Military Review

Find Invisible: Submarine Detection Systems

The invisible ship, capable of a sudden attack from the most unexpected point, was exactly the kind of submarine that had been thought of until very recently and remained so. The subtlety of submarines increased especially after the appearance of atomic and air-independent power plants (in the 50s of the 20th century). The twentieth century may someday be called the century of submarines. In the 21st century, the submarine fleet will either cease to exist at all or will change in a most radical way.

Find Invisible: Submarine Detection Systems

However, the submarine fleet in its current form is likely to die. The sea ceases to be a space where ships are able to remain invisible to the enemy. And this change occurred as a result of the emergence of systems that allow you to track any movement of any large underwater objects.

From noise-guiding systems to complex FOSS

History The development of submarines - and their mass construction began in the first quarter of the 20th century - is an illustration of the famous thesis about the rivalry of means of attack and defense. Initially, no means of detecting submarines submerged, did not exist at all. In the surface position of the submarine, due to the peculiarities of the design, had very little visibility. These fighting qualities, which made the submarine perhaps the most formidable sea weapons of their time, persisted until 1941. It was then on British anti-submarine aircraft aviation radar first appeared. He confidently discovered submarines that were on the surface, and the submarines of that time deserved the name not so much submarines as “diving”, because at least half of the military campaign had to go “above the water”. The boat detected by the radar did not have time to sink and was almost certainly destroyed. Almost at the same time - and also by the British - an effective sonar was created, and groups of anti-submarine ships began to confidently localize and destroy submarines in underwater position. As a result, by the end of the war, the effectiveness of German underwater fleet was practically reduced to zero.

However, with the advent of the nuclear submarine fleet, the ability to detect a submarine in the surface position disappeared - the boat no longer surfaced during the combat cruise. And to find submarines under water by the forces of search and attack groups was extremely troublesome. This was the impetus for the creation of global underwater lighting systems, especially hydroacoustic. At the same time, passive underwater acoustics, or noise-finding, became the main means of detecting submarines, mainly because of its relative cheapness, technological simplicity and the ability to detect targets at long distances. The most impressive sound system is the famous system created by the United States during the Cold War. SOSUS. It was a giant field of acoustic antennas, stretched in the Atlantic and Pacific oceans. In our near North, they were located on the whole space of the Lofoten basin - from the coast of Norway to the island of Jan Main. After the deployment of the system, the hidden passage of Soviet submarines to the Atlantic and the Pacific Ocean turned out to be almost impossible: the submarines were detected at a distance of up to several hundred kilometers.

Meanwhile, the nuclear submarine was originally a rather noisy structure. Noise first American submarines "Nautilus" и Civulf was about a hundred decibels. Ship mechanisms (engines, pumps, fans, shafts, etc.) make noise, propellers roar, water around a ship roars ... Noise reduction is the only way to counteract noise-finding detection stations and systems like SOSUS. Noise was reduced, however, for other reasons — for example, to reduce the response range of non-contact torpedo-mine bomb fuses. Designers perfected the geometry of the propellers, increased the accuracy of manufacturing shafts and machine parts, provided a system of shock mountings, vibration damping (and, therefore, noise) mechanisms, invented special hull coverings. Since the 70s of the last century, submarines reduced their noise level by an average of two years for 1 dB. Over the past 19 years alone - from the 1990 of the year to the present - the average noise level of the US NPS has declined tenfold, from 0,1 Pa to 0,01 Pa.

To illustrate: from the second half of the 20th century, the use of atomic submarines, the so-called “hunter boats”, became one of the most effective methods for detecting submarines. However, in our time, their search performance has fallen to a completely ridiculous level. According to data published in the open foreign press, the 688I SSN 772 “Greenville” type submarine (1995 built) detects the Los Angeles 688 type submarine (built 1978) at a distance from 10 to 35 km. This is an acceptable result. But modern Virginia (SSN 774, 2004, built) Greenville discovers everything from 1 to 4 km (according to an independent British expert Admiral Palmer) at a distance. If the boats "see" each other only at such distances, then their very maneuvering next to each other becomes deadly dangerous not only for the "victim" but also for the "hunter": the risk of an unexpected collision of ships not seeing each other sharply increases.

