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    GarryB

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    Re: Questions and Ideas

    Post  GarryB on Sat Apr 11 2015, 11:15

    Radar beam-riding is, of course, all-weather.

    You mean SARH? It is all weather, but also active and something the target would detect.

    But the wire guidance doesn't need to be optical.

    The only wire guided weapons that don't use optical tracking of the missile launched is in torpedos, where the sonar of the launch vessel tracks the outgoing torpedo and the target and calculates guidance corrections which are then transmitted down the wire to the torpedo to steer it to impact the target.

    TOW, HOT, Milan, AT-4, AT-5, AT-3, AT-1, AT-7, AT-13 all use wire guidance and a missile tracker called a gionometer that tracks the coded flare in the tail of the missile and calculates the distance from the missile to the point of aim of the gunners crosshair and calculates flight manouvers for the missile to get it on target and then transmits them down the wires. In very bad weather it wont see the flare and therefore wont be able to guide the missile on to the target.

    Actually the wire-guided missile supposedly used by Osa is guided very similarly with the other command guided missiles used by Osa, i.e., radar guidance with the secondary option of using optical guidance. The only difference is using a wired link vs a radio link; just the communication method is different.

    A bit like the difference between the AT-2 and AT-6 and AT-9 which use radio command guidance and the AT-3 which is still command guided but using a wire for data transmission.

    the wire limits the speed and flight performance of the launch helo during guidance.

    On the topic of radar beam-riding, the problem is the low accuracy that can be achieved, and the source of the problem is the large wavelength of the radars in comparison with the optical wavelengths.

    If you are going to actively emit radar waves from an actual aircraft radar you might as well use SARH guided missiles... a bit like SALH except using a radar beam instead of a laser to mark the target... the missile could then be lofted to a steep angle to deliver a diving top attack result...



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    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 11:50

    GarryB wrote:The only advantage of wire guidance is that it is a secure way of guiding a missile without emitting a guidance signal that could be intercepted or jammed.

    Laser beam riding guidance is rather superior in every way and allows for faster missiles.
    Actually laser beams or better radar waves can be maked ipossible to jam. Lets think this way: if a helicopter of russia guide a missile trought radar on a certain frecvency what the enemy would do? Will jam whit same frecvency. What that means? There is a noise where you cant distinguis nothing. Why? Because if you send a message to a missile whit letters ABC in case of noise would be like you getting others letters between message like ADEIBZXWC. What that means? The missile would not receive the accurate signal for correct steering so will have a bad path and miss target. But there are several ways to improve that. One solution would be that a missile to distinguis better between noise. How? By put several receptors that separate receive different frecvecies. By this a device will not be flooded by all frecvecies at once. Other method would be shorten the message and sent him in the same time to different frecvencyes. Like send just a A letter on several frecvencies. Also another method would be like this: when a missile receive ABC message other letter are comin in like i said but if a device could reject other messages and only accept those are a part of logical message would get the right message. You think : but if the message is in a form like AABCBC when the jam is on? Then letters must be formed that way a jam could not be used. Like accepting message only from non consecutive capitalized letters. Ofcourse that could be also jammed. But if for the every letter transmited is a keyword or speciwl number that qualify the letters are comming from own troops. A keyword that only helicopter and receiving missile would know. Or other form of cryptography of frecvencyes. Cryptographers know better.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 12:01

    flamming_python wrote:
    victor1985 wrote:
    flamming_python wrote:
    victor1985 wrote:Yes but a supersonic missile has problems to steer. A subsonic one will easilly correct his flightpath so can easilly intercept the supersonic missile. That means a subsonic wired missile has some chances against a faster enemy rocket. Thinking that the steer of wired one is made by wire so thus faster would have a better trajectory and so a better intercept rate. Also if no EW can be against wired one means only a wrong calculation when the missile was maked can be. But that is hard to believe. So the probabillity of interception of such a missile is high. And what you do whit a f22 for example if none of missile lauched hit the target? Well nothing.....

