ESM?

[stormrider_sp]

I thought that my ESM mast could detect radar sources ranging more than 60nm sometimes, but its not detecting anything farther than 15nm... Is it right??

[Kapitan]

depends on what depth and what sub

[LuftWolf]

The detection range of the ESM mast is determined primarily by the height of the radar array and the ESM mast.

That is to say, there has to be an uninterrupted straight line between the ESM mast and the emanating radar mast and if the ocean gets in the way due to the curvature of the earth, then the radar signals won't get to the ESM mast so no ESM detection.

Have you confirmed that it is limited to 15nm for radar-equipped aircraft as well?

[stormrider_sp]

I just confirmed that it is due to direct ilumination, yeah. Probably aircraft and helos can detect farther. I conclued this by removing the "earth curvature" parameter from its database. Anyway, 15nm are 27km. I remember from school, the horizon was something like 80km away or 43nm??? Than it is still wrong!

[LuftWolf]

The ocean is not a perfect sphere... seastate will heavily impact detection ranges, all those waves add up to increased height (deceased detection range) over what would be predicted on a perfect sphere.

In sea state five, your submarine radar will pick up next to nothing, because the waves are almost as high or higher than the radar mast!

[OKO]

I just confirmed that it is due to direct ilumination, yeah. Probably aircraft and helos can detect farther. I conclued this by removing the "earth curvature" parameter from its database. Anyway, 15nm are 27km. I remember from school, the horizon was something like 80km away or 43nm??? Than it is still wrong!

I don't remember the real value, but this should be around your 15 miles.
At sea (real sea) I can't see anything further, even with illimited visibility and binocular on a very good weather.
And I'm supposed to have a good view (12/10 and 14/10 2 years ago)

[Rip]

I just confirmed that it is due to direct ilumination, yeah. Probably aircraft and helos can detect farther. I conclued this by removing the "earth curvature" parameter from its database. Anyway, 15nm are 27km. I remember from school, the horizon was something like 80km away or 43nm??? Than it is still wrong!

The distance to the horizon id=s effected by height of eye. So much different at 1 ft than at 10ft.

[stormrider_sp]

My math is a bit rusty but I got this:

Think as the radial of the earth is 20.000km long
I don´t know the exact height of the Arleigh Burke Surface Radar, but from a picture it is more than the third part of the ship´s lenght and less than half, so, 500ft = 150m long. Let´s imagine that is it 70m height.
Think as the ESM mast height is 0m

We can get the exact point where the horizon is by doing the following calculation:
(square triangule)

a2 = b2 + c2
400,002,800= 400,000,000 + c2
c2=2,800
c=52.92km or 26nm

is it right??
The farthest flat point in the ocean that an Arleigh Burke can see is 26nm far. So, it can for sure see a 1m mast at 26nm away, and vice versa.

[stormrider_sp]

One more thing, I checked the database to verify an information provided by Fas.org, that the Arleigh Burke is also equipped with TASM missiles in its VLS and found out that there wasn´t no TASM in there.

Can anyone confirm that the Arleigh Burke is equipped with a mix of TASM/TLAM?

[LuftWolf]

The TASM are being removed from all American vessels, as far as I know.

Often, intelligence sites will NOT update their information to reflect retired weapons and other systems on otherwise fully active and up-to-date platforms, and I really don't know why. :hmm:

[SeaQueen]

The TASM are being removed from all American vessels, as far as I know.

Often, intelligence sites will NOT update their information to reflect retired weapons and other systems on otherwise fully active and up-to-date platforms, and I really don't know why. :hmm:

They WERE removed. They've been gone since the 90s.

[stormrider_sp]

why?
was it bad??
can harpoon be stored in the VLS???

[LuftWolf]

I think they were removing it based on the expectation that the next generation Anti-Ship Missile would be in service soon, but that program got cancelled.

I'm not really to sure about the rest of the details, but I do know that our ASM missile program is much lower priority for our Navy than the Russians, who have invested heavily in ASM missile technology as a means to try to offset the other dissadvantages of their Navy and to give them a solid export product.