(Separately, we note that it is impossible to see any close to the truth about the noise of Russian submarines and the distance of their detection except under the "secret" stamp.)

The sharp decrease in the detection range of the noise-attenuated GAS low-noise submarines, a revolutionary event from a technological point of view, coincided with the revolutionary changes in politics - the collapse of the USSR. At the end of the 20th century, submarines of the Soviet Union (and Russia) were actually no longer regarded as a military threat to the United States and Western Europe. These two circumstances had far-reaching consequences. The United States has changed its strategy of waging war and, in particular, the use of naval forces. Instead of a global confrontation with the enemy’s fleet on sea and ocean expanses, in local wars and armed conflicts, the main task of the Navy was to deliver blows from the marginal seas to the enemy’s territory.

The SOSUS system was conserved due to a decrease in efficiency and the actual absence of the enemy. And to solve the problems of anti-submarine defense in the United States, the question was raised of creating rapidly deployable multi-element regional underwater situation lighting systems (FOSS) designed to work in the planned combat areas. The main requirement was put before the FOSS: to immediately detect any underwater object when entering the designated area of ​​responsibility. So ended the time of the global submarine detection systems.

Modern FOSS become local and complex. They must be fast-deployable, multi-element, bi- or multi-static, working on different detection principles (not only acoustic), based on network-centric architecture methods with the mandatory provision of working elements with communication and positioning from space-based systems. To date, such systems are created and tested.

Giant network

In the middle of 1990-x - the beginning of 2000-ies in the US Navy were developed and adopted for execution documents defining the tasks of the Navy and the appearance of future wars at sea. Among other provisions, these concepts included a description of the promising principles of anti-submarine warfare. It was then that the refusal of stationary passive noise-finding systems (such as SOSUS) was proclaimed in favor of active-passive sonar systems for lighting the underwater situation of rapid deployment.

What are such systems? A group of radiators pre-placed in the sea (installed either at the bottom or at a predetermined depth or towed) sends acoustic signals according to a given program in the specified frequency ranges and time intervals. These signals are received by a whole network of pre-deployed special antennas (they can be placed on submarines, surface ships, systems of dumped radio-acoustic buoys, antenna arrays placed at the bottom, etc.). This group works as one giant sonar device, which allows, in the shortest possible time, using echo signals to obtain the coordinates of a target that has come into the area of ​​responsibility. From the FOSS command center, information about the target is transmitted via space communications to the command center of the joint operational unit. Thus the location of even the most modern and quiet submarine can be immediately established - and its destruction is extremely simple.

Actually the deployment of FOSS elements can occur from a variety of carriers - submarines (using uninhabited automatic submarines based on the parent submarine, as well as light divers), surface ships, airplanes and helicopters. The main means of delivery of underwater surveillance systems is supposed to make small high-speed surface LCS ships, as well as SSGN type submarines. Under the placement of the elements of the FOSS - emitters LELFAS (Long-Endurance Low-Frequency Active Source) and receivers ADS (Advanced Deployable System) - already refitted Ohio type submarine, SSGN 726-729. In addition, next year, the main multi-purpose submarine of the second SSN 2012 sub-series will be laid out and by the 774 year SSN 784specially equipped for the delivery and placement of multi-static FOSS.

LELFAS acoustic emitters have half dimensions torpedoes mk-xnumx (length about 3 m), placed in a standard torpedo tube and designed for continuous operation during 30 day. Their signal is picked up by ADS noise-finding receivers located on the seabed - optical sonar antenna garlands.

