LCA LSP-3 with ELTA radar to fly today

[Avatar]

A small correction here. The 650mm is only stated to be the diameter of MMR antenna array,but not the actual nose/radome inner diameter.

MMR being a mechanically scanned keeps itself safe from the radome inner lining.A considerable space is left between the antenna array and radome.Whereas the same is not justified with AESA antenna array.Hence it is highly possible for a thought that the hypothetical AESA antenna array might be more than 650mm diameter.

And when ,one is talking about the number of elements populated, they are strictly considering ones capabilities in the design and development of an MMIC. If company A can pull up with an X sq mm area,then B company might comeup with (X-5)sqmm area.Also populating the modules depends on the design philosphy one follows.Its all about that layout to get optimal number while satifying the cooling needs.

There is no yard stick kind of measurement in bringing up number of T/R modules.

Also regarding the Indian AESA developement, MMR was superseeded with AESA program after the sucessful flight test of an co-developed MMR with Israel.
AESA( radar for Tejas) development was supossedly started atleast 3 years back alongside AEWACS project. The only issues they had with the radar were known to be the overheating due to excess density of modules.

Thrust vectoring is not an requirement for LCA,only optional.

EADS wants to bring its TVC along with its engine,while GE is not.
EADS claims a fuel saving of 25%.

GRTE kaveri normally comes out with con-di nozzle,while there were plans of adding a TVC instead but not solid.
Russians are willing to offer TVC at any moment.

A TVC on Tejas certainly bring advantages in terms of controlling and fuel savings.It needs more modification to its FBW to allow this new TVC,which again will consume time.Tejas MKII has most likely chances of seeing a TVC onboard as EJ200 is considered as the most likely winner.

Thanks for the clarification.

EJ200 is the likely winner, which means HAL will have to work on the modifications for TV.

In case Kaveri engine is actually implemented on the Tejas, then it would be easier to implement an TV enabled one, since the modifications were already made.

If the fuel saving claims are true, would this mean a 20-25% increase in range ? Also I want to know if the handling advantages are significant enough, like they are on the Su-30MKI.

 

[DMLA]

Angle of attack posts radar not AESA!

Well it seems like the mystery has finally ended maybe a little on a sad note. As reported by us earlier that the radar recently tested on the Light Combat Aircraft (LCA) being a AESA is wrong. It was justed informed to us that the radar tested was not a AESA but a hybrid of Elta- 2032.
The Radar is a mechanically steered multi-mode radar based on Israeli's Elta-2032 which currently in service on-board Indian Navy's Sea Harrier's. It was confirmed to us that the radar is 100% Indian with only the processor of Israeli origin. This radar will be used on the first 40 LCA's which are on order for the Indian Air force(IAF). Later on the LCA Mk-2's will have a AESA which is in works.
Angle of Attack apologizes for the misinforming before and letting the readers down. However with very little information coming out of HAL airport we did our best. But this still is a great achievement for the project and we wish all the best to the team for the coming future.

link: Angle of Attack: LCA radar is not a AESA !

 

[gambit]

Look at the nose cone length of F-22 and F-18E/F, F-18E has longer nose cone than F-22 that means it can have larger number of T/R modules but in reality APG-79 has around ~1100 while APG-77 has nearly ~2000 T/R modules, still F-22 can accommodate APG-77.

No its not , length is not factor .
How much size you antennae is depends on height that is Circular space in case of circular or oval radar / in case of rectangular its height (antennae are not flat they stand vertical).
Secondly if you notice Radar antennae is kept in inclined position to allow minimal return and LPI mode
somewhat like this -

Means you need better space than length.
Same reason why NIIR-Phaztron officials moved Radar back in nose Mig35 to get more space to fit bigger antennae and more module .

Gents,

The way it works is this...

The aerodynamicists shape the aircraft. Now...If the company is a well functioning one, the aero-boys would keep the radar engineering boys in the loop.

Aerospaceweb.org | Ask Us - Rocket Nose Cones and Altitude

...the ideal nose for a model rocket is not the pointed cone or ogive shape you might expect, but the more rounded parabola.

