Re: [DS] Gently -- Capacity, Points

Alan Brain wrote:

> >>I think you're giving too much in one area and not in another.  I'd
have
> >>to think that if you're ballistic like Javelin, then yeah, the ADS
has an
> >>easy bead on you, but otherwise, I think the trajectory diff between
BILL2
> >>and TOW isn't much of a difference where ADS would be concerned.
> >
> >I can't refute your belief without going into classified stuff, but I
can
> >say this much: you're wrong.
>
>-->8--

And this emoticon means...? <g>

>Non-combat experiments are to be taken with a grain of salt, but at
least
>they answer this question - a Bill-2's trajectory is a lot different
from
>a Javelin's. Whether there's a difference to an ADS is another matter.
>*shrug*

Unfortunately the difference from the ADS's point of view is exactly
what 
we're discussing here :-/

Oh, BTW - there are quite a few suspicions that the demonstration shown
on 
StrategyPage had been rigged... a fair amount of extra explosives dumped

into the turret of the T-72 :-/ The explosion was rather more impressive

than it should've been...

***
John Atkinson wrote:

 >>What the sales literature you referred to didn't mention is that when
you
 >>fire a BILL you aim at the top of the target,
 >
 >Side note: Javelin (from my brief experience with a
 >simulator exactally once) doesn't work that way.

Correct. Javelin and BILL represent two different top-attack concepts 
(Dive  Attack vs Overflying Top Attack), which is why Ryan is
contrasting 
the two against one another.

I don't know where you're supposed to aim when firing TOW2B; I've never 
fired that one either in a simulator or for real :-( (I have fired two 
"shots" with a Javelin simulator though, and several with BILL2
simulators 
:-) ).

 >I may be mistaken, but IIRC it flies up above the aim point and then
drops
 >down. Don't know precisely how the ballistics work out.

Again correct. The Javelin rises *very* high above the aim point, then 
dives steeply down onto the target from high above - IIRC the final 
approach angle is around 70 degrees from the horisontal, thus the term 
"Dive Attack". The HEAT warhead of a Javelin missile faces straight 
forward, just like they do in the older side-attack missiles types 
(TOW-"anything earlier than 2B", all Russian ATGM, MILAN, Dragon etc.)

BILL2 and TOW2B are both Overflying Top Attack missiles, which means
that 
they follow an essentially horisontal trajectory which passes ~1 meter 
above the intended target. Their warheads are facing downwards, 
perpendicular to the trajectory. (The original BILL warhead was also
turned 
downwards, but not perpendicular to the trajectory.) This gives them a 
trajectory which is much lower than the Javelin one, but which at the
same 
time is considerably *higher* than the older side-attack ATGMs.

However, the controversy in this thread is not whether the Javelin flies

high or how you aim it; it is whether the BILL2 etc. fly high enough to 
group it with the Javelin for ADS purposes (my position) or if it flies
so 
low that the ADS should treat it like a side-attack missile (Ryan's
position).

***
Ryan M. Gill wrote:

 >>What the sales literature you referred to didn't mention is that when
you
 >>fire a BILL you aim at the top of the target, whereas for a
side-attack
 >>missile you aim at the center-of-mass - the hull of a modern AFV is
 >>usually less heavily armoured than the turret. This means that the
aim
 >>point for a BILL is ~1 meter higher up than it is for a side-attack
ATGM.
 >>This puts the BILL flight path closer to 2 meters above the
side-attack
 >>missile's flight path (unless the target is hull-down, of course).
 >
 >So its not a mode that one switches between in the system causing the
 >missile to fly at this path or this path, it has to do with employment
of
 >the aiming device.

Yes and no. It is both a switch in the system *and* how you use the
aiming 
device.

In the direct-attack "unarmoured target" mode (ie., when you want the 
missile to crash straight into the target and use the impact sensor to 
trigger the warheads) it flies directly along the line of sight, so in
this 
mode you aim directly at the spot you want it to hit. (Even FAS got this

part right. I'm impressed :-7 ) However, since this target mode is
useless 
against armoured targets I don't consider it particularly relevant for
the 
current discussion.

In the two Overflying Top Attack modes (basic and "soft target") the 
missile flies 1.05 meters above the direct line of sight, and since you 
want it to fly about 1 meter above the roof of the target to get the 
maximum effect out of the warheads you have to put the aiming point at
the 
top of the target.