These receivers look like a fiber optic cable with a diameter of 2 mm and a length of approximately 20 km. In each of the receiving systems there are two sections 10 km long, in each section up to 26 modules, in each module there are slightly more than a thousand hydrophone receiving signals. ADS receivers can be covertly deployed in less than five days, the installation of emitters takes even less time (they are made in the form of special buoys that can be installed including from aircraft). Lying on the ground elements of ADS communicate with command posts using uninhabited underwater vehicles - sea ​​gliders Sea Glider, performing the function of antennas.

Modern submarines have the ability to approach these systems, connect to them through special docking stations and, as a result, secretly control large areas of the marine area.

The ADS system was adopted by the US Navy in 2001 year, and today more than a dozen of its sets have been manufactured. During tests of the LELFAS - ADS system in July 2003, on the shelf near the island of Newfoundland, the range of confident detection by the system operating in the active-passive mode, PLA SSN 21 ranged from 30-35 km.

An SSGN 726-type submarine with four sets of ADS antennas on board can create an “underwater illuminated field” of about 2500 square miles.

A group of three ships of the LCS type, having deployed the ADS system and having onboard towed emitters for illumination of LFAS targets and anti-submarine helicopters, is capable of monitoring the water area with a total area of ​​more than 30 000 square x miles (96 100 km 2, which is a square with a side 310 km).

Not a single large underwater target as a result of the application of this system can go unnoticed.

The future is small

What now - to the submarine fleet as a military force comes to an end? This question is still open.

The weakness of the described FOSS lies in their local application. They can work effectively only if the fleet of the United States is the dominant force in the oceans. But if China decides to bring its nuclear submarine fleet to 2030 units by 300, of which 200 will be constantly deployed in the Pacific, it will in principle be impossible to solve the problem of anti-submarine warfare with such systems. There is no doubt that, technically, financially and organizationally, China is capable of that.

While maintaining the quantitative ratio of submarine forces, a means of countering such systems for detecting submarines can only be radical - this is a nuclear weapon, the use of which, for obvious reasons, is considered only as the most recent option. Brigade minesweepers and light divers theoretically could also be engaged in the search and destruction of emitters and receivers of the FOSS system - however, such work requires the use of a truly huge fleet, reliably covered by aircraft. In short, the game is not worth the candle.

Actually, it is already clear that the use of rapidly deployable FOSS will completely change the course of the armed struggle at sea. The use of submarines in the form in which they exist now will become almost impossible. This means that the future submarines are likely to have a fundamentally different look. Among others, for example, this is probably the most promising option: equipping large, “mother” submarines with small automatic underwater vehicles. These devices, in turn, as matryoshka, will contain other, even smaller, designed to perform a variety of tasks, from communication and intelligence to mine-torpedo strikes. "Maternal" boat will not even come close to the zone of responsibility of the anti-submarine forces of the enemy, there will go almost imperceptible, tiny, but numerous underwater robots of narrow specialization. No FOSS can detect underwater vehicles as large as a medium-sized fish.

One can only guess what countermeasures will be invented against them.

FOSS Principles

The submarine (in the center) is detected by a system consisting of a radiator towed by a surface ship, and numerous receivers: a towed antenna of a surface ship, the submarine's HAM, sonar buoys and linear antennas laid out on the ground. The coordinates of each FOSS element at any given time are known due to the satellite positioning system. The work of the ship's connection and FOSS is coordinated by space communications, the AWACS system; With any element of the compound - a submarine or surface ships - means of destruction of the detected enemy's boat can be used. The situation system is lit from both underwater and surface parts. Spacecraft, DRLO planes and surface ships are used to illuminate the surface part. Comprehensive information about the situation in the area of ​​hostilities concentrates on command posts located on surface ships and ashore.

Detection methods

To illuminate the submarine used helicopter lowered sonar station. Hydroacoustic buoys and deployed ADS array detect a submarine in a multi-static mode.

In addition to sonar, the boat can be detected by another three dozen different physical fields and phenomena caused by the actions of the boat.

