Radar thread - specs & discussions

Sumeet
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Postby Sumeet » 17 Apr 2006 17:36

here is the actual source of Pit's info:

http://www.chile.mid.ru/misc/fidae2006_e_03.html

babelfish translation into english from spanish follows:

Sukhoi bets by the SU-35 the official representative of holding Sukhoi said to FIDAE NEWS that Venezuela has expressed interest in acquiring the most modern Russian airplanes battle. The conversations are progressing to acquire a game of the new advanced huntings Su-35. This airship is the advanced military product more of that company. The work in new denominated Su-35 T10BM (Bolshaya Modernizatsiya or Gran Modernization) within the design office, began in 2004. It is anticipated that the prototype flies before the 2006 end, and from the 2009 hunting will be available in the market. Su-35 it is considered to fill the emptiness before beginning the production of the hunting of new generation of Sukhoi T-50 (PAK FA) near the 2015. The structural configuration of Su-35 is almost the same one of the series of Su-27, particularly, the new airplane does not have canards, which were the trade name of the more recent Sukhoi huntings, including also the previous prototypes of Su-35 (Su-27M). The aerodynamic propertieses have been updated; the control surfaces are smaller than those of Su-27. to increase the life on watch of the structure of the fuselage, many elements constructed in aluminum will be replaced by others of titanium. The alternative ones nail introduced in Su-35 include the new N035 radar Iris and the motors of increased push AL-41F1. The radar N035 Irbis (Irbis-E for export airplanes), developed by the institute Tikhomirov NIIP for Su-35 is the continuation of the Bars radar of Su-30MKI and, like his predecessor, it has antenna of I scan electronically passive (WEIGHT). According to the NIIP, the radar WEIGHT ' clásicó (for this company) is still far from being obsolete and is as good as the first radars with active antenna (AESA). The advantages of the Irbis on the Bars include a ampler reach of operational frequencies, greater angle of zone search (due to the best antenna and conduction of two steps), reaches greater and better resistance to interferences (jamming, thanks to a more powerful transmitter), as well as greater resolution, as much in the detection of aerial targets or surface. The Irbis-E radar is able of traquear-while-scans up to 30 targets, eight of which they can be almost continuously traqueados with sufficient exactitude for simultaneous enlistments by eight missiles air-air (AAMs) with active radar of midrange (RVV-AE) or by four AAMs of long reach with active radar (K-100). The Irbis-E is able to hook simultaneously up to four targets of surface. In the way of combined-arms operation, the radar is able to look for simultaneously in the airspace and the terrestrial surface including the enlistment of an only aerial target with sufficient exactitude to use a missile of active radar. Thanks to the power peak of 20Kw, the Irbis-E radar vee the aerial target of a section of three square meters from one distances nonsmaller 350-400Km not less On guard frontal or than 150 km On guard of tail (to great altitude). Targets ' furtivos' (with section of radar of 0,01 m2) are detected from a distance of 90km. The prototype of the Iris radar began aerial tests the 24 of June of the 2005 in the experimental fighter Su-30Mk2. The tests confirmed the reach search of the project as well as the possibility of the simultaneous work with nine targets, two real and seven imitation ones. The radar worked simultaneously in air-air and air-to-surface ways. Su-35 Kn instead of the 122,6 will be driven by two motor turbofans AL-41F1 with a power of 137.3 Kn of the present AL-31F. The updated motor began the flight testings in the experimental fighter Su-27M ' 710 ' in March of 2004. The primary target of the designers is how to increase the life on watch of the motors designed to a planned value of 4,000 hours (in comparison to the 1,500 present hours for motor AL-31F). Su-35 it must have a weight of nominal takeoff of 25,300 kg and a weight of maximum takeoff of 34.00kg; the load military Maxima is of 8,000 kg. The airplane can reach 1.400km/h near the level of the ground or Mach 2,25 to great altitude. The maximum range arrives at 1,580 km to low altitude, 3,600 km to great altitude or 4,500 km with two external auxiliary pools. The ample rank of armament options includes 12 missiles air-air RVV-AE of midrange, five missiles air-air long-range K-100 (KS-172S-1), six air-to-surface missiles Kh-31A/P, five missiles antiboat Kh-59MK, three missiles antiboat 3m5Â Biryuza or a heavy missile antiship 3M5Ä Onyx/Yakhont. The specification also includes guided pumps of 250, 500 and 1500 kg including the new LGB-250, KAB-500S and KAB-1500LG. Sukhoi takes part in shows aerial Fidae from 1994. In the exhibition of this year, Sukhoi appears like a company of ample profile of production. Excepting to the hunting model multirol Su-35, Sukhoi also exhibits a model of the transport airplane and Su-80 passengers, able to transport 30 passengers or 3,300 kilos of load to 1,400 km. Its prototype is in tests from the 2001. By the end of month, the first airplane of preliminary series will begin its tests in the factory Sukhoi-KnAAPO de Komsomolsk on Amur, said Igor Chernikov, director of the program of Sukhoi. Three airplanes are now in production and the next series of eight has been sent, added. The certification of Su-80 is predicted for the first fourth month period of the 2008. The first airplanes of production will be given to the Russian guard of borders shows the next ones will fly with Airlines Polestar based on Yakutsk, Russia


i think MKI equipped with Irbis would not require phalcon AWACS.

