Beyond Visual Range (BVR) fighter combat

Discussion in 'Military Aviation' started by Agnostic_Indian, Sep 9, 2012.

  1. Agnostic_Indian

    Agnostic_Indian Regular Member

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    This is my first attempt to write down my understanding (obviously from forum debates
    and other reads) of important systems, technologies and features, counter measures and
    their advantages and disadvantages in a BVR combat. For advanced readers this won’tbe interesting/ provide nothing new(but you can help with corrections and more inputs ),but I hope newbies will like it.

    RADAR
    It is the primary sensor of the fighter. There are different kinds of radars. PESA is oldergeneration passive electronically scanned array radar fitted in most of the 4th genfighters, there are some hybrid versions of PESA which stands between traditionalPESA and modern AESA radars (Active electronically scanned) these radars are hard tojam because jammers operate by determining the operating frequency of the radar andthen sending a signal on it to confuse the receiver .This technique works as long as theradar system cannot easily change its operating frequency. Most radars using modernelectronics are(including PESA though limited frequencies)capable of changing theiroperating frequency with every pulse. An AESA has the additional capability ofspreading its frequencies across a wide band even in a single pulse, to lowering theemission power,frequency-modulated continuous-wave signal,using of only theminimum power required for the task,Using of pulse compression etc .LPI(lowprobability of intercept ) is the name for variety of such techniques which degrade theperformance of modern RWR( Radar Warning Receiver ) and counter measures.

    AESAS can also be switched to a receive-only mode, and use these powerful jammingsignals(of enemy ) instead to track its source.

    As a general rule we say bigger radar with more t/r module and more power will helpyou detect and track the enemy before he can. That will allow you the first shot at thebest ranges missile is capable of ensuring a high PK. but you have to be clever indeciding when and where to switch it on and off other wise you will giveaway yourstealth/position , or you will attract a anti radiation missile homing locking on to yourradar emition.

    IRST(Infrared Search and Track)- modern irst with infrared imaging capacity is verymuch capable to substitute the use of radar to identify threats and engage them. Thoughit provides lesser data, has lesser range than modern radars it provides the important ability to engage targets passively.

    There are countering technology against radars and IRST .Those are stealth andECM.So it is important to have stealth to reduce your RCS against enemy radar signals.

    STEALTH or VLOis general shaping and RAM coating to reduce range which a fighteris detectable to a enemy radar. 5 gen fighters use shaping , internal weapon bays , RAMetc to achieve VLO while internal weapon bays are absent in 4.5gen fighters , stealthshaping also is limited so are not as stealthy as 5th gen fighters .

    Stealth shaping has to compromise on Aerodynamics but gains are much greater thanlosses. A good stealth fighter will be a good mix stealth and aerodynamic shaping.
    Traditionally stealth aircrafts are optimized against X band radars, Researches are onprogress to use L band AESA radars to detect and track stealth aircraft.As of now Lband is useful in long range detection rather than tracking and missile guidance becauseof lack of accuracy..but things might get change soon.

    INFRA RED STEALTH- it is achieved by special coatings and shaping of exhaustnozzles. however seducing heat signature below certain degree is difficult and seekertech is more likely to develop faster and easier than t heat signature reduction tech
     
    Last edited: Sep 9, 2012
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  3. Agnostic_Indian

    Agnostic_Indian Regular Member

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    ECM(Electronic Counter Measures )- ECM used against any kind of guidance systemssuch as fighter jet's radar, missiles seekers ,IRST, laser range finder etc. Though it isdefensive system it can be used defensively also.

    RADAR ECM
    RWR-It is used for identifying, avoiding,evading or engaging threats. it also givessuggestions on best options to evade a thread if avoidance has failed. modern RWR's arecatching up with the advanced Aesa radar technology.

    JAMMING AND DECEPTION-It is done by emitting interfering signals to confuse orproducing blanket noise .Unlike PESA radar, AESA radar is hard to jam ordecept.Spread spectrum technology can be used to jam multiple frequencies of AESAbut with less power availability (because power is divided across numerous frequencies)and less efficiency in jamming. Bigger platforms have the power and space to supportbigger Jammer,jamming power reduces as the distance between you Jammer and enemyradar decreases,generally bigger radar will burn through(over power) your jammingquicker than the smaller one. once you reach the burn through range you should switchoff the Jammer other wise you will be inviting HOJ(Home on jamming ) missiles. Adedicated jamming platforms like growler will be always better than limited size onboard Jammer.

    SENSOR FUSION & AUTOMATION-Better sensor fusion will allow pilot toconcentrate more on mission rather than lessor important tasks. modern Senserscombined with high power computers care capable of flight control, combining datafrom. different sensors , screening them and eliminating false alarms, threat warning andprioritising, automatic counter measures and maneuvering , suggesting best weapons touse, etc
    BVR MISSILES

    Bvr Missiles are the weakest link in a Bvr combat due to it's comparatively lesser rangewhen compared to the supporting radar's range , lesser Pk at maximum range, lessermaneuverability compared to WVR missiles, vulnerability to ECM etc . If you don'thave bigger range missile then having a bigger radar advantage is not much of a gamechanger. But things are changing now with high G capable missiles and new "Ramjetpropulsion " with duel pulse propalant and thrust vector control. What it dose is- it lastslonger, provides greater speed at start and then provides controlled but sustained speedtowards the end game and there by reducing the G force it needs to pull when handling amaneuvering target.

