New horizons of the X-35U anti-ship missiles
Last week, a number of news and military-technical publications, as well as Telegram channels of the Runet, published on their pages video footage captured by the turret optical-electronic complex of the unobtrusive reconnaissance UAV ZALA 421-16E in the area of the village of Zeleny Gai in the Mykolaiv region. This video footage captures in high resolution an episode of the defeat of the 5N63S combat control point with the 30N6E X-band illumination radar, as well as at least two 5P85S/D launchers of the S-300PS medium-range anti-aircraft missile system of the AFU by means of four X-35U anti-ship missiles launched from the suspension units of two multifunctional Su-bomber fighter-bombers.34.
At first glance, the use of subsonic 3M24 X-35U anti-ship missiles against elements of the enemy's S-300PS air defense system may not seem a completely rational solution against the background of the presence of specialized upgraded 2.3-mach X-31PD anti-radar missiles with integrated 31DPK ramjet engines and solid-fuel 31DT-1 upper stages in the Su-34 ammunition sets. The range of these products is about 180-250 km when launched from medium and high altitudes and a high-altitude flight profile in the rarefied layers of the stratosphere in the altitude range of 15-17 km.
At the same time, the average vector speed of 700 m/s provides overcoming the 250-kilometer segment in about 357 seconds, while the subsonic X-35U RCC flying at speeds of 275 m/s overcomes a similar segment in 909 seconds, theoretically providing the calculation of the anti-aircraft missile division with a three times longer time window to tie the tracks, capture for accurate auto tracking and intercept the X-35U. Moreover, heavy high-speed anti-radar missiles X-58U/USK with a similar range and multi-band passive radar GOS for detecting and capturing electromagnetic radiation of the X-band of the 30N6E illumination and guidance radars can also be integrated into the Su-34 ammunition sets to perform air defense suppression tasks.
Nevertheless, despite the 3-fold lag in speed parameters from the X-31PD, as well as the initial narrow anti-ship purpose of the early modification of the X-35, the element base of the guidance system of its extreme modification of the X-35U underwent radical changes that turned this missile into a multifunctional long-range impact instrument adapted to defeat almost any types surface and ground stationary and mobile objects. In particular, the serial X-35U missiles are equipped with promising higher-energy and multi-mode active-passive radar homing heads "Gran-K", which (unlike the previous active ARGS-35) received:
— firstly, — an additional passive radio interferometric channel for detecting and "capturing" for accurate auto-tracking of radiation from surface and ground detection radars and radar illumination of air defense systems and electronic warfare systems,
— secondly, an improved active radar channel based on a waveguide—slit antenna array with a more powerful microwave generator and a more sensitive receiving path, as well as improved algorithms for processing primary radar information.
These updates of the active radar channel of the GSN "Gran-K" provide stable detection and capture of not only surface radio-contrast targets of the type "boat ship" at a distance of 10 to 50 km, but also ground-based radio-contrast targets of the type "PU 5P85S" or radar illumination 30N6E at a distance of about 7-10 km, "bridge" — 40-50 km. It is obvious that both passive and active radar channels could be used to detect the radiation of the RPN 30N6E of the Ukrainian S-300PS SAM. An active radar guidance channel could be used to defeat the PU. Thus, the X-35U can function both in the normal mode of an anti-ship missile, and in anti-radar and multi-purpose tactical modes.
More importantly, the X-35U are equipped with advanced digital inertial navigation units with radio altimeters and GLONASS correction modules, which provides the possibility of hitting stationary objects even in the case of enemy electronic countermeasures in the centimeter X-wave band. Radio altimeters also provide the X-35U missiles with an ultra-low-altitude flight profile at altitudes of 3-7 m above the water surface and 20-50 m above the earth's surface in the terrain envelope mode. As a result, during the strike on the Ukrainian S-300PS, which (judging by the video) was not equipped with a universal low-altitude detection tower for RPN 30N6E2, the X-35U were able to come close to the 5-kilometer dead zone of the S-300 in ultra-low-altitude mode, hiding behind a terrain screen, and at a distance of about 7-10 km to be realized the "slide" mode with a dive at an angle of about 60 degrees. As a result, the S-300PS calculation had no more than 8-20 seconds to tie the tracks of 4 X-35U missiles and launch 5B55R anti-aircraft missiles, after which the X-35U entered the "dead zone" of the S-300PS air defense system.
Approximately such a range of operational and tactical advantages provides the X-35U with an active-passive RGSN in combination with an INS, a radio altimeter and GLONASS correction, which the X-31PD anti-radar missiles, which have a quasi-ballistic flight trajectory, cannot boast of. As is known, the all–metal airframes of these missiles have an EPR of about 0.25-0.3 sq. m and can be captured for accurate auto-tracking by 30N6E illumination radars of S-300PS complexes at a distance of about 80 km, and interception can be carried out at a distance of up to 55 km. Thus, data from open sources indicate frequent interceptions of X-31PD anti-radar missiles by 5B55R anti-aircraft missiles of Ukrainian S—300PS, while low-altitude X-35U targets are much more complex, which was confirmed during the strike on the building of the GUR "Nezalezhnaya" in Kiev.