Don's Weekly, 30 September 2024: Part 5

by Donald Hill

(…continued from Part 4…)

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The Evolution of Counter-battery Fire

Another Russian Zoopark counter-battery radar was destroyed, this time by Ukraine’s 45th Artillery Brigade. The radar spots the trajectory of an artillery or mortar shell and calculates the firing location. If the artillery fires at that location, they might destroy the firing weapon.

The two components of counter-battery (CB) fire is detection of the firing unit and having a weapon system within range to attack it. During World War I, advances were made in the detection of enemy artillery units. At night, the flash from firing the gun could be observed and then a stopwatch measured how long before the sound reached the observer. Knowing that the speed of sound (in dry air) traveled at 343 m/s, that provided the approximate distance. A compass azimuth gave the direction. Combining the distance with the direction gave the location.

A more accurate method is when multiple observation posts observe the flash and provide an azimuth to their artillery units. Where those azmuth’s intersect is the location of the firing battery. Because of the accuracy of this method of detection, German artillery started using flashless shells that reduced the muzzle flash, although it increased the amount of smoke. Both sides also moved their guns further away and deployed them behind ridges to try and mask the flash.

This led to an increased reliance on sound ranging, something the Russians pioneered in 1910 and was extensively used by the allies on the western front. It is similar to flash spotting: The sound reaches different microphones at different times and is recorded on a strip of film. The time to reach the microphones provides the distance. Spheres are drawn with the radius of those distances and where they intersect is the firing battery. The Germans didn’t use sound ranging but the allies used it not just to detect German batteries that fired, but also where their own shells from friendly guns landed. They could then adjust their own artillery fire to where they want it to land without a visual observation.

After November 1942, sound ranging became an important component of the US army, which had the most effective artillery in the war. By the end of the war, they had 13,000 men in 25 battalions. In the static phases of the Korean war the US counter-fire platoons used sound ranging to quickly and accurately identify Chinese artillery batteries hidden by terrain and caves, becoming experts in how the local terrain impacted the sound waves. The accuracy of US CB fire was a source of mystery to the Chinese until the end of the war.

The AN-MPQ10 used in the Korean war by the US Army.

But terrain does mask and distort the sound waves. In 1943 the British started experimenting with using radar to detect indirect fire. In 1944, a radar assigned to a US anti-aircraft unit detected German mortars. Radars have the potential of longer detection ranges as soon as the shell clears any masking terrain. By 1951, the US was using the AN-MPQ-10 in Korea. It provided a signal along a single plane and would detect a shell breaking the plane on its upward trajectory and on its downward trajectory. Operators would then do manual calculations to determine the location of the firing weapons. It was easier to detect mortars than artillery shells because the mortars had fins, which provided a better radar return. It was also easier to determine the firing location of mortars than artillery because the mortars have a more predictable ballistic arc. Later CB radars could track a shell throughout its entire flight and computers would calculate the location of the firing units.

Another method of CB acquisition began in WW1, when they used airplanes to observe artillery and other enemy dispositions. Efforts to eliminate these reconnaissance planes (and subsequent bombers) evolved into the air forces we recognize today. Air reconnaissance was widely used in WW2 and other wars, but in the Russian-Ukraine war, the air space is too heavily defended to risk manned flight reconnaissance. Drones filled that niche and artillery (and other targets) have been detected and eliminated not just by artillery CB fire, but CB fire from drones and missiles, as well.

CB radar still has a role in detecting enemy indirect fire. If friendly artillery is in range, they might be used to conduct CB fire, but their own artillery has to consider the likelihood of detection. Plus, the firing artillery could move immediately after firing. If there is any delay in CB fire, their rounds may be landing on unoccupied ground. So the CB radar info may be passed to a drone team which could then fly to the area in hopes of spotting the moving artillery piece and follow it to its hide location and attack it there.

Ukraine’s recent efforts to eliminate Russian reconnaissance drones and its continuing efforts to eliminate Russian CB radars will reduce Russia’s ability to detect their artillery and attack them with counter-battery fire.