Radar in counter-battery role

Artillery is dangerous because it is hard to find, hard to destroy, and has the ability to very quickly attack targets via indirect fire. Importance and difficulty of finding the enemy artillery was noticed early in World War I; French were the first to try to locate the enemy artillery, by locating the gun flash produced when firing. This was hard to do if the artillery was far away (reflections had to be used) and unreliable. This it was quickly replaced by sound detection techniques, which were also adapted by British and German militaries as well.

The basis of this technique is a row of 6-7 microphones in a 12 kilometre line. Since the sound spreads in the circles, microphones all detect the sound of a gun at different times, which allows calculating location of the origin of the sound. Original system was based on ordinary stopwatch and telephone cable or radio link, but it worked very well. Similar, but automated, system is in use today. Such system has major advantages in that it is low-cost and completely passive, making it very hard to find and destroy. However, it also has numerous disadvantages. Atmospheric state determination is crucial for its correct operation. The refractive index of air has to be found along the entire sound path, and wind affects system’s performance. Up until the appearance of GPS, setting up the system was also very difficult. Due to these and other issues, it is an inherently defensive technique, difficult to use in rapid movement (albeit it is possible to have two teams of “sounders” alternately set up the line ahead of each other).

Fixing these problems began in World War II through utilization of a then-new sensor – radar – for the role. First proof of concept was during Anzio landings, where radar operators completely accidentally detected shells fired by ships providing fire support. Germans noticed it as well, so both sides began a work on putting it into practice, albeit unsuccessfully. In mid 1944 British and Canadian army radar batteries were formed in NW Europe, primarily in a counter-mortar role. But it was only after the end of the war that United States and Great Britain started serious development. First practical radar appeared in 1950.; it was the US radar MPQ-10, designed for detecting mortars. Between 1951. and 1954., the US Army received 485 radars of that type. It worked in frequencies of 2.740 – 2.980 MHz, allowing good resolution along with small dimensions of the antenna. It was quickly followed by General Electric’s MPQ-4A using the 16 GHz (16.000 MHz) frequency, which was widely used in the Vietnam War. Higher frequency limited its range, but that compromise was acceptable for the purpose.

British Royal Radar Establishment also undertook research of counter-battery radars. At first, efforts were focused on the development of Blue Diamond anti-mortar radars, to be continued with Green Archer radar from mid-1950s, which was more or less identical in performance to MPQ-4A. After that, development stagnated until British Army requested a lighter and simpler-to-use radar with the ability to detect 81 mm mortars up to 10 km with error no larger than 40 m, and 120 mm mortars up to 12 km distance with same error parameters. Result of the request was CYMBELINE by Thorn EMI, which actually improved upon the required characteristics. It has vertical scan page width of 720 milliradians, and can determine the location of a mortar upon two intercepts of the mine. Effectiveness against cannon and howitzer fire is far lesser due to significantly higher velocities and flatter projectile path.

fv436_cymbeline_002

Cymbeline counter-battery radar

United States had similar requirement, but they decided to use a phase radar. After eight years of development, the result was the TPQ-36/37 system, where TPQ-36 was optimized against short-range weapons and TPQ-37 against long-range artillery. Typical unit has three TPQ-36 in the front and two TPQ-37 in the rear. It includes electronically scanned array, which results in good ability of rejecting false signals as well as simultaneous tracking of multiple targets along with path extrapolation, and covers 90* azimuth. Step-scan when combined with stable coherent transmitter allows good clutter rejection. Due to quick scanning ability, the possibility of missed detection is significantly reduced. However, large antenna presents a very vulnerable target, easily damaged even by small fragments, despite the kevlar armoring present. Also, as the requirements of detecting small, fast projectiles – especially in a cluttered / jammed environment – require high emission power, counterbattery radars are relatively easy to discover.

In 1986., France, Germany and UK agreed on a list of requirements for new counterbattery radar. The result of that was COBRA AESA system, while at the same time Norway and Sweden developmed a smaller, more mobile ARTHUR system. COBRA is a mobile long-range system with a detection range of 40 km and coverage of 1.600 km2. It is capable of locating and classifying up to 40 batteries in two minutes.

Radar is typically attached to an artillery battery or their support groups, and can also be used for correcting battery’s own fire. Basic technique is tracking a projectile for a sufficient time to record a portion of the trajectory; this can be either a continuous track or a composition of several individual interceptions. In the latter case, by measuring azimuth and distance of a projectile, flight path and its origin are calculated. Once a trajectory segment is captured it can then be processed to determine its point of origin on the ground by overlaying extrapolated trajectory with digital 3-D maps of the terrain.

fig4-7

One very basic problem is locating projectile in the first place. Modern AESA radars can cover a wide area, but with conventional radars (especially early manually-operated ones), acoustic detection was used to point radar in the right direction. Once located, the radar tracks it; due to small sizes involved, radars are typically of higher frequencies than usual, operating in C, S and Ku bands (though X band is also common).

More modern systems can detect howitzer shells at 30 km and rockets/morar shells at 50 km. They also use INS and GPS for precise determination of radar’s own coordinates, necessary to accurately determine target’s location, and can use datalinks to pass data for counterbattery fire. This allows quick counterbattery fire as soon as the point of origin of projectiles has been determined.

This has forced the artillery to switch away from its stationary tactcs, increasing the importance of mobile artillery systems. These systems practice what is known as “shoot-and scoot” tactics, where artillery must be able to rapidly engage the enemy, switch to new firing position and reengage the enemy. This allows them to avoid counterbattery fire, which takes about two minutes to hit back, and even that only if everything works perfectly (15 s to detect and calculate origin of the rounds, 2 s to send call of fire, 13-15 s to calculate return fire, 15 s to open fire and 15 s for projectiles to reach the targets). If the artillery pieces are towed and not ready, it can take 10-12 minutes for them to return fire (15 s to detect and calculate origin of the rounds, 2 s to send call of fire, 13-15 s to calculate return fire, 7 min to hook off the guns and get the battery ready, 3 min for the first gun to fire) – times recorded by the_shadow. That being said, towed artillery is difficult to physically destroy, so it can still be effective, assuming that adequate cover for crews and ammunition is available.

