Sensors

It looks like there are two camps, those that don't want to have an affect on
the battle itself (Look at what they brought in, we'd better RUN) and those
that want to be able to sucker their opponents in, of course, you could be the
sucker. With one off games the
second is a non-issue, each player gets X points you have a good idea
about the fleet size. It only becomes an issue in campaign games, and it has
major affects in campaign games.

In a campaign game I won't fight a battle unless I think I can do more damage
to my opponent than I will take. This makes knowledge of his fleet very
important.

This is what we are using for EW rules, compared to the other simple system
this one is extremely simple. No die rolls, everything is deterministic.

Yes, we realize that to fire your class 4's at max range requires enhanced
sensors. To fire a 5 at max takes superior.

One thing we are doing is ships equipped with ADFC may fire at any fighter
withing 6" of it. Also, EW phase occurs after point defense fire and dogfights
but before fighter attacks (so if you get your fighters within 6 inches and I
toast them they give no information).

Any comments?
------------------------------------------------------------------------
--
EWM/ECM

· Visual detection, within 12 inches all information on the opposing ships may
be detected visually, you may look at your opponent's sheet to see

any of their ships within 12 inches.

- Visual detection for fighters, reduce the range to 6 inches.

· Electronic detection · Within 12 inches all information as for visual
detection. · Within 24 inches apparent mass of ship (this may be modified by
ECM) · Within 36 inches targeting information only

· Enhanced sensors · Enhanced sensors take up 1 mass and cost 5 points ·
Enhanced sensors extend the range brackets by 1, so 1. Within 24 inches as for
visual 2. Within 36 apparent mass 3. Within 48 targeting information ·
Enhanced sensor information is available Fleet wide to the owning player. ·
Enhanced sensor information may be made available to any local allies.

· Superior sensors · Superior sensors take up 2 mass and cost 10 points ·
Superior sensors extend the range brackets by 2. · Superior sensor information
is available Fleet wide to the owning player. · Superior sensor information
may be made available to any local allies.

· ECM systems · Each ECM system takes 1 mass and costs 5 points · Range
brackets may be reduced by one using one or more ECM systems,
    they do not add.   So.
4. Within 12 inches mass only (although your opponent will then use visual) 5.
Within 24 inches targeting. · In mass detection ranges the mass of the ship
may be enhanced to appear as up to 50 mass greater per ECM used. For example
an ECM scout of mass 12 with 3 ECM systems could look like a capital ship of
mass 162.

· ECM/sensor interaction
· An ECM system when used for range bracket lowering cancels the affects of
enhanced sensors (so the ship acts as if it had normal sensors). · An ECM
system when used for range bracket lowering decreases the affects of superior
sensors so they behave like enhanced sensors. · ECM benefits apply only to the
ships equipped with ECM.

The question came up in a PBeM game I am running using the standard sensor
rules from FT/MT.
I ruled that the ship with large beam weapons (4+) could use active
sensors out to the maximum range of their beam weapon. I also ruled that
independent and area weapons (missiles, nova cannon,
etc.)
do _NOT_ gain this benefit.
How are other people handling this?

From: Roger Books <books@mail.state.fl.us>
To: gzg-l@CSUA.Berkeley.EDU <gzg-l@CSUA.Berkeley.EDU>
Date: Thursday, September 09, 1999 12:44 PM

> In a campaign game I won't fight a battle unless I think I

In a strategic sense, I presume you mean--there are always
targets that have to be defended regardless of cost, eh?

> This is what we are using for EW rules, compared to the

I think your ranges are way too short to be useful. You seem to go from "No
data" to "Targeting" in one jump, and that only at 36" for basic sensors. That
essentially cripples ships that rely on maneuver, since if you can see him to
run from him, his Class 3's are already pounding on you. Or am I missing
something?

> It only becomes an issue in campaign games, and

Thus my idea to remove sensor "battles" from the tabletop and limit them to
the campaign system only. This should keep both parties - maybe not
exstatic, but at least happy.