    It's very unlikely that a slower missile would be able to intercept a faster missile, if the faster one has any capability to manuever at all.
    Depends on the difference between the two speeds and the maneuvrability. Lets say the supersonic missile is very fast but low steering and the subsonic one has great steering ...the subsonic will simply steer early in flight to correct the path and go to the interception trajectory. There is a point in subsonic missile flight where the ration speed/steering matters. That point show from what to what ratio of Supersonic missile the subsonic one can intercept. There is a perfect speed/steering point of subsonic missile where a larger group of supersonic missiles whit different own ratios can be intercepted. Ofcourse all matters if the subsonic missile see early the supersonic one. That means IR and others.

    Doesn't work like that

    A smaller course correction by a faster missile could amount to a far larger distance difference between its original and new destination within a certain period of time; than a larger course correction but by a slower missile.

    It's like the difference between a person walking and a person driving a car.
    The person walking could walk for ten seconds, and then turn around the corner and walk for another 10 seconds in a different direction.
    The car could ride along at 60 mph for 10 seconds, then go around only a slight bend and keep going at the same speed in its new bearing.

    In 20 seconds time you'll find that the car is a lot further from where it would have been had it not turned into the slight bend, than the person walking is far from where he would have been had he not turned the corner and instead carried on straight ahead.

    The fact is that a slower missile would not be able to compensate for even the slightest change in course/manuever of a faster missile; unless it truly has a lot of time to spare - however in that case a manuever by the faster missile closer to the interception point would definately make the slower missile's task impossible; it just won't be able to get to the new interception point in time.

    A slower missile can only really intercept a faster one - if the faster one's flight path and speed are completely predictable and thus the interception point can be accurately calculated ahead of time without needing any sudden course changes during flight.
    A ballistic trajectory is an example of such a predictable flight path and speed; if the ballistic missile's profile is known, and what speeds it will attain at which stages of its flight; as well as its destination - then that's enough information to be able to calculate an interception point for your missile; even a slower one.

    Of course, modern ballistic missiles are not as predictable as that; unknown factors likely include variance in terms of when their various stages are engaged, the behaviour of their manueverable re-entry vehicles and some like the Iskander, are not entirely ballistic and do have some capacity for manuevers too.
    Yes but you forgot something : faster the missile is more correction must make. Cause faster going less angle steering is possible. That mean over a certain speed a supersonic missile would become vulnerable even to slow subsonic missiles. Also it matters how much steering a subwonic missile can do. If its excellent at this the supersonic would have problems. Against subsonic missiles a supersonic one has a perfect speed/steering ratio. Lower or upper that ratio problems occur. Also for subsonic missiles is a speed/steering ratio. What that means: only some supersonic missiles whit certain speed and ratio could become a real threath. But those could be counter whit other type of missiles special made for that supersonic missiles. Dont forget the radius of blast that is important too.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 12:06

    Think like this: faster the rocket is lower the steering till would be able just to fly in straight line. Because of the g loads. You have right but....your supersonic missile could escape only if make a steer in close of subsonic one. But faster is.....problem appear.
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    Morpheus Eberhardt

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    Re: Questions and Ideas

    Post  Morpheus Eberhardt on Sat Apr 11 2015, 13:37

    Radar beam-riding is, of course, all-weather.

    You mean SARH?

    SARH stands for semiactive radar homing.

    In SARH, a beam illuminates the target that is tracked by radar and the seeker in the missile tracks the target via the reflected signal.


    The relationship between radar beam-riding and SARH is like the relationship between laser beam-riding and semiactive laser guidance.


    It is all weather, but also active and something the target would detect.

    By far the most important reason for the existence of radars is their all-weather capability. The implications of this is tactical, operational, and strategic. If you have the best optically guided air defense but no radars, your enemy will rest during good weather and bomb you only during bad weather.


    But the wire guidance doesn't need to be optical.

    The only wire guided weapons that don't use optical tracking of the missile launched is in torpedos, ...