Counterbattery radars are also important in naval application, as landing forces require from a shipboard system to fill the gap between landings and the operational capability of the radars brought ashore. This can be done through either provision of dedicated shipboard systems, or sparing some resources from multipurpose AESA arrays already installed on ships.
Another application where counterbattery radars are increasing in importance is defense against unmanned aerial systems. AN/TPQ-53 has proved itself capable of tracking and identifying multiple drones while at the same time tracking incoming ordnance.

Further reading

Hrvatski Vojnik, Broj 81, 13. Siječnja 1995., ISSN 1330-500X (Croatian Soldier, No.81, 13. January 1995., ISSN 1330-500X)

http://nigelef.tripod.com/tgtacqcb.htm

http://www.usni.org/magazines/proceedings/1998-04/counterbattery-sea

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Categories: weapons

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12 replies

  1. Reblogged this on josephhokayem.

  2. I wonder if there was a way to use ground to ground Anti-Radiation Missiles to take out these counter-battery radars. These radars are no doubt a very specialized piece of equipment. You don’t need to destroy the vehicle even, just the radar dish and the whole thing is worthless until it gets a replacement. Another option is to prepare a second battery. This is how it would work:

    1. Your artillery fires the moves (shoot and scoot).
    2. Enemy radar is online and their artillery fires
    3. You use the enemies radar signatures to launch anti-radiation missiles (ground to ground rocket artillery with anti-radiation warheads) or even an anti-radiation shell (gun artillery)

    It might be a way to win an artillery duel.

    Maybe if they could make a passive counterbattery fire (they do for sound right now), using IRST it would be able to correct this problem.

    • “I wonder if there was a way to use ground to ground Anti-Radiation Missiles to take out these counter-battery radars. These radars are no doubt a very specialized piece of equipment. ”

      No, there is not. Terrain would block the signal from the radar too much, and signal itself is pointed upwards. You’d have better luck with cruise missiles or actual artillery.

      “1. Your artillery fires the moves (shoot and scoot).
      2. Enemy radar is online and their artillery fires
      3. You use the enemies radar signatures to launch anti-radiation missiles (ground to ground rocket artillery with anti-radiation warheads) or even an anti-radiation shell (gun artillery)”

      That is actually how it is done, except typically it is artillery barrage aimed at enemy artillery instead of the counter-battery radar itself. But it could work.

      • Ah I see.

        The goal is to disable counter-artillery fire.

        Hmm – the only other option is to put a radar warning receiver on a CAS airplane. Then send the CAS squadron towards the location where you detected the enemy radar signal. That should work. Even with 30mm, they should be able to knock out the radar. If the vehicle is on a heavy tank chassis, it might be harder to destroy the vehicle itself, but on a light tank chassis, there’s a good chance of a kill on the vehicle.

        I wonder how heavily defended the enemy would keep a counterbattery radar unit.

  3. Beware the drones… I just saw yesterday several glider drones in the Bay Area, flying in formation in a strong head wind by the sea. They were flown with astounding precision, going up, soaring, then dashing to the ground at 50 mph, feet from the ground, then regaining their soaring position, after acrobatics. Birds, gulls, crwos, and hawks were baffled. Clearly one could weaponize such clever device, including to find out where counter-battery raddars are located. Why? The electronics has become real tiny. Thus super light, cheap…

  4. Yes San Francisco Bay Area, right in the middle, 5 miles from the big new tower there. The drones were maintening formation occasionally. I was mesmerized. They could stay completely still in the wind, like hawks, or then dash at 50 mph… BTW, I approve Trump’s strike against Assad, as I have pleaded to strike Assad for the last SIX years….
    https://patriceayme.wordpress.com/2017/04/07/syrias-assad-struck-because-pacifist-fundamentalism-leads-to-horror/

  5. And you seem to be SO proud of it… Your gloating on global plutocracy and whatever evils globalists mobilize against noble civilizations just lost its credibility, as you clearly can not connect the dots between causes and consequences. The radical Islam you like to denounce as a threat to what once was western civilization is nothing but a by-product, a Golem engineered by the same western world you like to defend. Human rights, democracy or any semblance of morality has never had anything to do with US interventions, as the whole Syrian (or ISIS) situation should make clear to anyone looking beyond CNN’s emo rhetoric and with a little sense of contemporary history.
    I understand it is hard to admit to be on the bad guys’ side, it is difficult to question the “history” lessons we are taught at school and to lift the oh-so-gentle veil of propaganda that covers our eyes. But as the body count mounts, in Paris, London or Nice, in Aleppo, Mosul or Sanaa, the “roots of evil” are beginning to show. Too bad innocent people have to die before the madness stops, be it at a Bataclan’s concert or in Raqqa’s market.
    So yes, rejoice, your dear plutocrats have done it again. Making the world global (ie their home), a little step at the time.

    • Radical islam is not “radical” at all, it is literal islam because it literally follows the writings of Mohammad. It is being used by the Western plutocrats, but it is no golem or a by-product; even if the western plutocracy had never appeared, “radical” Islam would have still been around. As for US interventions, you don’t need to teach me about those – I am well aware of what is behind them. Fact that one side is bad doesn’t mean other side isn’t, but this type of non-binary thinking is too hard for most people.

      If this was meant to Patrice, you should comment on her comment. There is “reply” function under each comment.

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