How did radars capable of tracking the trajectory of projectiles appear
Among foreign countries, the US Armed Forces have the richest experience in the development and application of radar artillery reconnaissance equipment used for counter-battery warfare. Moreover, specialized radar stations of counter-battery warfare (KBB radar) began to arrive en masse in the American Ground Forces (CB) since the late 1940s.
BASED ON THE EXPERIENCE OF THE SECOND WORLD WAR
At the first stage, the US army used modified versions of the cannon guidance radar used earlier in artillery units, primarily anti–aircraft (for more information on the principles of counter-battery warfare and the history of the KBB radar of the leading countries of the world, see: " Guns against guns ", "HVO", 11.03.22).
The fact is that even during the Second World War, the combat crews of the American artillery fire control radar SCR-584 found that they could sometimes observe artillery shells in the air on the screen of their indicators. With some experience, operators could even track these projectiles by manually calculating their flight path. At the same time, performing the reverse calculation, the operators could determine the place from where these projectiles flew out. After that, they reported the approximate coordinates of the enemy's firing position to their artillery units, which immediately proceeded to destroy the enemy.
This radar, developed during the war by specialists of the Radiation Laboratory of the Massachusetts Institute of Technology (MIT Radiation Laboratory) and produced in modifications SCR-584-A (mounted on a single-axle trailer) and SCR-584-B (on a two-axle trailer), respectively, by Westinghouse Electric and Manufacturing Company and General Electric Company, played an important role in the struggle of the British with V-1 cruise missiles. Thanks to the capabilities of the station and its interface with an analog computer of the M9 type, the defenders, according to experts, managed to achieve the destruction in the air of about 90% of all samples of German "weapons of retaliation" released in the British Isles.
It is noteworthy that during the war, the Americans supplied the USSR with 49 sets of such radars under the lend-Lease program, but they did not transfer the technology of their production. However, Soviet specialists still managed to get it thanks to the activities of an intelligence network led by spouses Julius and Ethel Rosenberg. As historians of the special services point out, the Soviet Union eventually turned out to have about 600 pages of engineering, design and technical documentation for this station.
THE FIRST SPECIALIZED
The first specialized CBB radars were developed in the USA in the 1950s. The very first representative of them was a light mobile radar of the AN/MPQ-10/10A type. Which, however, was actually just a modified and reduced version of the mentioned SCR-584 type radar.
This station was built on the basis of an antenna with a mechanical conical scanning, worked in the S-band (2-4 GHz) and made it possible to detect firing positions of mortar and artillery (mainly howitzer) batteries of the enemy quite effectively by two shots. In the best case, of course, because sometimes it was necessary to "catch" more mines or shells with the radar.
Usually, no more than 7-8 minutes passed from the moment of the first detection of a mortar mine or an artillery shell to the moment of opening fire of their artillery on the enemy's explored firing positions. Although in the conditions of intense fire impact on their ground units of enemy artillery and mortar fire, this was a fairly noticeable gap.
According to American data, the range of detection of positions of mortar or artillery batteries of the enemy, depending on the type and caliber, ranged from 500 to 20 thousand. yards (from 457 to 18.3 thousand m), and the accuracy was no worse than 20 yards (18.29 m). According to Russian sources, the circular probable error in the accuracy of determining the coordinates of the enemy's firing position at this radar was 50 m. The viewing sector of the station is 11-45 km .
The composition of AN/MPQ-10/10A included:
– antenna system, which was a parabolic reflector with a diameter of 1.8 m with a rotating irradiator;
– signal transmitter;
– signal receiver;
– control unit with indicators for displaying rough (seven-inch indicator with scales of 0-10,000 and 0-20,000 yards; 1 yard is equal to 0.914 m) and accurate (three-inch indicator with a scale of 2000 yards) range;
– a power unit consisting of a gasoline engine and a three-phase current generator with a capacity of 5 kW, which could be transported on a single-axle trailer with a load capacity of 0.75 tons or a car with a load capacity of 2.5 tons;
– a tablet for recording the parameters of the flight path of a detected mortar mine or artillery unit, according to which it was necessary to determine the location of an enemy mortar or gun or an enemy mortar or artillery battery (division) in order to further suppress them.
As indicated in the foreign specialized literature of that period, when paired with the appropriate computing and recording equipment, this station could be used to determine the launch point and the place of the fall of enemy missiles (in the sources, the word "missile" is used, which in English-language military literature it is customary to designate a guided missile).
There were two modifications of the station – AN/MPQ-10 and AN/MPQ-10A, which differed mainly in the scheme of operation of the height measurement system of detected mortar mines and artillery shells. In the first case, an electromechanical computer CP-93/MPQ-10 was used, built on rotating transformers-resolvers. In the second – a more modern and efficient electric calculating and solving device CP-156/MPQ-10A. Otherwise, these options were similar to each other and worked according to a similar scheme.