Now...Just in case anyone wonder if any aircraft have a rounded, or parabolic shaped nose, I say take a look at the transports, like the C-130. Granted, transports are not supersonic...Yet...But the point here is that for any supersonic vehicle, it turns out that the pointed nose, like that on the MIG-21, is not as aerodynamic as the rounded parabola or the ogive. The reason why the MIG-21's nose look that way is because it must perform double duties:

1- House the radome.
2- Control engine airflow.

For item two, look at the twin 'spikes' on the SR-71's engines.

Complex ray analysis of beam transmission through two-dimensional radomes

Wedge-tapered radomes are then considered, and the complementary roles of direct and collective treatment of internal reflections are made evident as the taper angle increases.

Radome shaping does have an effect on the EM signal itself but that is for another discussion. For radar antenna dimension, or aperture, it is the radome's TAPER ANGLE, that determine the antenna's final dimension. The MIG-21's sharp taper angle, due to its double duties, limit its own radar dimension, so we ended up with the MIG-21 a formidable dogfighter but with terrible radar seeking performance. This is why radar engineering should NOT be excluded from aerodynamicists' meetings on how the aircraft is shaped. This is also why we believe the Soviets, based on our examinations of their aircrafts, do not have a consistent record of collaboration in their engineering depts.

Do not associate internal volume and shaping. A drinking straw can have the same volume space as a dice. You can have two radomes with identical internal volume space but if one is very long and sharply angled you will have a very small radar. So it is not radome length but radome taper angle, be it wedge or ogive or parabola, in other words, it is radome shaping, that will determine final antenna dimension. Very few radomes, like the MIG-21's, strictly adhered to absolute shapes. Most are usually a blend, like the F-111's or the F-22's, of two or more shapes.

 

[KEETARP]

WOW!!!!! Do they teach RADAR TECHNOLOGY in army medical science colleges?

No they don't .
My posting is all based on little talk i do with airmen in Pune Air-force base whom I look after.
While most other part is due to Internet , when i am free in hospital and there is no patient rush I always have my Blackberry up and running.

Gambit , thnx for info.

EJ200 is the likely winner, which means HAL will have to work on the modifications for TV

Actually its not done
Lets wait ,
If economical option is adopted GE-414 will win .
You are forgetting Naval LCA , and engine req for Navy should be tested one in sea,salty and humid conditions and rust protection. This is where F18 E has operated but Typhoon hasn't. So GE414 will require less modifications than EJ-2000

 

[gogbot]

Tejas LSP-3 was carrying Hybrid MMR radar

BY: IDRW NEWS NETWORK
Its now almost confirmed that the Radar carried by Tejas LSP-3 is a Hybrid version of Elta’s 2032 radar ,with Indian Inputs , Most of the inputs by India in this new Hybrid are most from the local MMR radar which was in development for a while now , but the Israeli 2032 back end processor unit has been used for the radar , new HYBRID MMR was flight tested in Israel in a Boeing Test Bed and as per sources few have been deleivered to Indian Labs which will it intergrate it with other LSP aircraft’s .
Next aircraft LSP-4 which has already conducted its ground trials and soon radar will be integrated and the first test is expected within a month or two and then followed by LSP-5 which is also almost ready , all aircraft’s will have a radar and soon LSP-1/2 will also be pulled put of test flying to be integrated with all the other avionics package and auto pilot with radars

Tejas LSP-3 was carrying Hybrid MMR radar idrw.org

 

[gogbot]

Actually its not done
Lets wait ,
If economical option is adopted GE-414 will win .
You are forgetting Naval LCA , and engine req for Navy should be tested one in sea,salty and humid conditions and rust protection. This is where F18 E has operated but Typhoon hasn't. So GE414 will require less modifications than EJ-2000

but your forgetting what it would mean if the EF won the MRCA.

It would mean HAL would become a partner on the Euro fighter program. Meaning the engine modifications can be made by Europeans in cooperation's with HAL .

And IF the EF won the MRCA , it has the extra chance of winning the NMRCA with its sea typhoon concept. Which means a navalised EJ-2000 becomes even more important.

