Radar Technology

Discussion in 'Strategic Forces' started by LETHALFORCE, Mar 30, 2009.

  1. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    http://www.everythingweather.com/weather-radar/bands.shtml

    General classification and use


    Doppler radar can be divided into several different categories according to the wavelength of the radar. The different bands are L,S,C,X,K. The names of the radars originate from the days of WWII.

    L band radars operate on a wavelength of 15-30 cm and a frequency of 1-2 GHz. L band radars are mostly used for clear air turbulence studies.

    S band radars operate on a wavelength of 8-15 cm and a frequency of 2-4 GHz. Because of the wavelength and frequency, S band radars are not easily attenuated. This makes them useful for near and far range weather observation. The National Weather Service (NWS) uses S band radars on a wavelength of just over 10 cm. The drawback to this band of radar is that it requires a large antenna dish and a large motor to power it. It is not uncommon for a S band dish to exceed 25 feet in size.

    C band radars operate on a wavelength of 4-8 cm and a frequency of 4-8 GHz. Because of the wavelength and frequency, the dish size does not need to be very large. This makes C band radars affordable for TV stations. The signal is more easily attenuated, so this type of radar is best used for short range weather observation. The frequency allows C band radars to create a smaller beam width using a smaller dish.
    C band radars also do not require as much power as an S band radar. The NWS transmits at 750,000 watts of power for their S band, where as a private TV station such as KCCI-TV in Des Moines only broadcasts at 270,000 watts of power with their C band radar.

    X band radars operate on a wavelength of 2.5-4 cm and a frequency of 8-12 GHz. Because of the smaller wavelength, the X band radar is more sensitive and can detect smaller particles. These radars are used for studies on cloud development because they can detect the tiny water particles and also used to detect light precipitation such as snow. X band radars also attenuate very easily, so they are used for only very short range weather observation. Also, due to the small size of the radar, it can therefore be portable like the Doppler on Wheels. (DOW) Most major airplanes are equipped with an X band radar to pick up turbulence and other weather phenomenon. This band is also shared with some police speed radars and some space radars.

    K band radars operate on a wavelength of .75-1.2 cm or 1.7-2.5 cm and a corresponding frequency of 27-40 GHz and 12-18 GHz. This band is split down the middle due to a strong absorption line in water vapor. This band is similar to the X band but is just more sensitive. This band also shares space with police radars.
     
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  3. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    http://www.faqs.org/faqs/sci/Satellite-Imagery-FAQ/part2/section-3.html

    Synthetic Aperture Radar (SAR)

    Synthetic Aperture Radar

    What is SAR?

    Synthetic Aperture Radar. An active microwave instrument, producing
    high-resolution imagery of the Earth's surface in all weather.

    There is a good introduction to imaging radar by Tony Freeman of JPL
    at http://southport.jpl.nasa.gov/desc/imagingradarv3.html

    _Should we have an embedded intro for the benefit of non-WWW readers?
    I can ask to include the above, or try and solicit an equally expert
    intro from someone here_

    What are the main SAR platforms?

    Several past, present and future Earth Observation Satellites. Also
    the Shuttle Imaging Radar missions. See the table for a full list.
    * ERS-1/ERS-2
    * JERS-1
    * Shuttle Imaging Radar SIR-C/X-SAR
    * Almaz
    * RadarSat

    the future...
    * ENVISAT (I'm not even making a link until I've something REAL to
    put there)!
    * _OK, what have I forgotten about (or never heard of)?_

    What distinguishes SAR from hi-res optical imagery?

    Two main properties distinguish SAR from optical imagery:
    * The SAR is an active instrument. That is to say, it generates its
    own illumination of the scene to be viewed, in the manner of a
    camera with flash. The satellite's illumination is coherent: i.e.
    all the light in any flash is exactly in phase, in the manner of a
    laser, so it does not simply disperse over the distance between
    the satellite and the Earth's surface. A SAR instrument can
    measure both intensity and phase of the reflected light, resulting
    not only in a high sensitivity to texture, but also in some
    three-dimensional capabilities. Experiments with the technique of
    _Interferometry_ (measuring phase differences in exactly aligned
    images of the same ground area) have shown that SAR can accurately
    model relief, and appears able also to detect small changes over
    time.
    Some consequences of being an active instrument (and using
    coherent light) are:
    + Works equally day or night
    + Polarised - can be used to gain additional information (esp.
    when different polarisations are available on the same
    platform - as on the most recent Shuttle missions).
    + Needs a lot more power than passive sensors, and can
    therefore only operate intermittently.
    + Suffers from speckle, an artifact of interference patterns in
    coherent light, sensitive to texture.
    * SAR is _Radar_ - i.e. it uses microwave frequency radiation.
    _(note that in consequence, references to "light" above should
    more strictly read "microwave radiation")._ Microwave radiation
    penetrates cloud and haze, so SAR views the Earth's surface (land
    and sea) in all weather. For general purpose Remote Sensing, this
    is probably _the_ major advantage of SAR.
    An example of its use is the ESA/Eurimage "Earthwatch" programme,
    producing imagery of natural and other disasters when weather
    conditions prevent other forms of surveillence. Earthwatch imagery
    is available at http://gds.esrin.esa.it/CSacquisitions

    What are SAR images good for ?

    * Sensitive to texture: good for vegetation studies.
    * Ocean waves, winds, currents.
    * Seismic Activity
    * Moisture content

    A list of SAR applications is available at
    http://southport.jpl.nasa.gov/science/SAR_REFS.html

    What is the meaning of colour in a SAR image?

    Of course, all SAR image colour is false colour: the notion of true
    colour is meaningless in the context of invisible microwave radiation.

