False Sonar Contacts

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vettim89
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False Sonar Contacts

Post by vettim89 »

As part of the comments about a recent new scenario in the scenarios and mods sub-forum, a poster suggested the scenario designer add biologics so that players would not be able to assume every under water contact was a submarine. While this indeed may be a necessary work around due to game mechanics, it struck me as "odd" for lack of a better way of putting it. My knowledge of SONAR is largely based on novels such as "The Hunt for Red October" which I fully recognize may mischaracterize how sonar works for dramatic effect. That said I do have basic knowledge of how sonar works, the systems involved, and how the SONAR department interacts with the Subs commander. My problem is that I would think any reasonably trained SONAR operator would be able to distinguish a biologic from a potentially man made noise fairly quickly. For those of you that have first hand knowledge, is that statement true?

My limited knowledge of sound propagation in water tells me that SONAR is not like underwater RADAR. Sound's movement through water is very unpredictable. I takes time to analyze a contact's characteristics and if the contact is faint it may take a long time to be sure of what is generating the sound. I have always disliked CMO/CMANO's way of depicting sonar contacts with the box of varying size and location that tends to "bounce" around. In my mind that is not how Target Motion Analysis (TMA) works in real life. My understanding of how TMA works in real life is that it starts with only a bearing. Then through monitoring the bearing changes over time the submarines crew (with now almost complete automation) is able to calculate an estimated range to the target, its speed and course. Initially because of the way sound travels in water even the bearing would no be 100% accurate. So in my mind the way TMA should be represented is initially as a cone that eventually narrows to a line of varying length. As the TMA improves the line shortens in length over time to a point or maybe small circle or box. Not that I expect the devs to make this change, but only to point out OMHO on how it should be

So with the preliminaries out of the way, I was wondering if instead of adding biologics to a scenario that a designer should instead add a "false contacts" side where there are actually clones of the enemy forces. Then set up a event with the trigger of "unit detected" with the specificity set at class. When the event fires a message box pops up informing the player that he has been chasing a false contact and the unit is deleted. Does that make sense and does it parallel real world experience better than having a bunch of whales the player has to chase down

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Rory Noonan
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RE: False Sonar Contacts

Post by Rory Noonan »

I thought about this quite a lot when designing The Silent Service scenarios. Scale is really important, probably the most important factor in deciding how to handle spurious contacts. In a single-unit scenario it's better to have more spurious contacts; both to keep the player interested and in suspense, and to add some variability to small scenarios so they don't have an essentially predetermined course. In a large theater-level scenario there's already a lot going on and adding too many spurious contacts might overwhelm a player, not to mention the CPU. If they serve an effect like masking enemy movements, providing tactical uncertainty, or simply just improving immersion by being realistic window dressing then it's worth having them. The trick is to balance the two.

When it comes down to which DB entities I use to model spurious contacts, that's also situation dependent. There's the old stand-by of biologics (we recently improved the AI of these entities so they better mirror the behavior of their real life counterparts, as well as adjusting the sonar model to better account for their unique sound-generating properties), which work especially well in submarine-centric scenarios. There are also various combinations of acoustic, magnetic, visual and active-sonar false contacts, including new-ish entities like lost shipping containers, wreckage, oil slicks, etc. You can strategically place these, but I find it better and far quicker to use a Lua script. Check the .lua files included with the CMO install to see some examples, particularly in Game_Setup.lua scripts.

You can definitely add in platforms as spurious contacts, but it starts to get a bit tricky there. With using actual false contact entities (whales, rocks, whatever) the simulated narrative is basically:
Contact detected ('It's underwater') -> Classified type ('It's probably nothing') -> classified class ('It's a rock'); all simulated using the sensor models and AI.

If you use a proxy to ensure you get a specific kind of false positive, the simulated narrative is:
Contact detected ('It's underwater') -> Classified type ('It's a diesel sub!') -> classified class ('It's a romeo!'); all simulated using the sensor models and AI.

You then have to make that work for the player's understanding of how the scenario is panning out. I prefer to just use the false contacts and let the players imagination run wild in the unknown phase [:)]
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Rory Noonan
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RE: False Sonar Contacts

Post by Rory Noonan »

ORIGINAL: vettim89
My problem is that I would think any reasonably trained SONAR operator would be able to distinguish a biologic from a potentially man made noise fairly quickly. For those of you that have first hand knowledge, is that statement true?

