Tikhomirov NIIP N035 Irbis E
new Irbis-E (Snow Leopard) hybrid phased array, in development since 2004 and planned for the Su-35BM block upgrade, and as a block upgrade or new build radar for other Flanker variants, such as the Su-35-1. It will enter production before the end of this decade.
The Irbis-E is a direct evolution of the BARS design, but significantly more powerful. While the hybrid phased array antenna is retained, the noise figure is slightly worse at 3.5 dB, but the receiver has four rather than three discrete channels. The biggest change is in the EGSP-27 transmitter, where the single 7 kiloWatt peak power rated Chelnok TWT is replaced with a pair of 10 kiloWatt peak power rated Chelnok tubes, ganged to provide a total peak power rating of 20 kiloWatts. The radar is cited at an average power rating of 5 kiloWatts, with 2 kiloWatts CW rating for illumination. NIIP claim twice the bandwidth and improved frequency agility over the BARS, and better ECCM capability. The Irbis-E has new Solo-35.01 digital signal processor hardware and Solo-35.02 data processor, but retains receiver hardware, the master oscillator and exciter of the BARS. A prototype has been in flight test since late 2005.
The performance increase in the Irbis-E is commensurate with the increased transmitter rating, and NIIP claim a detection range for a closing 3 square metre coaltitude target of 190 - 215 NMI (350-400 km), and the ability to detect a closing 0.01 square metre target at ~50 NMI (90 km). In Track While Scan (TWS) mode the radar can handle 30 targets simultaneously, and provide guidance for two simultaneous shots using a semi-active missile like the R-27 series, or eight simultaneous shots using an active missile like the RVV-AE/R-77 or ramjet RVV-AE-PD/R-77M. The Irbis-E was clearly designed to support the ramjet RVV-AE-PD/R-77M missile in BVR combat against reduced signature Western fighters like the Block II Super Hornet or Eurofighter Typhoon. Curiously, NIIP do not claim superiority over the F-22A's APG-77 AESA, yet their cited performance figures exceed the public (and no doubt heavily sanitised) range figures for the APG-77.
The existing N011M series lacks a Low Probability of Intercept capability, in part due to antenna bandwidth limits and in part due to processor limitations. This is likely to change over the coming decade, with the Irbis-E, as customers demand an ability to defeat or degrade Western ESM equipment and the technology to do this becomes more accessible.