    Most SAR images are monochrome. However, multiple images of the same
    scene taken at different times may be superimposed, to generate
    false-colour multitemporal images. Colour in these images signifies
    changes in the scene, which may arise due to a whole host of factors,
    such as moisture content or crop growth on land, or wind and wave
    conditions at sea. SAR is particularly well-suited to this technique,
    due to the absence of cloud cover.

    The shuttle SAR's images are the nearest to 'natural' colour, in the
    sense that they are viewing three different wavelengths, which can be
    mapped to RGB for pseudo-naturalistic display purposes (essentially
    the same as false colour in optical/IR imagery).
     
  4. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    http://www.ausairpower.net/APA-Zhuk-AE-Analysis.html

    Phazotron Zhuk AE/ASE
    Assessing Russia's First AESA

    [​IMG]
    The MiG-35 Zhuk AE AESA designed by Phazotron is the first Russian AESA design and is expected to spawn upgrade packages for Flanker variants, as Phazotron have been trying for over ten years to break NIIP's defacto monopoly on volume production Flanker radars (MiGAvia.ru).

    Abstract

    The Zhuk AE developed for the MiG-35 and legacy MiG-29 upgrades is the first Russian Active Electronically Steered Array (AESA [Click for more ...]) antenna equipped radar to be disclosed publicly. The manufacturer, NIIR Phazotron, has released a considerable volume of technical literature detailing the design philosophy and technology employed in this radar. This paper explores, in radar engineering terms, antenna and transmit receive channel related design features, and the cardinal performance parameters for this radar. While this pre-production radar operates at the lower end of the X-band and has a lower transmit receive channel count than Western radars of similar aperture size, it delivers power-aperture performance superior to all but the very latest Western small aperture fighter radars. The Zhuk AE employs lower density liquid cooled quad channel transmit receive module packaging technology which is comparable to first generation US AESA designs.

    A parametric analysis and power aperture modelling is performed on the proposed Zhuk ASE, which is a scaled up version of the Zhuk AE following the model of the Zhuk MSFE built for the Flanker. The Flanker sized Zhuk ASE radar with existing Russian transmit receive module technology will deliver around 60 percent higher raw power aperture performance compared to US APG-79 (F/A-18E/F BII) and APG-81 (JSF) class radars, and if fitted with transistor technology permitting 15 Watts/channel or more, as proposed by NIIR Phazotron, it will outperform the N035 Irbis-E (Su-35BM) and all currently deployed US fighter radars other than the APG-77(V)2 (F-22A Raptor). The earliest feasible IOC for the Zhuk ASE on the Flanker is estimated at 2010.
     
  5. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    Background and Zhuk Development History

    Russia's radar industry has survived the post Cold War trauma of collapsing budgets and has since then strongly reoriented towards export markets. Of the three most prominent radar houses, Tikhomirov NIIP, Phazotron NIIR and Leninetz, Tikhomirov NIIP has enjoyed the largest export sales volumes and earnings mostly by virtue of its entrenched position as supplier of Flanker radars. Phazotron on the other hand has carved out a niche as the technological innovators in the Russian industry.

    Phazotron has a long history as one of the leading Soviet era radar design bureaus, and were the primary designers of the N019 Topaz / Slot Back series of pulse Doppler radars for the MiG-29 Fulcrum fighter. The Zhuk family of radars, which has largely occupied Phazotron's designers since the end of the Cold War, are an evolutionary offshoot of the N019 family.

    The first of the Zhuk (Beetle) radars was developed for the stillborn mid 1980s MiG-29M/MiG-33 Fulcrum upgrade and production effort. Designated the N010 Zhuk, this was a relatively modern pulse Doppler design modelled on the US APG-65 and APG-68 radars, using a slotted planar array antenna with a 0.68 metre diameter aperture, with an average power rating of 1 kW and peak rating of 5 kW. With the end of the Cold War and Phazotron's emergence as an independent entity in an open market, the effort invested into the Zhuk was exploited to develop a family of radars designed for the MiG-29, Su-27/30 and older Soviet era fighters as upgrades.

    The Zhuk-27 was a variant of the baseline N010 but fitted with a much larger 0.98 metre diameter slotted planar array antenna, and possibly an uprated TWT, intended for the Su-27SK Flanker B. Its contemporary was the Zhuk-8P developed for the PLA-AF J-8-II Finback, with a smaller antenna and thus lower range performance. Importantly this period also saw the development of the Zhuk-F, a passive ESA (PESA) or phased array with a 0.98 m diameter aperture. The Zhuk-F evolved further into the Sokol, which is the basis of the current Zhuk-MSF/MSFE PESA variants for the Flanker. The PESA variants of the Zhuk compare most closely to variants of the N011M BARS, but use a fixed PESA aperture rather than NIIP's gimballed design. The nearest Western technological equivalent is the French RBE2 PESA radar in the Rafale.

    [​IMG]

    The Zhuk ME is a conventional derivative of the Zhuk M family, available in the 0.7 metre aperture configuration for the MiG-29, or the larger 0.96 metre aperture configuration for the Su-27/30 series. The Zhuk MSE was flight tested and certified on the Su-30MK3 variant developed for the PLA-AF but to date not ordered.

    The baseline mechanically steered Zhuk further evolved, with the N010M Zhuk-M and Zhuk-ME variants for the MiG-29 Fulcrum, and Zhuk-MS and Zhuk-MSE intended for the Su-27/30 Flankers. These incorporated an array of L-band IFF dipoles, a slotted planar array, and much improved processor hardware, to support strike modes including Synthetic Aperture Radar imaging [1].
    [​IMG]
     
  6. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    The Zhuk MSF/MSFE (above) is a passive ESA design intended to compete against the NIIP N011M BARS. It uses a Phazotron unique radial distribution arrangement in the backplane waveguide feed, and proprietary radiating element placement. The Zhuk MSFE has a .98 meter diameter aperture with 1662 radiating elements, and was developed for the Su-30MK3 Flanker G avionic suite intended for the PLA-AF. The Zhuk-MSFE is being flown in an Su-33UB demonstrator, the depicted example (below) with thrust vectoring Al-31FU engines (MAKS 2005/2007).