    Well, the topic under discussion here is about a radar command guided missile utilizing wire guidance ..., how about me just copying the following excerpt from my post above:

    Actually the wire-guided missile supposedly used by Osa is guided very similarly with the other command guided missiles used by Osa, i.e., radar guidance with the secondary option of using optical guidance. The only difference is using a wired link vs a radio link; just the communication method is different.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 15:09

    GarryB wrote:
    Laser beam-riding doesn't provide for all-weather performance.

    Extreme weather conditions could effect performance, but no different from wire guided... if the missile can't detect the laser beam through the weather at hand then I would suggest a wire guided system would not detect the flare in the tail of the missile and therefore the guidance system would fail as it could not see the missile in relation to the target and generate course corrections for the missile.

    The notion of a wire-guided Osa is absurd and quite frankly stupid.

    Once again I would love to see an ounce of proof it exists.

    Sounds a little strange to me too, but there have been plenty of documented cases where wire guided ATGMs have been used against helicopters hovering or on the ground quite successfully... so I don't see an issue in terms of it being effective.

    To a certain extent I have to disagree with GarryB on the merits of Laser beam riding primarily because  laser beam riding is generally limited to a short-range both for surface to air missiles as well as anti tank missiles.

    10km range for the HE variant of Kornet-EM for use against aerial and ground unarmoured targets, Vikhr-M for use against targets 16km away, 10km for SOSNA-R... ranges of 8km for Krisantema using laser beam riding or radio command guidance and radar target and missile tracking.

    Wouldn't call any of these short ranged.

    Note the SALH Hellfire uses a laser that travels up to 16km... ie from helo to target and back to 8km range... which can greatly be effected by the surface of the target.

    Compared to a wire guided weapon the main advantage is not only much better range but also significant speed... Wire draggers move at between 120mps and about 200mps, while the slowest LBR is Kornet-EM at 320mps, with Vikhr-M moving at 610 mps and SOSNA-R moving at about 1100mps. Smoke popped from a tank that lands 30m in front of the vehicle wont effect the missile till it has entered the smoke cloud so it wont even begin to effect the missile till it has nearly hit the target... with a Hellfire the laser spot will move from the surface of the tank to the cloud of smoke and will likely move with the moving shape of the cloud leading to an offset aim point and therefore even if the target tank moves behind its cloak of smoke the LBR will likely get some sort of hit with its very high speed, while the SALH will likely be misdirected and miss.

    Apart from that and more importantly countermeasures to Laser beam riding missiles are widely available. I cannot insert a link because I am new but I have a number of URLs that showcases the countermeasures against Laser beam riding missiles.

    As mentioned popping smoke is not that effective, and most DIRCMs try to attack the missile... which works with SALH, but with the LBR looking back at the launch vehicle, and the beam being so low power the target may not know they are under attack till impact, they are not so efficient either.  If you could mention any other methods I would be interested to hear them.

    Not that LBR is perfect, but it doesn't get much recognition in the west because it is not widely used except for the Starstreak... A British missile.

    It is very simple for the operator as most Russian systems have an autotracker to keep the crosshairs on the target once locked so in a way they consider it fire and forget.
    Well here is not about range is about the fact that wired ones resist at EW. What would you do whit a long range missile that miss the target because of EW?
    Not to mention that using radar waves would show the position and presence you have thus activating enemy defence.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 15:14

    Morpheus Eberhardt wrote:
    Radar beam-riding is, of course, all-weather.

    You mean SARH?

    SARH stands for semiactive radar homing.

    In SARH, a beam illuminates the target that is tracked by radar and the seeker in the missile tracks the target via the reflected signal.


    The relationship between radar beam-riding and SARH is like the relationship between laser beam-riding and semiactive laser guidance.


    It is all weather, but also active and something the target would detect.

    By far the most important reason for the existence of radars is their all-weather capability. The implications of this is tactical, operational, and strategic. If you have the best optically guided air defense but no radars, your enemy will rest during good weather and bomb you only during bad weather.


