Indian Space Capabilities

[gambit]

You will have to excuse my ignorance. What is the difference between a poled AESA and an Israeli Greenpine like AESA?

A poled design is exactly the descriptor 'pole'. The array consists of precisely length-ed and oriented rods arrayed to create a certain beam shape. A true square array would have a conical beam. Deviate from that square and you begin to have a more fan shaped beam.

The Israeli Greenpine system, from all descriptions and images available, seems to be a solid state system consists of solid state T/R modules. It is a more advanced design in terms of beam precision, from shape to direction. The antenna itself may have a few mono-poles in precise locations to create several 'anchor' main beams -- when needed -- for multi-beams operations. But this hybrid is generally from older AESA designs. Still useful, though, for development purposes.

Poled designs are not good for when the target is as dynamic as an aircraft or a descending ballistic warhead and it is because of the radiation pattern of a rod. After all, the rod or pole was the first foundation of wireless transmissions in the first place, and the pattern is omni-directional in azimuth (horizontal). The US Pave PAWS early warning system is a phased array composed of thousands of di-pole transmitters and all of them are against a back plane so all the poles' transmissions are directional. The working wavelength is in the mhz bands so the system was high power and long range detection of incoming targets. Good to know direction and coarse resolutions of speed and altitude of the target.

For example...

By 'coarse' I mean target updates are in meter intervals, as in timestamp 00:00 the target is at 1000 meters altitude, and in timestamp 00:10, the target is at 900 meters altitude.

By 'fine', as in solid state design quality, target updates are sub-meter intervals, as in timestamp 00:00 the target is at 1000 meters, and in timestamp 00:00:01 the target is at 999.99 meters altitude.

See the difference?

As the target gets closer and closer, the threat quotient increases, meaning you are going to die soon if you do nothing. So if you are going to do something, either you move out of the way, or you send an interceptor, you want to give yourself and your interceptor as fine grained information about the threat as possible. That is why long range detection can get by with coarse information from easily designed poled systems operating in the meter length wavelength, while tracking and targeting radars must or should have fine and very fine grained data from solid state systems in the centimetric or even millimetric bands.

 

[he-man]

A poled design is exactly the descriptor 'pole'. The array consists of precisely length-ed and oriented rods arrayed to create a certain beam shape. A true square array would have a conical beam. Deviate from that square and you begin to have a more fan shaped beam.

The Israeli Greenpine system, from all descriptions and images available, seems to be a solid state system consists of solid state T/R modules. It is a more advanced design in terms of beam precision, from shape to direction. The antenna itself may have a few mono-poles in precise locations to create several 'anchor' main beams -- when needed -- for multi-beams operations. But this hybrid is generally from older AESA designs. Still useful, though, for development purposes.

Poled designs are not good for when the target is as dynamic as an aircraft or a descending ballistic warhead and it is because of the radiation pattern of a rod. After all, the rod or pole was the first foundation of wireless transmissions in the first place, and the pattern is omni-directional in azimuth (horizontal). The US Pave PAWS early warning system is a phased array composed of thousands of di-pole transmitters and all of them are against a back plane so all the poles' transmissions are directional. The working wavelength is in the mhz bands so the system was high power and long range detection of incoming targets. Good to know direction and coarse resolutions of speed and altitude of the target.

For example...

By 'coarse' I mean target updates are in meter intervals, as in timestamp 00:00 the target is at 1000 meters altitude, and in timestamp 00:10, the target is at 900 meters altitude.

By 'fine', as in solid state design quality, target updates are sub-meter intervals, as in timestamp 00:00 the target is at 1000 meters, and in timestamp 00:00:01 the target is at 999.99 meters altitude.

See the difference?

As the target gets closer and closer, the threat quotient increases, meaning you are going to die soon if you do nothing. So if you are going to do something, either you move out of the way, or you send an interceptor, you want to give yourself and your interceptor as fine grained information about the threat as possible. That is why long range detection can get by with coarse information from easily designed poled systems operating in the meter length wavelength, while tracking and targeting radars must or should have fine and very fine grained data from solid state systems in the centimetric or even millimetric bands.

Can u pls tell me why we use the word SOLID STATE AESA??