    [​IMG]

    he most advanced of the Phazotron Flanker radars is the Zhuk-MSFE PESA variant, currently being flight tested on the Su-27KUB/Su-33UB side-by-side cockpit navalised Flanker variant, likely to be acquired by the PLA-N as part of their intended carrier airwing for the Varyag CVA. This radar is usually credited with a 2 KW average power rating and 8 kW peak power rating, putting it in the performance class of the NIIP N011 MSA radar on the Su-27K/Su-35 Flanker E. The PESA design has 1662 radiating elements.

    The Zhuk-AE AESA [Click for more ...] is an offspring of the Zhuk-MF/MFE variant, a 0.7 m diameter aperture PESA derivative of the N010M Zhuk-M and Zhuk-ME variants, and was developed for the MiG-35 Fulcrum being bid for India's MRCA requirement to replace initially 128 of around 400 legacy Russian fighters.

    The potentially large size of the Indian order has seen Western and Russian bidders disclose remarkably large amounts of data on their products, and Phazotron produced a special issue of their house journal Phazotron, which contains some very good technical papers by Phazotron engineers detailing the internals of the Zhuk-AE and its underlying design philosophy. This is the single biggest technical disclosure on any AESA design, globally, to date. This APA analysis is largely based upon this document, but also exploits other open source materials.

    The strategic importance of the Zhuk AE cannot be understated. Russian industry has crossed the key hurdles of designing and integrating viable GaAs MMICs and performing the overall integration and design of an AESA. From this point we will see increasingly convergence with Western technology for AESAs, as new technologies like Gallium Nitride HEMT transistors are incorporated, and US style tiled packaging technology emulated. The rate of advancement will be mostly limited by the scale of investment into development.

    This analysis looks closely at the technology of the Zhuk AE and its design philosophy, in more technical depth than previous APA analyses, and explores the implications of Phazotron's stated intent to scale the design up for the Flanker.

    [​IMG]

    Zhuk AE demonstrator on display at MAKS2007. It is conspicuous that the radar operates at the lower end of the X-band, following past Russian practice.
     
  7. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    Zhuk AE Design Philosophy - A Radar Engineering Perspective

    Phazotron's engineers have provided some excellent insights into the design philosophy and achievable performance, and performance growth, in the Zhuk AE design [click for more ...]. Less fortunately, the original works were not well translated into English, seeing much technical language translated improperly, making the original work less than comprehensible to readers without exposure to radar engineering.

    The starting point for the Zhuk AE design was the existing Zhuk MF, as Phazotron's engineers correctly assessed that the cost and risk of an entirely new design would be too great. In this respect they followed the model used by Raytheon in the APG-79 and Northrop-Grumman in the APG-80, rather than the 'all new' approach seen with the Northrop Grumman APG-77. The aim was to re-engineer the PESA design for a new liquid cooled AESA, retaining as much of the PESA design as was feasible. Key design aims were to provide improved reliability, agile beamsteering, reduced noise figure to improve range, and much greater bandwidth to provide frequency agility, facilitating aperture use in jamming and high rate datalinking. Frequency agility was clearly sought with Low Probability of Intercept (LPI) modes in mind, even if not stated.

    Phazotron contracted NPF Mikran at Tomsk, a semiconductor manufacturer, with support from the Tomsk Electronics University, to develop the Gallium Arsenide MMIC (Monolithic Microwave Integrated Circuits) technology for the radar's critical TR Modules.

    The new radar would use a new antenna and Analogue/Digital Converter (ADC) design, a new exciter/driver stage, but retain the existing receiver chain, processors, and coherent oscillator. Intended improvements for a production design include better processing and a broadband programmable master oscillator module. The latter is to provide many of the advanced capabilities seen in the latest Western AESAs.

    Phazotron summarise the key design components as:

    * Antenna face with radiator elements.
    * TR channel electronics, each connected to a radiator element.
    * Cold plate liquid cooling system.
    * Array power supply.
    * Control logic for each TR channel.
    * RF feed for the array.
    * Secondary power supplies.
    * Beam control processor to generate beamsteering commands.

    Design teams were formed to cover every specific aspect of the design, including aperture design, radiating element design, TR channel circuit design, TR channel MMIC and control logic EPLD design, TR channel and module layout, TR module thermal management, thermal efficiency and secondary supply design, TR module control design, TR module secondary power supply design, RF feed design from the master/oscillator and excite stage.

    The design aim was to build an X-band array with a maximum beamsteering angle of 70°, without any unwanted sidelobes arising. This is the basic problem in all AESA designs, insofar as grating lobes require element spacing of less than one half of a wavelength, while the resulting packing density presents heat transfer problems.

    The power rating and PAE (Power Added Efficiency) of the driver transistor was considered another issue, with initial estimation at 6 to 8 Watts CW (12 to 16 Watts peak at 50% duty cycle). The small size of the aircraft and its limited power and cooling capacity were seen to be serious constraints. The drive transistors are operated in A-class to provide best possible linearity, with a performance penalty in a design with an overall PAE of 22% to 25%. C-class operation was rejected due to its adverse impact on signal purity.

    Phazotron have stated, not surprisingly, that the biggest difficulties were encountered in engineering the TR modules. The approach taken after evaluating dozens of alternatives was to integrate four TR channels into a single "quad" module, as this was found to be the most practical tradeoff. An interesting observation is that this is a scheme identical to that used for first generation AESAs by US designers in the late 1980s, followed by the TR "stick module" scheme used in early US production AESAs.