The corresponding sensors track changes in the natural background of the environment, which are caused by the presence of the ship. For example, as a result of the passage of the boat, the water pressure changes, a wave of increased hydrostatic pressure is formed, which can easily be fixed. Seismic sensors can track the oscillations of the seabed caused by the passage of a submarine (the boat puts pressure on the water, and that in turn on the seabed). Due to the passage of the boat, the illumination of the underwater bottom, the magnetic field, the gravitational field of the Earth change. Finally, from a satellite, under certain conditions, you can see the wave trail of a boat, even if it goes deep under water. Modern anti-submarine warfare systems use a whole range of search tools — something should work.

Everything is under control

No one will slip unnoticed. With the help of underwater lighting systems, submarines can be traced literally immediately after they set sail.

One SSGN-726 type PLA as a means of delivering active-passive type positional quick-deployable systems with four sets of ADS antennas on board can create a “field of illuminated underwater conditions” with an area of ​​more than 2500 square miles. The map shows possible deployment options for FOSS in the basing areas of the Northern Fleet. Each circle is an area bounded by FOSS sensors in which the underwater situation is fully controlled.
Articles from this series:
And the ships have ears.
On the anti-torpedo protection of Russian submarines
Dear reader, to leave comments on the publication, you must sign in.
  1. 1c-inform-city
    1c-inform-city 30 December 2013 09: 59
    No one argues that it is necessary to develop hydroacoustics. But the article is very similar to an advertising booklet or a reprint from an amertabloid. I understood the meaning as follows: Urgently destroy your boats, especially with ballistic missiles, otherwise we will see them anyway. In the event of a real conflict, it’s half the battle to find, we still have to destroy it. By the way, our good friends do not have everything in order with the exception of torpedoes.
    1. vyatom
      vyatom 30 December 2013 12: 07
      Gentlemen, Let's not forget that our boats can shoot ballistic missiles from the ice of the Arctic, and tracking them there is quite difficult. In addition, the effectiveness of the Sosus system is very, very doubtful. In Soviet times, our boats safely overcame it. The American AUG recently failed to track an ordinary diesel boat, which crawled directly to the aircraft carrier.
  2. saag
    saag 30 December 2013 10: 37
    I just wanted to write about robots, the carrier - something like an autonomous torpedo with a manipulator, or small robots - either cut the cable or destroy the equipment yourself
  3. Fuzeler
    Fuzeler 30 December 2013 12: 08
    The author of this article, in my opinion, is a man of exclusively peacetime, and does not know that in the event of a war the sea ceases to be calm and quiet: all parties begin to actively interfere with any kind so that systems, especially the most global detection systems, begin to malfunction . Back in the early 1980s, during the exercises, it was concluded that with the number of obstacles created by anti-submarines, and the level of imitators (false targets), that submariners and submarines were not so easy to destroy each other. So do not rush, dear Mr. Nikolaev, to bury boats as a type of naval weapon)
    1. Know-nothing
      30 December 2013 12: 43
      Soviet submariners themselves about simulators spoke very unflattering
      K-258, when detached from the tracking of the US Navy CPUG, as part of the 2-x EM URO T. Spryuens and 2-X FR URO T. X., shot out:
      - MG-14 (Self-propelled interference device) - 2 pcs.
      - MG-34 (Drifting interference device) - 18 pcs.
      - HIP-1 (Hydroacoustic Imitation Cartridge) - 40 pcs.
      Fourthly, the use of EW in combat conditions, especially in such quantities, at the same time for 4 days (and not for 3 months) while being used with special maneuvering, prescribed in the guidance documents on detachment from tracking PLS and Funds, showed not only their INEFFICIENCY and the fact that they are morally yes and physically obsolete, and also the fact that they are obsolete and have proved to be ineffective methods and methods of their use, since the EW tools and documents for their use were developed in 50-60-x, and "in the yard" already was 1985 year !!! Yes, in 70-x and until 1985, EW funds were not used in such quantities, WE WERE THE FIRST !!! And then something I did not hear about it.
      SSBN “K-500” leaves the submarine base in Pavlovsk (Primorsky Territory) in the area of ​​combat patrol off the west coast of the United States. Just after leaving the base in Peter the Great Bay, they discover that someone else’s submarine is following them. Throughout the transition through the Pacific Ocean, this tracking continues. The measures taken to break away from the tracking boat did not help.