In the end this would Mean It is now easier for the navy and the air-force logistics wise and cost wise to operate the two fighter aircraft.

And HAL has now the experience in making a Carrier borne aircraft in both the Eurofighter and the LCA. As well as inputs on the engine.

This is a very attractive outcome, given no delays of course.

The GE-414 is just the more economical and safe option. We also loose out on the EJ-2000's super cruise and Trust vectoring. As well as a chance to work closely on what is one of the most advanced 4th generation engines out there. And be apart of the consortium that made it.

You know what i think i have sold my self on the this.

Eurofighter and EJ-2000 should be our picks.

Picking the Ge-414 is bit , buying of the shelf with nothing back.

 

[Avatar]

but your forgetting what it would mean if the EF won the MRCA.

It would mean HAL would become a partner on the Euro fighter program. Meaning the engine modifications can be made by Europeans in cooperation's with HAL .

And IF the EF won the MRCA , it has the extra chance of winning the NMRCA with its sea typhoon concept. Which means a navalised EJ-2000 becomes even more important.

In the end this would Mean It is now easier for the navy and the air-force logistics wise and cost wise to operate the two fighter aircraft.

And HAL has now the experience in making a Carrier borne aircraft in both the Eurofighter and the LCA. As well as inputs on the engine.

This is a very attractive outcome, given no delays of course.

The GE-414 is just the more economical and safe option. We also loose out on the EJ-2000's super cruise and Trust vectoring. As well as a chance to work closely on what is one of the most advanced 4th generation engines out there. And be apart of the consortium that made it.

You know what i think i have sold my self on the this.

Eurofighter and EJ-2000 should be our picks.

Picking the Ge-414 is bit , buying of the shelf with nothing back.

I hope the decision makers portray the same wisdom you do.

 

[Rashid..]

makes me feel proud jai hind!!!

 

[Chanakyaa]

Prateek bhai.. great info indeed.

 

[Kinetic]

Now the pic you are showing is F111 , it is a huge size nose .

here it is

But Size is limiting factor in case of LCA it will allow only 600-650 mm antennae.

I was talking about the size of AESA and its associated systems.

As LCA's MMR is a mechanically scanned radar the size of the radome is much larger than the size of the MMR ie 650 mm.

No its not , length is not factor .
How much size you antennae is depends on height that is Circular space in case of circular or oval radar / in case of rectangular its height (antennae are not flat they stand vertical).

somewhat like this -

Means you need better space than length.
Same reason why NIIR-Phaztron officials moved Radar back in nose Mig35 to get more space to fit bigger antennae and more module


.

If length is not the factor than where will you put the beamformer, exciter, receiver, computer or cooling mechanism?

The rectangular size of 2052 is not much more than the size of LCA MMR and above all the MMR have to move horizontally and vertically those need more space while AESA like 2052 doesn't need that.

No there is

I said the length, to put the AESA subsystems behind the antenna.

Secondly if you notice Radar antennae is kept in inclined position to allow minimal return and LPI mode.

All AESA radars doesn't positioned in inclined mode example CAESAR, EL/M-2052, RBE2 AESA etc. Above all as you can see in the image, "ESA tilt angle optimized for A/A uplook into turn as a primary requirement".

Actually the LPI on the AESA radar comes through the capability of different T/R modules to send and receive signals at different frequencies or say each module broadcasts its own independent signal. This makes jamming or intercept of the AESA radar almost impossible for the enemy. This also gives the capability listen for the reflections from another radar sources.

I cant understand what you meant by elements in PESA .
The power in PESA case is by TWT tubes , Bars has 2 TWT tubes and IBRIS has 4 TWT tubes.

By elements I mean radiating elements in PESA antenna.

Not only TWT but klystron and gyrotrons are also used. They areal used to power the transmitter. PESA's single transmitter needs very high energy. For same number of elements PESA needs much more power than AESA.

In case of PESA wave-shifters are placed before signal reaches the Transmitter unit so already Power reaching is quite less .
Additionally when Radar is not transmitting , it only works as receiver for that time and power generation is minimum.

