How to defend Brahmos?- American analysis.

[gambit]

Typically, how long is one sweep cycle?

Depends on the radar system design.

If the design is mechanical, then a sweep cycle is governed by the motor that move the antenna. For a missile which would naturally have a limited frontal view, the antenna would be sweeping side-side, a single sweep could be less than one sec.

It is very difficult to achieve target lock in one scan, even if the system is ESA type and even when the target is as large and slow as a ship. The first scan is for general detection for any body or bodies in the radar's view. The second and third scans would be for update just in case any of those bodies have changed spatial locations. So the situation could be for the missile to take up to ten seconds to digest the radar view of the area and to assign priorities, not yet homing in on a specific target programmed. Of course, the smaller the radar view, the less time required to process all these electronics data, but then the smaller the radar view, the greater the odds of missing that large prize.

This is why flying low and fast is not always the best solution, especially against mobile targets and even when that target is a slow moving ship. In a ship versus missile engagement, if the missile missed by just one meter, the ship win.

 

[The Great One]

Depends on the radar system design.

If the design is mechanical, then a sweep cycle is governed by the motor that move the antenna. For a missile which would naturally have a limited frontal view, the antenna would be sweeping side-side, a single sweep could be less than one sec.

It is very difficult to achieve target lock in one scan, even if the system is ESA type and even when the target is as large and slow as a ship. The first scan is for general detection for any body or bodies in the radar's view. The second and third scans would be for update just in case any of those bodies have changed spatial locations. So the situation could be for the missile to take up to ten seconds to digest the radar view of the area and to assign priorities, not yet homing in on a specific target programmed. Of course, the smaller the radar view, the less time required to process all these electronics data, but then the smaller the radar view, the greater the odds of missing that large prize.

This is why flying low and fast is not always the best solution, especially against mobile targets and even when that target is a slow moving ship. In a ship versus missile engagement, if the missile missed by just one meter, the ship win.

A typical ship moving even at typical top speeds of about 30 knots or 15m/s would be able to move no more than 1800m (in any direction) from the launch of the missile to eating it, if we take this scenario - LO-LO launch profile with its 120km range and the missile being detected at launch presumably by aerial AEW assets. Of course you are unlikely to find ships moving at full steam exactly perpendicular to the missile flight path and neither are aerial AEW assets always there (which cuteth detection time and thus response time by a factor of 3 {ofcourse there are further delay in actually maneuvering the ship too}).
Even if the missile activate its own seeker at only 20 miles out, how much scan sector would a radar realistically need to detect the ship with this scenario. I'd say NOT MUCH

 

[gambit]

A typical ship moving even at typical top speeds of about 30 knots or 15m/s would be able to move no more than 1800m (in any direction) from the launch of the missile to eating it, if we take this scenario - LO-LO launch profile with its 120km range and the missile being detected at launch presumably by aerial AEW assets. Of course you are unlikely to find ships moving at full steam exactly perpendicular to the missile flight path and neither are aerial AEW assets always there (which cuteth detection time and thus response time by a factor of 3 {ofcourse there are further delay in actually maneuvering the ship too}).
Even if the missile activate its own seeker at only 20 miles out, how much scan sector would a radar realistically need to detect the ship with this scenario. I'd say NOT MUCH

You are describing a situation that favors the attacker. There is no absolute rule on when a missile is supposed to go radar active. It depends on the missile's design and intention. Nevertheless, there are situations where the laws of physics cannot be defied, and one of them is the line-of-sight (LOS) limitation. The lower the missile's flight, the less time it will have in acquiring target lock when it does detect anything. So it is not about when the missile will go radar active but about its flight altitude. Other factors like target physical profiles presented to the missile's radar or countermeasures are for a different discussion.

 

[The Great One]

You are describing a situation that favors the attacker.

Whaaaaaat.
'1800m maneuver' is the MOST OPTIMISTIC and favorable situation for a ship, that is if you want to talk (which you did) about the missile maintaining a sea-skimming or LO-LO flight profile and its associated advantage/disadvantage.

line-of-sight (LOS) limitation.

LOS limitations applies equally to the ships radars as well (which I still ignored).
As for the missile, your Horizon calculator giveth about 35km LOS for this scenario if we take a 10m height for missile and only 30m for the ship. Reasonable, no?
At any rate, I think its not that bigofadeal but then no hostile ship is ever going to come 120km of an American warship so all this is probably moot.

 

[OrionHunter]

I do know.

