Anti-stealth technologies and weapons

b787

Captain
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Counterstealth technologies, intended to reduce the effectiveness of radar cross-section (RCS) reduction measures, are proliferating worldwide. Since 2013, multiple new programs have been revealed, producers of radar and infrared search and track (IRST) systems have been more ready to claim counterstealth capability, and some operators—notably the U.S. Navy—have openly conceded that stealth technology is being challenged.

These new systems are designed from the outset for sensor fusion—when different sensors detect and track the same target, the track and identification data are merged automatically. This is intended to overcome a critical problem in engaging stealth targets: Even if the target is detected, the “kill chain” by which a target is tracked, identified and engaged by a weapon can still be broken if any sensor in the chain cannot pick the target up.


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The fact that some stealth configurations may be much less effective against very-high-frequency (VHF) radars than against higher-frequency systems is a matter of electromagnetic physics. A declassified 1985 CIA report correctly predicted that the Soviet Union’s first major counterstealth effort would be to develop new VHF radars that would reduce the disadvantages of long wavelengths: lack of mobility, poor resolution and susceptibility to clutter. Despite the breakup of the Soviet Union, the 55Zh6UE Nebo-U, designed by the Nizhny-Novgorod Research Institute of Radio Engineering (NNIIRT), entered service in the 1990s as the first three-dimensional Russian VHF radar. NNIRT subsequently prototyped the first VHF active electronically scanned array (AESA) systems.

VHF AESA technology has entered production as part of the 55Zh6M Nebo-M multiband radar complex, which passed State tests in 2011 and is in production for Russian air defense forces against a 100-system order. The Nebo-M includes three truck-mounted radar systems, all of them -AESAs: the VHF RLM-M, the RLM-D in L-band (UHF) and the S/X-band RLM-S. (Russian documentation describes them as metric, decimetric and centimetric—that is, each differs from the next by an order of magnitude in frequency.) Each of the radars is equipped with the Orientir location system, comprising three Glonass satellite navigation receivers on a fixed frame, and they are connected via wireless or cable datalink to a ground control vehicle.

One of the classic drawbacks of VHF is slow scan rate. With the RLM-M, electronic scanning is superimposed on mechanical scanning. The radar can scan a 120-deg. sector mechanically, maintaining continuous track through all but the outer 15-deg. sectors. Within the scan area, the scan is virtually instantaneous, allowing energy to be focused on any possible target. It retains the basic advantages of VHF: NNIRT says that the Chinese DF-15 short-range ballistic missile has a 0.002 m2 RCS in X-band, but is 0.6 m2 in VHF.

The principle behind Nebo-M is the fusion of data from the three radars to create a robust kill chain. The VHF system performs initial detection and cues the UHF radar, which in turn can cue the X-band RLM-S. The Orientir system provides accurate azimuth data (which Glonass/GPS on its own does not support), and makes it possible for the three signals to be combined into a single target picture.

The higher-frequency radars are more accurate than VHF, and can concentrate energy on a target to make successful detection and tracking more likely. Using “stop and stare” modes, where the antenna rotation stops and the radar scans electronically over a 90-deg. sector, puts four times as much energy on target as continuous rotation and increases range by 40%.

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b787

Captain
Russia has begun deploying the next generation of Nebo-M anti-missile radar facility systems as part of a responsive measure to a threat stemming from NATO anti-ballistic missile systems in Eastern Europe.
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“The mobile multi-range programmable Nebo-M complex is capable of performing the tasks of providing information on small-sized aerodynamic and hypersonic targets in a difficult jamming background, as well as providing information for anti-missile weapon systems,” said colonel Aleksey Zolotuhin, a spokesman for the Russian Defense Ministry’s press service.
The development and deployment of next-gen anti-missile systems featuring Active Electronically Scanned Array (AESA) technology is a top priority for the Russian Defense Ministry, as US anti-ballistic missile system are springing up in Romania, Turkey, Poland, and even in Spain.

