Talk:Sonar

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128.189.151.122 (talk) 19:01, 17 December 2007 (UTC)

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Contents

[edit] Fisheries Echosounder Manufacturers

There are many, many fisheries echosounder manufacturers, HTI is not one. Reference removed.

[edit] ASDIC

The article contradicts itself as to what "ASDIC" means. Anyone know what it is supposed to stand for, or is it like BNC? Thanx 68.39.174.150 22:59, 26 May 2005 (UTC)

The article's defintiions are accurate. The article does not contradict itself - it accurately conveys the two alternative forms seen - both terms are frequently encountered and reported as alternates in the same reference.

For ASDIC see: http://uboat.net/allies/technical/asdic.htm

[edit] Target Motion Analysis

TMA requires that the submarine to change it course in order to exclude incorrect solutions of the target's location and trajectory.

Image:TMA.gif

Suppose the blue circle is your own ship, and the blue line indicates the course and speed. Yellow lines indicate the bearing of the target over time. There exists two solutions for the target. If the course of the target is left of the bearing lines, then the intersection of the bearing lines represents the maximum range of the target from ownship. If the course of the target is on the right of the bearing lines, then the intersection represents the minimum range to the target. Suppose ownship basically did a U turn, the next few bearing lines will help determine the location of the target. I know this isn't the best explanation, but one could look up guides on the 688(i) simulation games to have a better explanation of TMA

Actually, TMA does not require that the submarine change its' course for an accurate solution. There are a few different ways to lower the +/- of the bearing and range solution. Changing own ships' course can aid in the solution; frequency/bearing rate ananlysis; finally, the best of all worlds - more than one sonar platform (ship, air, submarine, directional sonobuoy) in contact.

[edit] Bogus return power levels

The article give "hypothetical" examples of 20W emitted power and 4W returned power. These figures look extremely suspicious. Radar usually emits kilowatts of power and listens for milliwatts or microwatts of power reflected from targets. I'd expect similar order-of-magnitude differences for sonar. --QuicksilverT @ 20:41, 5 December 2005 (UTC)


Yeah, the maths was rubbish. I've tried to sort it out. Greglocock 10:49, 28 December 2006 (UTC)

[edit] Target Motion Analysis

I am not an expert on SONAR however, if my understanding is correct, the Towed Array SONAR (TAS) gives two simultaneous readings for bearing, one of which is incorrect or 'ambiguous bearing'. In order to identify the true bearing of the target, the submarine should change its course (even by a few degrees). There is no mention of the ambiguous bearing in the article and may be that's what has caused the confusion of changing course and TMA. StarChaser 11:18, 11 January 2007 (UTC)Ali A

[edit] Alexander Behm?

German Wikipedia says: Alexander Behm erhielt am 22. Juli 1913 das Reichspatent Nr. 282009 für die Erfindung des Echolots

That means something like: Alexander Behm got in 1913 the patent for Sonar for inventing it. —Preceding unsigned comment added by Droschmisch (talk • contribs) 21:55, 16 June 2006 (UTC)

earl d. hernan

[edit] Sonar as a Weapon

I remember reading a few years ago about a proposal to use a large ship based sonar array as a CIWS system against incoming torpedos; using phased array technology to hit them with a focused over-pressure wave. I forget whether the intention was to simply blind the seaker-head or (IIRC) to actually damage it. Does anyone know of a good reference source so this can be added to the page? ANTIcarrot 12:29, 25 April 2007 (UTC)

Sounds like a fantasy to me. I imagine the proposer got a few mill to investigate it from the DoD! Greglocock 23:55, 25 April 2007 (UTC)


[edit] Acoustic Emission?

"Acoustic emission measurements can also be made for crack detection." I don't get what acoustic emission from cracks is doing here. How does that involve ranging or location? Just because it uses sound doesn't mean it's sonar. I'm going to chop it out, and whoever stuck it in there can justify it here if they want to put it back in. Tarchon 18:07, 5 June 2007 (UTC)

Let me clarify this since I just realized how someone's going to jump on it - AE is primarily used as a crack detection techique, not a mapping technique. In _some_ implementations of AE multiple receivers are used to infer the location of the crack in the solid via time of flight analysis. You could perhaps consider this to be some kind of "passive sonar," but under such a broad definition of sonar, you would have to consider every use of sound to infer location as some kind of sonar. Like when you hear a sound and know which direction it's coming from, would that generally be considered sonar? I don't think so, and AE location is only sonar in that extremely broad sense. I guess part of the problem is that in marine terminology especially the term "passive sonar" is often loosely used as kind of a dump term for virtually any kind of sound analysis, but I think we should be a little more restrictive. I think I'm going to move the AE thing down to the passive section and make it more tentative. Tarchon 20:12, 5 June 2007 (UTC) (originally 19:12, 5 June 2007 UTC)

Actually, I'm just going to leave it deleted - not being aquatic is the critical point for exclusion. Otherwise, this article could include everything from medical ultrasound to lunar seismology. Tarchon 20:12, 5 June 2007 (UTC)

[edit] Sonar not just sound propagation

At the start of the page it says that sonar is about underwater sound propagation. It is more that that and should say that it is about underwater sound applications.Adresia 12:11, 24 June 2007 (UTC)

[edit] Who is Lewis Nixon?

