Is AESA matured enough to enter into operation?
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Wide Angle View
Posted by Bill Sweetman at 8/31/2007 11:13 AM CDT
Sometimes, you have to look at something for a long time and then hit yourself on the side of the head. Take this image from the MAKS Moscow air show, showing the NIIP Irbis-E radar of the new Su-35 fighter.
It's a radar on a gimbal, you might say. Nothing unusual about that.
But it's also an electronically scanned array (ESA). Which means that its electronic scan angle is added to its mechanical scan angle. The result is that while most fighter radars scan to 60 degrees off the nose, the Su-35 radar covers twice that volume.
One tactical application, among many: the Su-35 can launch a datalink-updated missile like an R-27 or R-77 and then turn sharply away, avoiding the adversary's return shot while its own missile continues to guide.
Also, one disadvantage of electronically scanned radars is that their effective aperture and performance declines at the edges of the scan volume. The Irbis maintains full performance out to its full mechanical sweep limits.
It's not the lightest way to build a radar, and a bit of a compromise. Note that Sukhoi does not advertise the full search volume as being available in a helmet-sight-pointed mode: a good guess is that, in that mode, the array will not move fast enough (the moving parts are much heavier than a typical mechanically scanned antenna) and it is locked forward, the radar relying entirely on electronic scanning. But in the long-range missile fight - or, for instance, for guiding an anti-ship weapon - it's a potentially crucial advantage.
Pics: "Flateric" from Secret Projects; Sukhoi
Posted by Bill Sweetman at 8/31/2007 11:13 AM CDT
Sometimes, you have to look at something for a long time and then hit yourself on the side of the head. Take this image from the MAKS Moscow air show, showing the NIIP Irbis-E radar of the new Su-35 fighter.
It's a radar on a gimbal, you might say. Nothing unusual about that.
But it's also an electronically scanned array (ESA). Which means that its electronic scan angle is added to its mechanical scan angle. The result is that while most fighter radars scan to 60 degrees off the nose, the Su-35 radar covers twice that volume.
One tactical application, among many: the Su-35 can launch a datalink-updated missile like an R-27 or R-77 and then turn sharply away, avoiding the adversary's return shot while its own missile continues to guide.
Also, one disadvantage of electronically scanned radars is that their effective aperture and performance declines at the edges of the scan volume. The Irbis maintains full performance out to its full mechanical sweep limits.
It's not the lightest way to build a radar, and a bit of a compromise. Note that Sukhoi does not advertise the full search volume as being available in a helmet-sight-pointed mode: a good guess is that, in that mode, the array will not move fast enough (the moving parts are much heavier than a typical mechanically scanned antenna) and it is locked forward, the radar relying entirely on electronic scanning. But in the long-range missile fight - or, for instance, for guiding an anti-ship weapon - it's a potentially crucial advantage.
Pics: "Flateric" from Secret Projects; Sukhoi
qsaark
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AESA And Typhoon
Posted by Bill Sweetman at 2/19/2009 10:24 AM CST
Everyone buying fighters wants an active electronically scanned array (AESA) these days, no doubt after reading Dave "Mr AESA" Fulghum on the subject.
But Eurofighter remains wary about the issue. The consortium's executives still stay that - for today - the mechanically scanned (M-Scan) Selex Captor beats any in-service AESA for the Typhoon's mission, even though Selex itself is ready to go with its Vixen range of AESA radars. A clue as to why they think that way emerged at the Aero-India seminar last week.
Discussing future technologies, Dr, Peter Gutsmiedl, senior vp engineering at EADS Military Air Systems, pointed out ways in which AESA could be integrated into Typhoon - one being the conventional fixed, canted antenna. They included an antenna with auxiliary side arrays, an azimuth gimbal and the so-called "swashplate" radar, a canted antenna on a rotating mount:
What's behind this thinking? A few years ago, Prof. John Roulston - former technical director at BAE Systems' radar division, now part of Selex - presented a paper in which he pointed out a limitation of AESA: at extreme scan angles the effective aperture decreases, and the performance of the radar (range, sensitivity and jamming resistance) declines as a result. So today's M-Scan has a larger field of regard than a fixed AESA, and better performance at the edge of the scan envelope.
This is important for Typhoon because the whole system - in the air-to-air regime - is influenced by air-combat simulations in which a fighter-to-fighter engagement could involve multiple MRAAM shots, followed by a supersonic turn to evade the adversary's fire and extend the F-pole - the distance between the launch aircraft and the target at impact. To do this, it's essential to have a radar that can continue to track the target and guide the missile as the shooter turns away.
The gimbal of a pointable AESA does not have to be anything like as fast as an M-Scan gimbal. The high-speed stuff, tracking a moving target, is still done electronically, with the gimbal moving relatively slowly to optimize the field of view.
Moreover, the electronic field of view is now added to the gimbal scan: the swashplate design shown here adds the 60-degree AESA limit to its 45-degree cant angle, to cover 105 degrees in all directions - a total 210-degree field around the nose.
By the way, the designers of the Su-35 think the same way, and the F-22 has space, weight and cooling provision for side arrays, but so far they have been deferred due to budget cuts.
Posted by Bill Sweetman at 2/19/2009 10:24 AM CST
Everyone buying fighters wants an active electronically scanned array (AESA) these days, no doubt after reading Dave "Mr AESA" Fulghum on the subject.
But Eurofighter remains wary about the issue. The consortium's executives still stay that - for today - the mechanically scanned (M-Scan) Selex Captor beats any in-service AESA for the Typhoon's mission, even though Selex itself is ready to go with its Vixen range of AESA radars. A clue as to why they think that way emerged at the Aero-India seminar last week.
Discussing future technologies, Dr, Peter Gutsmiedl, senior vp engineering at EADS Military Air Systems, pointed out ways in which AESA could be integrated into Typhoon - one being the conventional fixed, canted antenna. They included an antenna with auxiliary side arrays, an azimuth gimbal and the so-called "swashplate" radar, a canted antenna on a rotating mount:
What's behind this thinking? A few years ago, Prof. John Roulston - former technical director at BAE Systems' radar division, now part of Selex - presented a paper in which he pointed out a limitation of AESA: at extreme scan angles the effective aperture decreases, and the performance of the radar (range, sensitivity and jamming resistance) declines as a result. So today's M-Scan has a larger field of regard than a fixed AESA, and better performance at the edge of the scan envelope.
This is important for Typhoon because the whole system - in the air-to-air regime - is influenced by air-combat simulations in which a fighter-to-fighter engagement could involve multiple MRAAM shots, followed by a supersonic turn to evade the adversary's fire and extend the F-pole - the distance between the launch aircraft and the target at impact. To do this, it's essential to have a radar that can continue to track the target and guide the missile as the shooter turns away.
The gimbal of a pointable AESA does not have to be anything like as fast as an M-Scan gimbal. The high-speed stuff, tracking a moving target, is still done electronically, with the gimbal moving relatively slowly to optimize the field of view.
Moreover, the electronic field of view is now added to the gimbal scan: the swashplate design shown here adds the 60-degree AESA limit to its 45-degree cant angle, to cover 105 degrees in all directions - a total 210-degree field around the nose.
By the way, the designers of the Su-35 think the same way, and the F-22 has space, weight and cooling provision for side arrays, but so far they have been deferred due to budget cuts.
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