China's Anti-Stealth Radars and Sensors

Discussion in 'China' started by Martian, Jul 26, 2015.

  1. Martian

    Martian Respected Member Senior Member

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    The easiest way to detect an F-22 is to look for its electromagnetic radiation emission (e.g. ELINT and SIGINT).

    In particular, an F-22 emits:

    a. radio communication
    b. satellite communication
    c. IFF transponder
    d. radar emissions

    China has three different sensors designed to locate electromagnetic radiation emissions.

    1. Chinese NOSS (ie. Navy Ocean Surveillance Satellite) satellite trios.
    2. China's YLC-20 passive surveillance radar
    3. China's CETC DWL002 Passive Detection System

    The NOSS satellite trios are interferometers.[1]

    The YLC-20 passive surveillance radar can be used as an individual unit (or in a network as an interferometer).[2]

    I have previously covered the Chinese CETC DWL002 Passive Detection System as an interferometer that is about 25 times more sensitive than the original Russian Kolchuga version.

    Citations.

    1. Rosie Finally Flies: Atlas V Inserts Classified NROL-36 into Orbit « AmericaSpace
    "The NOSS...use a technique known as ‘interferometry’ to detect radio transmissions from the ships and ‘geolocate’ them using Time Difference of Arrival."

    2. The Chinese great RADAR wall | Defense Update

    "The Chinese great RADAR wall
    Nov 13, 2014
    Airshow China 2014 Photo Report - Air Defense Radars

    [​IMG]
    The YLC-20 is a signals intelligence system detecting RF emitting targets beyond visual range. The system can be used as a single unit or a network of several sensors. According to the Chinese developers, it operates over a wide frequency range and delivers high location accuracy and powerful signal analysis capabilities. Photo: Tamir Eshel, Defense-Update
    ----------

    Analysis

    Why do you need three systems that basically perform the same function? The answer is redundancy.

    The Chinese NOSS satellites are likely to be destroyed by American ASATs at the beginning of a serious conflict.

    The YLC-20 passive radar is very large and requires a truck to carry the sensor. The control unit would be located on a different truck. To set up an interferometer, you need an atomic clock, fiber-optic cables, experts, and data-processing computers.

    To set up a YLC-20 interferometer, a minimum of three trucks are needed. Two YLC-20 detectors and one truck dedicated to controlling the system. I don't know if there is sufficient space for the data-processing computers. It is possible that a minimum of four trucks are needed for an interferometer.

    In contrast, the Chinese CETC DWL002 Passive Detection System is a compact unit. All of the equipment needed for a CETC DWL002 interferometer is located on the truck.

    Given its size, the YLC-20 has greater detection range. However, to set up a YLC-20 interferometer, it is more complex and requires multiple trucks of equipment.

    The CETC DWL002 provides quick regenerative ability. If a CETC DWL002 unit is damaged or destroyed, simply drive a replacement to the front line. However, the downside of the CETC DWL002 is its shorter range due to a much smaller detector.

    Also, the YLC-20 passive surveillance radar and the CETC DWL002 Passive Detection System could be complementary and focus on different frequency bands.

    Why are we seeing all of these Chinese interferometers? China built an atomic clock in 1972 at the Shanghai Astronomical Observatory (SHAO). However, we had to wait for Chinese supercomputers and processing software. With the Tianhe-2 33.86 petaflop supercomputer, China has demonstrated its mastery in building supercomputers.

    Using its experience with civilian interferometers (e.g. China's Deep Space Network and the Yuanwang ship space-tracking radio telescope array), China obviously has experience in writing software for interferometry.

    In my next post, I will cover regular radars, low-frequency radars, or infrared detection of stealth aircraft.

    More Information.

    China has world's second-largest fleet of satellites at 113 satellites | Asiawind

    China's highly-advanced CETC DWL002 Passive Detection System | Asiawind
     
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  3. Martian

    Martian Respected Member Senior Member

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    Chinese YLC-2V S-band 3D phased array radar Interferometer vs. F-35

    The conventional wisdom had been that an S-band radar cannot detect an F-35 at long range. I think that was true 20 years ago and probably true 10 years ago. However, is it true today?