 >>>I think you're giving too much in one area and not in another. I'd
have
 >>>to think that if you're ballistic like Javelin, then yeah, the ADS
has
 >>>an easy bead on you, but otherwise, I think the trajectory diff
between
 >>>BILL2 and TOW isn't much of a difference where ADS would be
 >>>concerned.
 >>
 >>I can't refute your belief without going into classified stuff, but I
can
 >>say this much: you're wrong.
 >
 >*shrug* Ok. So I take it that Bill flies above the trees or even
higher?

That is not implied by anything I have written. It is also quite
incorrect, 
unless the trees in question are less than some 3-4 meters tall.

 >All this really is is way off the scope of what I was trying to get
at.
 >For game purposes there isn't any difference made between the attack
 >profiles of any missiles. The game currently assumes that all missiles
 >have the same exposure to the ADS and all missiles attack the same
armor
 >as every other missile.

The current DS*2* doesn't make any difference between the attack
profiles 
of missiles. That's correct.

However, whether you're aware of it or not what you are arguing against
in 
this sub-thread is Brian B2's and my views of how the rules should be 
*changed* in DS*3* in order to reflect more realistic underlying
assumptions.

Specifically, we're talking about changing the GMS and IAVR rules to
allow 
DS3 to emulate the different attack profiles of real-world ATGMs, and 
consequently also implicitly change DS2's assumption "there are no 
top-attack missiles" to a DS3 "there are top-attack missiles".

(The reason for this change to GMSs and IAVRs is that while the DS2
armour 
distribution gives rather small differences between top and side armour
(at 
most a 1-level difference) which makes the choice of which side to
attack 
fairly unimportant, the less restricted armour distributions suggested
for 
DS3 make the choice of which armour to attack quite important indeed.)

This means that while your above observation about the current DS*2*
rules 
and their implicit assumptions is entirely correct, it is unfortunately
not 
very relevant for the current discussion...

Let's review what this sub-thread is about:

Brian's and my view is that GMSs and IAVRs should be changed to allow
them 
to choose (immediately prior to launch) whether they want to attack the 
side of the target facing the shooter or they want to attack the
target's 
top armour. Brian then commented that GMSs/IAVRs choosing the top-attack

option would be slightly easier for ADS to intercept, to which comment I

agreed. Note the "slightly", BTW.

You objected to the "slightly easier for ADS to intercept" bit by
referring 
to the RBS 56 BILL, implying but not explicitly stating that you think
that 
the BILL should be no easier for ADS to engage than side-attack
missiles. 
(It may be that this was not what you *intended* to say, but the way you

phrased it made it very difficult to interpret in any other way.)

The subsequent thread has all been about whether ADS should engage 
BILL-style OTA missiles as if they were side-attack missiles (Sagger,
older 
TOW versions) or as dive-attack missiles (Javelin, Hellfire), with you 
arguing the "as side-attack" point of view and me arguing the "as dive 
attack" one - both of us basing our arguments on more-or-less accurate 
real-world data rather than on the DS2 or DS3 game mechanics and their 
respective underlying assumptions.

 >When you compare low (saggar), medium (BILL2 and TOW2) and high
 >altitude (Hellfire) they all have a different profile or path that
they 
follow to
 >the target correct?

If by "TOW2" you mean TOW2B, then you are correct. TOW2 and TOW2A are
both 
side-attack missiles like the Sagger.

However, these trajectories can be divided into two main groups:

"So low that the ADS usually cannot get a clear shot", which includes
all 
side-attack missiles, and

"High enough that the ADS usually gets a clear shot", which includes
*all* 
top-attack missiles regardless of their exact flight profile.

 >My original point was that in the context of missiles fired from a
ground
 >platform there were situations where attacking the top armor is valid
when
 >compared to the catch all that is currently the armor attacked is the
one
 >facing the launcher (barring an air launched GMS).

I'm sorry, but I don't understand what you're trying to say here.

If you're trying to say that "the current (DS2) model (ie.,
ground-launched 
missiles always attack the armour facing the launcher) is valid for some

top-attack missiles", the yes - but *only* because DS2 doesn't really
allow 
much of a difference between front, side, top and rear armour (at most 1

armour point of difference). In other words, the DS2 way of modelling
ATGMs 
is valid only because the DS2 way of modelling *armour* is rather 
unrealistic - the features which makes top-attack missiles so attractive
in 
the real world simply don't exist in DS2.

If (which I hope) DS3 allows larger differences between the armour
ratings 
of different sides of vehicles, then the difference between side- and 
top-attack becomes a lot more important... just like it is in the real
world.

If you're trying to say something else, I can't figure out what it is
:-/

I've already said this at least once, but it bears repeating: the
important 
difference between the three trajectories is *not* how easy the incoming

missiles are to detect - it is avoiding blue-on-blue incidents with the
ADS 
raking friendly vehicles instead of protecting them against missiles.

