N035 Irbis-E radar mode and performance

[Hammer1231]

The description of the Irbis-E radar’s head-on detection range of 350–400 km against a target with an RCS of 3 m² is likely derived from data obtained in its “stare” mode. There are two other stated figures: a detection range of 220 km against a 1 m² RCS target, and 90 km against a 0.01 m² target. Regarding the stare mode of the Irbis-E, the radar has multiple scanning states. Wide-area search typically uses a scan volume of ±120° in azimuth and ±60° in elevation, while HUD narrow‑field scanning uses 30° in azimuth and 20° in elevation. In summary, for a head‑on target with 3 m² RCS in a high‑altitude, clutter‑free area, a nominal detection range of around 270 km is reasonable, and for a 1 m² RCS target, around 220 km is reasonable. It should be noted that the nominal cumulative detection probability is unknown. According to typical Russian practice, the single‑scan probability is stated as 0.5, while other standards commonly use a cumulative probability of 0.85. Although it is customary to treat these as roughly similar, they are not exactly equivalent, and further confirmation is required.