    An F-35 is described as having an RCS of a metal golf ball.[1] However, this is an average RCS from all angles. A ground-based S-band radar will be looking up and the S-band radar waves will reflect off the F-35 underside.

    [​IMG]
    YLC-2V is an S band 3D phased array radar covering long range all altitude alert and ground control radar. Photo: Tamir Eshel, Defense-Update [2]

    When you look at the bumpy F-35 underside and thick wing-roots, the F-35 does not look stealthy and violates the principle of flat faceting. Additionally, an interferometer is extremely sensitive (on the order of 100 to 1,000 times more sensitive than a single YLC-2V S-band radar).

    [​IMG]
    The F-35 has a non-stealthy bumpy underside and thick wing-roots.

    In conclusion, the F-35 is a flawed stealth fighter with a somewhat unstealthy underside. Coupled with the extreme sensitivity of an S-band radar interferometer, a grapefruit-sized RCS metal object traveling at Mach 1 and 45,000 feet could arguably be tracked by an S-band radar interferometer.
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    Citations.

    1. Radar Cross Section (RCS)
    "Nov 7, 2011 - In this region RCS is roughly the same size as the real area of target. ... size of a marble) while the F-35's is -30 dBm2 (the size of a golf ball)."

    2. The Chinese great RADAR wall | Defense Update
     
  4. Martian

    Martian Respected Member Senior Member

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    China's three important anti-stealth L-band radars

    China's three important L-band radars are as follows.

    1. KJ-2000 AWACS with L-band radar
    2. KJ-200 AEW&C with L-band radar
    3. YLC-2 ground-based L-band radar

    KJ-2000 AWACS and KJ-200 AEW&C

    The KJ-2000 AWACS and KJ-200 AEW&C both use L-band radars to detect stealth fighters. They are complementary and provide a high-low mix.

    Obviously, the KJ-2000 is much larger. All else being equal, a greater number of transmit/receive (T/R) modules means a more powerful radar. The wavelength of L-band (30 cm) is ten times larger than X-band (3 cm). Thus, each individual T/R module is about ten times larger. This results in a large KJ-2000 radar dome.

    The smaller KJ-200 has less L-band T/R modules, but the aircraft costs less and requires less personnel.

    Assessing the Tikhomirov NIIP L-Band Active Electronically Steered Array

    [​IMG]
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    YLC-2 ground-based L-band radar

    PLA Air Defence Radars

    [​IMG]

    Multiple YLC-2 ground-based L-band radars can be networked into an interferometer for unprecedented resolution and/or sensitivity.
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    Current tally of Chinese anti-stealth radars and sensors

    Passive radar systems (or Passive Coherent Location aka PCL)
    a. Chinese NOSS (ie. Navy Ocean Surveillance Satellite) satellite trios (interferometer)
    b. China's YLC-20 passive surveillance radar (single unit or interferometer)
    c. China's CETC DWL002 Passive Detection System (interferometer)

    S-band radar Interferometer
    d. YLC-2V S-band 3D phased array radar Interferometer (interferometer to have a chance against F-35)

    L-band anti-stealth radar systems
    e. KJ-2000 AWACS with L-band radar (single unit)
    f. KJ-200 AEW&C with L-band radar (single unit)
    g. YLC-2 ground-based L-band radar (single unit or interferometer)
     
  5. Martian

    Martian Respected Member Senior Member

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    VHF radar basics

    I want to cover China's VHF (ie. very high frequency) anti-stealth radars. However, it makes sense to review a few VHF radar basics.

    VHF is one to ten meters in wavelength.

    [​IMG]
    "The Winegard High Definition-Platinum model HD-7082P VHF/UHF TV antenna is an excellent choice for metropolitan to suburban reception areas."

    The VHF antenna is the larger section on the left of the picture.

    You will notice the antenna is disjointed. This is due to the half-wavelength design. Using AC current, an electron is forced down the antenna. Next, the electron is pulled back toward the base of the antenna. Obviously, the cycle repeats to generate a continuous VHF sinusoidal wave.