    Thermal management proved to be the single most difficult problem, and Phazotron claim to have finally produced a design with very high heat transfer efficiency.

    The intent of the production Zhuk AE configuration is to provide a package which allows direct upgrades of legacy Fulcrum radars in existing aircraft, as well as provide radars for new production aircraft.

    Phazotron's objectives for the production phase of the Zhuk AE lifecycle include full automation of AESA component testing, signal simulators to permit more extensive testing of operating modes and performance, better firmware and software for the radar's processing components, more effective algorithms for signal processing and beam control, and a statistical database for managing reliability over the lifecycle of the equipment.

    Extensive design tradeoff studies were performed, covering power aperture and range performance vs thermal load performance for average TR module power ratings from 1 Watt to 15 Watts. A major issue was beamsteering to 70° as issues arose with sidelobes and projected aperture area beyond 60° of beamsteering angle.

    An idea explored and rejected was the use of simultaneous multiple mainlobes, as this presented a range of unwanted difficulties.

    Phazotron appear to be exploring digital beamforming techniques in what Chief Designer Dolgachev describes as a two stage processing scheme, with initial beamforming performed in the AESA, and additional beamforming in the digital receiver, downstream of the ADC stage. Adaptive nulling of mainlobe jammers is also raised as a benefit of the AESA design.

    Dolgachev also observed that a key factor in the design process was maintaining a focus on key performance parameters, and exploiting computational simulations extensively throughout the design process.

    The starting point for the AESA design was the development of a complete computational simulation for the design, the aim of which was to explore various design tradeoffs to find those which worked best. Single channel TR modules were rejected in favour a more thermally efficient 4 channel quad module design. The proprietary diamond lattice placement of radiating elements used in earlier PESAs was rejected as it presented difficulties in splitting the array cleanly into the multiple phase centres required for monopulse angle tracking, nevertheless the stagger in the elements still provides a robust diamond lattice pattern. The resulting module configuration is designed to carry RF signals along the shortest geometrical path between the array face and the feed, with coolant flow transverse (normal) to the antenna boresight.

    The result of these tradeoff studies resulted in the final placement of the radiating elements in vertical columns, each comprising an integer multiple of four elements to accommodate the TR module structure. Performance achieved for the final element placement was a first sidelobe at -30 dB, an average of higher order sidelobes at -50 dB, mainlobe width degradation of 4 dB at maximum beamsteering angle, and no grating lobes within the sought beamsteering angular range.

    Computational simulations were performed to determine the appropriate quantisation increments for antenna TR channel phase and gain control. Five bits were found to be adequate for amplitude, and six bits for phase control. Each TR channel in the array is individually addressed on the control bus.

    The backplane feed uses an undisclosed radial waveguide design, rather than the segmented linear branched feeds seen in first generation Western AESAs and ESAs. A network of coaxial waveguide switches between the feed network and TR modules is used to manage phase centres and perform monopulse summing and differencing for angle track modes.

    Power supply distribution to the TR modules presented similar problems with module 'pulling' during current drain transients, and was accommodated by the pragmatic expedient of attaching a large charge store capacitor on the main power bus near each of the TR modules.

    Cooling was arranged by mounting each TR module on an integral frame cold plate, the latter being actively cooled by liquid flow. Heat is transferred from each MMIC or transistor into the base of the module, and then into the cold plate for removal. Phazotron have not disclosed the thickness of the cold plates or TR modules, but clearly the horizontal element pitch is the hard constraint here. Each TR module includes an embedded thermal sensor which forces a module shutdown if overheating occurs, and restart cannot occur until the module cools down. All modules are thermally compensated in amplitude and phase to ensure that the performance characteristics remain aligned regardless of temperature and operating frequency.

    Dolgachev describes the current TR module parameters as such:

    * Average power of 5 Watts
    * Transmit path gain of 34 dB
    * Receive path gain of 30 dB
    * Receiver noise figure of 2.5 dB [2]
    * Phase shifter control increments of 5.625°
    * Amplitude control increments of 0.7 dB
    * Dynamic range for amplitude control of 24 dB
    * Overall PAE of 25%

    Modules and channels are independently addressed, evidently with two low order bits reserved for the channel, and the remaining eight high order bits for module addressing.

    An exciter preamplifier stage was developed to boost the output from the master oscillator module to compensate insertion loss from injection into the antenna feed backplane. The liquid cooled amplifier module has four ganged amplifier chains with a peak power output said to be 20 Watts.

    An automated arrangement was set up to test amplitude/phase performance of the TR modules, to permit calibration and compensation of errors to meet the required 3° error bound. Further automated equipment needed to be developed to measure and calibrate the fully assembled array, since the average power output of around 3 kW presented a hazard to personnel. A test rig using a power sensor aligned with the antenna boresight was used, with each module driven separately (with all others shut down) to measure the installed phase and amplitude performance. Measurements were then processed in software to determine overall antenna performance.

    Phazotron believe that the existing Zhuk AE design is performing below its potential, since much of the processing it uses was taken unchanged from earlier mechanically steered arrays and is thus not optimised to exploit the AESA.

    A separate paper by Semyonov et al discusses in some detail the design of GaAs MMICs used in the gain control, driver and phase shifter blocks of the TR channel. These were packaged together in single 8 x 22.5 x 2.5 mm sized hybrid with a heat transfer optimised metal case.

    The 5-bit digitally controlled attenuator is a GaAs MMIC die which uses 50 Ohm/sq resistive film for resistor components. The active components are Schottky transistors. High order bit stages are implemented in two 8 dB stages, for a total of 16 dB of controlled loss. The low order bit control stages are implemented as 1 dB stages. The total insertion loss of the controlled attenuator is 8 - 10 dB, with an RMS error of 0.5 dB between 4 and 11 GHz, and total attenuator bandwidth of 4 to 14 GHz.

