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By: - 18th February 2017 at 08:40 Permalink - Edited 1st January 1970 at 01:00
New-ish missiles like 9M96, 48N6DMK (including naval use on Nakhimov) are being bought with Active Seekers as well.
By: - 18th February 2017 at 10:06 Permalink - Edited 1st January 1970 at 01:00
cost can be a factor, and an IR seeker can be used for end-game as well
By: - 18th February 2017 at 10:30 Permalink - Edited 1st January 1970 at 01:00
Some elements of the S-500 apparently also use SARH/SAGG SAMs. The lower tier and cheaper than S-400/S-500, S-350 with its 9M96 uses ARH yes. As there are physical limits to effective illumination range it would also be a Explanation why the long range 380km SAM of the S-400 and likely long range components of the S-500 would use ARH (because there is no SARH alternative)
By: - 19th February 2017 at 21:56 Permalink - Edited 1st January 1970 at 01:00
To be precise S-300, like patriot used TVM missile guidance, so to allow different engagement.
For the rest it is ARH+ intermediate guidance, that is usually considered an anti-stealth device as it can be activated at a constant distance from a target while efficacy of a SARH depends from how much CW radiating energy is reflected by it.
So in the first case the missile need only to be guided to a distance close enough to target using the data given by a search radar while in the second it need also a clear and constant illumination by a tracking one.
By: - 19th February 2017 at 21:59 Permalink - Edited 1st January 1970 at 01:00
Going forward Patriot isn't going to be building on or producing upgraded variants of the PAC-2's though. Both the PAC-3 and PAC-3 MSE are operational, and Raytheon has begun started looking beyond their PAC-2's to a more affordable future long range interceptor that could likely leverage their SM6 and ESSM seeker investments. AEGIS is finally also moving to the ESSM Block II and SM6 procurement with SM2 now only going to export customers that will probably begin transitioning to the SM6 now that it has been approved for export (that requires commitment to an AEGIS configuration upgrade as well).
In fact, the US Army could eliminate PAC-2 interoperability requirement altogether from their final LTAMDS RFPs and ask Raytheon to upgrade it with a new seeker. Given that Lockheed is likely to propose an out of band radar for the PAC-2, for LTAMDS..this is probably a good indication to the teams that the US Army will consider the sensors without slaving them to the legacy PAC-2's. Expect strong ESSM Blk. II seeker influence on the next US Army Interceptor proposal from Raytheon. What they are looking for is higher altitude i.e. narrowing the MSE and THAAD altitude gap.
By: - 19th February 2017 at 22:19 Permalink - Edited 1st January 1970 at 01:00
To be precise S-300, like patriot used TVM missile guidance, so to allow different engagement.
.
It actually used "SAGG" which is a more advanced form of TVM.
By: - 19th February 2017 at 22:21 Permalink - Edited 1st January 1970 at 01:00
Pierre Sprey believes the Rus can see em
By: - 19th February 2017 at 23:07 Permalink - Edited 1st January 1970 at 01:00
Pierre Sprey believes the Rus can see em
Spray also takes credit for an aircraft he had no part in designing. Furthermore he claims said F-16 is more maneuverable than the: F22, Su-35..... on and on.
By: - 20th February 2017 at 07:14 Permalink - Edited 1st January 1970 at 01:00
@Marcellogo
I think its possible that SARH SAMs and AAM with missile up-link course updates until terminal phase are more effective against stealth/VLO targets than the same for ARH seekers. As said, they work effectively as a bi-static radar. Given that the main technique of stealth/VLO designs is a geometry that avoids radar waves to directly bounce back to the radar receiver which sent them, --> the waves must be deflected into a other direction. This other direction where the RF energy is deflected to, can be exploited by a bi-static radar, which a SARH/SAGG/TVM guided SAM/AAM effectively is. Its auto-pilot/INS can position it via course updates at a position or angle where the radar waves are most likely deflected to, do a sniff maneuver in terminal phase, catch the RF source and home on it.
This bi-static feature is only present in SARH missiles, a ARH seeker must rely to be guided close enough to the target to receive a echo. Hence I think this property of SARH missiles have kept them alive for operators which have to face stealth opponents and not only the reduced cost/technology. To really exploit this possible effect against stealth targets, an advanced system and IADS such as the S-400 is necessary.