Are their other types of aesa too??

pardon my ignorance but i have had this for a long time.................

 

[BlueDot_in_Space]

Are the stated detection ranges already achieved? Got any write up on this? How tight is the resolution and noise level reduction?

Its a liquid cooled radar, how did ISRO get the liquid cooling challenges done with before CABS/DRDO?
@gambit doesn't look like a liquid cooled system, does it? Since mine amateur eyes can't gauge anything could you perhaps be of some assistance?

The detection range is official figure. Its a liquid cooled radar. ISRO is operating SAR satellites in space, so its obvious they have sorted out the thermal management challenges of such systems. Regarding DRDO AEWC, RAM air cooling is normal.

 

[HariPrasad]

Nahi Paaji sabhi aise soche ge to desh ka kya hoga
Himat rakho sab theek hojayaga

Modi ke liye vote karo aur das sal main transformed India me raho.

 

[Dillinger]

The detection range is official figure. Its a liquid cooled radar. ISRO is operating SAR satellites in space, so its obvious they have sorted out the thermal management challenges of such systems. Regarding DRDO AEWC, RAM air cooling is normal.

Arre yaara air-cooling is not an issue for the CABS product, ye toh mai bhi chilla raha hoon pata nahi kabse. What I meant is that abhi take ek bhi liquid cooled S-band ground based sensor operational nahi hua hai through DRDO.

 

[BlueDot_in_Space]

This apparently is a L-band active electronically scanned array radar. To the best of my knowledge, so far we have only an operational air cooled S-band AESA for the AEW&C designed and built by us, liquid cooling solutions are yet to be seen in any existing indigenous AESA sensor.

We also have C band on Risat-1

 

[Dillinger]

We also have C band on Risat-1

And where is ISRO sourcing its MMICs from, in country foundry for industrial level production toh exist nahi karti?

 

[he-man]

@gambit

The above developments went into the L-star sensor-

Which has been used then it the Indigenous AEW&C program-

SO HOW FAR BEHIND WOULD YOU SAY WE ARE, A DECADE PERHAPS TWO?

It all depends on the money we pour into it............by the way i think we should spend more on r&d as by the time we get GaA X-BAND world would have already moved on to GaN

 

[gambit]

The thing is we have already manufactured the TRMs and MMIC for S-band and X-band. But our first operational system is an air cooled one.

From this to a compact X-band AESA for fighter aircrafts will take 10 years, right?

Liquid cooling is problematic as the T/R module gets smaller. We simply cannot compress the liquid's molecule and if the liquid is a composite, like salted water compared to pure water for example, then it gets even more problematic for cooling small structures.

This is basic chemistry. If you 'dope' water with salt, for example, you raised its boiling temperature and lowered its freezing temperature. No big deal there.

But here is the problem...If you want to use this composite liquid to remove or absorb heat from a structure, you must leave them in contact with each other for a longer time than if you had use pure water.

Look at the cooling system for your car. If you use pure water, the engine's heat would overwhelm it and all the water would rapidly boil off.

Now you do three things:

- Use a composite liquid.

- Pressurize the closed system.

- Regulate the flow. Not too high because you want to keep the liquid in contact with metal long enough to absorb/remove heat. Not too low because you do not want to overheat the liquid.

This combination will allow you to minimize the amount of liquid to be just enough to keep your engine cool but not too cool.

It is no different with cooling a solid state AESA array -- in principle.

The problem lies in miniaturization and you cannot compress the liquid's molecules. You make the T/R modules smaller and smaller. You put them closer and closer, as much as radiation physics will allow so you can create a functional beam. But you are stuck with the same liquid formula.

A more advanced AESA design may require less liquid cooling than yours because of more advanced T/R modules manufacturing thanks to super-duper secret materials. So even if both yours and his have the same T/R modules because of radiation physics limits on a fixed array dimension, his will have a more refined beam, better multi-beams operations, and less cooling requirements.

So to answer your question of going from air to liquid cooling: Yes, it can take up to a decade to develop a true and pure indigenous compact liquid cooling AESA system. It all depends on finance and budgeting.

 

[he-man]

Liquid cooling is problematic as the T/R module gets smaller. We simply cannot compress the liquid's molecule and if the liquid is a composite, like salted water compared to pure water for example, then it gets even more problematic for cooling small structures.