> Yes, we realize that to fire your class 4's at max range requires

This unbalances the cost of the beam weapons. Forcing them to take an
additional system for effective use defeats the purpose.

> One thing we are doing is ships equipped with ADFC may fire at any

I'm becoming more inclined to give this a try. Has anyone playtested it yet?

[snipped rules]

Your ranges seem quite short to me - even for tabletop play. It seems
that you have to get REALLY close to see much of anything.

> On 9-Sep-99 at 23:39, Laserlight (laserlight@cwix.com) wrote:

Not in a campaign game. If you are fighting a battle that you will not win,
and loss of that territory will cause you to lose, then it is time to concede.

> I think your ranges are way too short to be useful. You

You could always put a scout with your fleet or put enhanced sensors on a
capital ship, then you go to 48".

I guess you could add another range band, you know something is there, but
that is all.

I find the concept of this crippling ships that rely on maneuver kind of odd
anyway. They are inaffective until their weapons are in range, maneuver
doesn't really start much beyond where your weapons are useful.

> On 9-Sep-99 at 23:55, Sean Bayan Schoonmaker (schoon@aimnet.com) wrote:

What would you recommend, doubling all the electronic ranges?

One thing I will point out, this is for a campaign game. If I can fool you
into thinking I have a bigger fleet than I do you may run away, but if you
have full info well out of weapons range you can't fool anybody and I would
say just drop EW all together as pointless. If I can disguise my ships until
they are close enough to fire you MAY stick around not realizing that those
two ships that just came into range 24 are SDNs, whereas if you knew they were
SDN's you would have saved your assets and jumped out of system long ago.

It is also easily nullified, bring one real scout with your fleet. The way the
rules are written the sensor has a major advantage over the detected.

> Schoon wrote:

> >Yes, we realize that to fire your class 4's at max range requires

The design system was set up to discourage outrageously huge beam
weapons, so I wouldn't be very concerned about this. Besides, 1-2 Mass
extra doesn't matter much when a single C5 battery is *at least* 16 Mass... I
don't think a ship with C5s will have only a single
single-arced one :-/ Similarly the 30 extra points for Superior sensors
aren't that much for a dreadnought.

Regards,

> Roger Books wrote:

> I find the concept of this crippling ships that rely on maneuver

Completely wrong IMO. Maneuvering starts long before entering weapons range,
to ensure that *your* weapons have targets in arc, and that *his* weapons
don't, when you finally do get into range.

Of course, if you don't fly faster than 10 or so you can't really
maneuver :-/

Regards,

> Roger Books wrote:

> One thing I will point out, this is for a campaign game. If I can

This, I believe, is one of the points Schoon is trying to make. If you
can't even *detect* the enemy until the standard long-range weapons can
open fire (the lowest detection level your rule lists is "targetting
info" - after that the rule seems to imply "no detection at all"), you
can't fool anybody until it's too late anyway.

Regards,

> Roger Books wrote:

> The estimable Oerjan wrote:

You use maneuvering to make sure you get to your optimum range (and arc) and
he does not. You need to know where he is *before* you get to weapons range.
Consider the case of an IF Saber class (5 Class 2's) against an AE Alacrity
class (2 Class 4's). The Alacrity wants to maneuver to keep the Saber at least
25 MU away at all times; the Saber wants to get to point blank range, if it
can.

> What would you recommend, doubling all the electronic ranges?

Perhaps not straight doubling, but definitely spreading out the range bands.
Perhaps making the "unit" range band 24" as opposed to 12" (I know that this
almost the same as doubling as it stands).

> One thing I will point out, this is for a campaign game. If I can

If this is for a campaign game, then why not extend the ranges. Your goal
seems to be to have the two forces almost in weapons range before things
are revealed. Exdend that to tabletop distance - perhaps more with a
dedicated scou. and you haven't really lost much. Usually, forces you set up
on the table are going to have one pass before they bug out.

> "Thomas.Barclay" wrote:

> ** However, it appears just about all that can be said has been.