By: - 20th February 2017 at 11:31 Permalink - Edited 1st January 1970 at 01:00
Both Active and Semi Active modes can coexist to provide options such as the retention of semi active modes on both the SM6 and the in-development block II ESSM despite upgrading the guidance section to an active seeker. Active seekers or modes are being sought to better counter swarms, for over the horizon targeting and to "enable any sensor, any shooter" netted concepts.
By: - 20th February 2017 at 12:34 Permalink - Edited 1st January 1970 at 01:00
@MarcellogoI think its possible that SARH SAMs and AAM with missile up-link course updates until terminal phase are more effective against stealth/VLO targets than the same for ARH seekers. As said, they work effectively as a bi-static radar. Given that the main technique of stealth/VLO designs is a geometry that avoids radar waves to directly bounce back to the radar receiver which sent them, --> the waves must be deflected into a other direction. This other direction where the RF energy is deflected to, can be exploited by a bi-static radar, which a SARH/SAGG/TVM guided SAM/AAM effectively is. Its auto-pilot/INS can position it via course updates at a position or angle where the radar waves are most likely deflected to, do a sniff maneuver in terminal phase, catch the RF source and home on it.
This bi-static feature is only present in SARH missiles, a ARH seeker must rely to be guided close enough to the target to receive a echo. Hence I think this property of SARH missiles have kept them alive for operators which have to face stealth opponents and not only the reduced cost/technology. To really exploit this possible effect against stealth targets, an advanced system and IADS such as the S-400 is necessary.
There are a few problems with your proporsal:
1/ what if VLO asset change direction ? since they are designed with very narrow RCS spike in mind, their reflection spike can get out of missiles FoV very quick
2/ Reflection from side aspect RCS has very low Doppler shift, so missiles seeker will have to deal with much higher clutter level
By: - 20th February 2017 at 17:15 Permalink - Edited 1st January 1970 at 01:00
@garryA
I think a change of aspect or direction of the VLO asset would not change to overall situation. First there is the question whether it would be worth the risk to change direction after the attack has been detected by sensors and the most optimized face (front) has been directed to the threat emitter.
Even a all aspect VLO asset would still be optimized to deflect waves away from the bore sight of the threat radar. If we assume that the biggest portion of the radar waves are deflected in a bore sight range of 15° to 90° in all directions, a limited degree portion can be determined from the bore sight of the threat radar where the SARH seeker has to search for deflected RF energy. However I'm no expect on RF wave behavior hence this deflection angle band could differ.
More so; if the VLO asset changes aspect relative to the bore sight of the threat illumination radar to change the direction of deflected radar waves, to decrease chances for the bi-static SARH seeker to pick up RF energy, this would force it to expose a less optimized face to the bore sight of the threat radar. So if the SARH seekers lock on the target is broken, the redundant SAGG/TVM system could switch back to command guidance mode as it now has got a own track of the VLO asset.
You may be thinking about a sudden maneuver that would suddenly break the lock of the SARH seeker. But any change would just reduce the amount of deflected RF energy e.g if the VLO asset exposes its least optimized face to the threat emitter, so that more RF energy is sent back to the radar and hence less is deflected to the bis-static positioned SARH seeker.
Advanced SARH missiles with missile up- and down-links + advanced autopilots only make use of the SARH seeker in terminal phase, not like the HAWK or S-200 which had to catch the RF energy at great distances while on the launcher. Hence they need much less of reflected or deflected RF energy. The deflection angles of VLO assets are confined and there should be enough RF energy deflected to that angle band to allow for terminal phase SARH guidance.
As for cutter levels. I'm not sure if doppler shift is a necessary effect in such a bi-static operation mode. The seeker just tries to get more RF energy, i.e it steers to the position/direction that offers this together with all the SAGG inputs. Range calculations are not essential and if, the performance of digital MTI (in SAGG guided missiles inside the ground based engagement radar) has greatly improved in the recent years, this should not be a dealbreaker.
By: - 20th February 2017 at 18:51 Permalink - Edited 1st January 1970 at 01:00
@garryAI think a change of aspect or direction of the VLO asset would not change to overall situation. First there is the question whether it would be worth the risk to change direction after the attack has been detected by sensors and the most optimized face (front) has been directed to the threat emitter.