    [​IMG]
    The half-wavelength antenna design permits a compact antenna that is only half the length of the desired VHF wavelength.

    Since VHF is 1 to 10 meters in wavelength, each VHF half-wavelength element is 0.5 to 5 meters in length.

    [​IMG]
    "[China's PLA] CETC JY-27 Wide Mat VHF Band Long Range 2D Surveillance Radar"

    Take a look at the top right of the JY-27 picture. Do you see the four different-length loops (which are repeated throughout the radar)? The JY-27 radar can broadcast and receive in four different VHF radar wavelengths.
     
  6. Martian

    Martian Respected Member Senior Member

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    China's VHF/UHF anti-stealth radars

    China has three more important VHF/UHF anti-stealth radars.

    1. Type 517M VHF radar (using half-wavelength resonance) on Type 052C destroyer[1]
    2. JY-26 UHF radar (using circular polarization)[2]
    3. YLC-8B UHF 3D radar[3]

    VHF radars like the Type 517M are almost impossible to jam. Each VHF T/R module is half-a-meter or larger. A small fighter jet could only carry a few VHF T/R modules at most. A small fighter could never generate a strong enough signal to jam the huge VHF radars on a naval ship or on the ground.

    UHF (ultra-high frequency) radars operate in the 10 to 100cm wavelength.

    [​IMG]
    "YLC-8B – a UHF 3D radar utilising full coherent digital pulse compression and moving target detection technology. Despite its size, the antenna fold-able array is designed for automatic, rapidly deployment and recovery. Photo: Tamir Eshel, Defense-Update"

    Obviously, the YLC-8B UHF 3D radar can be used individually or as an interferometer in a network of two or more YLC-8B UHF 3D radars. The following chart shows the susceptibility of the F-35 to different radar wavelengths.[4]

    [​IMG]
    Green = Stealthy. Difficult for a radar to detect the F-35 in that radar band and at that incoming angle.
    Yellow = Partially Stealthy. A radar has a reasonable chance of detecting the F-35 in that radar band.
    Red = Not Stealthy. A radar has an excellent chance of detecting the F-35 from that angle in that radar band.

    More information.

    1. Explaining Half-Wavelength Resonance | Asiawind
    2. China’s new counter-stealth radar JY-26 | Asiawind
    3. The Chinese great RADAR wall | Defense Update
    4. Assessing Joint Strike Fighter Defence Penetration Capabilities
    ----------

    Current tally of Chinese anti-stealth radars and sensors

    Passive radar systems (or Passive Coherent Location aka PCL)
    a. Chinese NOSS (ie. Navy Ocean Surveillance Satellite) satellite trios (interferometer)
    b. China's YLC-20 passive surveillance radar (single unit or interferometer)
    c. China's CETC DWL002 Passive Detection System (interferometer)

    S-band radar Interferometer
    d. YLC-2V S-band 3D phased array radar Interferometer (interferometer to have a chance against F-35)

    L-band anti-stealth radar systems
    e. KJ-2000 AWACS with L-band radar (single unit)
    f. KJ-200 AEW&C with L-band radar (single unit)
    g. YLC-2 ground-based L-band radar (single unit or interferometer)

    VHF/UHF anti-stealth radar systems
    h. CETC JY-27 Wide Mat VHF Band Long Range 2D Surveillance Radar (single unit or interferometer)
    i. Type 517M VHF radar using half-wavelength resonance on Type 052C destroyer (single unit)
    j. JY-26 UHF radar using circular polarization (single unit or interferometer)
    k. YLC-8B UHF 3D radar (single unit or interferometer)
     
  7. Martian

    Martian Respected Member Senior Member

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    L-band JY-29/Type 120 PLA self-propelled tactical 3D acquisition radar

    Surface to Air Missile Systems and Integrated Air Defence Systems

    [​IMG]
    "The L-band JY-29/Type 120 (depicted), YLC-18, JYL-1 and YL-11B are typical of the new generation of PLA self-propelled tactical 3D acquisition radars, designed to support a range of SAM systems (© 2009, Bradley Huang)."
     

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