A missile's radar lock do not happen instantaneously. At least one sweep cycle is required, but if we are talking about a low altitude flight, that mean the Brah-less radar must be active prior to it breaking the horizon of the area to detect anything. I pointed this out a long time ago. Were you asleep in my class ?

Radar is line-of-sight (LOS) limited.

Horizon calculator - radar and visual

The higher the flight altitude, the sooner the missile will expose its own radar emissions to the defender. Speed is actually the negative factor here when it comes to lower altitude. Too fast and by the time the Brah-less break the horizon of the general area, its radar will not have enough information to target anything, even as large as an aircraft carrier.

Ok, but WTF is 'Brah-less???

 

[gambit]

Whaaaaaat.
'1800m maneuver' is the MOST OPTIMISTIC and favorable situation for a ship, that is if you want to talk (which you did) about the missile maintaining a sea-skimming or LO-LO flight profile and its associated advantage/disadvantage.

Now we add in countermeasures and physical profiles.

LOS limitations applies equally to the ships radars as well (which I still ignored).
As for the missile, your Horizon calculator giveth about 35km LOS for this scenario if we take a 10m height for missile and only 30m for the ship. Reasonable, no?
At any rate, I think its not that bigofadeal but then no hostile ship is ever going to come 120km of an American warship so all this is probably moot.

When I was on the F-111, 100 meters TFR are routine and sometime even lower. Myself it was 15 meters over the Channel. But -111 crews usually stay above 80 meters. That give the jet enough hilltop clearance and often high sea state can produce waves over 10 meters in height, easily swat a low flying jet/missile.

For the Brahmos to fly a 10 meters altitude profile, we are talking about the desert or the seas and in clear weather. Where is the Brahmos's TFR ? The lower the TFR altitude, the more 'ahead' the TFR must look in order to calculate the best climb rate and angle. What is the TFR mode for the Brahmos anyway ? Is it soft, med, or hard ? Does the Brahmos have terrain avoidance as well as terrain following ? They are different modes of extremely low altitude flight profile. If the Brahmos have TA, what is the maximum TF limit, meaning if the obstacle ahead is of a certain physical height, where the TA mode will take over and the missile will fly around that obstacle instead of over it ? At 10 meters altitude, how can the Brahmos distinguish a ship's profile from a hill ? For an old F-111 dog like me, and you can research my avatar, I can pose plenty of questions of low altitude flight that you will not find in the Brahmos's sales brochures.

Ok, but WTF is 'Brah-less???

It is a word play on 'braless'. You do know what 'braless' mean, no ?

 

[The Great One]

Now we add in countermeasures and physical profiles.

So you concede that low flight altitude is no problem then then, wrt to your earlier points.

When I was on the F-111, 100 meters TFR are routine and sometime even lower. Myself it was 15 meters over the Channel. But -111 crews usually stay above 80 meters. That give the jet enough hilltop clearance and often high sea state can produce waves over 10 meters in height, easily swat a low flying jet/missile.

For the Brahmos to fly a 10 meters altitude profile, we are talking about the desert or the seas and in clear weather. Where is the Brahmos's TFR ? The lower the TFR altitude, the more 'ahead' the TFR must look in order to calculate the best climb rate and angle. What is the TFR mode for the Brahmos anyway ? Is it soft, med, or hard ? Does the Brahmos have terrain avoidance as well as terrain following ? They are different modes of extremely low altitude flight profile. If the Brahmos have TA, what is the maximum TF limit, meaning if the obstacle ahead is of a certain physical height, where the TA mode will take over and the missile will fly around that obstacle instead of over it ? At 10 meters altitude, how can the Brahmos distinguish a ship's profile from a hill ? For an old F-111 dog like me, and you can research my avatar, I can pose plenty of questions of low altitude flight that you will not find in the Brahmos's sales brochures.

Good questions, which I'm sure those making the brochure would have solved long before they put it in there.

BTW, The sales team put it at 3-4 meters
Ship-launched BRAHMOS can fly in sea-skimming mode, completely destroy target :: BrahMos.com

It is a word play on 'braless'. You do know what 'braless' mean, no ?

Really? I thought it was on Bra-'mos' - mos sounds like more and so brah-less. nvm

 

[gambit]

Good questions, which I'm sure those making the brochure would have solved long before they put it in there.

BTW, The sales team put it at 3-4 meters
Ship-launched BRAHMOS can fly in sea-skimming mode, completely destroy target :: BrahMos.com

Please...Am sure you are smart enough to know sales brochures do not reflect real world conditions that often places limits on a weapon system.

