Russian Wide-Angle Radar for Su-35

Shotgun SG

Okay, this one from alert5 really caught my attention.

http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3ab967dc21-1763-4f29-802d-a091b5e6495f

I hope this link works.

This AESA radar is mechanically enhance to allow it to scan up to 120 degrees off the nose. Of course, its not a 240 degree scan in all, but it turns its AESA array away from the nose to its side to scan along the aircraft's beam.

The reason why I found this to be really interesting is this.

In a BVR scenario, one of the approach to it is what is called F-Pole.

Scenario is this:

NO AWACs or other Datalink support.

2 opposing fighters detect and lock up each other at BVR. Assuming both shoot Active Radar Homing missiles like the R-77 and the AIM-120 at each other.

Both missiles require mid course update, which means, the radar has to stay locked on until the missile goes autonomous to improve Kill probability (pK).

In the F-Pole scenario, an aircraft attempts to put the offending radar signal as far to the its beam (90degrees port or starboard) as possible to minimise radar return as well as forcing the missile to make continuous course adjustment in hope of depleting its energy.

However, most conventional radars can only scan up to 60 degrees off the nose, which means the offending radar signal can only be placed at maximum of 60degrees off boresight. More than 60 degrees, and it will exceed the gimbal limit of the radar and your lock on the enemy fighter will be broken, resulting in an weapon with lower pK.

Also, at 60degrees off the nose, the fighter is still closing TOWARDS the offending aircraft and its missile, and not away (which is more ideal to defeat missiles.)

But with a 120 degree off boresight scan... it changes things a lot. The flanker now, F-Pole at 120 degrees to either side, at the F-16 (representing other aircraft with conventional radar), shoot its' missile, maintain its lock for midcourse updates, AND BEAM the missile or the F-16's radar, AND fly away from the F-16 at the same time.

This puts most of the Western combat aircraft, even those equipped with AESA at a considerable disadvantage when operating outside AWACs coverage, or without datalink-ed AIM-120Ds.

duotiga83 SG

more on the fighter itself

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Sukhoi unveils 'supercruising' Su-35-1 multi-role fighter

DATE:04/09/07
SOURCE:Flight International

Sukhoi unveils 'supercruising' Su-35-1 multi-role fighter
By Vladimir Karnozov

Cleaner layout and improved propulsion system thought to offer supercruise performance

Sukhoi expects to conduct the first flight of its all-new Su-35-1 single-seat multirole fighter within the near future, having unveiled the KnAAPO-built design at August's Moscow air show.

Launched in 2003, the Su-35-1 lacks the integral triplane configuration employed by India's Su-30MKIs, and its cleaner layout and improved propulsion system are believed to offer supercruise performance.

The new fighter has a lighter airframe than the legacy Su-27, due to its extensive use of aluminium, titanium and composite structures.

It also has a fully digital flight-control system incorporating engine and thrust vectoring control.

The Su-35-1 can carry over 2t more fuel than the Su-27 and has a ferry range of 4.500km (2,430nm) with external fuel tanks. Airframe life is quoted as 6,000 flight hours or 30 years, and Sukhoi general director Mikhail Pogosyan says the aircraft will be available for export delivery from 2010.

The Russian air force is expected to order several of the aircraft, which will also be promoted to nations such as China.

The aircraft was displayed with new weapons including NPO Machinostoyenia Yakhont and BrahMos PJ-11 supersonic missiles. The type is also believed to be equipped with a new air-to-air missile with a range of up to 200km.

The Su-35-1 is powered by two NPO Saturn Item 117S engines, developed from the Su-27's AL-31F under a joint project with Ufa MPO.

The new design uses a fully digital control system, swivel nozzle, enlarged fan and engine inlet for higher airflow, a redesigned turbine with improved cooling and has a design life of 4,000 flight hours.