This is basic chemistry. If you 'dope' water with salt, for example, you raised its boiling temperature and lowered its freezing temperature. No big deal there.

But here is the problem...If you want to use this composite liquid to remove or absorb heat from a structure, you must leave them in contact with each other for a longer time than if you had use pure water.

Look at the cooling system for your car. If you use pure water, the engine's heat would overwhelm it and all the water would rapidly boil off.

Now you do three things:

- Use a composite liquid.

- Pressurize the closed system.

- Regulate the flow. Not too high because you want to keep the liquid in contact with metal long enough to absorb/remove heat. Not too low because you do not want to overheat the liquid.

This combination will allow you to minimize the amount of liquid to be just enough to keep your engine cool but not too cool.

It is no different with cooling a solid state AESA array -- in principle.

The problem lies in miniaturization and you cannot compress the liquid's molecules. You make the T/R modules smaller and smaller. You put them closer and closer, as much as radiation physics will allow so you can create a functional beam. But you are stuck with the same liquid formula.

A more advanced AESA design may require less liquid cooling than yours because of more advanced T/R modules manufacturing thanks to super-duper secret materials. So even if both yours and his have the same T/R modules because of radiation physics limits on a fixed array dimension, his will have a more refined beam, better multi-beams operations, and less cooling requirements.

So to answer your question of going from air to liquid cooling: Yes, it can take up to a decade to develop a true and pure indigenous compact liquid cooling AESA system. It all depends on finance and budgeting.

Bhai what is SOLID STATE??

 

[Dillinger]

Liquid cooling is problematic as the T/R module gets smaller. We simply cannot compress the liquid's molecule and if the liquid is a composite, like salted water compared to pure water for example, then it gets even more problematic for cooling small structures.

This is basic chemistry. If you 'dope' water with salt, for example, you raised its boiling temperature and lowered its freezing temperature. No big deal there.

But here is the problem...If you want to use this composite liquid to remove or absorb heat from a structure, you must leave them in contact with each other for a longer time than if you had use pure water.

Look at the cooling system for your car. If you use pure water, the engine's heat would overwhelm it and all the water would rapidly boil off.

Now you do three things:

- Use a composite liquid.

- Pressurize the closed system.

- Regulate the flow. Not too high because you want to keep the liquid in contact with metal long enough to absorb/remove heat. Not too low because you do not want to overheat the liquid.

This combination will allow you to minimize the amount of liquid to be just enough to keep your engine cool but not too cool.

It is no different with cooling a solid state AESA array -- in principle.

The problem lies in miniaturization and you cannot compress the liquid's molecules. You make the T/R modules smaller and smaller. You put them closer and closer, as much as radiation physics will allow so you can create a functional beam. But you are stuck with the same liquid formula.

A more advanced AESA design may require less liquid cooling than yours because of more advanced T/R modules manufacturing thanks to super-duper secret materials. So even if both yours and his have the same T/R modules because of radiation physics limits on a fixed array dimension, his will have a more refined beam, better multi-beams operations, and less cooling requirements.

So to answer your question of going from air to liquid cooling: Yes, it can take up to a decade to develop a true and pure indigenous compact liquid cooling AESA system. It all depends on finance and budgeting.

Makes sense. But then the US has been using something akin to polyalphaolefin (PAO) as a radar coolant, yes?

 

[he-man]

And where is ISRO sourcing its MMICs from, in country foundry for industrial level production toh exist nahi karti?

We must prioritize the chip making industry.......

and not uncle chips!!

 

[Dillinger]

We must prioritize the chip making industry.......

and not uncle chips!!

You must stop with the staccato post firing.

 

[Firemaster]

Bhai what is SOLID STATE??

I think he is referring to semiconductor radiators.

 

[gambit]

Can u pls tell me why we use the word SOLID STATE AESA??

Are their other types of aesa too??

pardon my ignorance but i have had this for a long time.................

The other type is the poled or 'rod' design.

You can see that design here...

Russian / PLA Low Band Surveillance Radar Systems (Counter Low Observable Technology Radars)

To be 'solid state' mean you make those transmitters smaller and smaller on a silicon foundation.