    The 6-bit phase shifter function was split between two GaAs MMIC dies. Phazotron have stated that the shifters were intentionally built using a folded directional coupler design rather than switched filters. The four higher order bits, covering 180.0°, 90.0°, 45.0° and 22.5° shifts are implemented on one die, the two low order bits for 11.25° and 5.625° shifts on a second smaller die. This approach was chosen to bypass problems with device yield in production. It is intended that the 4-bit shifter be further improved to decrease the sensitivity of the 180.0° stage to production variations, and to reduce the per stage insertion loss from 2.5 dB to 1.5 dB. The design has been proven to perform between 8 and 11 GHz with an RMS phase error of around 6°, i.e. one bit. To compensate for the insertion loss of the attenuator and phase shifter stages, an additional buffer amplified was included in the hybrid design. This GaAs MMIC design provide 7 to 9 dB of gain between 8 and 11 GHz.

    According to Phazotron, the performance of the hybrids proved initially below expectations, with excessive phase and attenuation errors, due to problems with the alignment of the wires used to connect the dies to the package pins, assessed to be an inherent problem of the packaging used. The intent is to move to LTCC (Low Temperature Cofired Ceramic) and MCM-D (Multi Chip Module - Deposited) technology to get high production yields. In prototype modules, most of the gain and phase errors were actively compensated by control inputs to the array.

    Phazotron envisage the Zhuk AE as a new production radar, as well as an upgrade package for legacy MiG-29 Fulcrum fleets. A scaled up variant for the Flanker is also envisaged.
     
  8. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    [​IMG]

    [​IMG]

    http://www.ausairpower.net/Zhuk-AE-Arrangement-1S.jpg

    General arrangement of the Zhuk AE AESA radar. While prototypes have not used canted antenna placement, Phazotron claim to be planning a canted antenna arrangement as this improves coverage during aircraft turns and reduces structural mode RCS from the antenna face.

    [​IMG]

    Zhuk AE installed in the MiG-35 demonstrator. There are 652 radiating elements employed, in a diamond lattice pattern, each vertical row comprising groups of four quad TR modules, with a total of 163 used. This is a conceptually similar arrangement to the earliest US AESA arrangements, using a row length adjusted with displacement from the antenna centreline.
     
  9. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    [​IMG]

    The big long term prize for Russia's radar industry is the block upgrade market for earlier Flanker variant fleets. This market is dominated by early Su-27SK, J-11B, Su-30MKK, and Su-30MK2 variants, all of which are equipped with low peak power rated legacy N001/N001V series MSA radars, built using 1980s MSA technology. This market comprises up to 500 aircraft upgrades, especially the PLA-AF and PLA-N fleets (Xinhua).

    Zhuk ASE AESA - Scaling the Zhuk AE for the Flanker

    One of the stated intentions of Phazotron is to scale up the Zhuk AE for the Flanker, in the manner of the Zhuk-27 and Zhuk-MSFE variants, using a 0.98 metre diameter aperture.

    If we assume that such a scaled up design uses exactly the same quad module technology as the Zhuk AE does, and an enlarged cooling plate and mounting frame, then the achievable performance will scale with the aperture size. For the 0.98 m antenna outside diameter, assuming a similar unused area around the emitter array, the total usable aperture diameter will be around 0.8 metres, and the element count will sit at around 1160. If we assume tighter placement and a 1.1 metre antenna outside diameter, as used in the Pero PESA, then the total usable aperture diameter will be around 0.95 metres, and the element count will sit at around 1630, or about the same as the Zhuk-MSFE PESA design.

    With a peak power rating of 10 Watts/channel the latter yields a peak power of the order of 16.3 kW which results in a radar which outperforms the N011M BARS, APG-63(V)1, APG-71 and APG-79 in raw power aperture performance. Such a radar could reach IOC around 2010 if it is funded properly, in step with the timelines for the NIIP Irbis E.

    If Phazotron improve the TR channel power rating as they have stated an intent to do, then the results bear some careful consideration. Tabulating options yields some interesting results.

    [​IMG]

    Estimated detection range chart for variants of the Zhuk ASE AESA equipped with a range of Transmit Receive Module power ratings per channel. The detection range performance of the 10 and 12 Watt module equipped Zhuk ASE is similar to the Tikhomirov NIIP Irbis-E hybrid ESA in the Su-35BM/Su-35-1, and much superior to the N011M BARS. The performance of Zhuk ASE if equipped with modules rated above 15 Watts is superior to the Irbis E. Receiver noise figure and effective aperture area are assumed to be similar. N011M performance is based on parametric data and is better than NIIP cited figures (Author).


    Once Phazotron have engineered a Zhuk ASE with ~1630 TR Channels, then scaling up power aperture performance is only a matter of changing the TR Module design to use more powerful transistors, and improving the per module heat transfer performance in the AESA. Both of the latter represent fairly low risk incremental design changes.

    Much of the imperative in the US to pursue high density tiled packaging was the result of a high demand for reduced AESA mass production costs, good structural mode RCS performance, and tight element spacing to maximise bandwidth, so as to expand the functions the AESAs could perform and to maximise LPI capability via frequency agility. It is not entirely clear that these would be compelling near term motives for Russia's industry - they will become such as work on the avionics for the PAK-FA accelerates.

    There can be absolutely no doubt that Phazotron will aggressively market the Zhuk ASE as an upgrade package into the established Flanker market, which could be as large as 500 aircraft in China alone.
     
  10. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    (old offer for MIG-35 side deal in MRCA)

    http://www.flightglobal.com/articles/2007/02/20/212167/phazotron-eyes-asian-radar-manufacturers.html

    Phazotron eyes Asian radar manufacturers
    By Vladimir Karnozov

    Russian radar developer Phazotron-NIIR has inspected several Indian electronics companies to gauge their suitability to produce under licence advanced fighter radars, such as the Zhuk-ME and Zhuk-MA that equip the MiG-29M1/M2/K/KUB and MiG-35 respectively.