Its not like that. The transmit duty in PESA is very low compared to AESA. Thats why they need huge power for the transmitter.

There is single receiver module in PESA, so very few times the radar is on only receive mode. Without transmitting it is very difficult for PESA to operate until the enemy emission's frequency is not taken care. While AESA has thousand+ receivers that can operate in different frequencies at the same time that allows to be completely on receiving mode.

While in AESA the the Transmitter unit is itself Power source so less loss of power and cooling is required to control that power surge and then it reaches the wave-shifters which further controls it.
And even if its receiving many modules will still be transmitting

Yes, the AESA's every element has a power sources but all they need very small amount of power compared to over all power requirement of PESA. Distribution of small amount of power among every modules allow AESA to manage the emission and power loss more efficiently than PESA.

 

[Kinetic]

But in case of LCA jump is substantial .
In only 650 mm you are trying to pack 1500 modules . That is huge
Just calculate the avg power rating for half beam , 750 modules multiply by 5 (since ELTA-2052 specs are not known assuming 5 RF element in each array), keeping 50% as duty cycle , each RF unit having 1 KW as peak power. Even if duty cycle of that module is worse then also Power is quite high for this area.

Forget half beam just for 2 array you have 2.5.1 equal to 10 KW power and if duty cycle is 50% you have 5 KW avg power consistently .

As I said though MMR is 650 mm LCA can have larger radar because MMR is a mechanically scanned radar which needs more space than electronically scanned AESA.

What do you mean by RF in an AESA radar like 2052? Radio Frequency? In AESA every element has its own transmitter and receiver connected to the beamformer. If every T/R modules needs 5 W than 1500 will need 7.5 kW.

To spread this heat you at least require how much area??
Just to give an idea 900 mm antennae of Mig35 has 1100 module meaning for circular area of pi multiply R2 ( r being 900/2).
While ELTA is rectangular so L*B area , calculate and see how much size you will need.

As I said the the cooling mechanism doesn't matter upto certain level nor it has anything to do with area. If an AESA cooler can maintain 1000 elements it can also maintain 1500 elements but what matter is the size of T/R modules. Those countries can build smaller T/ modules they put more in the radar. Cooling is matter but not the main issue behind number of modules. Same cause behind the Mig-35's radar.

Compare the size of radar antennas and T/R modules of Mig-35 and PAK FA.........

Mig-35


PAK FA

 

[dbc]

As I said the the cooling mechanism doesn't matter upto certain level nor it has anything to do with area. If an AESA cooler can maintain 1000 elements it can also maintain 1500 elements but what matter is the size of T/R modules. Those countries can build smaller T/ modules they put more in the radar. Cooling is matter but not the main issue behind number of modules. Same cause behind the Mig-35's radar.

Area does matter for the following reasons:

1. Smaller than ideal element spacing cause mutual coupling effect. This results in increased side lobes, side lobes are generally undesirable and make the radar more susceptible to jamming. The extent to which mutual coupling impacts performance of the radar depends on the location of the element within the array and the distance between two radiating elements.

2. Larger than ideal element spacing cause grating lobes, grating lobes are also undesirable since it takes power away from the main beam.

3. T/R Elements are embedded on a cold plate. An increase in radiating elements from 1000 to 1500 will undoubtedly require more cooling, a larger cold plate and more liquid coolant to allow optimal performance of the radar.

While it is true that greater number of elements improve radar resolution it is important to note that this applies to evenly spaced array design. It is possible to achieve similar results with fewer elements employing randomly spaced elements.

I notice you mentioned the Raptor's APG-77 to prove your point, the antenna on the APG-77 is curved elliptical unlike conventional flat antenna on AESA systems like the EL/M 2052. The cold plate and liquid coolant for the APG-77 is especially developed for the Raptor the cold plate weighs the same as aluminum with four times the conductivity (thermal) of copper.

Finally, the manufacturers claim that the EL/M 2052 is suitable for the LCA – this should be enough evidence to support your argument. Personally I think the more pertinent question is – why increase the unit cost of the LCA with an expensive 1500 T/R AESA is it really necessary?