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Postby Dileep » 17 Apr 2006 19:13

20 kW Peak Power!!! Now, that is something to talk about. I think it will just fry the enemy plane :twisted:

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Postby Dileep » 17 Apr 2006 19:38

Dileep didn't understand this issue of blame game ...
The "cumulative" S/N ratio for the RF side (the chief contrbutors, IIRC, are the Tranmitter, Duplxer and LNA etc.) should be pretty well known by now - after all they've got the A/A mode working, right?
Now if the SAR mode "cumulative" S/N ratio is unacceptably low then isn't it pretty straight forward to conclude that the PSP is contribution too much of a noise ... thus requiring a new design.
JMT, of course ...

It is not that simple.
The DSP part, right from the baseband input connector, can be parametrically verified in the lab. Also, the technologies involved in those blocks are mature and widely available. So, that will not be a problem. Even the base noise figure can be established in the lab unambiguously.

The parameter of interest is the "available S/N ratio", which you can not test in the lab. You got to take it up and get the actual signal return to test it. The A2A is pretty simple that way. There is not much background clutter. You fly a single target, and you can easily find the blip on the SAR raster. You can even work on the resolution part without much trouble.

Now, coming to A2G mode, you get all kinds of returns, and you have to get the grain from the chaff, so to speak. That is when problem happen. It is very difficult to determine which stage contributes to the problem. It could be the beam definition. It could be the receiver. IT could be the scan synchronization. IT could be the DSP algorithms. Since it will not be obvious from the data, each of the groups will assign blame to another one. That is the blame game I talked about. It happens everywhere.

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Postby vina » 17 Apr 2006 21:53



Ah, so this is why the PV2 has been flying around without a radar and the PV3 is yet to make an appearance. But frankly, why do you need a radar at all to do carriage and separation trials , like carrying and dropping a fuel tank and dummy missiles was always beyond me..

But anyway, the info does come out of the cloak of secrecy and denial.. So the MMR is seriously behind schedule as well, and HAL and the DRDO dont have what it takes to see this through and want technical help from outside eh ? Good ..Atleast they are now out of denial and since that is the first and most difficult step, somebody somewhere can make the hard decisions necessary like say an off the shelf radar or get a partner to see this through to make sure that the IOC deadlines (is there an authoritative source on that date anywhere ?)

Dileep wrote:The time spent on this project is unforgiveably long. You can design a computer and ADC several times over during this time. And by my experience, "interface problem" is the classic indication of blame game.


Factor in the kind of skills and capabilities in DSP, hardware , software, microwave communications and everything available in India, especially in the broader industry in India, this is simply unforgivable. Also, consider the kind of work the India centers of mulitnationals do..

ArunS wrote: Unless failure translates to dismissal/censure and success translate to reward, DRDO and HAL will continue to flop.

Indian defense has the choice to run the ship in Russian style or in modern economics driven competitive management.

Pleading how low the Indian engineers/managers are paid when failures happen is not relavent


Right on the money.. I have said time and again here on this forum and I repeat again.

HAL has no competitive advantage in Radars/Electronics and Engines. HAL should be broken up into 3 separate companies , airframe, electronics and engines , with HAL retaining the airframe business and the govt mandated monopoly there alone . The electronics business should be thrown wide open to competition (easiest to do so of the 3 businesses) and someone like BHEL should be given an entry into aircraft turbine businesses (easiest potential entrant).. Use the MRCA deal to get a private sector biggie an entry into the airframe business too , as part of the joint venture requirements for the project.

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Postby JCage » 17 Apr 2006 22:04

vina wrote:But anyway, the info does come out of the cloak of secrecy and denial.. So the MMR is seriously behind schedule as well, and HAL and the DRDO dont have what it takes to see this through and want technical help from outside eh ? Good ..Atleast they are now out of denial and since that is the first and most difficult step, somebody somewhere can make the hard decisions necessary like say an off the shelf radar or get a partner to see this through to make sure that the IOC deadlines (is there an authoritative source on that date anywhere ?)


Well if you even knew something about radar development in India, it would be clear that DRDO has the ability to design and deliver SP's. They have what it takes and have had it for quite some time now & as regards the hard decisions - they are the ones making it. They werent made earlier because of cost, as anyone who has followed the LCA program would or should know. HAL is a different case- this is their first & only airborne radar. And, the private sector has been with them every step of the way. IOC deadlines- google for them.

