Muy buena data, PanZZer!!!
Video (impresionante, muy buena calidad del video)
http://www.youtube.com/watch?v=AEXKjBTG9iM
Ver:
http://warfare.ru/?linkid=2179&catid=271
EL SS-N-29 / RPK-9
Medvedka-
VE anti-submarine rockets es similar al ASROC de USA. Consiste en un MISIL cuya cabeza de guerra es un pequeño torpedo de 400 mm antisubmarino.
SS-N-29 / RPK-9 Medvedka
Target engagement:
range: m 0 ... 20,000
depth: m 15 ... 500
Total weight of the shipboard system with four missiles: kg 12,000
Missile
- weight: kg 800
- calibre: mm 400
- Launch mode inclined
Total weight of system with eight missiles: kg 19,400
Combat crew: men 1
Operational climate zone cold and tropical areas
---------- Post added at 08:30 ---------- Previous post was at 08:07 ----------
Encontré "ALGO" sobre Guerra ANTISUBMARINA
TACTICS 101: ANTI-SUBMARINE WARFARE (ASW): PART 2 - THE TOOLS OF ASW
Fuente:
http://harpgamer.com/harpforum/index.php?showtopic=3527
In Part 1, we learned the basics of naval oceanography, and in large part, how sound behaves in the subsurface ocean environment.
Now, in Part 2, we move to the tools of anti-submarine warfare (ASW), the sensors, platforms, and weapons. Much of the material contained here is probably "old hat" to seasoned Harpoon players, and certainly generally available to anyone who is willing to take the time and effort to dig up the information.
The purpose of this "Tactics 101" discussion, however, is to provide a workable foundation for those who may be completely new to naval warfare and its concepts. Part 2 tries to touch on many of those concepts.
A. ANTI-SUBMARINE WARFARE (ASW): A VERY SHORT HISTORY
War never changes (there's my
Fallout 3 quote of the day (IMG:
http://harpgamer.com/harpforum/style_emoticons/default/tongue.gif) ), but in the case of anti-submarine warfare (ASW), it has perhaps changed just a little.
The emergence of unrestricted submarine warfare in World War I and the early days of World War II led to grievous (and unanticipated) losses among all major naval powers and their merchant navies, and in turn, threatened both their economic lifelines (the sea lines of communication, or SLOC) and their only means of deploying troops to distant foreign shores.
The danger now posed by submarines to what had been, up to that point, somewhat of a grand surface war, was not particularly welcomed by those on the receiving end. In the words of the First Sea Lord, Admiral Lord Charles Beresford, circa 1900, submarines are "under-handed, under-water, and damned un-English"!
World War II was a watershed event for several major developments in undersea warfare. The Battle of the Atlantic saw the Kriegsmarine's U-boats pitted against emergent (and increasingly potent) ASW technologies as American and Allied forces herded their convoys to Europe. In the Pacific, US Navy submarines waged their own offensive war against Japanese SLOCs. The development of active sonar or ASDIC, believed to be an acronym for "Allied Submarine Detection Investigation Committee" (but in any event, with Canadian roots. Ahem! (IMG:
http://harpgamer.com/harpforum/style_emoticons/default/wink.gif) ), is a prominent example of emerging ASW technology during WWII.
Submarine performance during WWII was optimised for surface operations, and accordingly, the submarines of the era were more properly termed "submersibles". The first true submarine did not emerge until the end of the war (too late to be of any consequence in affecting the outcome) in the form of the German Type XXI. The new boat sought to address shortcomings in previous designs that were being vigorously exploited by Allied ASW efforts after 1943, most particularly the low submerged speed and endurance of the U-boat. (The Type XXI design had fallen into Soviet hands at the conclusion of WWII, leading in due course to the Project 611 (NATO codename Zulu) class submarine). The number of operational German U-boats peaked at some 240 hulls in March 1943, but by this time the Kriegsmarine force faced - in the British Royal Navy alone - some 875 ASDIC equipped surface escorts, 41 escort aircraft carriers, and 300 Coastal Command patrol aircraft. The tide had turned.
The final moments of German Type IXC-40 U-boat U-185
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/u185.jpg)
Image credit: S. Burbridge, "Final Moments", subart.net
In the post war era, and throughout the Cold War, as the hard lessons (and promising technologies) of WWII were developed and improved upon, the punch and counter-punch of ASW continued to develop at a fervent pace.
