the object detection method in the sub-marines?

Question

i wanno kno the methodology which is used by sub marines in navigation under water and object detection under the water n above the column

Answer 1

Submarines use sonar (SOund Navigation And Ranging) for object detection. Similar to radar, a signal is sent out and the echoes are picked up and analysed to determine what sort of objects are reflecting the signal.

To navigate, the crew plots their movement on a chart in order to determine where they are.

Answer 2

. The main object detection method in submarines is SONAR ( SOund Navigation And Ranging). Active sonar uses sound pulses which bounce (echo) off objects and return to the sub, where the patterns of returned echos, missing echos and weak echos can be used to determine where there is something around the sub, and where there isn't. The Navy probably has imaging sonar, similar to the ultrasound used to examine the inside of the body, but they are not talking about it.
. A similar method is passive listening (passive sonar). You just use microphones to listen to the sounds out there. You use multiple microphones to be able to determine the direction a sound is coming from, and you use computer based recognition software plus the ear of an experienced sonar technician to recognize what the sound is coming from. Passive sonar doesn't give away the users position because the user doesn't make sound pulses, as in active sonar.
. Another method is to use an electric coil to measure for magnetic anomalies, which would indicate where there are sizable magnetic objects nearby.
. Yet another method is the measurement of electric fields which surround some things. This has limited use, because many things are not surrounded by an electric field.

Answer 3

Submarines - U-Boats


There is something unique about diving a submarine - the U-869

U-550
U-853
U-869
There are several German u-boats in the region, most notably the U-853. There are also a number of American submarines sunk in the area.

Department of the Navy Policy Regarding Custody and Management of Sunken Naval Vessels and Aircraft Wreck Sites




U-853 Chart


U-853

Type: Type IXC/40 U-boat, Kriegsmarine, Germany
Built: 1943, Germany
Specs: ( 251 x 23 ft ) 1051 displacement tons, 48-56 crew
Sunk: Saturday May 6, 1945
sunk by destroyer escort USS Atherton - no survivors
Depth: 110-130 ft

The U-853 claimed the last victim of the Atlantic war in US waters, and then became the last U-boat sunk in US waters - all after the official end of the war. Either her captain never got the news, or he didn't care. Towards the end of the war, when most of the older commanders had been lost, U-boats were often captained by youthful ( brainwashed ) Nazi fanatics, a number of whom fought on even after the surrender.

In any case, we'll never know, as a Navy task force that happened to be in the area turned their full attentions to the situation, and sank the U-853 in short order, with all hands lost. In fact, they did enough damage to sink her several times over. Today the sub lies intact and upright on the bottom, with two large blast holes in the hull. The first is just forward of the conning tower, with a diameter equal to the width of the hull. The second is of similar size near the stern. It is easy to drop down into either hole and look around, but penetrating further into the confines of the hull would be much more difficult.

Answer 4

It is called sonar. It involves create a pulse of sound and listening for that pulse to come back. The time of travel of the sound (short time for close object, longer for far object, or never for nothing ahead) is mathematically converted to distance (considering speed of sound in water at current temperature). Fish finders also use that active ranging technique looking down into the water. Some Polaroid cameras used the same idea for focusing - bounce a sound off the subject and set the lens for that distance).

Answer 5

Sonar. (SOund Navigation And Ranging.)

By sending a series of sounds out in a direction and then 'listening' for the reflected sound, one can locate nearby objects and the sea floor, etc.

http://en.wikipedia.org/wiki/Sonar

Answer 6

SONAR (and it's sophisticated computerized systems). underwater GPS.