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Postby Dileep » 17 Apr 2006 22:07

One more thing. I can confidently say that there is more than enough technology capability to build any radar indigeneously. Why they screwed up? Well, you know the answer already.

I would imagine the first thing to do with the weapons would be to simply fly them and verify the aero prameters. The guiding part can wait. Are they doing that? God Knows!

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Postby JCage » 17 Apr 2006 23:08

Boss, its a coordination issue. It would have been better if the MMR had been left to an agency specializing in radars, but then HAL was chosen because they assembled/ license manufactured the Bis's radar, which was the only airborne FCR ever made in India till that point. This was mentioned by SR Valluri in his reminisces about the LCA program.

I wouldnt say there is more than enough technology to build any radar indigenously- that would be a tad overstating it though, that is if we want to build a modern long range TWT based unit (say our THD equivalent)- luckily though, the AESA units will solve that "missing link" in the product lineup by supplanting that technology. The MMR is the "final frontier" in terms of a basic product lineup spanning the entire spectrum. We have the SV-2000 for light aircraft & choppers, the in development AESA system by CABS which draws upon the Hs748 (ill fated), whats plainly missing is an airborne FCR. And of course the technologies for the same- we havent yet demonstrated the scale of hardware necessary to scale up the system. The MMR is a capable (for its size) design if it performs per specs, but the trend nowadays is for much more higher power (and expensive units).

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Postby bala » 17 Apr 2006 23:13

This stmt by the ex-chief is rather stunning, don't know whether it is DDM words but. .. A radar is a loose end.. ghosh.. when does a critical component like radar become a loose end. And what happened to the plan. I am with Vina/Dileep on this issue. No matter whatever competency HAL has, not realizing strengths/weakness for a strategic component like a radar is mind boggling.

‘Indigenous’ aircraft needs foreign lift, for its radar
Asked about the development, Natarajan’s predecessor V K Aatre, now a professor in Bangalore, expressed surprise. ‘‘It was the only loose end left in the LCA project when I retired (in August 2004). I am surprised it has not been taken care of even now,’’ he said.

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Postby Raj Malhotra » 17 Apr 2006 23:21

I think their were foreign consultants hired in mid-eighties for the radar and 3 antennas were also imported. Not getting together the radar after 20 years or so is really dis-appointing to say the least

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Postby JCage » 17 Apr 2006 23:33

Its hardly stunning..its all in the context. Please look up Atres interview about the LCA- he states that only two "issues" remained with the LCA- the MMR and the Kaveri, so when he handed over to Natrajan, the radar had still not been productionized or readied- a "loose end" as it were. HAL incidentally had explored tieing up with Israel for license manufacturing the Elta 2032 as the IAF was already very cut up over the delay.

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Postby JCage » 17 Apr 2006 23:40

This is the interview:
http://tinyurl.com/s93l5

INTERVIEW

Maybe a couple of years later, LCA will breed another LCA

An interview by INDIA TODAY Principal Correspondent Stephen David.

After India's first test of its indigenously built Light Combat Aircraft, one of the happiest persons was Vasudev K. Aatre, scientific adviser to the defence minister........
.............................

What is the next plan?
A. This is just the beginning. We have to productionise, get Kaveri [engines] through, get MMR through, the next three or four years. This is going to occupy us. We are looking at induction. We may look at building transport aircraft. Maybe a couple of years later, LCA will breed another LCA. I wanted the LCA to fly within a year of my appointment (December 29, 1999) but I am happy it happened within a year and five days.

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Postby JCage » 17 Apr 2006 23:44

As to which two modes are working:
http://tinyurl.com/qynd3

The MMR jointly developed by the electronics and radar development establishment (LRDE), hal, aeronautical development agency (ADA) and the centre for airborne studies (cabs) had already been successfully tested on hack aircraft in air to air look up and down modes.

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Postby Dileep » 18 Apr 2006 00:08

JCage wrote:Boss, its a coordination issue. It would have been better if the MMR had been left to an agency specializing in radars, but then HAL was chosen because they assembled/ license manufactured the Bis's radar, which was the only airborne FCR ever made in India till that point. This was mentioned by SR Valluri in his reminisces about the LCA program.


Exactly! Why something was not done all these years is my question.

JCage wrote:I wouldnt say there is more than enough technology to build any radar indigenously- that would be a tad overstating it though, that is if we want to build a modern long range TWT based unit (say our THD equivalent)- luckily though, the AESA units will solve that "missing link" in the product lineup by supplanting that technology. The MMR is the "final frontier" in terms of a basic product lineup spanning the entire spectrum. We have the SV-2000 for light aircraft & choppers, the in development AESA system by CABS which draws upon the Hs748 (ill fated), whats plainly missing is an airborne FCR. And of course the technologies for the same- we havent yet demonstrated the scale of hardware necessary to scale up the system. The MMR is a capable (for its size) design if it performs per specs, but the trend nowadays is for much more higher power (and expensive units).


