Eurofighter future exports hinge on advanced radar deal

Reuters ^ | Wed Jun 5, 2013 | Brenda Goh

[sukhoi-30mki]

Eurofighter future exports hinge on advanced radar deal

(Reuters) - The four nation-backed Eurofighter Typhoon jet will not receive any more export orders unless Britain, Germany, Italy and Spain formally agree to fund the development of an advanced radar, an executive at one of the jet's manufacturers said.

Potential customers for the multi-role Eurofighter, such as the United Arab Emirates (UAE), have demanded that the jets be equipped with so-called E-scan radars instead of the M-scan system the jet is fitted with, said Chris Bushell, the senior vice president of electronic warfare at Selex, the defence electronics unit of Italy's Finmeccanica (SIFI.MI).

The four nations agreed in principle to support the development of the new technology in 2011 but signing a formal contract has been delayed by upcoming German elections and the Eurofighter consortium is pressing for a deal to be signed in the first half of next year.

"To export Typhoon in the future around the world, if it's not equipped with an E-scan radar, I do not believe that there would be another sale made," said Bushell, whose company produces the jet alongside Britain's BAE Systems (BAES.L) and EADS (EAD.PA), which represents Germany and Spain.

"It is very well recognised by the partner nations, it is very well recognised by the four industries, and clearly particularly for the UAE, who are an exceptionally demanding customer."

Bushell added that the partners in the Eurofighter consortium needed to "convince" the UAE that the technology could be delivered "in the time scales they require".

The radar problem contributed to the Eurofighter consortium last year losing out on a $20 billion deal to sell 126 fighters to India, which instead chose France's Dassault (AVMD.PA) Rafale jet as preferred bidder.

[sukhoi-30mki]

[Telepathic Intruder]

What is it with delta wings and canards that Europeans find so compelling? Anyway, I don’t have a clue how E-scan radar compares to M-scan, other than what the E and M stand for.

[ThunderSleeps]

Are they talking about electronically scanned vs mechanically scanned?

[Telepathic Intruder]

Yes, I should have said that to save time.

[ThunderSleeps]

Ok, I understand now. Yes, it appears AESA or Active Electronically Scanned Arrays are the future of airborne military radars.

A "normal" radar steers the beam by physically moving an antenna and pointing it at the target it wants to find/illuminate/track/etc. An ASEA is a 2 dimensional array of hundreds, even thousands of small fixed antennas. By carefully timing when each antenna transmits (or receives) you can electronically steer the beam. For a one dimensional example, think of dropping two pebbles in a pond. The ripples will add together in some directions, cancel each other out in others. By dropping them at slightly offset times you can "steer" the added-together part of the ripple to the left and right. Now think of hundreds of little ripples adding and subtracting - you form a beam in 2 dimensions and it emits in the direction you want...

Typically ASEA systems offer weight and space savings over mechanically steered systems. They also have lower maintenance and higher reliability as there are no moving parts. The individual components are relatively low power - the system achieves high power due to the numbers of elements working together. ASEA offers increased capability as they can electronically steer beams all over very rapidly - there is no antenna to physically move (which takes time). So they can be scanning the ground, searching for threats, tracking other aircraft, guiding missiles, etc. all at once by allocating a little time and energy to each in a very rapid sequence.

I'm not surprised potential customers are looking for ASEA, and the aircraft manufacturers are pushing to develop and field the systems. Marketing a mechanical fighter radar or fighter with a mechanical radar is going to be a hard sell from now on...

[MHalblaub]

But there is one physical problem you can't solve with an fixed array: the visible surface of your receiver is getting smaller scanning objects out of centerline.

What you see above isn't an m-scan radar. The CAPTOR-E is a mechanically steered AESA radar (swashplate).

red: fixed array
green: movable EASA
(Description here: http://www.indiandefence.com/forums/u-s-europe/4731-eurofighter-typhoon-109.html)
Therefore this radar can even slightly look backwards.

One Eurofighter can look to the left while another look to the right.

This system is on test since 2006:
https://en.wikipedia.org/wiki/Euroradar_CAPTOR
http://www.eurofighter.com/capabilities/technology/euroradar/captor-e.html

Official program start was 2010.
http://www.eurofighter.aero/eurofighter/switzerland/de/medien/nachrichten/2010/AESA-Radar.html (German)

[Telepathic Intruder]

Still a bit beyond me, which probably can’t be helped, but fascinating anyway. Something to do with wave interference then. My archaic idea of radar is that it must scan one area at a time and then lock onto a particular signal to target it. The dreaded “radar lock”. But as long ago as about 15 years I heard this was to become obsolete, and multiple target locks would soon be possible. I wonder, is this what was to make that obsolete, or is this an additional advancement?

[ThunderSleeps]

You're right... When you electronically steer off the boresight of the array the apparent aperture size decreases. Thus you get a wider beam and "scan loss" - the delivered radar energy is spread out. There can be frequency and bandwidth issues off to the side too. Hey, this is physics, there is no free lunch! ;-) You want all those benefits of ASEA, there's gotta be a downside somewhere. Also that big flat array probably makes a wonderful radar reflector, making stealth from directly ahead problematic.

Now, for absolute performance... Where price, complexity, weight, etc. be darned... Yes, a hybrid combination of a movable ASEA array allows you to turn the boresight to, or closer to, a target of particular interest. Maybe allows you to turn it away from a threat you'd rather not reflect back at just yet... This reduces some of the downside of ASEA, while accepting some of the downside of mechanics...

[ThunderSleeps]

In operational terms (forgetting cost, maintenance, etc.) there are two main advantages to ASEA over mechanically steered antennas. (IMHO) One is that you can put radar energy on various targets, or search sectors, very rapidly - switch from one target to another, from one search sector to another in milliseconds or even microseconds. A mechanical antenna can do all the same tasks, just not as rapidly, it takes some finite amount of time to accelerate the antenna, move it, slow it down, and lock onto the angle you want it at.

The other advantage is graceful degradation. You lose the transmitter in a conventional radar, you're gadget-bent and done. If one, or even a dozen or so elements goes bad in your ASEA, maybe your beams aren't as well formed, a little off, more sidelobes, etc. but you're probably still in the fight.

It is really that first benefit - rapidly switching targets and keeping track of some number of them simultaneously that allows for multiple engagements. There's no real "lock" just "I've got enough confidence in the target's position and velocity that I can get a missile there and when it's seeker opens up, it'll find the target..." Though a lot of ASEA style radars do go into "high PRF" mode in order to get the information necessary to ensure a missile hit. That is, high PRF is pulse repetition frequency. It pings the target much more often to get a better estimate of position and velocity. Meanwhile the target is saying "Oh {expletive}, the PRF just jumped, he's not just tracking, he's after me!"