[stormrider_sp]

yeah, like the oscar. but the us is investing some big numbers on the Ohio SSGN upgrade. I wonder if they will equip it with TASMs.

One more thing, I was testing my Ohio a few minutes ago, and I discovered that it is IMPOSSIBLE to hit an Arleigh Burke using sub launched ASM.

Is it right?!
I mean, I launched TASMs from all of the VLS and the 4 Torpedo Tubes all at once, and none of them hit the Destroyer.

[LuftWolf]

Did it shoot them down, or did they miss? If they simply missed, then that is an aiming or enable point issue as they are generally able to home on targets when fired accurately and enabled properly.

However, in practical terms the TASM is not terribly effective. Russian ships routinely shoot down whole flights of them, and their CIWS systems are not as sophisticated as the AEGIS system of the AB DDG.

The Russian ASM missiles are modelled as being much better (more difficult to intercept) in the game, especially some of the supersonic missiles.

[Kapitan]

im real life luft wolf they still are harded to intercept there not onvincible but they are pretty hard to shoot now nd notibly phlanx goalkaeepr does nothing to ASM missiles

the SS-N-19 was tested a few years ago the CIWS or the battle cruiser peter the great used her AK650 (russian version of phlanx) and the missile just flew right on by

[Molon Labe]

Did it shoot them down, or did they miss? If they simply missed, then that is an aiming or enable point issue as they are generally able to home on targets when fired accurately and enabled properly.

However, in practical terms the TASM is not terribly effective. Russian ships routinely shoot down whole flights of them, and their CIWS systems are not as sophisticated as the AEGIS system of the AB DDG.

The Russian ASM missiles are modelled as being much better (more difficult to intercept) in the game, especially some of the supersonic missiles.

I've found SM-2s to have about 70% success in hitting subsonic missiles, and about 30% success in shooting down supersonic missiles. Likewise, the CIWS seems about 50% to 0%. Throw in the fact that with subsonic missiles you have time for multiple salvoes, and it's no wonder the TASM can't get through while the SS-N-27 tends to overwhelm.

[timmyg00]

back to ESM... IRL the range at which you can detect a contact also depends on its frequency. Higher frequencies (medium range SS/navigation, fire control, missile guidance) offer shorter ESM detection ranges. Lower frequencies (long range ss/nav, air search) have long ESM detection ranges.

At a given frequency, any platform in the air will be detectable at longer ranges than a platform on the ground.

The radar horizon (https://ewhdbks.mugu.navy.mil/rdr-hori.htm) is longer than the visual horizon. Additionally, even at the range beyond which a signal produces useful returns for the emitting platform, it can be detected by an ESM receiver.

Having said all that, it would not surprise me that there might be hard-coded ESM detection limits in Dangerous Waters, not unlike the ones discovered for passive sonar.

TG

[stormrider_sp]

I just unchecked the earth curvature parameter, now esm is detecting sources over 70nm. But the weird thing is that the AI Sub Commander don´t seem to care about his ESM!

[Rip]

back to ESM... IRL the range at which you can detect a contact also depends on its frequency. Higher frequencies (medium range SS/navigation, fire control, missile guidance) offer shorter ESM detection ranges. Lower frequencies (long range ss/nav, air search) have long ESM detection ranges.

At a given frequency, any platform in the air will be detectable at longer ranges than a platform on the ground.

The radar horizon (https://ewhdbks.mugu.navy.mil/rdr-hori.htm) is longer than the visual horizon. Additionally, even at the range beyond which a signal produces useful returns for the emitting platform, it can be detected by an ESM receiver.

Having said all that, it would not surprise me that there might be hard-coded ESM detection limits in Dangerous Waters, not unlike the ones discovered for passive sonar.