Yes, probably on the TWT. I am not exposed to domestic capability on TWTs. But I don't think it is not reachable either.

For the MMR as it is, we have no dearth of technology. The RF side already exists, and works. Otherwise we wouldn't have A2A. Even if it is a little bit inefficient and underperforming.

Look, statements like "interface problem" touches a raw nerve in me, and I can feel my chair kicking my @$$. I have seen enough of that, and it annoys me a lot.

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Postby bala » 18 Apr 2006 00:11

JCage, thanks for those links. But I have an issue with choice of words here. Perhaps it is a PR thing but using a phrase like 'Loose End' has connotations that imply not important, an afterthought, can be easily surmounted. Had they used a phrase like hurdle then things would be construed much differently. But the ex-Chief in 2000, one yr after his appointment in end of 1999, knows the hurdles for the LCA. It has been 5yrs since and we are still at major issues. Something is not right here. I hope this MMR thing is resolved quickly if basic limited functionality has already been demonstrated.

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Postby Arun_S » 18 Apr 2006 02:34

pratik_das wrote:
Dileep wrote:I have a question on PESA.

I understand from literature that the phase shifting is at discrete intervals, and the typical resolution is 4 bits => 16 levels.

My question is, will not this discreteness impart a similar discreteness in the beam placement? How can you make a smooth beam transition with discretely switching phases?

You can't have a smoothly transitioning beam with digital delay periods, be it in AESA or PESA systems. You need a totally analog phase shifter to do that. But the point to remember is that you don't need that fine a resolution if your beamwidth is wide anyway. Beam orientation precision can be improved with a greater resolution in the delay period (i.e. more bits). But beam width is limited by the number of Tx/Rx elements. So it doesn't matter if you can only move your beam by 6 degrees at a time if your beam is 30 degrees wide anyway.

Ahhhhh.... let me answer from my eons old memory moonlighting at CARE/IIT-D when I did the test jig controller for ferrite phase shifter under development. The unit to unit variations of the phase shifter (inherent varience and also due to drive voltage sag when the coil was pulsed, in spite of my VCO based pulsewidth compensation) was many degrees (now when I see 4 bit in above reference, I think those shifters were much better than 4 bit).

So I asked the same question to Brahaspati (God of knowledge: Jupiter), and he said when used in large units the varience is cancelled and the resultant beam accuracy is a function of average. One of few places in engineering where "Average" lords over "Standard Deviation" :wink:

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Postby karan » 18 Apr 2006 06:23

maitya wrote:
karan wrote:JCage
And before we have another wail about SP's- we have designed & productionized SP's for the Rajendra, the Indra 1&2, CAR, LW series, BFSR...as well as made one (and tested it successfully) for the Hs 748 based AEW unit before the program was scrapped..

Am I reading you right, we have produced something that works and then we scrap the program? I don't know what to say to that. I am so stunned, I have never seen anything like this in my entire life, where a project leader, nation or some agency will scrap a project or part of project that has worked, and was successful. If you are right then it is time to fire project leader. It is so obvious that project leader is incompetent and a complete loser.

JC, lemme give it a shot!!
karan, where are you from - Mars or somewhere else? :x
You seem to know a lot about Indian defence R&D (also quite a lot about DARPA etc.) but are ignorant of the simple fact that the Indian AEW effort was scrapped after almost the entire team perished in the HS-748 prototype crash in late 90's. :cry:
What JCage is trying to say is that the SP for that AEW program was designed successfully and was being tested while this crash happened and the entire AEW program was scrapped!! No doubt this experience would have been percolatd to other Radar effort mentioned above.

Enough of a hint, and now try to do some searching and satisfy yourself ...

Nice Dude...So you are a project manager, you place your entire team on testbed. Bravo! What can I say? Like the old adage among fighter pilots there is no second chance in Air. Even if the whole team was lost what happened to all the schematics, drawings, documentation? Another fine example of project management? GOI could not find another team, half way decent scientists and engineers, who could continue their work. What a nice tribute from a nation of One Billion Souls. There was not a single man of vision in enitre Indian Defense Establishment who would rise up to the occassion and pick up from where those pioneers left. Guess we all know the answer to that. Congratulations to Israelis for the Phalcon deal.

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Postby Dileep » 18 Apr 2006 06:39

Arun_S wrote:Ahhhhh.... let me answer from my eons old memory moonlighting at CARE/IIT-D when I did the test jig controller for ferrite phase shifter under development. The unit to unit variations of the phase shifter (inherent varience and also due to drive voltage sag when the coil was pulsed, in spite of my VCO based pulsewidth compensation) was many degrees (now when I see 4 bit in above reference, I think those shifters were much better than 4 bit).