Sounds right, I'm going to opt out of this thread. Just because I don't reply
to any more posts in this doesn't mean you've convinced me, if you do I'll say
so.

If you want to take it offline I can (as shown) live in the "I can shout
louder so I'm right" environment if you would like that.:)

Smoke? Chemicals? Something that reacts with optical sensors not coated with
"X" optical coating? Nanites? What have you.

** And these won't bother or affect the human? Hmm. let's see. he's looking
through an open eye or through a lens. If I can fox a camera lens, I can fox
his goggles/mask. If I can hit the sensors (distributed as they are and
hardened as they are), his ass is grass. The same Nanites that can take out
hardened sensors ought to smoke him some good. And smoke and chemicals that
force him and his crew to fight MOPP4 are pretty great too.

**

If theyare reading in EM spectrum other than light we already fox radars, and
heat seekers just fine.

However we do not have the "all-seeing" sensors yet - so no one ahs
foxed them.

** Not deployed in tanks, but in other fields synthetic vision is pretty far
along (not compared to where it will be, but in terms of approaching
deployable state). Airlines and military aviation are working on (maybe
deploying already) systems that use a composite of many sensor types and
fooling one of them won't cut it. And if I can fox these things, I can fox the
human eye EASIER (this might mean taking out the human... permanently).

** You don't think the passenger airliner is a place where perception is
important? They are headed to synthetic vision for its great all weather
capability and higher SA.

** However, it appears just about all that can be said has been. Both sides in
this debate appear polarized. Perhaps we should let it die and get on to new
subjects where people might actually do more than cling to their versions of
reality <*grin*>. I'm willing to concede an extra set of eyes has some
advantages. Whether they are offset by costs I'm still unconvinced. I'm
willing to concede that today eyeballing the situation is fine. In the future,
you may well have better perceptions and more data in a useful form (no info
overload) at hand INSIDE the vehicle. Maybe not. I can agree to disagree with
the proponents of the "mine eyes must see it" school of thought. I'm just glad
the space program isn't full of them.... they learned you can trust your
equipment (most of the time) and you have to have that trust to accomplish
some jobs. I suspect if everyone had the "eyes are better" point of view, we'd
never have developed a robotics industry, today's sytethetic vision systems,
night vision, etc.....

** Whereas I agree that any system can be foxed, you get around that by
layering your systems. And if you can fox all those sensor types, then why not
just think the tank into exploding? It'd be less work. And the Human is far
less capable as far as perceptions and so probably more easily foxed yet.
Ultimately we are a system just like a mechanical system. Unlike a mechanical
system or electronic system, it is arguable if we've been getting smaller,
faster, more capable, and tougher by the generation....

In a message dated 2/4/00 4:56:42 PM Central Standard Time,
> Thomas.Barclay@sofkin.ca writes:

<< Maybe not. I can agree to disagree with the proponents of the "mine eyes
must see it" school of thought. I'm just glad the space program isn't full of
them.... they learned you can trust your equipment (most of the time) and you
have to have that trust to accomplish some jobs. I suspect if everyone had the
"eyes are better" point of view, we'd never have developed a robotics
industry, today's sytethetic vision systems, night vision, etc..... >>

I tend to agree with your point on letting it go - however the simplest
is
usually the best and last option you will have -even in the Space
program it was the pilot flying the LEM pushing the command capsule BY EYE and
star
position that let them get home during Apollo 13 - don't forget that. In
the event of so many equipment and power failures happening one right after
the other it was the Mark I eyeball that saved the crew.

> On Fri, 4 Feb 2000, Roger Books wrote:

> "Thomas.Barclay" wrote:

i think i'll follow Mr Books' wise lead. let's postpone this discussion until
more information becomes available; say, 2183?:)

tom

From: <kaime@mindspring.com>

> That's fine, so he'll be doing it. I might have some suggestions soon

Go for it! None of us have a direct line to God, and all suggestions are
welcome. We may rip em to shreds (though hopefully with some politeness), but
we may instead say "If I'm so smart, how come *I* didn't think of that?".