 

[Kinetic]

Area does matter for the following reasons:

1. Smaller than ideal element spacing cause mutual coupling effect. This results in increased side lobes, side lobes are generally undesirable and make the radar more susceptible to jamming. The extent to which mutual coupling impacts performance of the radar depends on the location of the element within the array and the distance between two radiating elements.

Thanks for the info. Mutual coupling is a problem in antenna's ever decreasing size of the modules. But appropriate technologies like digital beamforming being developed to look at the issue. For example calibration and equalization. With these they were able to reduce element to element variation in angle.

2. Larger than ideal element spacing cause grating lobes, grating lobes are also undesirable since it takes power away from the main beam.

Antennas create radiation patterns with energy in unwanted areas but this can be reduced by appropriate processing techniques.

3. T/R Elements are embedded on a cold plate. An increase in radiating elements from 1000 to 1500 will undoubtedly require more cooling, a larger cold plate and more liquid coolant to allow optimal performance of the radar.

As I said upto certain point, say with nearly 1500 T/R modules the radar doesn't need any major changes over current 1000 T/R modules. If one can build a cooling mechanism for 1000 modules antenna, he will be able to build for 1500 modules antenna also without major changes ie. But the main point is how one can place more and more T/R modules in the nose of fighter aircrafts. This mainly depends on size of the T/R modules and processing powers.

While it is true that greater number of elements improve radar resolution it is important to note that this applies to evenly spaced array design. It is possible to achieve similar results with fewer elements employing randomly spaced elements.

As far as I know fewer elements may allow range but not the resolution. It may also cause less number of target tracking at long ranges.

I notice you mentioned the Raptor's APG-77 to prove your point, the antenna on the APG-77 is curved elliptical unlike conventional flat antenna on AESA systems like the EL/M 2052. The cold plate and liquid coolant for the APG-77 is especially developed for the Raptor the cold plate weighs the same as aluminum with four times the conductivity (thermal) of copper.

Thats good. I think other countries radars with high number of modules also have some type of good cooling system.

Finally, the manufacturers claim that the EL/M 2052 is suitable for the LCA – this should be enough evidence to support your argument. Personally I think the more pertinent question is – why increase the unit cost of the LCA with an expensive 1500 T/R AESA is it really necessary?

Tejas is a low cost high tech fighter with all modern technologies available except AESA. Low RCS, FADEC engine, glass cockpit, Mayavi EW, complex aerodynamics with relax static stability, quad digital FBW flight control, DASH helmet mounted display, Lightening-III pod.... AESA will fulfill the capabilities of Tejas.

 

[indiarocks]

Angle of attack posts radar not AESA!



link: Angle of Attack: LCA radar is not a AESA !

radar used was a hybrid mmr and elta radar:hal officials in official release

 

[dbc]

Thanks for the info. Mutual coupling is a problem in antenna's ever decreasing size of the modules. But appropriate technologies like digital beamforming being developed to look at the issue.

Digital beamforming has only been reliably achieved with larger land based systems such as Ballistic Missile Defense (BMD) and theater air defense radar at the sub array level (partitioned AESA). Even at the sub array, the larger the number of T/R elements the greater the complexity and cost. At the element level digital beamforming has only been achieved in a lab with a mere fifteen elements.

Today's state-of-the-art DBF phased arrays are primarily of laboratory prototype quality, and employ digital receivers only at the subarray-level. This is due to challenges both with RF receiver hardware, including reduction of size, mass, and DC power consumption, as well as digital challenges that include increasing ADC sampling rate, implementing digital sub-banding and digital time delays, and processing enormous data loads associated with DBF algorithms

Space Based Radar (SBR)

Reducing element spacing has both military and civilian applications and is being aggressively researched. The military possibilities include conformal adaptive antenna design(smart skin?) while miniaturization of MIMO(Multiple I/O) systems combined with digital beamforming has both civilian and military applications and will spawn the next generation of mobile wireless data communication devices.

More later...time permitting.