So I asked the same question to Brahaspati (God of knowledge: Jupiter), and he said when used in large units the varience is cancelled and the resultant beam accuracy is a function of average. One of few places in engineering where "Average" lords over "Standard Deviation" :wink:

Arun, A lot happened after that question. The LRDE L-Band AESA system has a 6 bit phase shifter giving a +/- 60Deg scan > around 2 Degrees resolution. That makes a lot of sense. And yes, stuff averages a lot when you add wavelets.

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Postby JCage » 18 Apr 2006 07:26

bala wrote:JCage, thanks for those links. But I have an issue with choice of words here. Perhaps it is a PR thing but using a phrase like 'Loose End' has connotations that imply not important, an afterthought, can be easily surmounted. Had they used a phrase like hurdle then things would be construed much differently. But the ex-Chief in 2000, one yr after his appointment in end of 1999, knows the hurdles for the LCA. It has been 5yrs since and we are still at major issues. Something is not right here. I hope this MMR thing is resolved quickly if basic limited functionality has already been demonstrated.


Bala not to digress but have you seen Aatre talking? Hes a soft spoken gent and this is the way he speaks. Its all in the context- "loose end" rings true because they came up with a plan and everything, but this was something they couldnt pin down. Hurdle may have been a better choice of words, but we should try (imho) to get at what they meant as compared to what they're said to have said. JMHO.

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Postby JCage » 18 Apr 2006 07:38

Dileep wrote:
JCage wrote:Boss, its a coordination issue. It would have been better if the MMR had been left to an agency specializing in radars, but then HAL was chosen because they assembled/ license manufactured the Bis's radar, which was the only airborne FCR ever made in India till that point. This was mentioned by SR Valluri in his reminisces about the LCA program.


Exactly! Why something was not done all these years is my question.

My WAG (partly based on reading tons of reports) is that they thought that HAL etc would lick the problem. They have managed to pull up all the other hardware, from producing the TWT to getting BARC to develop the servos for the antenna, plus coming up with a standardized design suite to develop any slotted array antenna. Then all the other breakthroughs in RC, DSP etc- all this allowed them to field the SV-2000 quick.
I dont think software is a problem either for a bunch of reasons and reports.
But, this is one hurdle they fell at and they simply dont have more time to tinker with it. Its pretty much sure that no private firm can solve it asap as well- they have been marching lockstep in MMR development from a long time, especially on the COTS hardware. This was probably decided by the IAF-ADA review meeting, so it seems that they are more willing to get the MMR out of the door than just import & supplement it with an AESA (which is what I was thinking would happen).


Look, statements like "interface problem" touches a raw nerve in me, and I can feel my chair kicking my @$$. I have seen enough of that, and it annoys me a lot.

Thats what the reporter wrote. So we had to discuss it.
Last edited by JCage on 18 Apr 2006 07:42, edited 1 time in total.

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Postby JCage » 18 Apr 2006 07:41

karan wrote:
maitya wrote:
karan wrote:JCage
And before we have another wail about SP's- we have designed & productionized SP's for the Rajendra, the Indra 1&2, CAR, LW series, BFSR...as well as made one (and tested it successfully) for the Hs 748 based AEW unit before the program was scrapped..

Am I reading you right, we have produced something that works and then we scrap the program? I don't know what to say to that. I am so stunned, I have never seen anything like this in my entire life, where a project leader, nation or some agency will scrap a project or part of project that has worked, and was successful. If you are right then it is time to fire project leader. It is so obvious that project leader is incompetent and a complete loser.

JC, lemme give it a shot!!
karan, where are you from - Mars or somewhere else? :x
You seem to know a lot about Indian defence R&D (also quite a lot about DARPA etc.) but are ignorant of the simple fact that the Indian AEW effort was scrapped after almost the entire team perished in the HS-748 prototype crash in late 90's. :cry:
What JCage is trying to say is that the SP for that AEW program was designed successfully and was being tested while this crash happened and the entire AEW program was scrapped!! No doubt this experience would have been percolatd to other Radar effort mentioned above.

Enough of a hint, and now try to do some searching and satisfy yourself ...

Nice Dude...So you are a project manager, you place your entire team on testbed. Bravo! What can I say? Like the old adage among fighter pilots there is no second chance in Air. Even if the whole team was lost what happened to all the schematics, drawings, documentation? Another fine example of project management? GOI could not find another team, half way decent scientists and engineers, who could continue their work. What a nice tribute from a nation of One Billion Souls. There was not a single man of vision in enitre Indian Defense Establishment who would rise up to the occassion and pick up from where those pioneers left. Guess we all know the answer to that. Congratulations to Israelis for the Phalcon deal.