Some thoughts on sensors, mainly stolen from the way sonars and radars work in
naval warfare today.

These principles should hold true, regardless of whether the radiation is
standard Electromagnetic ( such as Radio, Light, Gamma Rays...), Gravitational
(via vibrating singularities and Forward Mass Detectors), or via Herr
Professor Doktor Von Kuckucksheim's Aether Perturbation and Modulation
Gornokifier (Patent Pending)

Sensors can be grouped into 2 types - Active and Passive.

Passive Sensors

Passive sensors rely on the radiation of the target being detected. As
different targets tend to have different radiation "signatures", Passive
sensors are very good for Identification.

"Those Engine Theta-Curves look like one of our old Heath-Robinson
Mk IVa's, Ma'am. Our database confirms they match those of the
Kinshasa, a Victoria-class Battlecruiser we sold to the PAU..."

Passive sensors can be either quite long ranged, or quite short, depending on
whether the target is trying to hide or not. If the target is doing a lot of
energetic stuff, like firing beam or similar weapons, or using Active sensors,
or even using a lot of thrust, then they can be detected from Yonks away,
depending on your PSB background. If you're using Fusion Torches for drives, a
Yonk could be several light years. Even if not acting energetically, targets
are bound to give out some signature: it's difficult hiding mass, it's
difficult hiding thermal emissions, and it's difficult not occulting
backgrounds. Generally, the larger the vessel, the greater the signature when
running silent, but even an escort operating active sensors will stand out a
mile by comparison.

"All Hands Here This! Rig for Silent Running! Engage Cloaking field!"

Passive sensors on the other hand are not so good for localising the target.
Tracking via passive means is a statistical process, the more measurements you
have over time, the tighter your estimate of the target's position, course and
speed becomes.

"We first detected an active transmission on the Kappa band
at azimuth 40, elevation -10, range unknown at 0100. Classification
as Military-grade ESU Active Search Sensor. We lost the
contact shortly thereafter, regaining at 0170. Initial Target Motion Analysis
suggested a range between 100 and 200 MU,
which was refined at 0340 to 130 MU. +/- 5, well outside
counter-detection range.."

Passive sensors - including data relayed from other friendly
vessels - are not in general accurate in localisation enough
to be used as fire control solutions. YMMV on this one, area.volume effect
weapons may be OK, and seeking weapons such as MT or SM missiles may just have
their homing radius reduced on the very best of solutions.

Active sensors

Active sensors don't rely on the target being co-operative
enough to emit: they operate by shining a beam of radiation in the target
area, and measuring the return. As you know the exact characteristics of the
outgoing radiation, and can make it as tight a beam as desired, you can get a
pretty accurate fix on the target's position instantly, quite adequate for
aiming weapons.

"At 2120.2, target's range was estimated as 35 MU, +/- 0.4.
We engaged active fire control, and locked on immediately at a range of
34.87365. Fire was opened at 2120.4, and several hits were registered at 2122.
Return fire commenced at 2124, with no effect..."

Active sensors are good at localisation, but not so good at identification.
The physical size of the returned energy may give you an estimate of the
target's reflective area, and hence it's physical dimensions, but you'd get
most of your identification through analysing the kinetic motions.

"Initially, target 456 was thought to be an NAC Cruiser of the Furious class.
Upon illumination by our fire control radars, it immediately executed a 90
degree turn characteristic of Kravak evasive manouvres..."

For navigational safety (avoiding errant asteroids...) any civilian ship needs
a minimal active sensor. Military ones would be
longer ranged and more powerful, but usually have a civil-grade
active sensor as well as a backup, and when they're pretending to be civilian
vessels. Fire Control sensors can be operated in a scanning mode, and indeed
some systems may be "track while scan", dual Fire Control and Search. The
signature of any military grade active sensor would be unmistakeable. It says
to all nearby "Hello, I'm definitely a warship, and you can make a pretty good
guess who I belong to, and maybe even what class I am."