    High off bore sight- Is the ability of the missile to engage a threat at wider angleswithout pointing the nose towards a threat.This in combination with helmet mountedcueing system allows a pilot to simply look at the target and fire the missile.

    Guidance System
    There are many kinds of guidance systems for missiles- active homing, semi activehoming and passive homing , infra red homing, optical sensors etc
    active homingare the latest missiles which are fire and forget, advantage is that as soonas it is fired you can escape from there or engage another threat. disadvantage is it hasslightly lesser range compared to semi active missiles.
    Semi active homing- it has longer range because it carries lesser electronics so it canafford bigger amount of fuel. Like all radar guided missiles this also can be jammed butif it has a HOJ capability it can be dangerous.
    Disadvantage is that the it needs mid course update so launching aircraft needs to stay inthe fighting area which can be dangerous.

    Passive Homing
    Infrared Guided missiles-modern infrared seekers has infrared imaging capacity ,itcannot only detect engine exhaust but also the heat generated in the Air frame becauseof friction. Modern IR missiles are tough to counter by flares, and decoys. coupled withHMS( helmet mounted sight ) + IRST+ IR guide missiles one can hunt stealth aircraftspassively..if the attacking platform got very less structural RCS then it can be adangerous combo.
    Draw back is it is prone to climate changes, it's head on range is less because seekercan't trace small heat signatures from from longer ranges , at tail chase seeker can trackthe enemy engine exhaust from long ranges(because you are positioned right behind it )but here the ranges is limited by the fact that enemy is running away from you andmissile get out of fuel quickly though it has greater speed. so you need to get closer tofire.
    Countering technologys are - infra red missile approach warners and laser warningreceivers.
    Anti radiation missiles- They are passive and and they target enemy radar radiation orjamming originals.
     
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  4. Agnostic_Indian

    Agnostic_Indian Regular Member

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    OTHER MAJOR FACTORS

    Acceleration,speed and altitude - A good twr provides good acceleration which helpsyou to gain speed quickly to evade a missile or to get quick momentum to reach desiredspeed to fire a missile.higher the speed more the kinetic energy missile carries.
    fighters capable of higher altitude flight( delta, cropped delta or diamond shaped wingwith low wing loading ) can utilise the natural velocity and thinner air at high altitudesto boost your missile's speed.f22 with it's high altitude super cruise gains about30%boost in missile performance in terms of speed and range.

    Bigger fighters can Carry more number of missiles, more fuel there for more range,morepowerful radar and electronics etc.

    Generally twin engine fighters are better than single engine one's because they givemore power to fly and also for radar and electronic systems, and even if one enginefails other one can help you safely return. super cruise ability helps to save a lot of fuel.

    Thrust vector nozzles will give you more agility, turn rate ,better nose pointingauthority,better climb rate etc . one of the draw back of TVC is drag and energy loss.modern computer controlled Fly By Wire systems has minimized this draw back.

    More use of composites in structure makes the fighter lighter and it improves TWR.

    These features will guide us to make a educated guess to know which fighter standswhere. But there are things which are not comparable because of lack of data,comparingsystems are not battle proven etc. for example quality of RAM coating, quality of ECM,etc. if no data is available to support either then one can consider legacy and experienceof particular system manufacturer, money spend on developing the systems/ fighters incomparisons etc because of two reasons.
    1. we can expect a advanced, experienced manufacture to come up with a better systemthan a new player.
    2. You get what you paid/ spend for.Chances are very less that cheaper fighter/ or it'ssystems will out class a costly fighter unless there is big cost over runs,major designflaw, big difference in labour cost/ production numbers etc which we are aware of.


    BVR ENGAGEMENTS AND TACTICS

    Bvr engagements does not often happens one vs one so it is very difficult to analysebecause of the complexity. Apart from different fighter formations with differentnumbers, tactics, and maneuvers ,it also includes various platforms such asawac,dedicated Jammers, sams, etc.

    A bvr battle win is depends on the pilots skills to make use of available technology atright place, right time, considering the mission, strength and weakness of enemy. Toachieve that he needs to have better training, knowledge of his own strength andweakness as well as the enemy's also. As always said by experts He wins by forcing theopponent to fight under his rule not by letting opponent to decide the rules ofengagement.

    Reference -post cold war air to air evolution by Dr.Carlo kopp.
    en.m.wikipedia.org/wiki/Air-to-air_missile
    en.m.wikipedia.org/wiki/Low_probability_of_intercept_radar
    Eurofighter Technology and Performance : Defences
    The Boresight: Airborne Infrared and Supersonic Stealth
     
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  5. p2prada

    p2prada Stars and Ambassadors Stars and Ambassadors

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    Excellent. This is a good compilation of information for newbies. Nice work AI.

    I would suggest anybody to read this for a decent understanding of modern airwarfare.

    There is only a small minor error here;
    Semi active homing needs guidance throughout the flight whereas active homing needs guidance until it's seeker lights up the target. That's around 18Km on the Aim-120C-5 and RVV-AE.

    Kopp wrote this back in 1982.
    ACTIVE AND SEMIACTIVE RADAR MISSILE GUIDANCE

    It is very easy to read and will explain difference between semi-active and active missiles.
     
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