    Phazotron-NIIR deputy general director and Zhuk-MA chief designer Yuri Guskov said at the Aero India 2007 air show this month that Astra, Icomm and Samtel have been screened for further consideration. He added that if India selects the MiG-35 following its tender for 126 fighters, series production of Zhuk-MA radars could be outsourced to a consortium of Indian companies.

    "We are prepared to transfer 100% of the radar production to India should this be an Indian [defence ministry] requirement," Guskov said. He added that this also applies to the radar's active electronically-scanned array.
     
  11. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    http://www.military.com/features/0,15240,186678,00.html

    [​IMG]

    AESA Radars are a Highlight of Aero-India
    Aviation Week's DTI | Bill Sweetman | March 11, 2009
    This article first appeared in Aviation Week's Defense Technology International.

    Active electronically scanned array (AESA) radar technology is a requirement for India's Medium Multi-Role Combat Aircraft (MMRCA) competition, the biggest in the world. Consequently, a lot of maneuvering was apparent at the Aero India show last month, as fighter manufacturers worked to define their AESA answers and (in some cases) stall competitors.

    Boeing's F/A-18E/F Super Hornet has the simplest answer. Raytheon's APG-79 radar is standard on the Block 2 airplane, the current variant, and Boeing has not indicated it's considering alternatives. This allows Boeing to wave a low-risk banner, offering, essentially, the aircraft flying with the U.S. Navy and on order for Australia.

    Lockheed Martin had a choice of three radars. Raytheon's Advanced Combat Radar (RACR) and Northrop Grumman's Scalable Active Beam Radar (SABR) fit in an F-16, but Lockheed ultimately chose Northrop Grumman's APG-80, in service in the United Arab Emirates' F-16E/F. Two reasons are behind this, says Northrop Grumman: The proposed F-16IN for India is similar to the E/F and can accept the APG-80, which needs more power and cooling than RACR or SABR, and is lower risk. Northrop Grumman says no APG-80 antennas have had to be repaired, in normal use, since tests started over four years ago. "The antenna will outlast the airframe," the company says. A few modules might fail over its lifetime, but they won't affect performance enough to make it worth unsealing the radome and replacing them.

    Eurofighter holds a unique view of the AESA issue. Executives say the Selec Captor mechanically scanned array (MSA) beats any in-service AESA for the Typhoon's mission. A clue to their thinking emerged at an Aero India seminar. Peter Gutsmiedl, senior vice president of engineering at EADS Military Air Systems, pointed out ways in which an AESA could be integrated into Typhoon, including small side arrays, an azimuth gimbal and the so-called "swashplate" radar, a canted antenna on a rotating mount. The goal is to overcome drawbacks of a fixed AESA: narrower field of view than an MSA and diminishing effective aperture and performance at the edges of that field.

    Meanwhile, a spat between France and Sweden is developing. In 2007, Saab struck a deal with Thales to provide an AESA antenna for the Gripen Demo program, to be mated with the signal processor from the JAS 39C's Saab PS-05 MSA radar. The Thales AESA replaced the passive-scan antenna of Rafale's RBE2.

    But three things happened: Thales and Dassault were given the go-ahead to develop and produce the AESA for Rafale; Dassault has taken a large shareholding in Thales; and the Gripen NG has emerged—in India and Brazil—as a competitor to Rafale. Thales will honor the Gripen Demo contract but its AESA will not be available for a production NG.

    Sweden has talked about RACR, but would prefer the PS-05/A's "back end" modules for ease of integration and to stay away from control issues associated with U.S. components. The answer may lie with Selex, which, first as Ferranti, then as GEC-Marconi and subsequently as BAE Systems, was Sweden's partner on the original PS-05/A.

    Selex, in accordance with the philosophy of John Roulston, leader of the Captor design team, has been working on simpler, lower-cost *AESAs—in fact, its first production contract was not for a fighter radar but a retrofit to U.S. Coast Guard HC-130s. Its Vixen series of forward-looking radars, banned by the U.S. from South Korea's F/A-50, also received a launch order from U.S. Customs and Border Protection, with the 500-module Vixen 500 to be integrated on Cessna Citations.

    It's not surprising, therefore, that Saab is in talks with Selex about using its AESA technology in the Gripen NG radar. The NG is not competing with the Typhoon except in India. It is also unlikely (as different as they are) that both aircraft would make an MMRCA short list.
     
  12. LETHALFORCE

    LETHALFORCE Moderator Moderator

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  13. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    http://in.news.yahoo.com/20/20090326/1416/tnl-radar-imaging-satellite-ours-not-isr.html

    Radar imaging satellite ours, not Israel's, says ISRO Chairman

    Thu, Mar 26 11:16 PM

    Bangalore, Mar 26 (PTI) The Indian Space Research Organisation today asserted that the Radar Imaging Satellite (RISAT), expected to be launched by the Polar Satellite Launch Vehicle from Sriharikota spaceport next month, is not an Israeli one. Denying reports in a section of the press that RISAT is from Israel, ISRO Chairman G Madhavan Nair said it is an Indian spacecraft.

    Asked if RISAT is an Israeli satellite or an Indian one, the Secretary in the Department of Space said "we don't launch any Israeli satellite. It's an Indian satellite".

    On whether Israel has contributed to the satellite, Nair said "no. That many countries contribute, not only Israel.

    It's our satellite". Asked if Israel supplied Synthetic Aperture Radar for the satellite, he said "those finer details.

    We will talk when we make the launch". He said the exact date for the launch has not been finalised.

    "It could be within two weeks or so", he said, adding that preparations are in progress at the launch pad. "May be sometime in the middle of next week, we will fix the exact date", he said.

