AFMS-2
The artillery radio measuring station AFMS-2 , abbreviated AFMS-2 . was an artillery reconnaissance radar developed in the former Soviet Union until 1950 . The Russian name was станция наземной артиллерийской разведки-2 , or СНАР-2 for short . and translates to mean station for ground-based artillery reconnaissance . The radar was used to clear up enemy targets, determine target coordinates and guide one's own fire. In this function, it replaced its predecessor, SNAR-1 .
development
As the range of the artillery increased, the problem of determining the target coordinates arose early on. At firing ranges of more than 10 km, a real-time optical reconnaissance of targets and the sufficiently accurate determination of their coordinates was difficult, and at night and with poor visibility, it was no longer possible at all. With sound measurement methods have already been in World War II enemy artillery positions tracked even in the absence of direct visual connections and their coordinates are determined. The advantage of this procedure is that it is a passive procedure that cannot be investigated remotely. The disadvantage is the limitation to a range of around 20 km - which was mostly sufficient during the war - and the fact that it can be used to measure the shooting down of enemy artillery. Artillery that has not yet started fire fighting, as well as other military vehicles, cannot be detected with it. However, the advances in radar technology achieved during the Second World War made it possible to develop powerful and compact radar devices that could be used for artillery observation. The Artillery Headquarters of the Soviet Army began considering the use of radar technology for this purpose as early as the Second World War. In 1943, the Research Institute NII-244 (НИИ-244) of the Ministry of Defense of the Soviet Union was commissioned to develop a corresponding station. The head of development was AA Raspletin (А. А. Расплетин). The SNAR-1 was the first Soviet radar that was developed and used for this purpose. The SNAR-1, which was taken over by the Soviet Army in 1947, had basically proven itself, but had a number of shortcomings. Two vehicles were required to accommodate the electronic systems, the antenna and the power supply units, which limited tactical mobility. Another problem was the low resolution of the station, which made it difficult to recognize the target signals against the background of the fixed targets.
The NII-244 (НИИ-244) was commissioned with the development. The SNAR-1 had already been developed there. The previous model served as the basis for the development. The basic construction remained the same, but the electronic systems were converted to miniature tubes. Due to the reduced volume of the assemblies, the electrical unit could be accommodated on the equipment vehicle together with tools, spare parts and accessories; the unit car was no longer required. The station now worked in the millimeter range with a wavelength of 8 mm. The predecessor SNAR-1 still used centimeter waves with a wavelength of 1 to 3 cm. The use of millimeter waves increased the resolution, which made it easier to distinguish between fixed and moving targets. However, this change also had a disadvantage: Waves of this wavelength are much more attenuated by precipitation. This property is used in weather radar , in this case the attenuation leads to a reduction in the range or the obscuring of targets. This disadvantage was acceptable, however, since an average of 10 to 15, a maximum of 90 hours of precipitation per month was expected.
The station was still under state testing in 1950 and was taken over into the armament of the Soviet Army.
construction
Structure of the station
The system consists of
- the equipment vehicle
- the electric unit AB-4-0 / 115 / Tsch-425
Basic interaction of the elements of the weapon system
The equipment vehicle accommodates the essential electronic components of the system and the antenna system in the case. In use, the electrical unit is operated remotely. Clarification while driving is not possible.
Basically, the SNAR-2 is used from measured positions. The sector search is used for reconnaissance, a sector with a width of 25 to 28 ° is searched. The enlightened goals are displayed on a panoramic device , on which a representation of the boundaries of the sector is also generated electronically. The station can also work in an all-round search mode. In this procedure, the station can be oriented using known points in the area. The targets to be accompanied are displayed on a viewing device , with the help of which the lateral angle and distance to the target can also be determined. The calculated coordinates are transmitted to the firing batteries by telephone and radio. The target escort viewing device also serves to display the impacts of your own artillery and to measure the stowage area. The determined deposit is also passed on by telephone and radio to the firing batteries for fire correction. An R109 VHF radio and two telephones are available to transmit the information.
