Su-35’s Irbis-E FCR: A Glorified Soviet-era Phased Array Radar

An Irbis-E radar is mounted on Su-35 fighter jet. According to manufacturer documentation, Irbis-E's development is dated back in 1980s, however some of the components such as cooling gauge and processors are dated in 1970s.

German Ace Eric Hartmann said, ‘He who sees first has half the battle.’

Radar control system “Irbis” is a multifunctional X-band system based on a phased array with electronic beam control, located on a two-degree drive (azimuth and roll) and a promising computing system. The radar control system also includes state identification interrogator equipment operating in Mk-XA modes and a micronavigation unit.

Radar control system “Irbis” provides detection, tracking and measurement of coordinates of air, ground, surface targets day and night, in any weather conditions in the presence of natural and organized interference. Tactical and technical characteristics “air-to-air” mode with detection range of targets with 5m2 at 350 km distance.

19970’s analog temperature and coolant guages of Irbis-E radar.

Read More Tikhomirov NIIP BARS: A Glorified Soviet-era Phased Array Radar

Specifications by manufacturer

  • Viewing area: – in elevation: ± 60 degrees;
    • in azimuth: ± 120 degrees.
  • The number of detected and tracked targets – 30 pcs.
  • The number of simultaneously fired air targets – up to 8 pcs.
  • “Air-Surface” mode:
    • mapping with a resolution of 3 square meters;
    • mapping with a real beam in the DOL mode;
    • selection of ground moving targets;
    • tracking up to 4 ground targets;
    • tracking one ground target while maintaining an overview of the airspace.

The Irbis radar control system is used at all stages of combat use when interacting with the airborne equipment of the Su-35 aircraft. The assigned service life of the product must be at least 6000 hours during 30 years of service life.

Operational Results of Irbis Radar

Irbis-E’s 350 km detection range is in a tiny 10×10 degree search cone and the range shrinks to 200 km in volume search.

Read More Why Russia Can’t Make An AESA Radar?

According to HAL’s upgrade package proposal to IAF’s Su-30MKI, The Irbis-E’s flight test video where it allegedly detected a single target from 268 km but wasn’t able to get a track until 100 km – all the while having just a single target to track.

This shows just how misleading the 350 km range figure is in real world. In air-ground, Su-35’s radar can’t engage a Destroyer beyond 100 km and an aircraft carrier beyond 200 km. This is in an era when the F-16’s APG-83 radar having 160 nmi (300 km) range just for creating high-resolution SAR maps. The above picture are examples of disadvantages of having an phased array radar with no SAR capability.

Comparing with the western counterpart, the result matters regardless of using a phased array because Su-35’s Targeting range shows how unrealistic the 350 km figure is — on the contrary American F-35’s APG-81 radar detecting a ballistic missile warhead from 1,300 km based on cued-search from DAS.

Irbis Product Documents
Irbis Product documents
DAS track = Magenta circle. AN/APG-81 track = Yellow

The Irbis-E’s 350 km range isn’t just in a narrow-search cone – it’s from a cued-search by AWACS or any other radar already tracking the target. According to NIIP and UAC data, Su-35’s Irbis radar could track a Bomber only from 250 km, but it won’t be tracking a Fighter-sized target beyond 100 km.

Irbis Product Document

NIIP did claim Irbis-E having 1 squre meter SAR resolution in 2011. However, since then as Su-35 became operational NIIP has reduced that figure to 3 squre meters. NIIP don’t mention SAR resolution lately but this is their archived page from 2018. In fact, SU-30’s Bars radar have 10–30 meter SAR resolution.

The F-22’s older APG-77 radar could detect a 1 m^2 target from 240 km in volume search. The original AN/APG-77 was manufactured forty years ago. The current APG-77v1 could detect 1 m^2 target to over 403 km in narrow search. The F-15E, F-18E or almost every modern 4th gen. aircraft with a large AESA radar can engage Bombers from much longer range than 250 km. The upcoming AIM-260 JATM will have a range close to 250 km for ‘Fighter-sized’ target.

Target Tracking

The Su-35 is marketed as having superior performance in visual range – what’s often ignored is that Su-35’s R-73M/R-74 lacks an Imaging IR seeker – being restricted to 60° off-boresight compared to Western counterparts (AIM-9x, ASRAAM, Python-4) having >90° off-boresight angle along with much better IRCMs & clutter rejection.

Off-boresight missiles play a far bigger role than raw kinematic performance in today’s visual combat. It’s similar story for BVR missiles, AIM-120D and Meteor have over 90% greater envelope and significantly better ECCMs than R-77–1.

Hence the Su-35 fly with older IR and semi-active variants of R-27 because R-77 is in short-supply. Lack of competent armament puts Su-35 at a significant disadvantage because the fighter doesn’t have a capable radar.

Despite being marketed as 4++ gen, Su-35 has the least capable avionics suite among its competitors. Su-35 is the only major 4th gen. aircraft without an AESA radar or any form of Sensor Fusion like the Gripen E. The Irbis-E is marketed as having a 350 km range against 3 m^2 target while in reality that’s only in cued-search in a tiny FoV. What’s rarely stated is that in normal volume search that range shrinks down to 200 km. More importantly, Su-35’s radar has a maximum targeting range of 250 km – even for a B-52 like target.

The Irbis-E’s flight test video where it allegedly detected a single target from 268 km but wasn’t able to get a track the target until 100 km – all the while having just a single target to track.

This shows just how misleading the 350 km range figure is in real world. In air-ground, Su-35’s radar can’t engage a Destroyer beyond 100 km and an aircraft carrier beyond 200 km. This is in an era when you’ve F-16’s APG-83 radar having 160 nmi (300 km) range just for creating high-resolution SAR maps.

In addition to already poor performance, Irbis-E is vulnerable to jamming by modern EW suites owing to a smaller bandwidth, which you can tell from inferior SAR resolution. Combined with substantially short-ranged missiles put Su-35 at a significant disadvantage in BVR combat. Especially against an adversary with a capable AESA radar offering not only superior range but also being highly resistant to DRFM jamming from Su-35’s L-175V Khibiny.

The super heavyweight American defense contractors Raytheon, Northrop Grumman, and Lockheed Martin define the leading edge in radar technologies. Russia lacks microelectronics industries, resources, experience, manpower, talent, expertise, and technologies to build an AESA radar. The most important factor, Russia doesn’t have money to invest in latest technology.

Russia is the ONLY country offering fighter jets to export markets without an AESA radar.

The Su-35 and Flanker family in general a crowd pleasure in air shows with its cobra manoeuvre but look beneath the propaganda and they really don’t excel anywhere outside the air shows.

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