Missile-Range Instrumentation Ships (MRIS) VC 11184

Gautam

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Radiation shields are made up of radiation absorbing material and those wavelength's reflected are of diffient than that of the radar. The sheiding barrier is made in such a way, it not just a reflective surface.
There are no perfect absorbers or reflectors of radiation. The best of absorbers will reflect some amount of radiation and the best of reflectors will absorb some amount as well. A radiation shield is usually made of materials that don't allow radar waves to pass through them, radar-opaque objects they are called. Such objects have both absorbing and reflecting properties, some materials are more on the absorber side than reflector and some other materials are opposite. The selection of material is obviously done depending on application.

Here in lies the problem. The proximity of the shield to the radar means you are dealing with a lot of energy fired from near point blank ranges. As such any radiation shield here will end up being a reflector. There is a limit to how much energy a absorbent can absorb away. going past that limit would mean the absorbent becomes a reflector.

Is this the same as what they use in stealth?
Very similar. You see, if you could absorb all incident radiation you wouldn't need stealth shaping at all. But that can't be done, at least not yet.

As for the reflected wave having a different frequency and wavelength, that's true. But it can be accounted for during design of such a radar.
 

screambowl

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There are no perfect absorbers or reflectors of radiation. The best of absorbers will reflect some amount of radiation and the best of reflectors will absorb some amount as well.

That's true even black body radiates some radiation.

So with this radar we will be able to track foreign projectiles as well. Especially China's. But how this radar is different from the ones which ISRO deploys near Asia Pacific for telemetry of LV.
 

Gautam

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So with this radar we will be able to track foreign projectiles as well. Especially China's.
This radar, like all other radars, will search and track any projectile within its range be that Chinese or someone else's. What the VC11184 brings to the table is that other land based radars as powerful as this(like the Swordfish, LRTR, MOTR in increasing order of power/range) don't is mobility. That mobility allows a wide variety of applications some of which weren't previously possible.

But how this radar is different from the ones which ISRO deploys near Asia Pacific for telemetry of LV.
We don't know for certain what radars are present at the foreign based TTC. Since those TTCs are part of ISRO's ISTRAC network it is safe to say they have the PCMC radars. But whether something like the MOTR is present there is not known.
 
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Ashutosh

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There are no perfect absorbers or reflectors of radiation. The best of absorbers will reflect some amount of radiation and the best of reflectors will absorb some amount as well. A radiation shield is usually made of materials that don't allow radar waves to pass through them, radar-opaque objects they are called. Such objects have both absorbing and reflecting properties, some materials are more on the absorber side than reflector and some other materials are opposite. The selection of material is obviously done depending on application.

Here in lies the problem. The proximity of the shield to the radar means you are dealing with a lot of energy fired from near point blank ranges. As such any radiation shield here will end up being a reflector. There is a limit to how much energy a absorbent can absorb away. going past that limit would mean the absorbent becomes a reflector.

Yes. The high intensity illumination will do that. Yet reflection depends on the material nad surface design. however there are solutions.
  1. Radar Absorption/deflection is possible, without having much reflection. thanks to the wavelength of operation. Ever seen insides of an anechoic test chamber? that's one way Radar shielding/energy absoption.
  2. I do understand black body radiation. however radars only see what wavelengths they send out and what they expect to see reflected back. to other wavelengts thay are blind, and the Shield is designed to take care of these.
 

Gautam

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Radar Absorption/deflection is possible, without having much reflection. thanks to the wavelength of operation. Ever seen insides of an anechoic test chamber? that's one way Radar shielding/energy absoption.
That is an excellent point. Here is my counter :

The polyester acoustic sponge material used in anechoic test chambers are excellent absorbers of RF radiation. However their design(shape & size) needs to be adopted based on the frequency they are subjected to, they are not perfect absorbers of all frequencies. More importantly they don't absorb all radiation in a single incidence. Most of the energy is absorbed away, some of it is reflected back. The reflected energy is then absorbed by the sponge on the opposite side. If the sponges could absorb all radiation incident on it there would be no need to cover up the entire room by those sponges when testing unidirectional radars.

I'll give you an example, remember the photo of the radar of the Indian AWACS being tested in a chamber ? Notice the sponges directly opposite to the radiating element ? Why would you need that if the sponges facing the radar absorbed all the radiation ?
1571461636270.png

The point I am trying to make is that those polyester sponges are excellent absorbers but still not perfect. They will still reflect some amount of energy.

