succeeded to bring Israel closer to its destruction as our friends succeeded with those concessions. Now on China please check how much China got from OUR GOVERNMENT and OUR CORPORATIONS and INTERNET if anything Israel perhaps should consider buying some of their technologies? Like ammunition.. which US White House bared Israel from purchasing. F-35? F-16I with locked transponder so Israel is unable to put its own software. In EW environment it is critical the line of software you are able to add to the platform. Once transponder is locked and our Saudi “friends” mysteriously got the code Israeli F-16 platforms are a sitting ducks. Israel could buy a T-50 or Chinese “stealthy” crap and to utilize its own electronics solutions they did it with Mirage III and its own derivative Kfir. Israel is at the crossroad it is brought to the edge of the cliff with various gestures our friends demanded, only question is are Israeli such IDIOTS as to jump in order to show how dedicated friends they WERE.

          • Secundius

            @ R’ Yitzchak M.

            In your case, quite trying to justifiy SHTUMPIK…

          • R’ Yitzchak M

            Secundius I really tried to contextualize complexity of that alliance in sum is the balance of costs and benefits.. so far any war against the Israel enemies got EVERYTHING they even could not dream of in winning in battle trough Israeli idiocity of doing more to preserve alliance (which DOES NOT EXIST) than to preserve its TERITORIAL INTEGRITY and sovereignty. Israel de facto becomes DELEGITIMIZED and MARGINALIZED and slowly WILLIFIED the same as the approach on dismantling of Yugoslavia.. slowly eroding its legitimacy to exist. And believe me I am not Sthumpig you around, I do respect your position and I hope you will take in consideration whole context from both sets of “reference”? I really believe what I wrote to be truth. Truth might be overrated or perhaps even too expensive but in overall alternative to IT IS lot more expensive.

  • Earn_Your_Freedom

    Guess it’s not all that secret any more…

  • john

    Sigh. The “tips”, or more properly angle changes, of a stealth aircraft are not discernible. Only edge length matters. If you look at structural edge length on the F-22 and F-35 there is no feature with an edge length less than a foot.