    PTI.
     
  14. shiv

    shiv Regular Member

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    can you guys explain the usefulness of a PESA radar vs an AESA.....
     
  15. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    one basic difference is the field of view is much greater and the distances covered are also greater, scanning rate is also much greater than PESA in AESA and PESA mostly operates on one frequency while AESA switches so enemies can not pick it up and also jam it, also there are many more transmitters on AESA so it is always active.
     
  16. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    http://www.spacemart.com/reports/RISAT_Is_A_Home_Grown_Satellite_999.html

    RISAT Is A Home Grown Satellite

    File image: RISAT
    by Staff Writers
    Bangalore, India (PTI) Mar 30, 2009
    The Indian Space Research Organisation has asserted that the Radar Imaging Satellite (RISAT), expected to be launched by the Polar Satellite Launch Vehicle from Sriharikota spaceport next month, is not an Israeli one.

    Denying reports in a section of the press that RISAT is from Israel, ISRO Chairman G Madhavan Nair said it is an Indian spacecraft.

    Asked if RISAT is an Israeli satellite or an Indian one, the Secretary in the Department of Space said "we don't launch any Israeli satellite. It's an Indian satellite".

    On whether Israel has contributed to the satellite, Nair said "no. That many countries contribute, not only Israel. It's our satellite".

    Asked if Israel supplied Synthetic Aperture Radar for the satellite, he said "those finer details...We will talk when we make the launch".

    He said the exact date for the launch has not been finalised. "It could be within two weeks or so", he said, adding that preparations are in progress at the launch pad.

    "May be sometime in the middle of next week, we will fix the exact date", he said.
     
  17. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    Rafele's radar

    [​IMG]
     
  18. LETHALFORCE

    LETHALFORCE Moderator Moderator

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  19. pyromaniac

    pyromaniac Founding Member

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    Aesa vs pesa

    Since LF already has a thread on Radar, I will post this info in here..


    AESA VS PESA


    PESA

    In a passive electronically scanned array (PESA), the microwave feed network in the back of the antenna is driven by a single high-power Radio frequency(RF) source (transmitter), sending its waves into phase shift modules (usually digitally-controlled), which, in turn, feed the transmitting/receiving elements.Using beam steering they provide stealth, interleaving modes and reliability. However, the shift in phase of the radar signal comes at a cost. High-power phase control leads to losses in the signal and a consequent reduction in radar sensitivity. Typical total losses in early systems resulted in a factor of 10 reductions in radiated power; in modern systems these losses are still in the factor of 5 ranges.

    Electronic steering and shaping of a beam provides unprecedented beam agility - beam shape and direction can be digitally controlled by a computer within a matter of tens of milliseconds. Such beam agility makes it possible for one phased array radar to act as multiple radars each with its own beam shape and scan pattern! This is referred to as interleaving radar modes. The same radar can be tracking for airborne threats using one beam shape and scan pattern while searching for ground targets using another beam shape and scan pattern.

    The Russian NIIP N-011M Bars radar fitted on the Su-30MKI and the NIIP Bars-29 radar proposed to be fitted on the MiG-29M2 being offered to the IAF are examples of phased array radars

    AESA

    An AESA, instead, has an individual RF source for each of its many transmitting elements. This provides for a graceful degradation, so that many T/R(transmitter-receiver) modules may fail and the radar would not stop functioning. AESA employs a grid of hundreds of small (TR) modules that are linked together by high-speed processors. Each TR module has its own transmitter, receiver, processing power, and a small spikelike radiator antenna on top. The TR module can be programmed to act as a transmitter, receiver, or radar. The TR modules in the AESA system can all work together to create a powerful radar, but they can do different tasks in parallel, with some operating together as a radar warning receiver, others operating together as a jammer, and the rest operating as a radar. TR modules can be reassigned to any role, with output power or receiver sensitivity of any one of the "subsystems" defined by such temporary associations proportional to the number of modules.

    AESA provides 10-30 times more net radar capability plus significant advantages in the areas of range resolution, countermeasure resistance and flexibility. In addition, it supports high reliability / low maintenance goals, which translate into lower lifecycle costs. Since the power supplies, final power amplification and input receive amplification, are distributed, MTBF is significantly higher, 10-100 times, than that of a passive ESA or mechanical array. This results in higher system readiness and significant savings in terms of life cycle cost of a weapon system, especially a fighter.


    CONCLUSIONS

    So, in summary A PESA radar is simpler to construct than an AESA. However, they both their drawbacks. Due to the heat generated by these devices, there has to be a very good cooling system on board to make sure that they don't fry themselves. In addition, another problem is that they have a somewhat limited range. With that said, this is really not a big concern right now because of the fact that the majority of the countries that use these radars have a well built network of Land based radar in addition to AWACS support. This will help overcome the shortages of AESA and the PESA radars.

    With that said, The advantages of AESA and PESA are numerous - they can scan an area much faster (miliseconds compared to seconds), their signals are much harder to detect, and some advanced AESA models can scan, track and even work as a jammer at the same time. Advanced versions can also scan for air and ground targets at the same time in addition to tracking much more targets than normal radar. With that said, AESA is the future of radar technology as it offers features that cannot be matched by any other radar platform. Its combination of high durability and its potential for tremendous multi-tasking makes it an attractive options for countries that seek to build a modern air force.
    Like I have already stated, AESA radars are remarkably good at multi tasking. In addition to emitting radar signals, then can also be employed for non traditional ISR, as well as electronic attack. For example, some of the elements can transmit and receive signals modulated with datalink waveform, transferring large amounts of data (such as live video or aerial imagery) over high bandwidth datalinks. Similar techniques can be used for electronic attack, to jam or deceive electronic systems operated by enemy forces.