It changes the situation alot if you think about it.
1/ If missiles are launched at aircraft then it is expected that pilots will try to dodge them. They will not maintain a constant course
2/ The high RCS spike is very small and often concentrated to the side so your missiles will have to approach target from very awkward angle, which isn't good for kinematic either
3/ When do you know when to launch your missiles if the signal is too weak for your fire control radar to detect target in the first place ?. If the signal is strong enough for radar to detect then why need bi static ?
You may be thinking about a sudden maneuver that would suddenly break the lock of the SARH seeker. But any change would just reduce the amount of deflected RF energy e.g if the VLO asset exposes its least optimized face to the threat emitter, so that more RF energy is sent back to the radar and hence less is deflected to the bis-static positioned SARH seeker.
Not very practical, you are assuming that all high RCS spike and low spike aspect are covered by main fire control radar and SARH missiles.
The deflection angles of VLO assets are confined
The deflection angle is not confined because it will change depending on what direction the aircraft pointing at
As for cutter levels. I'm not sure if doppler shift is a necessary effect in such a bi-static operation mode. The seeker just tries to get more RF energy, i.e it steers to the position/direction that offers this together with all the SAGG inputs. Range calculations are not essential and if, the performance of digital MTI (in SAGG guided missiles inside the ground based engagement radar) has greatly improved in the recent years, this should not be a dealbreaker.
The only effect of Bi static configuration is that your receiver can be put at location/ aspect where there is strongger reflection. However, the problem with Doppler and the need for range measurement is still there. They don't just disappear.
Without Doppler processing , missiles will missiles everytime VLO aircraft release chaff. Without range measure your missiles will suffer in kinematics because it cant take advantage of lead intercept
By: - 20th February 2017 at 20:53 Permalink - Edited 1st January 1970 at 01:00
@garryA
If missiles are launched at aircraft then it is expected that pilots will try to dodge them. They will not maintain a constant course
Yes it will maneuver at the last phase agreed. But the concept does not change, there will only be more RCS fluctuations. As said a good stealth design deflects radar waves from a threat radars boresight. A ideal all aspect design would do this at every aspect with the same performance. Let me make a simple example: A car on a turntable is sprayed by a high pressure firefighting tube --> the deflected water around it will fluctuate at different aspects but the position of the tube dictates most of the deflection behavior/direction.
2/ The high RCS spike is very small and often concentrated to the side so your missiles will have to approach target from very awkward angle, which isn't good for kinematic either
A typical energy optimized trajectory via autopilot updated missile up-link with a dive down maneuver at terminal phase (at long ranges) or a climb from below (short ranges) would likely do it. Energy cant be eliminated; the deflected RF energy (minus the RAM/RAS absorbed portion) will be a strong signal, in quantity about the same amount of RF energy reflected by a conventional design.
3/ When do you know when to launch your missiles if the signal is too weak for your fire control radar to detect target in the first place ?. If the signal is strong enough for radar to detect then why need bi static ?
I explained this in the first post of this thread. The basic idea is to use other sensor assets input into the IADS/GCI to enable a x-band attack system to do something it would be otherwise unable to do via this proposed bi-static effect.
The deflection angle is not confined because it will change depending on what direction the aircraft pointing at
Above I explained the behavior of a ideal all-aspect stealth design, it always deflects the waves away from the boresight of the attack radar. This will probably never be realized. The weaker the design gets at different sections, less waves are deflected and can travel back into the direction of the emitter, causing fluctuations at the SARH seeker. However a SAGG guided missile will also benefit from aspects where less RF energy is deflected because the ground based fire control radar will start to receive echos and use command guidance if seeker lock has been brocken.
Lets put it simple, a good stealth design deflects more RF energy into direction where a potential bi-static SARH seeker/receiver can be positioned.
A bad stealth design deflects less into presumably safe directions and sends back echos to the attacking radar boresight.
A SAGG guided missiles makes use of both of this worst and best case scenarios and the fluctuations between them.
The only effect of Bi static configuration is that your receiver can be put at location/ aspect where there is strongger reflection. However, the problem with Doppler and the need for range measurement is still there. They don't just disappear.
