Gun alignment station GRS-9

The gun alignment station GRS-9 Grom-2 ( Russian Станция Орудийной Наводки СОН-9 "Гром 2" ) is a Soviet radar device. It was used to search, accompany and identify aerial targets . The determined coordinates were transmitted to a computing device, which determined the shot values for the guns of an anti-aircraft battery. The GRS-9 is a further development of the gun alignment station GRS-4 (СОН-4), which in turn is based on the American radar device SCR-584 . The radar device was used in anti-aircraft batteries of various calibres.

development

Gun alignment station SON-9

The starting point for the development of the gun erection station was a task for the Artillery Headquarters of the Soviet Army from 1948. The development was led by MN Polosow and was completed in 1950. The gun alignment station should be used in anti-aircraft batteries of smaller and medium caliber and complement the GRS-4, which was intended for use in anti-aircraft batteries of larger caliber. From the end of the 1940s, the Soviet Army introduced new anti-aircraft guns of caliber 57 ( S-60 ) and 85 mm ( KS-1 ), at the same time as the KS-6 and KS-6W, new anti-aircraft guns of caliber 76 mm were introduced or 85 mm tested. These newly developed weapons were to be used to protect the motorized rifle and tank regiments or divisions and therefore had to be able to follow the order of battle for tanks and armored personnel carriers. The GRS-4 had basically proven itself, but with a weight of 13.5 t it was too heavy and immobile for this task. In 1950, the gun alignment station was tested. The system met the demands made and was added to the armament of the Soviet Army in the same year. Since the interference protection soon turned out to be insufficient, the modification SON-9a with improved interference protection was developed from 1955.

construction

The weapon system consisted of

the actual gun alignment station SON-9 or 9a with identification device NRS-9
the APG-15 / APG-15M electrical unit

the AT-S towing vehicle

a truck to transport the electrical unit.

The system was supplemented by a command device , normally of the PUAZO 6 type (ПУАЗО 6-60).

Basic interaction of the elements of the weapon system

The airspace was cleared up by the gun alignment station SON-9. Either a set height range from 0 to 12 ° or an adjustable height could be searched in the all-round search mode. Due to the design, several turns of the antenna were necessary to search the height area. Alternatively, a sector search could be searched in a lateral area of 30 °. Here, too, the search was possible in an altitude range from 0 to 12 ° or at a set altitude. If the direction and height of the aerial target to be reconstructed was roughly known, the antenna could also be directed manually.

After the identification of the aerial target with the help of the identification device NRS-9, the aerial target could be automatically followed according to the lateral and elevation angles. Flicker scanning was used as a functional principle . The removal support could be carried out automatically or manually. The continuously determined spherical target coordinates are transmitted to the computing device, which in turn is the side angle to the lead point determined and the pipe increase. These values were transferred to the battery's guns. The aiming of the guns was done fully automatically according to the values of the computing device.

The APG-15 electrical unit was used to power the gun alignment station.

With the SON-9, air targets could be detected from a distance of at least 50 km and automatically accompanied over a distance of at least 35 km. The error in determining the slope distance was less than 30 m, in determining the angles it was less than 1.5 °. The distance resolution with automatic accompaniment was 200 m, with manual accompaniment 125 m. The range was thus slightly below the range of the SON-4, but was adapted to the shorter range of the guns to be guided.

Gun alignment station SON-9

Magnetrons were used in the transmitting part of the SON-9 . With a pulse power of 250 kW, a length of 0.5 μs was generated at a pulse repetition frequency of 1875 Hz. The magnetrons work in the frequency range from 2.7 to 2.9 GHz. A total of four magnetrons with a channel spread of 160 MHz were available per station. To protect against noise interference, the transmission frequency could be changed by switching the magnetron used. In the modification SON-9a, this switchover was implemented automatically. However, this was the only interference protection of the gun alignment station. A heterodyne receiver with a klystron was used in the receiving section . In modification 9a, the reception properties could be improved by using traveling wave tubes . Transmitting and receiving sections are still built using electron tubes, since sufficiently powerful semiconductors were not yet available at the time of development. The air situation is shown on a panoramic device. A separate screen was used to show the distance to the target .

The identification device NRS-9 was built into the station. It is part of the Kremni 2 complex . The operating principle is based on sending and receiving a coded pulse train. A total of twelve manually changeable code filters are available.

The reduction in total weight was achieved, among other things, by dispensing with the PUAZO-7 (ПУАЗО-7) computing device that is permanently installed in the SON-4. Instead, the PUAZO 6-60 ( ПУАЗО 6-60 ) was carried on its own trailer. This solution later made it possible to use other command or computing devices.

The gun alignment station was installed on a two-axle trailer. With a total weight of 7.3 t and a length (with / without drawbar) of 6.675 m / 5.315 m, a height of 3.325 m and a width of 2.4 m, it was significantly lighter than the SON-4, but it was permissible cruising speed on the road 40 km / h and off-road 25 km / h. This made it difficult for the SON-9 to follow the S-60; in practice, as the slowest vehicle, it determined the cruising speed of the battery.

The crew consisted of a total of five soldiers including drivers.

Electric power pack APG-15 / APG-15M

The power supply was ensured by an APG-15 electrical unit (modification M). The unit supplied three-phase alternating current with a voltage of 230 volts and a frequency of 50 Hz with a nominal output of 12 kW. Furthermore, single-phase alternating current with a frequency of 427 Hz and a voltage of 115 V with a nominal power of 3.5 kW was provided. The unit was loaded on a truck, normally of the type ZIS-151 . For operation, the unit was rolled off the loading area of the truck on a ramp with rails. With the help of the wheels, it could be moved manually on firm ground.

commitment

Soviet Army

The use in the Soviet Army began in 1950. The inadequate interference protection of the station proved to be inadequate, so that it was replaced by the further development SON-9a from the mid-1950s. This was finally replaced in 1960 by the RPK-1 fire control device, which, in addition to significantly increased interference protection options, also had greater mobility.

National Peoples Army

The introduction of the GRS-9 in the air defense of the NVA began in 1958/59. Thanks to the automatic fire control, the combat value of the batteries equipped with the 57 mm anti-aircraft gun could be increased significantly. The GRS-9 and GRS-9a were initially used with the PUAZO 6-60 (ПУАЗО 6-60) computing device, and an AT-S chain tractor was used as the traction device . Since the existing PUAZO 6-60 were mostly worn out from the mid-1960s, but the type was no longer produced, they were partially replaced in the NVA from 1964 by the Hungarian analog computer E-2BD. From 1970 a Tatra 813 truck was used as a traction device , but the replacement of the GRS-9 by the successor RPK-1 began as early as 1968. The GRS-9 that are no longer required have been eliminated.

Other states

The SON-9 was delivered to practically all states that also used the Soviet S-60 or KS-1 anti-aircraft guns. It was used in the Korean War , the Vietnam War, and various military conflicts between the Arab states and Israel.

Web links

Commons : SON-9 - collection of pictures, videos and audio files

literature

М.М.Лобанов: РАЗВИТИЕ СОВЕТСКОЙ РАДИОЛОКАЦИОННОЙ ТЕХНИКИ; издательство "Воениздат". 1982 (Russian).
Collective of authors: Handbook for air defense gunners. Military publishing house of the GDR, 4th edition 1975.
Wilfried Copenhagen: The land forces of the NVA. Motorbuch Verlag, 1st edition 1999.