This included such rapid post war developments as the teardrop hull form (derived from the USS
Albacore (AGSS-569) design, circa 1948), the emergence of nuclear powered propulsion (from Admiral Hyman G. Rickover's USS
Nautilus (SSN-571), circa 1951), and the arrival of the ballistic missile submarine in the mid 1950s.
The evident teardrop hull form of the USS
Albacore
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/Albacore_launching.jpg)
Image credit: US Navy.
Submarine warfare in the modern era has been much less exciting, or perhaps more accurately, much less outside the gaze of the public eye. The examples of successful engagements, both by submarines and against them, are fairly well publicised.
For example, the sinking of the Argentine cruiser
General Belgrano by the British Royal Navy nuclear attack submarine HMS
Conqueror during the 1982 Malvinas war and, on the other side of the equation, the destruction of the Pakistani Navy submarine PNS
Ghazi during the 1971 conflict with India.
Much less well known are the countless times during the Cold War when submarines have attempted to affect, directly or indirectly, the course of geo-political events by their very presence, without a shot ever having been fired.
For example, the deployment of HMS
Dreadnought to the Malvinas in November 1977 under the auspices of Operation Journeyman; or the report that a Dutch Walrus class sub was stationed off Kotor during the 1999 Kosovo conflict and tasked to engage any Yugoslavian submarines that might emerge to threaten NATO ships.
In modern times, submarines have been more notable for tasks that defy traditional undersea warfare, such as launching cruise missiles against distant shore targets, or delivering special operations forces ashore to conduct clandestine small unit operations.
Suffice to say, undersea warfare - both from the point of view of the submariner, and from that of those attempting to hunt him down - has been a complex, fluid, and militarily important affair. It remains so today. And, notably, the see-saw battle of how to find, hunt and destroy submarines - and on the other side, how submarines evade, hunt and attack their enemies - continues to push technological boundaries.
B. SONAR: THE MAINSTAY OF ANTI-SUBMARINE WARFARE (ASW)
Stealth is arguably
the defining characteristic of the submarine. The foremost, and by far the most difficult task in the ASW cycle, therefore, is actually finding them.
The acronym ASW has sometimes been translated as "awfully slow warfare", and this is probably a good description. A couple of anecdotal references serve to highlight this portrayal of ASW: Being in a submarine is like "being stuck in the boiler room of your high school for several weeks"; or, that the weather on a "sealed people tube" is always the same, “69 degrees and fluorescent”. (IMG:
http://harpgamer.com/harpforum/style_emoticons/default/biggrin.gif)
One can rest assured that it is an equally mind numbing exercise for the crew of the ships and aircraft that are scouring the ocean for a hint of an enemy submarine, the proverbial search for a "needle in a haystack".
When ASW does get exciting, however, and perhaps more than a little nerve wracking, is when you finally do get that "contact". So, the question naturally follows: How does one get (and ultimately prosecute) a contact?
1. Active Sonar
As we learned in Part 1 of this discussion, active sonar operates much like active radar, sending out a burst or pulse of sound energy (the "ping") through the water, which then reflects off a target and returns as a reflection (or echo) to the sonar transducer.
A single transducer has little directional control over the ping, but by arranging or stacking multiple transducers in an array, and using special signal processing techniques, it is possible to use "beam forming" to send active sonar pings in specific directions.
The Sonar 2051 transducer array aboard Oberon class submarines
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/Sonar2051_array.jpg)
Image credit: web.ukonline.co.uk.
Generally speaking, the power of the transducer will dictate its maximum range. It also directly impacts signal frequency, since the longest ranges will be achieved with the lowest frequencies, and therefore only the largest transducer array will be able to produce the necessary long wavelengths.
All of this means that, in order to increase the transmitted power for a given array configuration, it is usually necessary to increase the size of the array. The necessity of a large sonar array obviously leads to physical limitations, especially when space aboard a warship or submarine is at a premium. Large arrays can add significant drag and require large power sources together with their supporting electrical and electronic equipment.
Hull mounted sonar arrays are typically cylindrical in shape, to give good coverage outward and downward, while those fitted to modern submarines are often spherical in shape, providing a much wider vertical field of view (useful in the subsurface environment, where you need coverage both above and below).