But still your point stands. Those sponges are excellent absorbers and they would absorb away most of the incident radiation while reflecting a minuscule mount in some random direction. So the question arises if the sponges are so good at absorbing radiation, why aren't they used in stealth aircrafts or ships ? Why the whole drama with RAM/RAP if some good old sponges can get the job done ?

Because their physical properties make them pretty unusable. Imagine these sponges on the VC11184, all we need is a good rain and they are rendered useless. The sponges absorb so much energy because of their huge surface area to weight ratio. Once the gaps are filled with water, they lose their properties. It is simply not practical to carry sponges on ships, exposed to the elements, and expect them to replicate the properties they display in controlled lab test environment.

I do understand black body radiation. however radars only see what wavelengths they send out and what they expect to see reflected back. to other wavelengts thay are blind, and the Shield is designed to take care of these.
Didn't understand this. Could you please elaborate ?
 

Ashutosh

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The point I am trying to make is that those polyester sponges are excellent absorbers but still not perfect. They will still reflect some amount of energy.

The reflected energy will not be of the same wavelength of the incident energy. It will be in IR range most likely radars wont pick them up. Also, the radar dome serves a purpose. Aslo Sponges are used in an Anechoic chamber, That was used as an example by me I didn't mean to say they will be using Sponges on an exposed area which they can albeit it will be made of a different material, with the liberty of space and surface design other RAM/Coatings can be used, as there are no such restrictions like aircraft have. The surface coating (RAPs) can be much thicker and applied on varied geometry.

But still your point stands. Those sponges are excellent absorbers and they would absorb away most of the incident radiation while reflecting a minuscule mount in some random direction. So the question arises if the sponges are so good at absorbing radiation, why aren't they used in stealth aircrafts or ships ? Why the whole drama with RAM/RAP if some good old sponges can get the job done ?

Because their physical properties make them pretty unusable. Imagine these sponges on the VC11184, all we need is a good rain and they are rendered useless. The sponges absorb so much energy because of their huge surface area to weight ratio. Once the gaps are filled with water, they lose their properties. It is simply not practical to carry sponges on ships, exposed to the elements, and expect them to replicate the properties they display in controlled lab test environment.

Didn't understand this. Could you please elaborate ?

Explained above.
 

Gautam

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The reflected energy will not be of the same wavelength of the incident energy. It will be in IR range most likely radars wont pick them up. Also, the radar dome serves a purpose. Aslo Sponges are used in an Anechoic chamber, That was used as an example by me I didn't mean to say they will be using Sponges on an exposed area which they can albeit it will be made of a different material, with the liberty of space and surface design other RAM/Coatings can be used, as there are no such restrictions like aircraft have. The surface coating (RAPs) can be much thicker and applied on varied geometry.
This conversation borne out of speculations is now going to curious places.:ROFLMAO:I agree broadly to what you said above except for some areas but we are straying off topic.

The initial speculation I made was at the possibility of using the shield as a reflector for radiation and thus using the set up as a OTH radar. I agree that the reflected energy will have different wavelength than the incident radiation, the wavelength will increase after the reflection. But that can always be accounted for. Radar transparent materials like the radome also changes the properties of the wave, so radar manufacturers experimentally account for the losses. Simply put, losses caused by the radome=(energy radiated by the radar without the radome - energy radiated by the radar with the radome). Just like that the reflected energy and losses can also be calculated and accounted for.

The reason why I was going on about the possibility of such a set up being used as a OTH radar is the frequency chart here :
1571466841458.png


The main radar of the VC11184 works in the S-band(IEEE classification) and most OTH radars work in the shortwave(3-30 GHz, lies in the UHF-SHF band) by ITU classification. You will notice that the S-band and UHF/SHF-band has a degree of overlap. So the task at hand for us is to design a reflector that causes the reflected waves to stay in the UHF/SHF band(nothing less than 3.5 GHz), this is not a very difficult task. At most you need a few months of experimentation.

This is why I formed this theory in my head, it seems like a very doable task to me. I could be totally wrong though.

Also if the shield's only purpose was to protect the crew from the radiation, why not just use a heavy dose of RAM/coating on the deck and superstructure of the ship ? Conversely why not just program the radar to not throw radiation in this direction ? Modern day radars are very programmable and there are 2 other radars on the front deck, combined data from all 3 radars should paint a full picture with no bling spots. Another point would be, where are the radiation shields for the front deck radars ? Those 2 radars are very close to the bridge with the crew there all the time.
 

screambowl

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Radar transparent materials like the radome also changes the properties of the wave, so radar manufacturers experimentally account for the losses

We are talking about the insertion loss here and not just that the surface of radome must be hydrophobic or else the signal will get attenuated
Also if the shield's only purpose was to protect the crew from the radiation, why not just use a heavy dose of RAM/coating on the deck and superstructure of the ship ?