Dude
1. The project would be delayed- the IAF didnt want that
2. The Phalcon is AESA as compared to the ASP's conventional array
3. The CABS AWACS project will draw upon the earlier one, 3 are to be delivered
4. Project manager- entire test team on testbed...when you fund projects with peanuts...you take risks..as simple as that. We are not the US.

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Postby NRao » 18 Apr 2006 08:27

...... Even if the whole team was lost what happened to all the schematics, drawings, documentation? ......


They have since rebooted. Just took some time.

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Postby kantak » 18 Apr 2006 08:32

we have just ordered 3 Phalcons ,even the aussies ,saudis,french have a minimum of 4 so as to have 24hour coverage over a area.

The CABS awacs will surelly be welcome as gap fillers :lol:

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Postby Arun_S » 18 Apr 2006 08:33

Dileep wrote:Russians are touting a design feature of unequal distances between array elements. The elements at the edges are closer together than the elements in the middle. There should be some advantages to that, because otherwise they wouldn't have taken the pains to design it. I don't have the faculty to figure out how/why that it better. I would imagine it might give wider beam angle. That is a wild guess.

Sharp beam formation/descrimination. Aka resolution of the optical telescope is determined by the outer edge of the mirror (it not about just power/area its about phase sensitivity). So its about FCS for longer range.

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Postby Dileep » 18 Apr 2006 09:36

Arun_S wrote:
Dileep wrote:Russians are touting a design feature of unequal distances between array elements. The elements at the edges are closer together than the elements in the middle. There should be some advantages to that, because otherwise they wouldn't have taken the pains to design it. I don't have the faculty to figure out how/why that it better. I would imagine it might give wider beam angle. That is a wild guess.

Sharp beam formation/descrimination. Aka resolution of the optical telescope is determined by the outer edge of the mirror (it not about just power/area its about phase sensitivity). So its about FCS for longer range.

Yup, sketching a parabola and drawing a ray diagram made that clear to me later 8) . It suites the russian habit of using rigorous mathematical design to solve problems, instead of more processing.

You should read these techie threads more often boss :wink:

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Postby Dileep » 18 Apr 2006 09:43

The "interface problem" may be DDM, but the fact remains that they are stuck on the A2G modes. That is not good. Other thing that bugs me is that why can't they fly it with just A2A mode? Do they have integration problems? Like heating, power hogging, noise sensitivity etc that prevents it from being integrated to the LCA airframe? Is that they mean by "interface"? They did have similar problems (eons ago) with other avionics units.

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Postby srai » 18 Apr 2006 10:09

It's time that ADA also simultaneously integrated other off-the-shelf radar just like with F-404 engine. For the first few batches, let LCA be produced with foreign radar. At least this way MMR can get some time to rectify its issues possibly with some foreign assistance without further risk of delaying/derailing the whole project.

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Postby JCage » 18 Apr 2006 10:13

Of course, not having A2G is not ideal. Dont see anyone here who said the opposite!

As to why they cant just do A2A and going with it alone, the IAF would rather they had a tested radar in without having to rework the trials and validation, or having to replace it with a different unit because A2G still doesnt work. The thing here is that they racing against time, the problem has been worked on for a couple of years & its best they solve it asap. And we are no longer broke so we can pay for what we want or at least as much as possible.

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Postby Arun_S » 18 Apr 2006 11:05

Dileep wrote:You should read these techie threads more often boss :wink:
With a Guru like you on this thread, I am assured it will be nurtured well; even if I am short on time and can't participate much, although there is so much more to learn on this techie thread.

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Postby maitya » 18 Apr 2006 11:31

JCage wrote:
karan wrote:
maitya wrote:
karan wrote:JCage
And before we have another wail about SP's- we have designed & productionized SP's for the Rajendra, the Indra 1&2, CAR, LW series, BFSR...as well as made one (and tested it successfully) for the Hs 748 based AEW unit before the program was scrapped..

Am I reading you right, we have produced something that works and then we scrap the program? I don't know what to say to that. I am so stunned, I have never seen anything like this in my entire life, where a project leader, nation or some agency will scrap a project or part of project that has worked, and was successful. If you are right then it is time to fire project leader. It is so obvious that project leader is incompetent and a complete loser.

JC, lemme give it a shot!!
karan, where are you from - Mars or somewhere else? :x
You seem to know a lot about Indian defence R&D (also quite a lot about DARPA etc.) but are ignorant of the simple fact that the Indian AEW effort was scrapped after almost the entire team perished in the HS-748 prototype crash in late 90's. :cry:
What JCage is trying to say is that the SP for that AEW program was designed successfully and was being tested while this crash happened and the entire AEW program was scrapped!! No doubt this experience would have been percolatd to other Radar effort mentioned above.

Enough of a hint, and now try to do some searching and satisfy yourself ...