Active sonar arrays are generally mounted in the bow or keel, giving good coverage ahead of the ship, except in the area directly behind the array (the "baffles"; more on those later). Sound absorption materials are mounted directly behind the array, both to protect the occupants of the ship or submarine from the very loud sound energy (recall, up to 250 decibels!) and to prevent reflections back into the system. Streamlining and shielding around the array is done both to reduce drag and to reduce self-noise (including flow noise created by the passage of water around the array).
Modern surface ships and submarines are also likely to have a "suite" of active and passive sonars (a collection of bow, hull, flank, and/or towed systems) rather than relying on a single system.
Sonar suite on the Type 212 submarine
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/sonar_212.jpg)
Image credit: Gerwalk, subpirates.com
As we discussed in Part 1, surface ships or submarines performing ASW will only rarely employ their active sonar, as it may be heard at over twice the distance (and given the proper acoustic conditions, much further) it can effectively return an echo. Banging away with active sonar in the blue water ocean environment typically serves only as a beacon for lurking enemies or, worse, invites a spread of torpedoes or cruise missiles in your general direction.
There are circumstances, however, where active sonar is useful or even preferable. (Always keeping in mind the drawbacks already mentioned, of course). For example, in shallow water, where your towed array is unavailable (due to the risk of it hanging up on the bottom) or where the topography prevents good acoustic conditions (e.g. no CZ formation).
Active sonar may also be your only useful choice when dealing with diesel-electric submarines, since these are extremely quiet when running on their batteries. Here's an (alarming) analogy to get an idea of just how difficult (with thanks to Scott Gainer): Try to locate a refrigerator by listening for it from outside the house. (IMG:
http://harpgamer.com/harpforum/style_emoticons/default/ohmy.gif)
2. Passive Sonar
The preferable approach for detecting enemy submarines has historically been the use of passive sonar. It is the instrument of choice for ASW, and as stated, active sonar is most often relegated to the attack phase or special circumstances.
As already discussed, passive sonar involves an array of dedicated hydrophones, or the receiver portion of an active sonar array, being used to "listen" for the acoustic signals generated by a target. As with active transducers, hydrophones can be arranged in an array to improve beamwidth and directivity.
A dedicated passive hydrophone array is much lighter and considerably less complex than an active transducer array, generally because it does not have the same high power requirements. Conformal arrays, placed alongside the length of the ship or submarine (often the latter), take advantage of this reduced weight and complexity.
As mentioned in Part 1 of this discussion, a ship or submarine's self-noise, both narrowband and broadband in combination, forms its "acoustic signature". This signature can be exploited by an enemy's passive sonar to identify the target. For example, the broadband noise from a target's propellers (generally of low frequency, less than 1000 Hz) can be detected and demodulated to measure the shaft or propeller blade rate (blade rate tonals) - a useful identifier. (Narrowband noise is typically plotted and shown on the famous "waterfall display").
3. Variable Depth Sonar (VDS)
To improve the ability to hunt for submarines that might be hiding in shadow zones or below the thermocline (the "layer"), the Variable Depth Sonar (VDS) was developed in the 1950s. A VDS employs a streamlined body (the "fish") which contains the transducer and is towed behind the ship. In conjunction with the speed of the ship and the length of the tow cable, and by employing control vanes and depth sensors, the fish can be deployed at depth.
The principal advantages of VDS, of course, are the ability to move the transducer away from the ship's self-noise, penetrate the layer, and provide 360 degree coverage by placing the transducer behind and below the baffles.
VDS does have its limitations, however. Early models (such as the SQS-9) were streamed over the side, a rather cumbersome method, though in later practise the fish was streamed from the fantail via a hoist or winch system. The system does restrict ship maneuverability while in operation, and its bulky equipment is difficult to handle during inclement weather.
Thales TSM 2640 Salmon VDS aboard Royal Danish Navy frigate
Thetis (F357)
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/TSM2640_Salmon_VDS.jpg)
Image credit: www.naval-technology.com, SPG Media Limited.