Other two reasons are
1. to prevent the movables in radar from icing when sailing in cold water
2. to hide radar's orientation/direction to which it is facing, for example if the vessel is near Vietnam and radar is facing North West this would mean the surveillance is on China
 

Gautam

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We are talking about the insertion loss here and not just that the surface of radome must be hydrophobic or else the signal will get attenuated
True, but I think you are missing the point here. The point is radar equipment, like all other equipment, performs differently in operations than in lab tests. So manufacturers/designers often device various tools/methods to ascertain the real world performance of the equipment. Such tools exist for every kind of equipment. Just because we will have some losses during operations is no reason to think such a system cannot be designed.

Other two reasons are
Reasons for what ? Having the shield ?

1. to prevent the movables in radar from icing when sailing in cold water
The actuation system of the radar is under the deck of the ship, inside the ship not on the deck. As such the machinery sits in the air-conditioned surroundings of the interiors of the ship not exposed to the elements outside. The AC works quite well you know, recently we've had a single ship going to the freezing Scandinavia on route to St. Petersburg and sail back with no problems. Besides we don't go to freezing waters a lot do we ? Its is quite rare.

Speaking of Scandinavia, where is @Fafnir ? Haven't seen her in a while. Who is going to give us the latest on what the Norwegians are up to now ?

to hide radar's orientation/direction to which it is facing, for example if the vessel is near Vietnam and radar is facing North West this would mean the surveillance is on China
The orientation of the radar is visually obscured away by the radome. However if you are looking at China from Vietnam's coast, they would probably know anyway. From that distance the radiated energy is too high to hide, even if the radar is sweep scanning(lowest power mode) the Chinese would be able to sense the energy.

If you want the Chinese to not know then move away from China, that would reduce the sensible energy. Vietnam is too close. But this will decrease the quality of radar images generated.
 
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Ashutosh

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This conversation borne out of speculations is now going to curious places.:ROFLMAO:I agree broadly to what you said above except for some areas but we are straying off topic.

The initial speculation I made was at the possibility of using the shield as a reflector for radiation and thus using the set up as a OTH radar. I agree that the reflected energy will have different wavelength than the incident radiation, the wavelength will increase after the reflection. But that can always be accounted for. Radar transparent materials like the radome also changes the properties of the wave, so radar manufacturers experimentally account for the losses. Simply put, losses caused by the radome=(energy radiated by the radar without the radome - energy radiated by the radar with the radome). Just like that the reflected energy and losses can also be calculated and accounted for.

The reason why I was going on about the possibility of such a set up being used as a OTH radar is the frequency chart here :
View attachment 10912

The main radar of the VC11184 works in the S-band(IEEE classification) and most OTH radars work in the shortwave(3-30 GHz, lies in the UHF-SHF band) by ITU classification. You will notice that the S-band and UHF/SHF-band has a degree of overlap. So the task at hand for us is to design a reflector that causes the reflected waves to stay in the UHF/SHF band(nothing less than 3.5 GHz), this is not a very difficult task. At most you need a few months of experimentation.

This is why I formed this theory in my head, it seems like a very doable task to me. I could be totally wrong though.

Also if the shield's only purpose was to protect the crew from the radiation, why not just use a heavy dose of RAM/coating on the deck and superstructure of the ship ? Conversely why not just program the radar to not throw radiation in this direction ? Modern day radars are very programmable and there are 2 other radars on the front deck, combined data from all 3 radars should paint a full picture with no bling spots. Another point would be, where are the radiation shields for the front deck radars ? Those 2 radars are very close to the bridge with the crew there all the time.

bhai.... I wasn't talking about the radome... the radome will ward off some reflection from the shield. I think it not just for the crew but hte ship's Comms and other equipment. The construction constraints may have necessitated such a design. This is all speculation.

For the bold part, I am pretty sure the radar is for something else they could ahve placed the radar in the front side avoiding any obstruction. and the two in front are far enough for energy disbursal. These posts would be all in waste if that turns out t be some antenna for communications.
 

Gautam

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bhai.... I wasn't talking about the radome... the radome will ward off some reflection from the shield. I think it not just for the crew but hte ship's Comms and other equipment. The construction constraints may have necessitated such a design. This is all speculation.
You are right. Let's stop.
These posts would be all in waste if that turns out t be some antenna for communications.
:ROFLMAO::ROFLMAO::ROFLMAO:
Don't give me more ideas, I'll start again. That would be quite anticlimactic though.
 