The designers of the early infrared guided missile did not anticipate the pilot's defensive move of using the sun as a distraction. The designers of the first generation HARM did not anticipate the defensive method of 'blinking'. So you go on and believe those sales brochures.

 

[The Great One]

Please...Am sure you are smart enough to know sales brochures do not reflect real world conditions that often places limits on a weapon system.

The designers of the early infrared guided missile did not anticipate the pilot's defensive move of using the sun as a distraction. The designers of the first generation HARM did not anticipate the defensive method of 'blinking'. So you go on and believe those sales brochures.

I thought Sales brochures (made public) reveal only downgraded data or even tried to willfully misinform its readers and even then I took only 10m in my example. NVM Since neither you or I are privy to the actual tests (44 so far) and the conditions in them I think it would be foolhardy to blatantly dismiss it like that. I've read your posts on how 'all tests are scripted' and frankly I don't buy it. Perhaps thats how they do it in the States.
Plus whatever you said there has no relevance to the BrahMos missile or its brochures so you go on and dismiss it.

 

[Guynextdoor2]

Brahmos is almost 10 years old... now this is coming....

Will take time

 

[Kinetic]

Will take time

Yes five years. But thats also good.

 

[gambit]

I thought Sales brochures (made public) reveal only downgraded data or even tried to willfully misinform its readers and even then I took only 10m in my example. NVM Since neither you or I are privy to the actual tests (44 so far) and the conditions in them I think it would be foolhardy to blatantly dismiss it like that. I've read your posts on how 'all tests are scripted' and frankly I don't buy it. Perhaps thats how they do it in the States.
Plus whatever you said there has no relevance to the BrahMos missile or its brochures so you go on and dismiss it.

The Brahmos had 44 tests (so far) but you do not believe me when I said all weapons tests are scripted.

What do you think those 44 tests contained ? Am willing to guess that one of those tests are for radar multipaths propagation.

Determination of scattering center of multipath signals using geometric optics and Fresnel zone concepts

In this study, a method for determining scattering center (or center of scattering points) of a multipath is proposed, provided that the direction of arrival of the multipath is known by the receiver. The method is based on classical electromagnetic wave principles in order to determine scattering center over irregular terrain. Geometrical optics (GO) along with Fresnel zone concept is employed, as the receiver, the transmitter positions and irregular terrain data are assumed to be provided. The proposed method could be used at UHF bands, especially, operations of radars and electronic warfare applications.

In radar detection, especially in low altitude where the transmission path is near parallel to Earth, there is a serious issue called multipaths propagation. This is where the radar receives multiple, hence false, targets from a single reflection point. If this problem is so easily solved, then why is that article dated so recently ?

Article history:
Received 6 December 2013
Received in revised form
7 March 2014
Accepted 23 March 2014
Available online 24 April 2014

The article is from Turkey and very well done. Am sure Indian scientists and engineers are well aware of this issue. May be that was in test 18 or 29 or 44 ?

 

[The Great One]

What do you think those 44 tests contained ?

I am not aware and neither are you. With your experience I'm sure what you state is true of American and western weapons tests, but that doesn't necessarily make it a 'Global Best Practice'. Whats to stop from the IN to take the missile one boring day, put up a target above a dinghy and perform one of their 'user trials'.

Am willing to guess that one of those tests are for radar multipaths propagation.

Determination of scattering center of multipath signals using geometric optics and Fresnel zone concepts
In radar detection, especially in low altitude where the transmission path is near parallel to Earth, there is a serious issue called multipaths propagation. This is where the radar receives multiple, hence false, targets from a single reflection point. If this problem is so easily solved, then why is that article dated so recently ?

These problems can be overcome by incorporating a ground map of the radar's surroundings and eliminating all echoes which appear to originate below ground or above a certain height.

Multipath propagation - Wikipedia, the free encyclopedia
Good informative post. I have no clue on these issues as I am but a humble internet warrior.

The article is from Turkey and very well done. Am sure Indian scientists and engineers are well aware of this issue. May be that was in test 18 or 29 or 44 ?

Good, we have no problem with the 3-4m figure then.

 

[jaiind]

The US has no need to worry about brahmos. you guys need to worry about your stuff being copied by the big bandit and using them against you..

 

[SrNair]

Well.This was a balanced article and Brahmos compared with worlds best system.But this is just a missile advantages and disadvantages.

Any this is not going for a US force.We developed it for some neighbour friends.A Supersonic version is already a head ache for world best system.Then what would be the effect when we completed the hypersonic version.