TG

That would not suprise me. I haven't found the ESM simulation all that exciting. That would explain the lack of very low signal strength contacts. I don't think I have had one less than 3. Even though you and I are the only ones that might enjoy it, I wish they had a more realistic ESM emulation. It would be nice to actually classify intercepts before having to raise the ESM mast. :|\

[timmyg00]

well, i am taking some programming courses, so maybe i'll have a primitive ESM-only sim built for next year ;)

TG

[LuftWolf]

yeah, like the oscar. but the us is investing some big numbers on the Ohio SSGN upgrade. I wonder if they will equip it with TASMs.

One more thing, I was testing my Ohio a few minutes ago, and I discovered that it is IMPOSSIBLE to hit an Arleigh Burke using sub launched ASM.

Is it right?!
I mean, I launched TASMs from all of the VLS and the 4 Torpedo Tubes all at once, and none of them hit the Destroyer.

The cruise missiles being equipped on the Ohio SSGN conversions are most likely exclusively TLAMs or other strike missiles. I'm not sure the US Navy considers it necessary to have dedicated anti-ship platforms, but I am pretty sure that the Pentagon want to expand the capability of our standoff strike forces for support of land operations.

[Ramius]

back to ESM... IRL the range at which you can detect a contact also depends on its frequency. Higher frequencies (medium range SS/navigation, fire control, missile guidance) offer shorter ESM detection ranges. Lower frequencies (long range ss/nav, air search) have long ESM detection ranges.

At a given frequency, any platform in the air will be detectable at longer ranges than a platform on the ground.

The radar horizon (https://ewhdbks.mugu.navy.mil/rdr-hori.htm) is longer than the visual horizon. Additionally, even at the range beyond which a signal produces useful returns for the emitting platform, it can be detected by an ESM receiver.

Having said all that, it would not surprise me that there might be hard-coded ESM detection limits in Dangerous Waters, not unlike the ones discovered for passive sonar.

TG

Couldnt get the link to work Timmy, but i know exactly what your on about :up: .

Like you say, im sure there is some sort of hard coded (or even db) limited range for ESM detections.
Thus elimenating effects such as super refraction, sub refraction, surface ducts etc etc etc.
Plus as well as the frequencies of the radars, other thing also effect their ranges - which again are not modelled in DW.
And before anyone says anything im not bitching about the lack of this. To put a fully modelled radar and ESM model into DW would require at least another stand alone game never mind just 2 stations within DW.

[Ramius]

My math is a bit rusty but I got this:

Think as the radial of the earth is 20.000km long
I don´t know the exact height of the Arleigh Burke Surface Radar, but from a picture it is more than the third part of the ship´s lenght and less than half, so, 500ft = 150m long. Let´s imagine that is it 70m height.
Think as the ESM mast height is 0m

We can get the exact point where the horizon is by doing the following calculation:
(square triangule)

a2 = b2 + c2
400,002,800= 400,000,000 + c2
c2=2,800
c=52.92km or 26nm

is it right??
The farthest flat point in the ocean that an Arleigh Burke can see is 26nm far. So, it can for sure see a 1m mast at 26nm away, and vice versa.

I very much doubt that the mast head is that high ( and its not something i can remember off the top of my head :oops: )

But using the figures you use...

70m and 0m

this gives the following

Radar Horizon - 13.57Nm
Visual Horizon - 11.75Nm

[stormrider_sp]

how did you get there? Any classified info involved?

[Kapitan]

stuff the maths use a calculator :D

[Ramius]

how did you get there? Any classified info involved?

Nope, just a simple google search :up:

To be honest, im not 100% sure if its that accurate anyway, but heres the link

http://radarproblems.com/calculators/horizon.htm

:know:

[compressioncut]

how did you get there? Any classified info involved?

Nope, just a simple google search :up:

To be honest, im not 100% sure if its that accurate anyway, but heres the link

http://radarproblems.com/calculators/horizon.htm

:know:

I'm not really closed up on radar theory, because it's boring and not my job (I should pay attention to AREPS briefs on occasion), but keep in mind that the same factors that effect sound wave propagation in the ocean effect radio wave propagation in the atmosphere, so that calculator is pretty theoretical. But I also have no clue how complex the meteorlogical model in DW is, either.