      One day a sonar report was received that he hears the noise of the opened torpedo tubes of a tracking submarine and supposedly the exit of torpedoes. In fact, they were imitators. The commander is in a panic. In his cabin, he consults with the chief and the political officer. What to do? Maybe war already? Can torpedo a tracking boat? They persuade him not to get excited. Ultimately, K-500 surfaced and was returned to base with shame.
      1. kalif2004
        kalif2004 21 May 2015 12: 19
        To describe events, you need to know what you are writing about. And you certainly shouldn't write such things about the K-500 commander. I would look at your face if you heard the noise of a torpedo / simulator / coming at you.
    2. mine
      mine 14 January 2014 22: 36
      Quote: Fuzeler
      and that level of imitators (false goals)

      do not tell people
      the only low-frequency simulator that really existed was a towed acoustic trawl (and even then its power in the low-frequency range was weak)
  4. jjj
    jjj 30 December 2013 12: 15
    This whole theory is valid for a pool of limited volume with a mass of standing water of the same temperature. Change the conditions a little and the picture is completely different. And the living ocean will always cover and hide. In the seventies they were still breaking through in the "azukhs". BDRMs in the Arctic are no longer visible even to “impromptu” moose. ”Against Virginias - pr. 955. Therefore, we will leave all the stories about“ rattles ”for history and the living pen of the fiction writer.
    In this situation, one thing is not clear: why all boats in the Middle East are black. Thirty-five years ago, the British discovered that black boats against the background of the shallow waters of this region are clearly visible from the air. And they started repainting their ships. I saw (in the pictures) the old "Trafalgar" in a sandy color
    1. Old_kapitan
      Old_kapitan 30 December 2013 15: 44
      In this situation, one thing is not clear: why all the boats in the Middle East region are black.
      Who told you that?

    2. mine
      mine 14 January 2014 22: 34
      Quote: jjj
      Change the conditions a bit and the picture is completely different.

      the author of the article is a very competent specialist, especially in accounting real sound propagation conditions ...
      1. _Slavs
        _Slavs 25 November 2016 18: 45
        In general, how many here have a specialty sonar engineer (it is a systems designer who knows a lot about water and the distribution of sounds in it)? This is not special. naval - the head of the RTS in a boat or ship. The Department of Hydroacoustic in the USSR was only in TRTI, in view of the rarity of the specialty, it was not in the list of specialties - they wrote in the diploma - an electrical engineer! Or secrecy played a cruel joke ...

        Above, the man wrote that water (or rather sea hydrology) is an assistant for the submarines and helps the experienced, smart and cunning (+ 3D maps of sea hydrology - without them too! + Intelligence data on the area of ​​the campaign or patrol) Hide the boat cap - make it invisible by entering in the shade of underwater ridges or moving along the edge of underwater canyons (there are always strong currents. But what about those beautiful pictures - hydro buoys, receivers, antennas descended from helicopters, and between them such helpless submarines rushing about ...? untruth picture (everything is remarkably simplified ):
        1. Sound (from hertz to a couple of megahertz, at high frequencies hydroacoustic sees min-turnips of the 2nd World War - on several cable ones, + now there is also underwater vision in submarines - optical and laser) from the source it spreads in a kind of zigzags from the sonar to the target and reflected the signal comes randomly to the receivers. And where is the real purpose? Adds chaos to the salinity of the water - it is different and the sound spreads at different speeds - how many cables to the target?
        2. Sound propagates to the introductory environment NOT DIRECTLY - water is not monolithic. The currents, or rather, not even they themselves, but their borders of contact with different temperatures, cavitations, the presence of suspensions and different salinity, + the near-surface jump layer (5-10 m from the surface), different depths and bottom topography, are peculiar curved mirrors for the zook! They repeatedly reflect the sound and distort the vision of the underwater space. And also diffraction and interference. Receivers must have a good selection of signals in these conditions.
        .... EW under water is also available in large quantities.