Gautam

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Savor this Cosmonaut Yuri Gagarin, telemetry tracking ship

Ah....magnificent. She is beautiful, although I do hope it doesn't rain. The crew could probably bath in the water stocked up in those dishes.:ROFLMAO::ROFLMAO:

This is more the size of the VC11184, the Kosmonavt Vladimir Komarov :
1571480088431.png


We gotta stop we've gone well off topic.
 

screambowl

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Reasons for what ? Having the shield ?
Yeah
The AC works quite well you know, recently we've had a single ship going to the freezing Scandinavia on route to St. Petersburg and sail back with no problems. Besides we don't go to freezing waters a lot do we ? Its is quite rare.

I was talking about the hydrolics and mechanical parts whose moveable parts gets frozen if there is no dome.
Savor this Cosmonaut Yuri Gagarin, telemetry tracking ship

So we can even track the satellites with more precision with that, I mean the one which we are developing.
 

Gautam

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So we can even track the satellites with more precision with that, I mean the one which we are developing.
Yes you can use it for that but there is no need for it. As of now satellite tracking is the work of ISRO's MOTR and PCMC radars(for foreign and domestic satellites respectively). I've written about them on post #522 on this thread :

Indian Space Program: News & Discussions
 

screambowl

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Yes you can use it for that but there is no need for it. As of now satellite tracking is the work of ISRO's MOTR and PCMC radars(for foreign and domestic satellites respectively). I've written about them on post #522 on this thread :

I believe soon India might conduct 9000km range icbm test and for that this ship would be required as well. Obviously ISRO can't be involved all the time for this.
 
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Gautam

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India’s 1st floating test range ready, ballistic missile defence trials on cards

Designed by the Defence Research and Development Organization (DRDO), the new FTR is a 10,000 tonne ship, 200 metres long and 60 metres wide, equipped with state-of-the art electro-optical missile tracking (EOTS), S-band radar tracking and telemetry devices apart from a launch pad, a launch control and mission control centre.

Updated: Oct 27, 2019 13:27 IST
By Shishir Gupta
New Delhi, Hindustan Times

India is set to test its ballistic missile defence (BMD) Phase II interceptor missiles and other futuristic weapons next year with its first floating test range (FTR) in place to allow trials at different ranges without a land mass limitation or threat to the population. Only a select group of nations has FTR capability .

Designed by the Defence Research and Development Organization (DRDO), the new FTR is a 10,000 tonne ship, 200 metres long and 60 metres wide, equipped with state-of-the art electro-optical missile tracking (EOTS), S-band radar tracking and telemetry devices apart from a launch pad, a launch control and mission control centre.

While the missile establishment is tight-lipped about the FTR, Hindustan Times has learnt that the ship will be able to launch conventional missiles upto a range of 1,500 kilometres from a distance of 400 to 500 nautical miles in the sea without fear of the weapons threatening any populated area on India’s east coast.

The FTR will not be used for testing the Agni series of ballistic missiles as it is not designed to handle the thrust of a long-range weapon. “ The FTR has all the capabilities of Interim Test Range (ITR) with the capability to test missiles in deep sea with minimum safety precautions as the latter allows only a cone of two to three degrees to launch a missile. It is for testing all missiles including BMD,” said a senior official who didn’t want to be named.

According to authoritative sources, the idea behind FTR is to test missiles from a range of 100 kilometres to 1,500 kilometres without any land mass or sea lanes limitations. This means that the FTR will be used for the BMD Phase II system, which is designed to destroy enemy missiles mid-air at different altitudes and different ranges with a long-range DRDO missile.

Phase II of BMD envisaged intercepting and destroying enemy missile with a range of 2,000 kilometre. The FTR will be also used to test tactical missiles like Prahar and other futuristic missiles.

With the FTR allowing live tests, not simulations, to interdict long-range missiles fired from the APJ Abdul Kalam Island off the Odisha coast, the Indian BMD system will become more efficient with improved single -hot kill probability (SSKP) ratio, a term used for surface-to-air weapons.

“The FTR will speed up missile projects as it provides a ready-made safety corridor without getting caught into the advances notices to ships and aircraft flying in the area as well as the fear of hitting populated areas while testing BMD system. With this we can use interceptor missile to interdict enemy missiles both endo and exo-atmosphere,” said a second senior official.

India’s 1st floating test range ready, ballistic missile defence trials on cards