ZSU-23-4 Shilka Self-Propelled Air Defense Gun Mount

The modernization seeks for state-of-the-art design and technologies to update the self-propelled (SP) air defense gun mounts and make them effective in heavy electronic countermeasures (ECM) environments, in adverse weather and dust-laden conditions, in any season and at any time of day or night. The modernization envisages:
1. Integration of the modernized Shilka gun mounts into a unified army information system of air target reconnaissance and designation by organically assigning a mobile air target reconnaissance and control post (MRCP), Sborka, to the battery as its command post (BCP).
2. Improvement of the gun mount’s main part—the RPK-2 radar-computer complex (85 percent of the equipment accommodated in the turret) and creation of a new complex, the RPK-2U.

Battery command post:
Sborka MRCP

The radar has been virtually replaced by a new one, operating on the same frequency band but based on solid-state components: all units and systems of the radar have been subjected to modernization and the radar equipment is accommodated in five cabinets (instead of seven). The RPK-2U complex incorporates:
— digital computer system (DCS) which jointly with the radar makes up a fire control radar system (base system);
— television-aided sight and laser rangefinder which together with the radar and digital computer system form an optical-radar fire control system (ORFCS) operating in the passive mode both day and night (moonlight at a quarter of the moon);
— equipment, including:
(a) data receiving/transmitting (DRT) equipment for the gun mount to exchange information with the Sborka battery command post via a telecoded communication channel for reception of external target designation signals and operational control of the Shilka battery engaging a target by one, two, three and more gun mounts;
(b) digital-to-analog and analog-to-digital converters;

Ranzhir

(c) trainer for radar operators;
(d) built-in equipment for check and adjustment of the RPK-2U complex low-frequency automatics and turret laying drives (2E2) in static and dynamic conditions;
(e) commander’s guidance unit (CGU).
3. Replacement of a number of systems, units and assemblies by up-to-date ones boasting higher technical and operating characteristics.
4. Updating of the base tracked vehicle and crew life support system.
The fire control radar system has been modified with the aim to:
— extend the air situation information field by integrating the gun mount into the unified field AD system;
— reduce the time of information processing in the fire control system (dead time);
— redistribute regular and random errors and pass bands of the follow-up systems and groups of the radar- computer complex systems;
— change the principle of introducing corrections for the angles of tilt and turn of the mount on the move;
— change the principle of error determination in the generation of total laying angles of the automatic guns;
— introduce and automatically account for meteorological data, corrections for changes in the muzzle velocity due to barrel bore wear, corrections in orientation and others (all refer to know-how);
— change the method of processing secondary information;
— modify some existing modes of battle performance.
The following innovations have been introduced:
– modes of operation to handle low-flying targets in heavy ECM environments (by the stored rate of range variation, stored target coordinates received from the digital computer system, moving target indication (MTI) by radar angular coordinates;
— automated control of the gun mount battle performance from a higher command post (HCP);
— built-in check of the electronic equipment;
— mode of radar operators’ training.
The above innovations have made it possible to:
— cosiderably enhance the air target search potential and acquisition probability;
— improve the radar immunity to passive jamming (with the introduction of angular automation channel protection and modernization of the MTI system range channel), active range deception jamming and tracking a jammer by angular coordinates (with the introduction of modes of tracking by the stored rate of target range variation and its inertial range and angle-aided tracking by signals from the digital computer system);
— provide the security of operation in heavy ECM environments (with the introduction of the optical-radar system);
— improve the precision characteristics of the follow-up systems and groups of the radar-computer complex systems;
— reduce the surveillance time of the fire control system.
The implementation of the above modifications has enhanced the effectiveness of fighting high-speed (up to 500 m/s) and small targets maneuvering at altitudes down to 25 m (0 m with the introduction of the ORS) rather than 100 m.
The air target (aircraft, helicopter) kill probability during one pass of the engagement zone at an ammunition expenditure of up to 300 rounds per gun mount constitutes 0.3 to 0.74 (rather than 0.07 to 0.12) and depends on the organization of control over the combat activity of the battery gun mounts from the higher command post and engagement of the target by one, two, three and more mounts. In addition to better technical characteristics, the operating characteristics have been also improved by providing:
— prompt functional check of the radar-computer complex and its components;
— means to upgrade training and practice of radar operators in handling air targets in heavy ECM environments without aircraft flights (up to five targets with simulation of operation under conditions of passive and noise jamming);
— better controllability and maneuverability of the tracked vehicle and reduced labor ******* required to maintain and operate the vehicle;
— higher reliability of starting the traction engine;
— better habitability conditions.
The service life of a modernized gun mount after the overhaul of non-modernized systems, units and assemblies has been extended, with spare parts being supplied.
The modernization of the Shilka SP gun mount changes the latter into a modern AD system which fits readily into training, repair and operating structures of clients and can provide cover of stationary installations, tank and motorized columns on the march in adverse weather and dust-laden conditions, in any season and at any time of day or night where other systems outfitted with optical guidance and control systems prove ineffective.