The new Nebo-M 3-D radar system features a programmable multi-band design. The complex includes central data fusion and command post module as well as three radars, all deployed on separate high-mobility 8 x 8 24-ton vehicles. According to Aviatioweek, radars feed data to the command post using high-speed narrow-beam digital data links in the microwave band.
The radar is designed to automatically detect and track airborne targets such as ballistic missiles, stealth aircraft, or drones, as well as hypersonic targets. In the circular scan mode the complex is able to track up to 200 aerodynamic targets at a distance and at altitudes of up to 600 kilometers. In sector scan mode, Nebo-M can track to 20 ballistic targets at ranges of up to 1,800 kilometers and at an altitude of up to 1,200 kilometers.

In October, the Russian Defense Ministry unveiled plans to build several new anti-missile radars in order to cover the entire territory of Russia by 2020. Moscow also announced that an early warning radar station in the western Kaliningrad Region would be put on full combat duty by the year’s end.


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b787

Captain
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.

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
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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.
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SamuraiBlue

Captain
Although in Japanese Japan Ministry of Defense Technical Research and Development Institute(TRDI) is doing some research on MIMO(Multi-Input Multui-Output) radar technology where they seperate the emitting array and recieving array in different locations so the radar can pick up the deflected radar emissions from the stealth object. Basically it's the same concept that defeated the F-117 in Europe.

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b787

Captain
Although in Japanese Japan Ministry of Defense Technical Research and Development Institute(TRDI) is doing some research on MIMO(Multi-Input Multui-Output) radar technology where they seperate the emitting array and recieving array in different locations so the radar can pick up the deflected radar emissions from the stealth object. Basically it's the same concept that defeated the F-117 in Europe.
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they also are trying smart skin like PAKFA to detect other stealth fighters

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Brumby

Major

b787,
Is there anything in the s400 marketing brochure that you would like to emphasize in support of your assertion that the S400 system is an effective area denial to the F-22? I can't from what you have shared.
With regards to the Nebo M 3-D system, admittedly it is an innovative approach but it is heavy on marketing but lacking specifics to demonstrate that somehow it is an effective aerial denial system against the F-22.

It is important for you to understand that there is a difference between taking some materials and presenting them as evidence in support of your case and actually explaining how the contents actually support your case. In other words, we are having a conversation with you and not the materials. Having said that, this tri band approach which is meant to narrow the search box through cueing of data does not inherently address a fundamental issue when dealing with VLO platforms such as the F-22. The UHF/VHF band by nature has poor resolution even if it might be capable of detecting the F-22 at a greater distance. It is meant to cue that information to the next band so that the acquisition box is more defined in terms of search and dwell time so that there is greater probability of detection at the next band. The problem is without information on bearing attitude, velocity and range the idea of a derived acquisition box is simply no different from one that is not derived.
 

b787

Captain
b787,
Is there anything in the s400 marketing brochure that you would like to emphasize in support of your assertion that the S400 system is an effective area denial to the F-22? I can't from what you have shared.

With regards to the Nebo M 3-D system, admittedly it is an innovative approach but it is heavy on marketing but lacking specifics to demonstrate that somehow it is an effective aerial denial system against the F-22.

It is important for you to understand that there is a difference between taking some materials and presenting them as evidence in support of your case and actually explaining how the contents actually support your case. In other words, we are having a conversation with you and not the materials. Having said that, this tri band approach which is meant to narrow the search box through cueing of data does not inherently address a fundamental issue when dealing with VLO platforms such as the F-22. The UHF/VHF band by nature has poor resolution even if it might be capable of detecting the F-22 at a greater distance. It is meant to cue that information to the next band so that the acquisition box is more defined in terms of search and dwell time so that there is greater probability of detection at the next band. The problem is without information on bearing attitude, velocity and range the idea of a derived acquisition box is simply no different from one that is not derived.
“Nebo-SVU” (1L119) Radar System
The “Nebo-SVU” (1L119) radar system is designed to automatically detect, pinpoint, and track a broad range of current aircraft and air weapons: strategic and tactical aircraft, ASALM type air missiles, small targets, and low-visibility targets, particularly targets using Stealth technology.

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S-300VM (“Antey-2500”) ADMS
The S-300VM (“Antey-2500”) mobile multichannel ADMS is designed to destroy current and future tactical and strategic aircraft (including those using Stealth technology), medium-range ballistic missiles, theater, tactical, air ballistic, and cruise missiles, as well as radar surveillance and guidance aircraft, reconnaissance and attack systems, and patrolling jamming stations.


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