Equipment vehicle
The equipment vehicle is built on the basis of the light AT-L chain tractor . Instead of the flatbed, a box body was placed on the chassis, which houses the electronic assemblies, the antenna system and the workplaces of the crew. The vehicle weighs a total of 8.2 t, is 5.52 m long, 2.20 m wide and 3.07 m high. The cruising speed is 30 km / h. The station's crew consists of four soldiers.
The rotatable antenna is mounted on the roof of the vehicle. In the marching position, the antenna is folded forward and lashed. The antenna forms a 0-05 to 0-0 rad wide beam, in the vertical plane the beam is focused on 0-20 to 0-22 rad. When searching for a sector and accompanying the target, the beam is swiveled horizontally in a range of 26 ° with a frequency of 11 Hz.
With the exception of the high-frequency block, the electronic systems are combined in two equipment cabinets that also accommodate the display units. The high frequency block is attached to the antenna frame and is swiveled horizontally together with the antenna. The transmitter / receiver switch, the antenna equivalent switch, transmitter, the tuning oscillator of the heterodyne receiver and the mixer of the receiver are combined in it. The air pump required to generate the negative pressure in the waveguide system is also attached to the frame of the antenna. The transmitter works with a magnetron in the millimeter wave range . Pulses with a pulse power of 20 to 30 kW and a switchable pulse repetition frequency of 6000 or 3000 Hz are sent out. The low pulse repetition frequency is used to accompany the target, the higher in all-round search mode. The pulses are 0.07 or 0.15 μs long. A klystron is used in the tuning oscillator .
The installed radar range is limited to 32 km due to the target escort display device , the display device can be switched between the scales 32 and 9.16 km. The display device accompanying the destination also has a switchable display, here you can switch between the distance scales 1 and 4 km.
The SNAR-2 can detect tanks and motor vehicles from a distance of at least 12 km and ships the size of a destroyer from a distance of at least 25 km. The exact determination of the target coordinates is possible up to a distance of 16 km. Although these values are below those of the SNAR-1, they were sufficient for the guns then in the armament of the Soviet Army. The dead zone has a maximum radius of 200 m; targets cannot be detected in this area around the radar station. The error in determining the distance is less than 5 m for moving targets and less than 2 m for immovable targets. At a lateral angle of less than 0–02 rad. The resolution is 15 m at a distance and 0–07 in the azimuth, which means that moving targets can be recognized much better.
Electrical unit
An AB-4-0 / 115 / Tsch-425 is used as the electrical unit. The electrical unit generates single-phase alternating current with a nominal voltage of 115 V and a frequency of 425 Hz and direct current with a voltage of 26 V. In addition to the main unit, there is also a reserve unit of the same type. One of the units is housed in a separate compartment in the rear of the body. It can be operated there, but also up to 15 m away.
commitment
Operational principles
The SNAR-2 was used at division level to guide the artillery grouped into division artillery groups. For this purpose, it was assigned in the structure to the command batteries of the chief artillery or the chief missile troops and artillery.
States of operations
The system was introduced in the Soviet Army, but was replaced by the revised SNAR-6 as early as 1960 . The SNAR-2 was also exported to individual countries such as the GDR.
Use in the GDR
In the National People's Army of the GDR , the SNAR-2 was used in small numbers from 1956. Deviating from the original name, the designation artillery radio measuring station AFMS-2 was chosen . Because of the high operating costs of the caterpillar vehicle, the existing stations in 1974/75 in the maintenance base for armament 2 (IBB-2) in Doberlug-Kirchhain were converted to the Ural-375D truck . In the formations of permanent combat readiness , the AFMS-2 was replaced by the AFMS-10 in the 1970s . The stations that became free were used as training equipment or assigned to the command batteries of the head of the rocket troops and artillery of the mobilization divisions. When the NVA was dissolved in 1990, there were still some AFMS-2 in the NVA's inventory.
literature
- М. М. Лобанов (MM Lobanow): Развитие советской радиолокационной техники ( development of Soviet radar technology ), издательВство "оениздат", 1982 (Russian)
Web links
- Missile and weapons technical service in Kdo. MB III, technical catalog, artillery radio measuring station AFMS-2
- СНАР-2 - станция наземной артиллерийской разведки on Российская военная техника ( memento from April 17, 2013 in the web archive archive.today ) (Russian)