    Well there is a problem here. The enemy would have same problems as you if bomb in bad weather. Thus all will depend on sistems others than radar that work on bad weather.
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    Morpheus Eberhardt

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    Re: Questions and Ideas

    Post  Morpheus Eberhardt on Sat Apr 11 2015, 15:28

    victor1985 wrote:Well there is a problem here. The enemy would have same problems as you if bomb in bad weather. Thus all will depend on sistems others than radar that work on bad weather.

    The enemy can do blind bombing. Blind bombing is perfectly adequate for use against stationary targets and for strategic bombing.

    Also, if one of the sides has radar with full air-to-ground capability and the other side doesn't have any radar-guided air defense, then the side without the radar-guided air defense would be in a very bad predicament.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 16:42

    If a missile knows the interval at which certain frecvency is used by own troops could bypass electronic war.
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    jhelb

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    Re: Questions and Ideas

    Post  jhelb on Sat Apr 11 2015, 19:40

    Guys, any idea whether the aircraft that RuAF operates (Su 30, Su 34, Su 35 etc) are vulnerable to cyber attacks?

    I came across a number of reports that states that the F-35 is vulnerable to cyber attacks

    http://rt.com/usa/fight-f-35-vulnerability-cyber-464/

    http://cyberwarzone.com/new-f-35-fighter-jet-vulnerable-cyber-attacks/


    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 20:55

    What mean cyber atack? If you say jamming that means Electronic War (EW). If you mean cybernetic attack meaning stealing from somehwere the ways the schemes upon aircraft is made that is hard. Because those are top secret files in the producer facility well guarded by army also army use LAN areas not connected to internet. If you say something like a hacker from usa steal trought internet the files is no way. Like i said the army and weapons producers have LAN also everyting and everyone entering the place is verified. Latest james bind like tehnologies in spying area are known by army so is very unprobable that someone steal the plans.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sat Apr 11 2015, 20:56

    *james bond

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sun Apr 12 2015, 13:55

    Would not be easier to emit ABC frecvencies in this known order and if get a error like BAC the computer to take position of enemy aircrafts in corect order of ABC frecvecies?
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    jhelb

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    Re: Questions and Ideas

    Post  jhelb on Sun Apr 12 2015, 14:16

    victor1985 wrote:What mean cyber atack?

    The vulnerability which is currently embedded in the Autonomic Logistics Information System (ALIS) system of the F-35, disallows the human pilot to take-over the control of the F-35 Fighter Jet.Once the hackers are able to infect the ALIS system, they will be able to ground the F-35 Fighter Jet.

    Here is the detailed explanation

    http://defensetech.org/2014/02/25/let-humans-override-f-35-alis-computer/

    I am concerned if Russian military aircraft suffer from any such vulnerabilities?


    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sun Apr 12 2015, 15:46

    How russia stay whit this
    Lock in amplifier
    Can someone explain in simple terms what is noise and lock in amplifier? Few formulas would be well wellcomed
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    mack8

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    Re: Questions and Ideas

    Post  mack8 on Sun Apr 12 2015, 16:00

    Victor1985, you have been suggested before, why don't you open a specific thread dedicated to asking whatever questions that you have, you have littered all topics with very elementary and simplistic questions that serves only to derail the discussions on the specific themes in those topics and burry actual important and relevant news on said themes.


    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sun Apr 12 2015, 16:12

    I saw on wikipedia that a lock in amplifier is made from a homodyne detector and a low pass filter. Well some short explanations would be wellcomed. Question: low pass filter what does measuring the electric or magnetic field of radio waves? There can be made a low pass filter for the magnetic field? Or i am wrong and the radar just measure the the electric current?

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sun Apr 12 2015, 17:14

    Noise can be reduced whit a parabollic antena that makes the opposite to concentrate waves?