Nice Dude...So you are a project manager, you place your entire team on testbed. Bravo! What can I say? Like the old adage among fighter pilots there is no second chance in Air. Even if the whole team was lost what happened to all the schematics, drawings, documentation? Another fine example of project management? GOI could not find another team, half way decent scientists and engineers, who could continue their work. What a nice tribute from a nation of One Billion Souls. There was not a single man of vision in enitre Indian Defense Establishment who would rise up to the occassion and pick up from where those pioneers left. Guess we all know the answer to that. Congratulations to Israelis for the Phalcon deal.


Dude
1. The project would be delayed- the IAF didnt want that
2. The Phalcon is AESA as compared to the ASP's conventional array
3. The CABS AWACS project will draw upon the earlier one, 3 are to be delivered
4. Project manager- entire test team on testbed...when you fund projects with peanuts...you take risks..as simple as that. We are not the US.

JC, I admire ur enthusiasm to even engage these ilk of IIPs (Ill Informed Pub@$)!! I'd strongly suggest you do a search on the recent posts of these individuals before even bothering ... :P
Betw the above mentioned gent has this to say (in the Kaveri thread) - "I say, shelve the whole kaveri program, give rest of the money to mafia to steal engineering drawings, metallurgical composition, blue prints for us. I am sure they can do a better job so we are not ...". And all that talk of Proj Mgmt, Competency Mgmt, Risk Mgmt, Schedule Mgmt yada yada yada ... :x
Sometimes one feels we're so lucky to have such enlightened souls out of our SDRE land toiling for the betterment of universal humankind!! :roll:

No ... being a know-all, these folks are very averse to do any basic search before posting. I even tried telling him that - Silly me, :oops: how can a know-all not know such simple facts viz.
1) 4 of Key Scientists were lost - along with the AISTE team.
2) 90% work was already done (~225hrs of flying testing was validated)
3) The crash took back the effort by minm 3 years
4) The crash happened in 1998 - the decision (and NOT the deal) to buy the Phalcon was taken in 2000.

And, lastly, where's the good doctor (with his HTML scalpel) when one needs most ... :twisted:

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Postby maitya » 18 Apr 2006 12:29

Dileep wrote:
Dileep didn't understand this issue of blame game ...
The "cumulative" S/N ratio for the RF side (the chief contrbutors, IIRC, are the Tranmitter, Duplxer and LNA etc.) should be pretty well known by now - after all they've got the A/A mode working, right?
Now if the SAR mode "cumulative" S/N ratio is unacceptably low then isn't it pretty straight forward to conclude that the PSP is contribution too much of a noise ... thus requiring a new design.
JMT, of course ...

It is not that simple.
The DSP part, right from the baseband input connector, can be parametrically verified in the lab. Also, the technologies involved in those blocks are mature and widely available. So, that will not be a problem. Even the base noise figure can be established in the lab unambiguously.

The parameter of interest is the "available S/N ratio", which you can not test in the lab. You got to take it up and get the actual signal return to test it. The A2A is pretty simple that way. There is not much background clutter. You fly a single target, and you can easily find the blip on the SAR raster. You can even work on the resolution part without much trouble.

Now, coming to A2G mode, you get all kinds of returns, and you have to get the grain from the chaff, so to speak. That is when problem happen. It is very difficult to determine which stage contributes to the problem. It could be the beam definition. It could be the receiver. IT could be the scan synchronization. IT could be the DSP algorithms. Since it will not be obvious from the data, each of the groups will assign blame to another one. That is the blame game I talked about. It happens everywhere.

Back to the issues ...
And I thought the first thing one does while processing the A/G mode returns is to first "tune"/"filter" out those that're nearer to the known aggregate noise level of the "devices" involved - becomes something like the "base-sensitivity" figure. Only then, one would start looking at the other returns to filter out the probable clutter noises ...
JMT again ... :P

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Postby maitya » 18 Apr 2006 14:18

Dileep wrote:... Yes, probably on the TWT. I am not exposed to domestic capability on TWTs. But I don't think it is not reachable either...

Dileep, check this page MTRDC - Achievement
Specially look for the "6.5 kW pulsed X-band Coupled-Cavity TWT for airborne radar" - looks to be the one for MMR.

JC - you mean indigenous capability of producing TWTs in the 2MW average (and 20MW peak) range in the E/F band :shock: :cry:

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Postby JCage » 18 Apr 2006 16:47

Maitya, yup hence AESA GBAD radars should address that issue. CSIR also does TWTs (for ISRO) & now theres AMPL in Hyderabad. Then there is BEL.
But you know how it was- only TWT's for existing radars were to be designed etc and projects launched. Basically, whats required are (as you noted) high average power TWTs, ie duty cycle* Peak power, just the peak power alone is misleading. (all other things being equal). I'd sure appreciate another bunch of AMPLs or the usual suspects getting into all such niche but necessary areas.