Without Doppler processing , missiles will missiles everytime VLO aircraft release chaff. Without range measure your missiles will suffer in kinematics because it cant take advantage of lead intercept
The kinematic penalty would be negligible because its limited to terminal phase. CW designs such as the HAWK/SA-6 seekers have no doppler range measurements. Even if your argument is right and a modern FMCW illumination radar would have problems to create the necessary doppler shift of such deflected waves: A SAGG based system will have analytic means to distinguish between chaff and target.
By: - 20th February 2017 at 22:07 Permalink - Edited 1st January 1970 at 01:00
Yes it will maneuver at the last phase agreed. But the concept does not change, there will only be more RCS fluctuations. As said a good stealth design deflects radar waves from a threat radars boresight. A ideal all aspect design would do this at every aspect with the same performance. Let me make a simple example: A car on a turntable is sprayed by a high pressure firefighting tube --> the deflected water around it will fluctuate at different aspects but the position of the tube dictates most of the deflection behavior/direction.
I honestly dont get what are you trying to say ? Both the shape of the car and the position of the tube will dictate the deflection angle of the water, not just the tube position.So if the car turn obviously the defection angle change too
A typical energy optimized trajectory via autopilot updated missile up-link with a dive down maneuver at terminal phase (at long ranges) or a climb from below (short ranges) would likely do it. Energy cant be eliminated; the deflected RF energy (minus the RAM/RAS absorbed portion) will be a strong signal, in quantity about the same amount of RF energy reflected by a conventional design.
Normal BVR always climb at initial phase and dive down at terminal phase.So this have been taken in to account of stealth aircraft designer. But if you want your proporsal to work, your missiles need to dive down target but from side aspect , not from front. And the major problem is that if target change direction then the location of their spike will change also
I explained this in the first post of this thread. The basic idea is to use other sensor assets input into the IADS/GCI to enable a x-band attack system to do something it would be otherwise unable to do via this proposed bi-static effect.
Your explaination isn't sufficient
You cant just blindly illuminate a space then launch missiles randomly at the blind space and hope that the there would be some reflection from something there and the missiles can home on the reflection to target.
There are plenty of problems:
1/ Rule of engagements
2/ Chaff , decoy
3/ Do you launch enough missiles to cover every possible aspect that target can have high RCS spike ?
4/ When to launch the missiles if you are not intended to measure range?
Above I explained the behavior of a ideal all-aspect stealth design, it always deflects the waves away from the boresight of the attack radar. This will probably never be realized. The weaker the design gets at different sections, less waves are deflected and can travel back into the direction of the emitter, causing fluctuations at the SARH seeker. However a SAGG guided missile will also benefit from aspects where less RF energy is deflected because the ground based fire control radar will start to receive echos and use command guidance if seeker lock has been brocken.
The problem is you assumed that once aircraft turn aspect with low RCS toward the missiles, it will present the fire control radar with a high RCS spike. But that is not neccessary true.
Lets put it simple, a good stealth design deflects more RF energy into direction where a potential bi-static SARH seeker/receiver can be positioned.
A bad stealth design deflects less into presumably safe directions and sends back echos to the attacking radar boresight.
A SAGG guided missiles makes use of both of this worst and best case scenarios and the fluctuations between them.
Stealth aircraft are generally have bow tie signature, meaning most of scattering is to the side, and they have low frontal and tail aspect RCS. Theoretically you can put a receiver so that it always be at the side of target, and thus take advantage of their design, but side aspect generally mean less Doppler shift, which mean seeker has to deal with higher level of clutter and harder to distingush target from chaff/ ground return.
The kinematic penalty would be negligible because its limited to terminal phase
Well, no. How exactly to you imagined the missiles fly profiles would be ?. Fly directly at target then make an U turn to approach it from the side ?
CW designs such as the HAWK/SA-6 seekers have no doppler range measurements. Even if your argument is right and a modern FMCW illumination radar would have problems to create the necessary doppler shift of such deflected waves: A SAGG based system will have analytic means to distinguish between chaff and target.
The reason radar can distingush between chaff and target is due to Doppler shift. Doppler shift is created due to the radical velocity of target and the transmitter.