        So do not be surprised when the submarine surfaced in the middle of the order. Or two modern submarines hit each other. The sea is not predictable! Submarines can be real black holes ....
  5. bubla5
    bubla5 30 December 2013 12: 44
    But there are many ways to get through these traps, a suppression system, a clean system, or when on the contrary they give out such signals as if the area is literally teeming with boats, where almost nobody is there, so it's not so simple
    1. Old_kapitan
      Old_kapitan 30 December 2013 15: 55
      But there are many ways to get past these traps.
      There is no reception against scrap. Okromya second scrap. fellow
  6. Andof odessa
    Andof odessa 30 December 2013 14: 22
    Well, an advertisement for American power. In my unprofessional opinion, this system can be jammed like a fish. The main thing on a torpedo is to put the necessary multi-frequency generator on the torpedo and no one hears anyone.
  7. sub307
    sub307 30 December 2013 15: 01
    You need to develop everything: submarines and PLPL detection equipment. Whoever succeeds has more chances to win. Chances, but not guarantees of victory. In fact, there is nothing new in the "competition" between technical means of delivering weapons and means of detecting them. As a rule, if one of the means "suppresses" the other so much that the use of this very "other" becomes completely unprofitable - "something else" is invented. If you have time of course. This is probably the essence of the notorious "arms race".
  8. Old_kapitan
    Old_kapitan 30 December 2013 15: 38
    For a couple of years, the first article, which I with a clear conscience put a minus.
    Threat. You can also get a super-duper body armor, with a cool submachine gun, equipped with a laser sight, from Ryazan Vanka to get a sapper blade on the Bosko and go to the forefathers to give a rapport, why did you turn out so premature ...
  9. Voodoo
    Voodoo 30 December 2013 18: 15
    No wonder they say that the oceans have been studied much less than the cosmos. Only this one, in my opinion, determines the significant prospects of the submarine fleet. If we put aside the financial component, then everything is just beginning ...
  10. sevtrash
    sevtrash 30 December 2013 18: 20
    Good article, gives new knowledge. And, of course, questions arise about the real ability to perform a combat mission in these conditions. Counting on the sapper blade is a weak argument, except to attach a crowbar.
  11. nightingale
    nightingale 31 December 2013 00: 49
    it is necessary to pay tribute to the literary abilities of the author while you read only believe The author again misleads the destroyer they are sweating how to drink give the above have already described how this will happen and the author has not challenged them. now if you take five of them to equalize the price, you get a draw. Ford just doesn't have enough planes. Only this, in theory, in practice, an aircraft carrier in a compartment with protection will chase them and will finish half-blind half-lame.
  12. Sibiriya
    Sibiriya 31 December 2013 05: 37
    The article is complete nonsense.
  13. xomaNN
    xomaNN 1 January 2014 22: 09
    Well, tell me, colleagues, after all, what is it to discover submarines or surface KR? So the subfloor has an advantage in stealth for a long time to come.
    1. Know-nothing
      2 January 2014 07: 35
      Do you have an American? Yes. But most importantly, now everything goes to the fact that the visibility of the boat is determined not only by the noise level, but also by its size. And for sure this was one of the reasons for decommissioning boats of 941 Ave.
  14. vthrehbq
    vthrehbq 9 January 2014 18: 52
    Strange article. it’s really a feeling that it is copied from an advertising booklet. The reality is that existing submarines are almost impossible to detect. damn last year the English boat collided with the French, they could not find each other
    1. mine
      mine 14 January 2014 22: 31
      Quote: vthrehbq
      The reality is that existing submarines are almost impossible to detect.

      Caution! smoking bad for health.
  15. mine
    mine 13 January 2014 19: 07
    The author of this article has more than one BS behind his back. as KPL.
    Not I said, but a well-known and respected acoustics scientist at the RPF wink