In recent years, the VDS has been supplanted by the linear towed array for ASW work, while VDS systems have become more specialised tools in the field of mine countermeasures (MCM). In this role they are often equipped with high frequency side scan sonars which are short ranged but provide excellent resolution, sufficiently high in most cases to perform imaging of the bottom and object classification.
4. Towed Arrays
During the Cold War, when the North Atlantic was the main hunting ground of both NATO and Warsaw Pact submarine forces, the low frequency passive towed array sonar emerged as the prime ASW sensor for surface ships. Exploiting advances in signal processing, and taking advantage of the excellent acoustic propagation characteristics in the deep sound channel (DSC), towed arrays were capable of detecting and holding contacts at ranges at dozens of miles.
Unlike a VDS, in which the sonar array is encased in a streamlined body or "fish" at the end of a relatively short tow cable, the towed array or "streamer" comprises a hose or sheath of an elastomeric material (such as rubber) between 2 and 4 inches in diameter and containing numerous transducers (typically of ceramic piezo-electric design) or receivers arranged in a linear fashion. The array can be thousands of feet (even miles) in length.
The towed array's sheath is filled with an acoustically transmitting material (typically a fluid) that provides structural integrity, dissipates internal heat, and provides some isolation from flow noise. Since the array's diameter has a direct correlation with flow noise, it is desirable to reduce the diameter of the array to as small as possible. This is difficult from an engineering point of view, but even so, modern "thin line" towed arrays have been able to achieve a minimum diameter of about one inch.
In addition to the engineering and design obstacles, towed arrays have their own characteristic problems: these include boundary layer noise; internal self-noise caused by waves propagating between transducers inside the array; or external self-noise or "cable strumming" caused by towing the cable through the water. The cable may vibrate, that vibration is passed into the array, and is picked up by the transducers.
A fundamental problem with towed arrays is that the position of the hydrophones or "nodal points" within the array is inherently unstable. Because of ocean currents, their position in the array, the speed of the host platform, or other factors, their relative positions are changing continuously. Because of the negative effect this can have on acoustic properties, it is important to monitor the relative positions of the nodal points of the array at all times. One common method is to use multiple "birds" clipped onto the tow lines, each comprising a transducer used to calculate the range between nodal points. The results are used to determine the shape of the array, which in turn is critically important to its performance.
Towed array
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/SQR-19_towed_array.gif)
Image credit: Federation of American Scientists.
Surface Ship Towed Arrays
Notably, towed array systems have offered the surface ship, for the first time, the possibility of parity with the submarine in passive sonar capability. The long range detections made possible by towed arrays are of limited value to surface ships, however, without some means of localizing and prosecuting an enemy submarine contact. And, of course, this is the function performed by aircraft acting in conjunction with the surface ship.
From an ASW point of view, the US Navy surface fleet evolved slowly from a sensor/weapon suite based on the SQS-26 hull mounted active/passive sonar set of the 1960s, the RUR-5 ASROC (Anti-Submarine Rocket) stand-off weapon, and the SH-2 Seasprite LAMPS I (Light Airborne Multi-Purpose System) helicopter.
By the mid 1980s, it had become a system based largely on variants of the SQS-53 hull mounted sonar first introduced in 1972, the SQR-19 TACTAS (Tactical Towed Array) passive towed array, and the longer range SH-60B Seahawk LAMPS III helicopter. (There never was a LAMPS II system).
Along the way, during the period of this evolution, the US Navy conducted:
(1) Its first experiments and deployment with the ITASS (Interim Towed Array Surveillance System) towed from VDS fish on the Dealey class destroyer escort USS
Van Voorhis (DE-1028) in 1970;
(2) Its first experiments and deployment with an interim tactical towed array design (the SQR-18) on the Knox class frigate USS
Moinester (FF 1097). The SQR-18 was a passive towed array some 800 feet long streamed from the SQS-35 IVDS (Independent Variable Depth Sonar) body on a tow cable nearly 5,600 feet long. (The SQS-35 was evolved from the EDO Model 983, a 13 kHz VDS).
(3) Its first experiments and deployment of a higher speed tactical array (the SQR-19) on the Spruance class destroyer USS
Moosbrugger (DD 980) in the early 1980s.
The most recent, new generation towed arrays, such as the British Sonar 2087 and the US SQR-20 Multi-Function Towed Array (MFTA), employ both active and passive arrays, exploit the range advantages of the low frequency range, and are more tolerant of high speeds.
