Do I understand this sonar SSP stuff correctly?

[timmyg00]

Originally Posted by MarkShot

TG,

Thanks very much for your time to review and comment. I shall now sail forth with much greater confidence. (If only the crew would stop their infernal wispering when I turn my back!)

No problem. One thing I should have mentioned was that the shadow zone operates as much to hinder the hiding sub as it does to help it; if its sensors are within the shadow zone, it will be as blind to other subs as the other subs are to its presence.

And don't worry about the whispering. It's your navy, you can make your own rules, and bring back flogging to keep them in line.

TG

[XabbaRus]

Oh my head is spinning

You know I thought that if SSP is such that speed is increasing with depth then the speed of sound is slowest near the surface and faster deeper down and therefore I would have thought that the deeper sub would pick up the shallower sub cos the sound gets to him that little bit quicker...

I really need to read up on this.

Actaully what would be good would be a diagram for each condition

eg....Positive gradiet Sub A can hear better Sub B, Sub A can hid better.

Negative Gradier...same thing

etc and etc....

Always has been a headf**k for me...

[Bellman]

Good stuff - posted it up at 'Tips and Tweaks' with credits.

No doubt Landlubber will encompass it too.

Just give the crew 'chips with everything' but please no beans !
Mind with pay these days its 'caviar and...'

[MarkShot]

Bellman,

Don't look to me for any materials ... with EAW I was an expert at online H2H ... I knew it and others did too. With SC and SCX, I wouldn't enter the water without a life guard on duty.

XabbaRus,

Part of the whole reason I started this thread is that in many discussions I have seen, the interpretation of the SSP is completely inverted.

In regards to the speed of sound in water, I think the issue of the SSP is not so much where might two sounds created at the same time and different locations be heard first due to the relative speed of sound travel ... refraction (bending) is the thing ... the issue is where the two sounds might be heard at all and the degree that the sound has attentuated or gotten lost in the background.

Interesting but OT note:

I was watching the History Channel regarding Civil War Combat. A particular segment was talking about how important sound was to battlefield commanders in terms of having a sense of what was going on. In particular, they were looking at the Gettysburg battlefield and how certain "acoustic shadows (as called in the ACW)" may have led to certain ill informed decisions during the battle. Remember that ACW battles had lots of smoke, since smokeless powder had yet to come into use.

[Bellman]

I would quite simply like to know from SS what layer features are actualy in the sim and how they are implemented.

The manual outlines three ocean environments claimed to be modeled in DW. (3 paras. just over a page)
Player observations seem to report patchy, irregular, sketchy and infrequent experience of any effects.
Possibly ths is real ?

If the effects are modeled then how ? Is it a Banquos ghost dice throw accompanied by variable water conditions ? :hmm:
What are the software mechanisms ?

It would be great if Jamie could take the chair and answer some of our questions.

[timmyg00]

Originally Posted by The Bellman

The manual outlines three ocean environments claimed to be modeled in DW. (3 paras. just over a page)
Player observations seem to report patchy, irregular, sketchy and infrequent experience of any effects.
Possibly ths is real ?

Yes, I'd say that these reports reflect the ambiguity and random effects of a large fluid environment - much like our atmosphere. And when have you ever known meteorologists to be 100% accurate? The SSP, and how sound will behave because of it, is not predictable to the degree that it will always do what you expect.

TG

[Bellman]

TG,

Thanks - I will take that to mean then that you as an ex-officer accept that the sim is reasonably 'realistic' in this area.

[Dr.Sid]

I tested a lot yesterday. I was trying to test how deep goes the surface noise. I found several things: you can set sea state to 0, which leads to absolutely quiet sea. You can see contacts at great distances and there is no noise on waterfall displays AT ALL, unless you go too fast. Very interesting (very unrealistic, bug good for some types of tests or training).
The difference between surface noise at sea state 1 and seastate 5 is quite small when you are deep. Wilder seas makes surface noise go deeper. At seastate 5 I started to see effects about 350ft (just where the layer was), at seastate 3 about 150 ft, seastate 1 is hard to say, but it is quite shallow. It affects you in PD but then it dropes quite fast.
The layer effectivnes (I tested it too) seems to depend of 'steepnes' of SSP. Several times during this testing I was able to really loose NB lines with sphere sensor. I was moving on the border of detection range. Sometimes there is only very faint darkening on NB lines.
I was even once able to see layer effects on BB display ! It happened with seastate 1, so there was not there was not much noise in layer depth. I had 2 lines on NB sphere sensor. After crrosing th layer I lost the higher line and the other got very dark, it almost vanished too. On BB, you could see line getting thinner on slow display. On fast display, the already very thin line vanished !
All these changes happens instantly in the moment you cross the layer depth. Surface noise changes gradualy. Layer effects are wasy to see only on faint contacts. You ususaly get not SNR change, because it is 0 all the time.
There are also other noises .. sensor washout, noise from extended masts, noise from opened tube doors, noise fro explosions .. all these can make your contacts weaker, so watch out !
SSP in DW can't be exactly reproduced. You only set SPP type (all test was made with convergence zone), but the depth of layer (and maybe steepnes) is random.

[Bellman]

Interesting test results and thanks for sharing them.

I think given software limitations we have to accept clean cut offs and randomisation. I have observed the fading
tonals and sometimes an exciting experience where you get a fleeting mirage like glimpse of long distance
tonals swithching on and off with SSP performance.


If the long range hearing bug cant be fixed in a patch perhaps the game balance could be restored by
increasing the subs baffle areas ! And/or stopping the feature where torps explode on CMs !! :hmm:

[timmyg00]

which "long-range hearing bug"? :hmm:

TG

[Rip]

Originally Posted by PeriscopeDepth

Is this how it is real life concerning bottom reflection? It's always struck me as weird that mud is better at 'bouncing' sound than sand.

Thanks

Sand is rough and porous reflecting the sound waves at different angles. Ocean mud is smooth and flat, although it doesn't take much for something with mass to disturb it sound reflects very well off of it. Actually better than some hard bottoms that are rocky or unflat. Mud is almost always nearly flat.

[Dr.Sid]

[quote="timmyg00"]which "long-range hearing bug"? :hmm:

At least Kilo and MH60 sonar can hear contacts at unrealistic distances.

[Bellman]

TG, Kilo BB is over- efficient is'nt it ?

My 'long -range hearing bug' was vague.

[OKO]

Originally Posted by The Bellman

TG, Kilo BB is over- efficient is'nt it ?

My 'long -range hearing bug' was vague.

not BB, only cylindrical BB, the conformal looks clean

[Bellman]