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Sun Apr 12 2015, 17:15

    In combination whit a delayer for waves

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    Re: Questions and Ideas

    Post  victor1985 on Sun Apr 12 2015, 17:26

    I saw on tv that in the sun light materials are becoming other materials that are heavier. This can be replicated on earth? I know is needed a lot of pressure. But the magnetic field can be replicated? Would keep materials squeezed under own presure. Maibe nuclear fusion may give the answer.
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    Mike E

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    Re: Questions and Ideas

    Post  Mike E on Sun Apr 12 2015, 20:07

    jhelb wrote:
    victor1985 wrote:What mean cyber atack?

    The vulnerability which is currently embedded in the Autonomic Logistics Information System (ALIS) system of the F-35, disallows the human pilot to take-over the control of the F-35 Fighter Jet.Once the hackers are able to infect the ALIS system, they will be able to ground the F-35 Fighter Jet.

    Here is the detailed explanation

    http://defensetech.org/2014/02/25/let-humans-override-f-35-alis-computer/

    I am concerned if Russian military aircraft suffer from any such vulnerabilities?

    AFAIK this is an issue isolated to the F-35 and no others. Need not worry... 

    ^ The reason why it is having many software vulnerabilities is simple the amount of software the plane requires, all of it newly-written. All software will (to some extent) have bugs and such vulnerabilities, especially when the lines of code grows in number. - Something in the billions or crazy like that.
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    Morpheus Eberhardt

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    Re: Questions and Ideas

    Post  Morpheus Eberhardt on Mon Apr 13 2015, 12:03

    victor1985 wrote:How russia stay whit this
    Lock in amplifier
    Can someone explain in simple terms what is noise and lock in amplifier? Few formulas would be well wellcomed

    Lock-in amplifiers have been nothing special for Russia for a long time.


    An RF lock-in amplifier nonlinearly mixes the input signal with a sinusoid that has a frequency equal to the signal's carrier frequency (in effect multiplying them) and then applies low-frequency filtering to the mixer output. The output would be a noise-filtered demodulation of the input signal.


    Optical lock-in amps are defined slightly differently. Of course, the technology is very different.


    Deriving the equations in time domain to illustrate the major points of an analog lock-in amplifier can be done as follows:

    1- Take, let's say, an AM input signal and multiply it with a sinusoid that has a frequency equal to the signal's carrier frequency.

    2- Apply trigonometric identities to convert the multiplicative expression to a summation.

    3- The lowest frequency components are the demodulated signal plus a bias.

    4- Suitable low-pass filtering "filters out" all excepts the two lowest frequency components, which, of course, are the demodulated signal plus the bias.


    Any difficulties with the above derivation, just ask and I'll do it and post it when I have a little bit of time.

    victor1985

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    Re: Questions and Ideas

    Post  victor1985 on Mon Apr 13 2015, 16:53

    Ok thanks you very much.
    What i didnt understand: multiply whit a sinusoidal? what that means? How asignal can be multiply?

    Wait i think i got it. You have 4 frecvencyes that come A yours A of enemy B and C. To find wich A is yours you amplify signal that all A to be seen. Is that corect?

    And trigonometric identities also i didnt understanded.

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    Re: Questions and Ideas

    Post  victor1985 on Mon Apr 13 2015, 16:57

    Well i readed again. Amplify whit a sinusoid. Mean exacly what? You make frecvency or carrier frecvency bigger to the AM from your example?
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    Morpheus Eberhardt

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    Re: Questions and Ideas

    Post  Morpheus Eberhardt on Tue Apr 14 2015, 13:09

    victor1985 wrote:Ok thanks you very much.
    What i didnt understand: multiply whit a sinusoidal? what that means? How asignal can be multiply?

    Wait i think i got it. You have 4 frecvencyes that come A yours A of enemy B and C. To find wich A is yours you amplify signal that all A to be seen. Is that corect?

    And trigonometric identities also i didnt understanded.


    victor1985 wrote:Well i readed again. Amplify whit a sinusoid. Mean exacly what? You make frecvency or carrier frecvency bigger to the AM from your example?


    Victor,

    I'll answer these questions in the "Questions and Ideas" thread.

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