The work of Richardson, Fessenden and Behm is well documented, but I have never come across the name Lewis Nixon before. Please supply a proper reference to his work (not an internet link) Thunderbird2 15:04, 1 July 2007 (UTC)

I do not see what is wrong with the references provided. If you google "Lewis Nixon sonar", you will get dozens of references to his invention. Lewis Nixon was a prominent shipbuilder of the time and was instrumental in several major ships. --rogerd 19:12, 1 July 2007 (UTC)
The problem with the internet references is that they are not verifiable. I am interested to learn more about this man, but there are no citations in his Wikipedia biography to check out. If he really did invent sonar, he should be acknowledged, but I see no hard evidence for this assertion. How did his sonar work? What materials did he use? Why did it take the combined efforts of two European physicists (Paul Langevin and A B Wood) to repeat something that had been done more than 10 years before in the USA? etc. Please tell us more Thunderbird2 19:30, 1 July 2007 (UTC)

I return to this point 4 weeks on. I still know almost nothing about how Nixon's "sonar" is supposed to have worked, and whether he actually made something or whether it was just an idea that he patented (or didn't patent?). According to wikipedia's guidelines on verifiability, a "Surprising or apparently important" claim that is "not widely known" requires "multiple high quality reliable sources". Last time I checked, the intute link [1] returned a "page not found" error. It seems to me that this claim is an important one that fails the test for multiple reliable sources. Therefore it should be removed from both sonar and Lewis Nixon. Comments anyone? Thunderbird2 14:15, 29 July 2007 (UTC)

I can't find any real sources mentioning Lewis Nixon's invention of sonar, so I'm going to remove the claim from his page and also from here. TomTheHand 13:23, 13 August 2007 (UTC)

I have removed the claim from this one also, but I'm not sure how to deal with wikibooks. Thunderbird2 15:25, 13 August 2007 (UTC)

I just deleted the two sentences that were lifted from about.com. We'll see if they pop back up. TomTheHand 15:32, 13 August 2007 (UTC)

[edit] Multibeam echosounders

There is a serious dearth of information on multibeam echosounders on wikipedia. The MBES article itself is very small, while the topic only had a passing mention (and until now no links) in both the sonar and echo sounding articles.

I've put in the links, and will have a go later at sorting out the three articles. (Probably best to sort out the multibeam echosounders article first, so it will be easier to work out how much they should be described in Sonar and Echo Sounding). Wardog 16:16, 23 September 2007 (UTC)

[edit] wikipedia

wikipedia is crap and needs to be edited by professionals instead of people who don't know what they're talking about it. But the free knowledge is definitely a great idea. —Preceding unsigned comment added by 128.200.69.133 (talk) 22:12, 19 November 2007 (UTC)

[edit] Something is Wrong

"In 1916, under the British Board of Invention and Research, Canadian physicist Robert Boyle …" Robert Boyle?! That is complete nonsense. Would someone who knows something about Sonar please rectify this. 128.189.151.122 (talk) 19:01, 17 December 2007 (UTC)

Apparently it's not nonsense, but of course it's not that Robert Boyle. I've added the middle name to the link, making it a redlink (for future expansion). -- Coneslayer (talk) 20:41, 17 December 2007 (UTC)
The book Shield of Empire says that scientists in France were developing an active system, no date given. And also the Lancashire Anti-Submarine Committee in the Mersey and Menai Straits. These areas were not ideal so the work was transferred to the Clyde, initially Ardrossan. In the meantime the Clyde Anti-Submarine Committee had been set up using scientists from Glasgow University, it took over the Shandon Hydropathic Hotel on the Gareloch. Some scientists were transferred from Aberdour. A few ships were fitted out at Parkeston Quay in the middle of 1918 but they were too late to have any effect on the war. —Preceding unsigned comment added by Jmb (talk • contribs) 14:24, 25 January 2008 (UTC)
The French work (by Langevin and Chilowski) is already mentioned in the article. Thunderbird2 (talk) 15:18, 25 January 2008 (UTC)
I was just adding a bit more detail about the UK work in case wanted, I thought I had better include the reference to France of someone would get upset! --jmb (talk) 16:58, 25 January 2008 (UTC)
I see. The book you mention Shield of Empire is unfamiliar to me, but I wonder whether it may shed some light on a controversy that arose here some months ago. Does the book mention Lewis Nixon anywhere? Thanks Thunderbird2 (talk) 17:30, 25 January 2008 (UTC)

[edit] Sonobouy Development Reference

The point about sonobouys being developed by the British in 1944 is a bit misleading, as the US was also developing sonobouys at the same time (AN/CRT-1). Edit needed?Wdonzelli (talk) 04:19, 2 January 2008 (UTC)

[edit] Mathematical sonar modelling

This is a bit OT, but I'm having a hard time navigating (!) sonar research papers, and I'm on the hunt for a state space sonar model (x'=Ax+Gw; y=Cx+v). Does anyone know if any current research is done on sonar simulation models and sonar estimates? —Preceding unsigned comment added by 130.236.245.182 (talk) 10:55, 19 February 2008 (UTC)