 >>There's a very significant difference between the *horisontal*
separation
 >>between those tanks and the *vertical* distance between them.
 >
 >I can only assume then that the missile is then flying several meters
 >above the ground such that there isn't any possibility of the
(currently
 >non existent) ADS not seeing it.

I wouldn't call it completely *impossible* for the top-attack missile to

avoid detection, but as long as there's a LOS between the ADS and the 
target the ADS should have a high probability of detecting a missile 
attacking the target.

"Several meters above ground" is quite correct - AFVs are typically 2.2
- 
2.8 meters tall over the turret roof, so if the OTA ATGM is to fly 1
meter 
above the target's turret roof it'll be some 3-4 meters above ground
during 
the final part of its trajectory.

 >The closest thing we have to ADS in modern times is CIWS, Goal Keeper
(a
 >bit large for a vehicle mount) and the Russian 30mm thingy.

The closest thing to ADS we have *in service right now* is CIWS and its 
equivalents. They're rather too big to work as ground-vehicle-mounted
ADSs, 
and as I noted in a previous post the very fact that they use cannon to 
destroy the incoming threat makes them rather dangerous to the units
they 
"protect".

The closest thing *currently under development* is the vehicle-mounted 
version of the THEL (Tactical High Energy Laser), which is developed by 
TRW. Originally intended to stop everything from RPG rounds to enemy 
aircraft (at least according to the early announcements from TRW),
they've 
now narrowed the range of targets down to "short-range rockets [ie. 
Katyushas] and
artillery, UAVs, cruise missiles, pop-up helicopters". Unconfirmed
rumour 
has it that one of the reasons they dropped the anti-RPG capability was 
that no-one wanted a huge laser fire at ground-level targets right next
to 
them <g>

 >>If you have different armour ratings on top and sides, then the
 >>difference between side-attack and top-attack is definitely large
enough
 >>to capture in the game. So is the difference between side-attack and
 >>top-attack. The difference between DA (Javelin-style) and OTA
 >>(BILL-style) is however likely to be below the granularity of the
game 
rules.

Argh. This should have read "...then the difference between attacking
the 
side armour and attacking the top armour is definitely large enough to 
capture in the game. So is the difference between side-attack and 
top-attack from the ADS perspective. The difference between DA and OTA
is 
however likely to be below the granularity of the game." Sorry about
that!

 >What of then the difference between Javelin and air launched like
Hellfire
 >which is ballistic in it's path or TOW when launched from the air?

Hellfire, whether fired from the ground or from high altitudes, is a 
dive-attack missile just like the Javelin and should be treated
identically 
for ADS purposes. (In other ways, eg. range and warhead size, the two
are 
obviously quite different.)

Air-launched TOWs have lower trajectories than Javelins but higher 
trajectories than ground-launched BILLs. If the difference between the
BILL 
trajectory and the Javelin one is not important enough to make the game
use 
different rules for each of them, why would a trajectory which falls 
*between* these two warrant special treatment?

 >Also, can't one assume that by 2183, ATGM's are at least imitating the

attack
 >profile of the better ASMs that hug the surface and then finally
execute a
 >pop up and dive attack on their targets with very little time for 
engagement by the target?

We can assume that ATGMs in 2183 are ground-skimming and pop up if they 
want to make top attacks, certainly.

However, "very little time" is rather more dubious. Today's Russian AFV 
point defence systems need around 30 milliseconds to detect an incoming 
ATGM or RPG round against a very cluttered background, lock on to it,
fire 
at it and destroy it... and they do this using fragmenting explosive 
charges in mountings fixed on the main turret, and vac-tube electronics.

Granted, Russian vac-tube electronics are faster than any Western
vac-tube 
electronics, but our integrated circuits are faster still... and I would

expect electronics in 2183 to be even faster.

Most of these 30 ms are used to turn an anti-missile charge to face the 
threat (which means turning the vehicle's turret), plus the time it
takes 
for said charge and/or its fragments to move from the vehicle to the 
missile (which is intercepted some 15-25 meters from the vehicle). A
laser 
might take longer to aim (but with a good projector design able to
rotate 
independently of the main turret it may well be faster), but the flight 
time of a laser beam is *much* shorter than that of a fragmenting
charge.

Finally, keep in mind that DS2's (and DS3's, unless we change the game 
mechanics completely) ADS and PDS are far less effective against DS2
GMSs 
than today's AFV point defences are against today's ATGMs. The game 
mechanics already assume that the  GMSs have improved their performance 
more than the anti-missile defences have :-/

Regards,

Oerjan
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."