Soviet (Hard-kill) APS development
The development of an Active Protection System in the Soviet Union dates back to the 2nd half of the 1950s. The creation of the first operational prototype which included the usage of an active method of protection was started in 1958 within the "Дикобраз" - "Porcupine" APS framework.
The basic principle of operation of this APS consisted of covering the probable direction of attack against ATGM. This was achieved by separating the system into different sectors and each sector was protected by a launcher that fired a counter-projectile at an incoming threat.
The development of the next APS prototype, which showed the fundamental possibility of detecting an incoming chemical projectile and countering it at a distance of 1000-1500 meters relative to the tank equipping such APS, was started in the 1960s. The APS was called "Веер" - "Fan", development was carried out by NIIStali together with NIIETI.
The system was made out of 15-20 protective modules, which were mounted around the perimeter of the vehicle. Each module contained a projectile with a fragmentation warhead, which included a built-in radar sensor to detect incoming projectiles. The sensor itself utilized the Doppler effect. Incoming projectiles were detected by one of the sensors, which, with a certain delay issued a signal for detonating the corresponding fragmentation charge.
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In 1969 the first operational tests of "Веер-1" - "Fan-1" were carried, which resulted in:
- Confirmed by field tests the operability of the fragmentation charges, provided almost reliable destruction of chemical projectiles, fired from 100mm and 115mm cannons, including ATGM within speeds from 100m/s - 970m/s
In 1970-1971, 2 "Веер-2" - "Fan-2" APSs with optical detection sensors were developed and tested by NIIStali. The optical display system, which operates on daytime light contrasts, showed reliable operation with small contrast dispersion in the response area. However, the noise immunity of the APS turned out to be insufficient, due to the optical sensors causing false signals when interacting with natural interferences such as; dust, sand, water splashes, sun glare. This required more testing.
As a result of further development, NIIStali created the "Азот" - "Nitrogen". This complex included a two-stage radar detection system using the Doppler effect, non-contrast sensors using a new photo-based element and an early warning channel.
The early detection channel (EDC) was a transmitter-receiver radar device with noise frequency modulation and correlation processing of the reflected signal using the Doppler effect, which created a selective detection zone at a selected distance from the antenna.
When signals from the EDC are transmitted to the LED (Logical Executive Device), a pulse is generated. For optimal alignment of the triggered launch sector, the pulse trigger signal leaves the LED with a delay, which is proportionally the same length as the signal leaving the EDC.
Further, the pulse trigger signal enters the 'Safety and Execution Unit', where the signal is amplified and fed into the counter projectile launcher, which detonates and sends a cloud of fragmentation bits into the direction of the incoming threat. This increased safety during the usage which was provided by the 'Safety-Execution' block.
Non-contact sensors system was placed around the perimeter of the tanks hull. In this case, the system would provide a solid 360 detection zone.
The complex of the functional support system includes; control panel, power supply unit, transfer device for protective charges, equipment for cleaning the early detection system and non-contact sensors.
While NIIStali was working on "Fan-1" and "Fan-2" APSs, Leningrad started their development on a new APS system named "Дождь" - "Rain".
As the result of a so-called 'engineering synthesis of research and development of "Porcupine", "Fan-1/2", "Rain", "Nitrogen", "Hedgehog" and other different research programs, in 1977-1982 "Дрозд" - "Drozd" APS was created and accepted in 1982. As a result, the developers of the system received the Lenin and State Prizes.
"Drozd" APS was primarily developed by Tula TsKIB (SOO), which in 1997 became part of the State Unitary Enterprise "Design Bureau of Instrumental Engineering".
After the implementation of "Drozd" APS into the military, "Арена" - "Arena" APS entered service. "Arena" was developed by the FSUE "Design Bureau of Machine Building" (Kolomna).
Back to "Drozd"
"Drozd" APS uses the principle of detecting and defeating incoming projectiles at a relatively large distance from the tank itself (more than 150 meters). A radar station was used as the detection system, which operated in a centimetre wavelength. This allowed the system to not only detect incoming projectiles but also received the necessary information to determine the speed and calculate the target trajectory, as well as program the moment/delay of the counter projectile charge and its detonation.