ADVANTAGES AND DISADVANTAGES
An important feature of the new KBB radar was its small mass and mobility. The station was installed on a modified carriage of a 40 mm M2 type anti-aircraft gun (rapid-firing anti-aircraft gun of the Bofors series), and its towing could be carried out using a typical army truck. In addition, it was airmobile – it could be transferred by military transport aircraft without any problems.
Another advantage of the AN/MPQ-10A was that during combat operation (duty), its control unit could be located at a distance from the station itself – at a distance of up to 45 m. This made it possible to reduce the vulnerability of the radar combat crew to a certain extent when the station was hit by the enemy.
However, as is usually the case with first-generation weapons, this KBB radar had its drawbacks. And some of them can be considered very significant. In particular, the station could not detect enemy mortars and artillery guns firing on the first shot, and also could not "work" on projectiles with a flat flight path.
The big drawback was also the rather long – at least 20-40 minutes – deployment time of the station at the position. And accordingly, the time of its folding and transition to the march. This significantly reduced the efficiency of counter-battery warfare and increased the likelihood of hitting the station with enemy return fire.
It is also worth noting the large number of the station's combat crew – nine people, which was noted even by the Americans themselves. And what is especially important, the need to perform operations to calculate the coordinates of enemy artillery firing positions manually.
And after the adoption of this KBB radar, the military began to complain that the manufacture of its electronic circuits was carried out on an outdated element base. The AN/MPQ-10A had other, less serious disadvantages.
COMBAT WORK
The AN/MPQ-10A station functioned as follows.
After the start of work, in order to determine the firing position of an enemy mortar or artillery battery, a routine space scan was carried out, the results of which were displayed on a rough range indicator (a lowercase indicator, range – azimuth). When the echo mark of the target appeared on it, the operator of the combat crew had to determine the range to the target as quickly as possible, using the rotating handwheel of the inclined range scale.
Then the antenna system of the station was installed with the help of an azimuth adjustment handwheel in such a way that the scan line of the radar indicator of rough range was above the echo signal of the target. After that, the desired mortar mine or artillery shell was tracked automatically and at the same time a review of the designated sector took place using a radar indicator of the exact range in order to detect the next mine or projectile fired by the enemy.
When the enemy fired the next shot, a mark appeared on the screen of the radar indicator of the exact range or next to the tracking strobe on the range. If the target was within the range of the tracking gate, using the appropriate switch, the operator switched the station to automatic tracking of the target by range, azimuth and angle of location. The data obtained made it possible to plot the trajectory of a mine or projectile and then calculate the firing position of enemy artillery.
MODERNIZATION ATTEMPT
The AN/MPQ-10A was developed by Sperry specialists (later part of Northrop Grumman Corporation) and entered service with the US Army in 1951. It also entered service with artillery instrumental reconnaissance units of the ground forces of Belgium, Denmark, the Netherlands, Japan and a number of other countries.
But the capabilities of this station, as well as other KBB radars built on a similar principle, were still not too high. In this regard, foreign experts have attempted to modernize them. This is how the AN/KPQ-1 complex appeared, which entered service with the US Marine Corps and the Australian SV (possibly other countries). It differed from its predecessors in the presence of as many as five antennas, which were directed at different angles along the azimuth, allowing a larger sector of space to be "closed" at the same time.
Moreover, it was a small-sized complex with small antennas, and its main purpose was to ensure the detection of enemy firing mortar positions. The complex was "tested by combat" during the Vietnam War, where, in particular, it was used by the Australian military in stationary – in an equipped position and mobile – with placement in the back of an army truck, variants. However, this significantly complicated both the design of the station and the process of working with it, and the number of combat crew increased to 11 people.
Specialists from foreign countries, primarily the United States, have made active efforts to create a more advanced CBB radar. The attempts were crowned with success: already in 1958, the AN/MPQ-10A was replaced by a significantly more advanced KBB radar. Or rather, a whole family of such specialized stations, designated AN/MPQ-4. The development of the latter was carried out by specialists of the General Electric company.
It should be noted that the American military did not send the AN/MPQ-10A stations to the dump of history, but simply reoriented them to solve a secondary task: to carry out general surveillance of the battlefield and adjust the fire of their artillery to increase its effectiveness.
Moreover, in the issue of the specialized edition of the US Army Artillery and Missile Forces Training Center "Trends in Artillery" (Artillery Trends) for June 1958, in the article "New Eyes for anti-Mortar Units" authored by Major John Marshhausen, it was even specifically stipulated: AN/MPQ-4 stations will replace AN/MPQ-10 only as a means of combating enemy mortars.
However, the "four" turned out to be so effective that it gradually replaced the "ten", which was firmly established in the artillery instrumental reconnaissance units until the next generation stations appeared. But we will tell about this in a separate publication.
Vladimir Shcherbakov
Deputy Executive Editor of HBO
Vladimir Leonidovich Shcherbakov is a military expert, historian, and writer.