Submarine Towed Arrays
Submarines can deploy "fat line" towed arrays using a process known as flushing, wherein water is pumped into the tube to exert pressure upon and hence deploy the array. The US Navy's TB-16 is an example of a fat line towed array, which consists of an acoustic detector array weighing some 1,400 lb, measures about 3.5 inches in diameter, and 240 feet long. The TB-16 array is towed at the end of a cable some 2,400 feet in length.
Alternatively, submarines may deploy "thin line" towed arrays using mechanical handling systems. A thin line array comprises an outer sheath or hose that contains the hydrophones and supporting wiring and electronics. When the array is deployed or retrieved, it is fed through a guide by a handling system. The US Navy's TB-23 is an example of a thin line towed array.
Winch system for the Type 212 submarine's TAS-3 towed array
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/towedarraywinch_212.jpg)
Image credit: Gerwalk, subpirates.com
Advances gained from commercial off the shelf (COTS) computer processing (such as that made available through the Advanced Rapid COTS Insertion, or ARCI, program) has substantially reduced cost while significantly improving processing power, which in turn permits the use of powerful new algorithms for better towed array detection ranges. The US Navy's TB-29 thin line towed array, for example, is a version of the legacy TB-29 array utilising commercial off the shelf (COTS) telemetry.
Towed array technology has advanced rapidly with longer, multiple line systems that provide increasing number flexibility for submarine based ASW. Many existing Navy tow cable systems have single coaxial conductors, 1-2 kilometers in length, within which power, uplink data, and downlink data are multiplexed. These systems typically run at uplink data rates of less than 12 Mbit/sec due to the bandwidth limitations of a long coaxial cable.
Operational beam formers for towed arrays have traditionally assumed the array geometry to be straight and horizontal aft of the host platform, but in reality there is always some deformation in this geometry. "Chain link" and "stiff stick" models have been used to estimate towed array position and heading, but the newer arrays (such as the TB-29) are equipped with their own sensors to accurately determine the position of the array and its heading. This is more accurate than either of the previous methods, and will be used to optimise TMA solutions.
5. Dipping Sonars
Dipping or dunking sonars are a variant of the VDS concept. While principally fitted aboard helicopters, they can also be found aboard some small patrol craft and surface ships (such as the MGK-345 Bronza (NATO Rat Tail) dipping sonar found aboard Project 1241.2 (NATO Pauk) class corvettes).
While operating in the hover, a helicopter can use a winch and cable to lower a sonar transducer into the water and to the desired depth. Again, self-noise is minimal because the array is isolated from both the noise and vibration of the power source and the helicopter.
AQS-13 dipping sonar deployed from a Sea King helicopter
(IMG:
http://i471.photobucket.com/albums/rr74/cbleyte/AQS-13_dipping.jpg)
Image credit: www.solarnavigator.net
A helicopter dipping sonar typically consists of a "wet end" or transducer; a cable (at least 1,000 feet in length) and reel/winch assembly; and a "dry end", consisting of the power supply and sonar processing systems.
There are, of course, no baffles or blind spots with a dipping sonar. It has full 360 degree capability, and for the size of the transducer, most are quite capable, with source levels exceeding 200 decibels (dB) and an effective range of several thousand yards. Newer systems also have a sonobuoy interface, allowing them to process the returns from three or more sonobuoys, and the ability to communicate with friendly submarines via underwater telephone.
Power was supplied to the transducer via a lead-acid battery in most older systems, and recharged between transmission cycles, but newer dipping sonars are powered directly by the helicopter rather than by a battery.
Helicopter dipping sonars have also joined the drive to enhance capabilities in the littorals, both in terms of locating ultra quiet diesel subs and in the mine countermeasures role. Examples of the latter include the AQS-14 and AQS-20 systems.
The new AQS-22 FLASH (Folding Low Frequency Active Sonar for Helicopters) system is being fitted to the new MH-60R Seahawk (as well as other types), and is claimed to provide submarine detection, tracking, localization and classification; acoustic interception; underwater communications; and environmental data acquisition, both in blue water and littoral zones. The AQS-22 transducer/receiver weighs only 100 lb and has a cable length of over 2,500 feet.