By: - 21st February 2017 at 01:30 Permalink - Edited 1st January 1970 at 01:00
Normal BVR always climb at initial phase and dive down at terminal phase.So this have been taken in to account of stealth aircraft designer.source ?
By: - 21st February 2017 at 03:10 Permalink - Edited 1st January 1970 at 01:00
source ?
Source for what ? that BVR missiles like AIM-120 use a lofted trajectory ?
Even HUD has indicator for loft angle
By: - 21st February 2017 at 04:37 Permalink - Edited 1st January 1970 at 01:00
source that the aircraft designer has in any instance taken into account that a missile would be descending towards the a/c
By: - 21st February 2017 at 04:52 Permalink - Edited 1st January 1970 at 01:00
source that the aircraft designer has in any instance taken into account that a missile would be descending towards the a/c
Why wouldn't they when air to air with loft trajectory have existed for decade ?
The nose shape also indicate that radar wave will not be deflected straight up
By: - 21st February 2017 at 07:10 Permalink - Edited 1st January 1970 at 01:00
as you know, i knew it was bs from the start,
on contrary the AESA angle on US fighters are canted upwards to deflect echo upwards rather than back to front or downwards, meaning its rcs is higher from above
Posts: 114
By: PeeD - 18th February 2017 at 08:29
There is a strange notion which the Russians have with their SAMs and AAMs which results in the use of SARH/SAGG missiles, although ARH seekers are available.
I will concentrate on SAMs here because the developments there make the case more clear.
Russians have developed various active radar seekers for their SAMs, especially the BUK series and their very long range S-300 with 200km+ range missiles would be candidates for ARH seekers.
However, they stick to SARH seekers even for their new century designs, the S-400 and BUK-M2/-M3, where others like the French, Japanese went for ARH seekers (Aster, etc).
Either their ARH perform bad, or the illumination power of their engagement radars offer still more RF energy on target or there are other benefits for a SARH seekers.
I read much of "anti-F35" Dr. Carlo Kopps articles back when APA was active and I know that he has not many friends on this forum. There is a effect which Russian SARH SAMs have which he didn't describe, which could increase their effectiveness against VLO/stealth targets significantly:
Stealth designs rely on deflection rather than absorption as the key physical effect for their VLO performance. Systems like the e.g S-300/-400 work in a bi-static mode with their SAGG/TVM guidance, means that the RF signal receiver is at a different position and at a different angle than the attacking illumination radar. The deflected RF energy may would not reach the emitting radar, but a bi-static SARH receiving seeker in the SAM that can attack from angle below the VLO target or above it and perform angle search pattern would have better chances to catch deflected RF energy, enabling a lock on the stealth target. This method would decrease the biggest problem with missile radar seekers, namely that they have to work in X-band, for which stealth designs are optimized and no effects like aircraft feature size can be used for improved performance (VHF-band).
One key element for this method to work, is a blind illumination capability of a portion of airspace (without actual track) based on coordinates from a radar system that actually detects the target. There is much debate about this; APA and Russians say that VHF band radars can see smaller stealth designs such as the F-35 like any other radar. Here on this forum some might say the F-35 has the same pie size in VHF-band as in X-band. We can take something in between, but a highly advanced IADS like the Russian one has assets such as the "Container" OTH system for early warning and coarse location, as well es high power static line of sight systems with very large apertures such as the Voronezh and Resonaz systems, with systems like the mobile Nebo-M acting at lower tiers. There is more, such as passive means, EO, IR, multi-static "trap" radars networks.
There must be rough target coordinated available for such a bi-static SARH engagement, with a accuracy as provided by multi-band systems such as the Nebo-M or single VHF-band Nebo-SVU, otherwise the RF energy of the illumination radar wont be sufficiently accurately concentrated on target (airspace portion).
The S-300/400 SAMs have robust missile up- and down-links, hence they would work with course updates via VHF-band target coordinates until terminal phase where the SARH seeker would try to catch illumination RF energy deflected to different directions by the stealth design.
The addition of positioning systems to the engagement radars of S-300PMU2 and S-400 could be a hint for the use of this method.
Hence I have the feeling that this described bi-static method directly benefits from the main function of stealth designs, RF-energy deflection, and could be the main reason why even the S-400 is still old fashioned SARH and possibly why the R-27 soldiers on.