The first vehicle to ever mount "Drozd" was the T-55AD (see image 1). "Drozd" consisted of 3 radar modules, 4 launcher modules each having 2 counter-projectile launchers, a radar control module and the main control panel. The radar modules and launch modules were symmetrically placed on the turret and the main radio module was installed on the back of the turret. The main control was mounted on the commander's control panel inside of the tank. "Drozd" APS total weight was 1000kg and consumed 700 Watts of electricity, which was generally enough since that amount was produced by the tanks electronic system. During stationary vehicle operation, the entire APS is powered by an auxiliary generator.
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| Image 1. "Drozd" APS mounted on T-55AD |
"Drozd" is activated automatically after switching the remote control to the "On" position and is disabled using a safety feature using an internal locking scheme, where the system shuts down when one of the crew hatches is open. The radar array operated in Microwave wavelengths.
By launching a counter-projectile, the system's control panel lights turn on to indicate the sector which is being fired at by the APS. The actual counter-projectile launch sequence is based on an already preset range of 150-190 meters from the tank. Counter-projectiles make up a good portion of the weight of the entire system. Each counter-projectile is 107mm in diameter, 693mm in length and weighs 19kg. There were also ideas to increase explosive mass filler of the counter-projectile because the spread of fragmentation increased exponentially the further away it travelled from the vehicle.
Further research and development were done, the usage of improved projectile detection and signal processing, more effective explosive fillers, allowed the creation of a more improved variant with enhanced performance. "Drozd-2" improved on the performance of "Drozd".
"Drozd-2" used an all-around azimuth coverage design (refer to image 2), which still satisfied the needs to protect the vehicle in open frontal attack but also provide protection in urban combat. In comparison, the new version had smaller dimensions compared to its predecessor, while the total launcher array was increased by 4 times. "Drozd-2" counter-projectiles stayed almost untouched only now their length was reduced to 445mm.
The modularity of "Drozd" and "Drozd-2" APS, allowed it to be mounted on practically any AFV. This improved the overall protection performance of any vehicle. The probability of detecting and defeating an incoming projectile was 0.9 on "Drozd-2". The operation cycle between a performed counter to standby was 350ms, while the time needed to fully rearm the system was 15 minutes.
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| "Drozd", "Drozd-2" general characteristics |
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| Image 3. T-80U equipped with "Arena-E" "Arena-E" consists of:
"Arena-E" is used for:
"Arena-E" is designed to operate in all types of weather conditions and at any time of day. The detection and defeat of incoming projectiles can be executed in any type of weather conditions, also while the vehicle is mobile. "Arena-E" coverage is 220°-270° on azimuth, which is enough to protect the vehicle from the front and sides. "Arena-E" complex offers:
Mounting variability allows the entire system to be mounted on different platforms, this includes tanks and IFVs. Due to the system being fully automated only small human input is required, the commander has to activate the system, after which the whole process is automated. During combat usage, the radar array provides automatic search and detection of targets that are approaching the tank. After analysing the received information, the radar array goes into "TRACKING" mode, in which it gains information about the projectiles speed, trajectory which then is sent to the computing device. After finalizing calculations the computing device decides which launch shaft should be used and in how many seconds it should be activated. By which the signal is sent to the launch shaft and commands for counter-projectile detonation. The system also offers the ability to control manual launch shaft operation through the use of the aforementioned control panel, which should generally be used to prevent accidents. Each counter-projectile is designed for a specific sector in which it will detonate, while also capable of overlapping into sectors that are covered by the neighbouring counter-projectiles, allowing the usage of sending out several charges in an overlapping counter. The system is capable of carrying out (22-29) deflections depending on how many counter-projectiles have been armed, which is sufficient enough to counter a large number of tank threats. Rearming is carried out by the tank crew. "Arena-E" is an autonomous, automatic, all-weather, around the clock, analyzing, self-testing active protection system. The usage of ERA in the 1980s was highly prevalent, which offered increased protection against tank threats, but after the detonation of certain ERA blocks, the tanks overall protection in that area drops drastically. "Arena-E" mitigates that by providing protection against tank threats, such as ATGMs and RPGs, reducing the need to rely on ERA as one of the main means of protection. |
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