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Postby Dileep » 18 Apr 2006 19:29

maitya wrote:Back to the issues ...
And I thought the first thing one does while processing the A/G mode returns is to first "tune"/"filter" out those that're nearer to the known aggregate noise level of the "devices" involved - becomes something like the "base-sensitivity" figure. Only then, one would start looking at the other returns to filter out the probable clutter noises ...
JMT again ... :P

The device noise is not the problem really. You already know how big it is from the lab and A2A tests So it is already eliminated. See, the device noise is the same whether the mode is A2A or A2G (well, not exactly, but the variance is predictable). Now you end up with data that is really from the returns.

The problem happens when you try to make a SAR raster from this data. If you have a spot pencil beam, like a laser, all you got to do is to plot all those amplitudes on an x/y screen and you got the SAR raster. But you don't have a spot beam. The beam is rather wide. So, there is a lot of algos involved. You will have to consider the scan elements in the neighbourhood also to compensate for beam width. And also, you have to calculate phase and doppler shift as well, in relation to the neighbouring elements.

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Postby Dileep » 19 Apr 2006 22:35

Saw a funny thing. Look at the Vixen 500 brochure.
http://www.selex-sas.com/datasheets/Vixen500E.pdf

They try to pass an aerial photo as the SAR imagery. Look at the shadows.
Where is the salt shaker :twisted:

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Postby maitya » 20 Apr 2006 16:03

Dileep, JC - look what I've found - excellent data-point for the GaAs based PA ... Mimix Broadband - XP1006

Now let's do some calc, :P
Since, PAE = (RFout - RFin)/Input DC Power
Thus for a 10W o/p PA with 30% PAE, the input power requirement is ~34W. So for a 1500 element array, the input power requirement is 51KW!! :shock:

Even if we ask for about 3.75Kw o/p power (from 1500/4 = 375 elements, approx), the input power reqt is around 13kW :shock: ... what gives!! :?:

[Added Later]
The EL/M-2052 operates on 10KVAmp ... pretty close to the figures quoted above!!
Now I feel better ... :twisted:

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Postby Arun_S » 20 Apr 2006 20:03

Dileep wrote:Saw a funny thing. Look at the Vixen 500 brochure.
http://www.selex-sas.com/datasheets/Vixen500E.pdf

They try to pass an aerial photo as the SAR imagery. Look at the shadows.
Where is the salt shaker :twisted:

I also noted that on first look when you posted the ref, that radar does not capture shadows, a sure sign f vapourware or incompetent marketing manager. Very funny. :lol:

Wanted to post it earlier but the forum s/w was playing tricks in accepting posts.

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Postby Arun_S » 20 Apr 2006 20:38

maitya: I am sure you realize that Radar peak power requirement is different from average power requirement, mostly determined by duty cycle. Ultracap or other storage devices easily take care of few microseconds of Tx power (as most AESA use long tx period and use pulse compression signal processing)

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Postby Dileep » 20 Apr 2006 21:52

The TWTs typically do 60% PAE. The Solid states do 30%. That is half. But you got to consider a loss of 3-6dB with the phase shifters for PESA. 6dB is 4 times power. In all, I think AESA will have a reasonable edge over PESA in terms of power conversion efficiency. The problem as we already know, is removal of the heat from the modules, instead of the TWT.

and what about cooling the phase shifters themselves. The loss in them goes out as heat.

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Postby SaiK » 20 Apr 2006 22:28

Dileep wrote:Saw a funny thing. Look at the Vixen 500 brochure.
http://www.selex-sas.com/datasheets/Vixen500E.pdf

They try to pass an aerial photo as the SAR imagery. Look at the shadows.
Where is the salt shaker :twisted:


is it not a cheating?

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Postby maitya » 21 Apr 2006 10:47

Dileep wrote:The TWTs typically do 60% PAE. The Solid states do 30%. That is half.

:lol: He he ... the GaN ones claim to do about 60% :lol:
Sorry Dileep, couldn't resist that!!

But you got to consider a loss of 3-6dB with the phase shifters for PESA. 6dB is 4 times power. In all, I think AESA will have a reasonable edge over PESA in terms of power conversion efficiency.

Yep ... agree!! However, this paper in IEEE claims the loss can be less than 3dB loss by using FEM (Ferroelectric materials) based phase-shifters. I quote:
"A phase shift of 165° was obtained at 2.4 GHz, with an insertion loss below 3 dB by using a bias voltage of 250 V"
and
"how the use of thin ceramics reduces the required bias voltage below 250 V, with almost no power consumption required to induce a change in the dielectric constant"

and what about cooling the phase shifters themselves. The loss in them goes out as heat.

I think, heat generated by the phase-shifters are adequate enough to be handeled by air-cooling!!


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