    The mechanical scanning systems used in previous systems were prone to failures, which grounded the entire aircraft. The new systems use solid-state technology and electronic scanning, to replace the mechanical systems but also introduce multiple elements to replace the single channel design of previous systems. Therefore, AESA radars can sustain certain degree of failure without grounding the aircraft or disabling the entire radar system. Furthermore, when designed with modular approach, AESA radars can be gradually upgraded, by replacing the solid-state receive/transmit modules based on Gallium-arsenide semiconductors technology with more advanced elements, thus significantly improving performance.

    *NOTE: AFTER A LOT OF RESEARCH I HAVE PUT TOGETHER THIS INFO....AS SUCH I AM UNABLE TO CITE SOURCES BECAUSE WELL...CITING ALL THOSE SOURCES WOULD TAKE ABOUT A PAGE*
     
  20. A.V.

    A.V. New Member

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    some of the best radars and planes which use them.

    Phazotron Zhuk AE
    AESA
    Zhuk-AE can detect aerial targets at ranges up to 160 km (head on) in both look-up or look down modes. Look-up tail-on detection range is 50km (40km look down). The radar can track 30 aerial targets in the track-while-scan mode, and engage six targets simultaneously in the attack mode.

    used by :- Mig-35



    Phazotron Zhuk ME
    PESA, 0.7 metre aperture,
    Capable of detecting fighter-type targets at a 120 km range, acquiring and tracking up to 10 air targets with a simultaneous engagement of 4 of them.
    used by :-MiG-29K



    Phazotron Zhuk MSF/MSFE
    PESA.
    98 meter diameter aperture with 1662 radiating elements
    Developed for PLA-AF Su-30MK3




    Tikhomirov NIIP Irbis E
    20 kW hybrid ESA
    Largest antenna in any agile fighter.
    Peak power and range performance claimed to be competitive against the publicly disclosed figures of F-22A's APG-77. NIIP claim a detection range for a closing 3 square metre coaltitude target of 190 - 215 NMI (350-400 km), and the ability to detect a closing 0.01 square metre target at ~50 NMI (90 km). In Track While Scan (TWS) mode the radar can handle 30 targets simultaneously, and provide guidance for two simultaneous shots using a semi-active missile like the R-27 series, or eight simultaneous shots using an active missile like the RVV-AE/R-77 or ramjet RVV-AE-PD/R-77M. The Irbis-E was clearly designed to support the ramjet RVV-AE-PD/R-77M missile in BVR combat against reduced signature Western fighters like the Block II Super Hornet or Eurofighter Typhoon. Curiously, NIIP do not claim superiority over the F-22A's APG-77 AESA, yet their cited performance figures exceed the public (and no doubt heavily sanitised) range figures for the APG-77.
    used by :- Su-35




    Tikhomirov NIIP Bars
    Hybrid ESA
    used by :-Su-30MKI



    APG 77
    AESA
    It is believed to have a detection range of 110-115 mile and can detect aircraft with a cross section as small as a steel marble, though probably not at its max range.
    used by :-F-22 Raptor



    APG-63(V)2
    AESA, Estimated range 125 mile
    used by :-F-15



    APG-79
    AESA,
    Estimated range 100 mile
    used by F/A-18E/F Block II Super Hornet
    APG-80 AESA F-16 Block 60, IN




    APG-81
    AESA
    Estimated range 100 mile
    J-37



    AMSAR
    AESA
    used by :-Eurofighter CAESAR replacement




    ELTA EL/M-2052
    AESA

    used by F-16, LCA



    Thales RBE2
    AESA
    Final validation of software functions is expected to end in the first quarter of 2010 with the delivery of AESA radars to Dassault Aviation
    used by :-Rafale



    SABR AESA.
    The Scaleable Agile Beam Radar is designed to retrofit into all F-16 without any structural, power or cooling modifications, and the same F-16 mounting points are used for SABR installation. SABR retrofits are expected to take less than a day.
    used by :- F-16



    VIXEN 500E
    AESA
    Range 35 nautical miles (65 km)
    Saab has tied up with SELEX Galileo to co-develop an Active Electronically Scanned Array (AESA) Radar for the Gripen Next Generation (NG) based on the Vixen 500E.
    The VIXEN 500E is being developed for use on small lightweight fighter aircraft. The radar currently does not have any customers. It has approximately 500 T/R modules. There is also a variant with 750 T/R modules under development.

    Gripen NG
     
  21. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    ASIAN DEFENCE: Israeli Radar for India’s LCA?

    Israeli Radar for India’s LCA?

    [​IMG]

    [​IMG]


    India is seeking to buy an EL/M-2052 active electronically scanned array radar from Israel’s Elta for its Light Combat Aircraft (LCA), after efforts to develop a radar failed, Indian Defence Research and De*velopment Organisation (DRDO) sources said. The aircraft’s developer, the Bangalore-based Aeronautical Development Agency (ADA), also is seeking a foreign firm to advise it about the flight tests. ADA is offering a two-part contract for 18 months of work leading up to initial operational clearance, and 24 months of work leading to final operational clearance.LCA prototypes have already flown about 600 test flights, one ADA official said. The single-seat, single-engine, supersonic LCA will soon begin weapons integration work, and the aim is to achieve initial operational clearance with the EL/M-2052 radar aboard.A DRDO team flew to Israel within the past two weeks, hoping to secure the radar in time to have it aboard the under-development LCA by next year, Indian Defence Ministry sources said.The radar will allow the LCA to detect, lock onto and pass information about 64 targets to the plane’s mission computer.Since 1991, India has spent more than $50 million to develop a Multi Mode Radar, which was originally to have been designed by Hindustan Aeronautics Ltd. (HAL) and the DRDO for service beginning in 1998.The LCA program was launched in 1983. ADA is leading the development with help from HAL.
     

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