The aircraft is also equipped with a Tikhomirov NIIP Irbis radar with an electronically scanned passive array antenna. A further development of the Su-30MKI's N-011M Bars sensor, with a more powerful transmitter and higher-speed processing, the design has a claimed detection range of more than 300km against airborne threats.

coolant SG

1st, modern BVR is becoming farther & farther, in a range easily pass 30kms, two head on fighter jets can roughly be treated as 2 dots at each end of a straight line, beaming away of one fighter at such a distance in an allowable speed is unlikely to fly off the opponents radar cone view, even the others cone view is in narrower angel than yours. For example, a fighter beaming away at mach 1, after 10 seconds, its 3kms in tangent distance away from original position, however, 3kms vs 30kms, the angular change is so small.

BTW, modern RWR works in full aspect, so it always will give you a warning provided the buster is illuminating you, IMO, a wider angel radar will benefit the most in A2G role, which allows you to scan and lock on the vast surface target quick. There is one saying that PLANAF picked up A2G orientated Su30MK2 utilizing traditional mechanical scanned radar of N001VEP over air superiority Su30MKIs BARS PESA is because of the wide angel issue and weight, BARS is terribly over-weighted. To some extent, in WVR or near WVR, the benefit of the wider angel radar will become more significant as distance is much shorter. Off course, a wider angel radar will give you better situational awareness.

The Irbis-E radar of Su35 is still not an AESA as it still uses TWT for power transmission

datafuser SG

The Brits also thought about fitting an AESA antenna on a gimbal. The picture above shows "fire and escape" tactics, which is possible only with such a radar.

Cheers,
Sunho

coolant SG

The range shown in the above diagram is not far, but Shotgun was talking about BVR, even extreme long range AIM-120D was mentioned. Very Happy

Anyway, from the diagram, in a angular fast changing cum relatively short distance air fighting, we can see, a wider angel radar does benefit the pilot a lot.
Cool

Shotgun SG

Okay, in layman's term what i said means,

The F-Pole game is simply, "who can pull further (in terms of angle), while maintaining radar lock for accurate weapon's delivery."

An aircraft with Wide angle radar like the one described, has the advantage in gimbal limits, and thus can "fire and escape/set up escape" more effectively.

The more perpendicular u are to the radar or missile, the more energy you deplete from it, the better your chances of survival.

Coolant, I think you may need to explain further on the A2G environment.

For most guided bomb/ or missile delivery, attacks are prosecuted with the target as close to the nose as possible.

Due to:

1. Free fall weapons, (guided included) are affected by the aircraft's flight path. In fact, for preferred loft deliveries, a steady motion towards the target results in least amount of course correction for the GBU.

2. TV/IR guided weapons such as the Mavericks themselves have Gimbal limits. Slaving such a weapon to a high off-boresight radar doesn't help much since the weapon's view is narrower than the radar's

Exception is when the attack is prosecuted at higher altitudes and greater distance. However, it might be faster to turn the aircraft to gain targeting information in the first place.

Please feel free to correct. =D

coolant SG

Wider angle means wider scan and translates into wider sector coverage. Taking into account a Su30Mk2 mainly designated for long haul anti-ship mission, from the strike instruction receiving from CC to take-off preparation till fly all the way reach the initial scene, the targeted vessels position has already changed substantially, in which case, the striking fighters have to locate the targets on spot by their own radar, a wider angel radar for the obvious reason, covers more area in one sweep and detect faster, which means your fighter needs less maneuver to do search and subsequently track and attack faster.

tankee1981 SG

Anyway our RSAF fighters such as the F-15SG and the F-16C/D can counter Su-35 with wide angle radars? BVR missiles? Very Happy

Shotgun SG

Icic, let me clarify that the sector coverage is still the same. Just that the coverage can be steered WAY off the nose. Otherwise, the coverage is still only 120 degrees towards which ever direction its pointing.

coolant SG

So steer the antenna to the high off bore sight while still keeping the course easier or change course to do sector search easier? Therere many doctrines involved in fleet formation and sector search. Wider angel coverage does give the obvious convenience Laughing