No. If it were, there would be a lot more whales in the south Atlantic from 1982 onwards [:)]
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Gunner98
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RE: False Sonar Contacts

Post by Gunner98 »

I was wondering if instead of adding biologics to a scenario that a designer should instead add a "false contacts"

I add both, but not as clones of enemy forces. I see no need for the added complication.

I think the question needs to be: what are you trying to achieve?

I don't treat CMO as an acoustic simulator, the same as I don't treat it as a a Fight Simulator. When I add false contacts and biologics I am trying to give the player distractions and perhaps a bit more to worry about. Some sonars in some conditions will almost immediately identify them for what they are. Other, older or less capable sonars won't, especially if you place a them in difficult ocean terrain.

I also add them for aesthetic reasons, wrecks on underwater reefs, fish with fishing fleets etc.

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Randomizer
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RE: False Sonar Contacts

Post by Randomizer »

ASW scenarios in CMO are my favourite so I always use at least some false contacts and or biologicals. These have randomized start locations and one one occasion I set up events to redeploy them at random times. This, in theory, provides the Player with variable background "noise" as he conducts operations. Not sure if it delivered the desired experience though since I never got any feedback one way or the other.

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thewood1
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RE: False Sonar Contacts

Post by thewood1 »

"I don't treat CMO as an acoustic simulator, the same as I don't treat it as a a Fight Simulator."

Probably one of the most cogent comments about avoiding over-engineering the game and a scenario.
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HalfLifeExpert
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RE: False Sonar Contacts

Post by HalfLifeExpert »

As I said in my comment on that scenario thread, I think that as long as there are enemy submarines in the scenario (or even just a sub on your own side), there should be biologics and false contacts. It's just the nature of the ocean.

In fact, I had an idea for a while for scenario building. Perhaps there should be a feature where, instead of manually adding biologics and false contacts, have a feature where the designer can designate an area and instruct the side (biologics) to randomly populate that zone with biologics and false contacts, with options for approximately how many and types, so that you could, say, not include schools of fish and small false contacts.

ORIGINAL: Rory Noonan
ORIGINAL: vettim89
My problem is that I would think any reasonably trained SONAR operator would be able to distinguish a biologic from a potentially man made noise fairly quickly. For those of you that have first hand knowledge, is that statement true?

No. If it were, there would be a lot more whales in the south Atlantic from 1982 onwards [:)]


In addition, CMO models Sonar tech of a wide range of generations. Sure the modern stuff would somewhat easily identify a whale, but what about the tech from the 60s, or as stated above, the early 80s with the Falklands War.

ALOT of ASW ordinance was wasted in that conflict on false contacts. Ultimately the Argentinians deployed only one submarine in the war.

ORIGINAL: Gunner98
I was wondering if instead of adding biologics to a scenario that a designer should instead add a "false contacts"

I add both, but not as clones of enemy forces. I see no need for the added complication.



I agree. There really isn't any reason to make dummies of specific units. Having an unknown Goblin---> False contact is enough.



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BeirutDude
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RE: False Sonar Contacts

Post by BeirutDude »

ORIGINAL: Rory Noonan
ORIGINAL: vettim89
My problem is that I would think any reasonably trained SONAR operator would be able to distinguish a biologic from a potentially man made noise fairly quickly. For those of you that have first hand knowledge, is that statement true?

No. If it were, there would be a lot more whales in the south Atlantic from 1982 onwards [:)]

What he said, and yes my ASW experience in the 1980s is biologics are a huge issue with ambient noise. Look up Snapping shrimp! We lost Soviet subs due to them be very active.
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Randomizer
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RE: False Sonar Contacts

Post by Randomizer »

In fact, I had an idea for a while for scenario building. Perhaps there should be a feature where, instead of manually adding biologics and false contacts, have a feature where the designer can designate an area and instruct the side (biologics) to randomly populate that zone with biologics and false contacts, with options for approximately how many and types, so that you could, say, not include schools of fish and small false contacts
You can pretty much do all of that with Lua scripting that executes when the scenario is loaded. Another event timeed maybe 10-seconds after loading activates the mission(s) as necessary. The big thing to remember when using Lua like this to disable the event once it's been tested and found to deliver the desired results. If you don't, every time you open the scenario the script adds to the false contact/biological population and eventually your ocean will be solid contacts if you edit the scenario frequently. I learned this the hard way!

-C
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