Experts brainstorm on anti-submarine systems

[vivINDIAN]

KOCHI: Stealth submarines capable of launching long-range missiles are a threat in any naval warfare scenario. Enhancing the detection capability of the anti-submarine warfare systems is of vital importance in such situations.

Indian Navy experts and scientists and engineers from the Defence Research and Development Organisation (DRDO) met to discuss the challenges in the development of airborne systems and sensors involved in anti-submarine warfare at a national workshop in Kochi on Friday.

"Unlike the threats from the surface and air during any naval war, the threat that comes form under water, from submarines, is the most unpredictable. The biggest advantage in war at sea is having airborne surveillance systems mounted on aircraft or helicopters operating from ships," said the Indian Navy's assistant chief of naval staff (ACNS), Rear Admiral D M Sudan.

Delivering the inaugural address at the workshop, he said that the Navy always supported indigenization in its systems and worked closely with DRDO scientists so that user-inputs can be incorporated in the systems at the design development stage.

"The helicopter-mounted dunking sonar is ideal for detecting submarines. Once the submarine is detected, the helicopters can launch an attack on their own or along with the ship. This is a big advantage against a submarine hiding in the waters," he said, adding that lot of progress has been made on the low frequency dunking sonar (LFDS) which is being developed by DRDO's Kochi-based Naval Physical and Oceanographic Laboratory (NPOL).

Replying to a query on the sidelines of the workshop, Rear Admiral Sudan said that reorganization of the DRDO into clusters, as recommended by the Rama Rao committee, will help in the laboratory-industry-services relations in the development of indigenous systems.

Vikram Sarabhai Space Centre (VSSC) director (R&D) John P Zacharia, in his keynote address, spoke on the need to indigenize and maintain the quality of every bit of the system. "All our computer systems have a micro-processor developed by us. Just like you see the Intel processor for all MS systems, we have fabricated our own and named it Vikram 1601. So no company in the world can hold our work to ransom by denying us technology. We don't use anything from outside. Every bit and piece is developed by our own R&D," he said.

source:TOI

 

[HariPrasad]

Great news. Increase defense budget and spend More on R & D. I am particularly impressed by Vikram 1601. Every peace and component should be ours.

 

[kbd-raaf]

It's sad that ISRO had to develop their own processors.

There should be private enterprise in the country to do this.

 

[invincible]

Great.... Now they have to only channelise this technology to private industries

 

[Skull and Bones]

Submerged magnetic anomaly detector dispersed over a wide region should be the answer.

 

[Shankranthi]

It's sad that ISRO had to develop their own processors.

There should be private enterprise in the country to do this.

Necessity is the mother of invention. US & EU embargo forced ISRO to take that path. Those days there was no private industry who could take up this challenge.

Hopefully the future looks brighter.

 

[neehar]

It's sad that ISRO had to develop their own processors.

There should be private enterprise in the country to do this.

hopefully industry will evolve.drdo faced similar situation in earlier stages but most of the missile parts today are outsourced to indian companies .fabcity is not yet completely developed in india we planning to establish a new one in delhi mumbai corridor.perhaps things will be better a decade later.

 

[Echo_419]

Submerged magnetic anomaly detector dispersed over a wide region should be the answer.

 

[anant_s]

Here i'll try brother

Magnetic Anomaly Detection (MAD)


Another method of detecting a submerged submarine is through the use of MAD equipment, which uses the principle that metallic objects disturb the magnetic lines of force of the earth.


Light, radar, or sound energy cannot pass from air into water and return to the air in any degree that is usable for airborne detection. The lines of force in a magnetic field are able to make this transition almost undisturbed, however, because magnetic lines of force pass through both water and air in similar manners. Consequently, a submarine beneath the ocean's surface, which causes a distortion or anomaly in the earth's magnetic field, can be detected from a position in the air above the submarine. The detection of this anomaly is the essential function of MAD equipment.


When a ship or submarine hull is being fabricated, it is subjected to heat (welding) and to impact (riveting). Ferrous metal contains groups of iron molecules called "domains." Each domain is a tiny magnet, and has its own magnetic field with a north and south pole. When the domains are not aligned along any axis, but point in different directions at random, there is a negligible magnetic pattern. However, if the metal is put into a constant magnetic field and its particles are agitated, as they would be by hammering or by heating, the domains tend to orient themselves so that their north poles point toward the south pole of the field, and their south poles point toward the north pole of the field. All the fields of the domains then have an additive effect, and a piece of ferrous metal so treated has a magnetic field of its own. Although the earth's magnetic field is not strong, a ship's hull contains so much steel that it acquires a significant and permanent magnetic field during construction. A ship's magnetic field has three main components: vertical, longitudinal, and athwartship, the sum total of which comprises the complete magnetic field, as shown in figure 9-3.


The steel in a ship also has the effect of causing earth's lines of force (flux) to move out of their normal positions and be concentrated at the ship. This is called the "induced field," and varies with the heading of the ship.


A ship's total magnetic field or "magnetic signature" at any point on the earth's surface is a combination of its permanent and induced magnetic fields. A ship's magnetic field may be reduced substantially by using degaussing coils, often in conjunction with the process of "deperming" (neutralizing the permanent magnetism of a ship); but for practical purposes it is not possible to eliminate such fields entirely.


The lines comprising the earth's natural magnetic field do not always run straight north and south. If traced along a typical 200-kilometer path, the field twists at places to east or west and assumes different angles with the horizontal. Changes in the east-west direction are known as angles of variation, while the angle between the lines of force and the horizontal is known as the angle of dip. Short-trace variation and dip in the area of a large mass of ferrous material, although extremely minute, are measurable with a sensitive magnetometer.


The function, then, of airborne MAD equipment is to detect the submarine-caused anomaly in the earth's magnetic field. Slant detection ranges are on the order of 500 meters from the sensor. The depth at which a submarine can be detected is a function both of the size of the submarine and how close the sensor is flown to the surface of the water.


Improving MAD detection ranges have proved extremely difficult. Increasing the sensitivity of the MAD gear is technically feasible, but operationally, due to the nature of the magnetic anomaly, is not productive. The magnetic field of a source, such as a sub, falls off as the third power of the distance; hence an eight-fold sensitivity increase would serve merely to double the range. Additionally, magnetometers are non-directional; the physics of magnetic fields do not permit the building of instruments that would respond preferentially to a field coming from a particular direction. Hence, a valid submarine caused disturbance frequently is masked by spurious "noise". Also, the ocean floor in many areas contains magnetic ore bodies and similar formations of rock, which can confuse the signal. Further confusion comes through magnetic storms, which produce small but significant variations in the earth's field.

MAD equipment is primarily used as a localization/targeting sensor by aircraft with optimum employment being by helicopters considering their smaller turn radius. Additionally, fixed-wing ASW aircraft MAD configurations are fixed in the tail boom, and helicopters tow the sensor on a 25 - 55 meter cable below and behind the aircraft, which reduces "noise" caused by the helicopter. Because of the relatively short detection ranges possible, MAD is not generally utilized as an initial detection sensor.

UNDERWATER DETECTION AND TRACKING SYSTEMS Chapter 9

Dipping Sonar