Both active and passive sensors can be jammed. A good analogy is trying to see
something on a dark night. An active sensor would

> On Tue, 29 May 2001, Alan and Carmel Brain wrote:

> Passive sensors rely on the radiation of the target being detected.

I agree in principle with this, but I have a few things to note.

If we use Radar and Sonar as a reference here for principles. Passive Sonar
will give you some general information about the vessel and allow you to get
some pretty good ideas of what it could be. It'd be hard to get a specific ID
on a specific vessels' hull number with passive sonar.

Active sensors (say like the MMW radar the S-3 Viking
carries) is very fine in detail and allows one to view a picture of the vessel
based on the processed radar data. Such data allows one to determine the
class, specific
weapons/sensor/superstructure fits and after a quick look at
a data base (electronic version of Janes in 2180's anyone?) what the hull
number would likely be.

In the onld days of WWII, you could get this after you got close enough to
figure this out. Naturally there was some Jamming that one could do against
the mark one eyeball. Witness the profusion of fals bows and wakes, darkly
painted turrets with the next one back clearly defined, stacks painted a
darker color than their next and even a similar outline to vessels of much
larger classes (Scharhorst, Gneissau, Bismark, Prinz Eugen and Graf Spee all
had similar lines, several engagements had one being identified as one of the
others).

It would seem that passive at closer range would give you adequate fire
control solutions after several readings. Eventually once you got really
close, you could tell what it was.

Long range, poor detail, active would give you hard info on how big, where and
how fast it was. Not much else. It's navigational in basis or for those that
don't plan on really looking close at the enemy.

Long range, fine detail, active would give you a really good idea but also say
"Here I am look at me". How to rectify the common fitments of similar sensor
systems on different platforms is a trick (this is from the sense of
identifying an emmitter of active sensors). "Is that a Majestic or is that an
Agincourt SDN pointing its Mk 30 Fire control and ranging radar at us? They
both use the same systems..."

Perhaps a further profusion of fine-detail/poor-detail
passives would make sense?

ECM could have passive and active modes as well (though passive ECM really
aught to be "stealth") and would have chances for decoying ordinance. I'm
wondering if rather than a per shot basis one should perform a per battle
basis of a
die roll for each vessel's passive/active sensor quality as
well as ECM quality number based on the Die type.

ie at the start of the battle my Santa Maria Class BDN rolls a D10 for
Passive, a D8 for Active Sensors, a D6 for passive ECM and a D10 for Active
ECM. Each of these numbers based on their difference against your foe's
numbers would give a basis for modifying other results.

Theoretically a vessel could stack its numbers with other freindly vessels for
a shot at inferometricly influenced data or buddy jamming (if they have Area
ECM).

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Some very nice ideas here, just one bit where I can't help but
disagree/cpmment.

> On Tue, 29 May 2001, Ryan Gill wrote:

> If we use Radar and Sonar as a reference here for

Actually, as far as id-ing a target is concerned, almost the reverse is
true for 'passive radar' (ESM). A good ESM suite, supported by a
well-filled ESM database, will give you a very solid ID of a target
based on the target's emissions. So perhaps sonar isn't as good an example? In
any case, I wouldn't be surprised if modern day passive sonar has much the
same capabilities?

Cheers,

> On Tue, 29 May 2001, Derk Groeneveld wrote:

> Actually, as far as id-ing a target is concerned, almost the reverse
In
> any case, I wouldn't be surprised if modern day passive sonar has much

That assumes that targets are emmitting. A target at total EMCON will
presumably be relying on totally passive sensors. Say a vessel (in space)
moving ballistically and not thrusting.

By relying on ESM systems you are looking at the various fire control radars,
navigation radars, long range communications, search radar, weather scopes,
data links, Talk between ships radio, and other electronic garbage that ships
emmit.

Further, just relying on passive sensors to recognize a vessel will lead to
funny incidents of "seeing" a harmless tanker when in reality it is a CVA
dressed up with the same active emmissions.

The above has happened in exercises where a very large CVN (Nimitz class) was
dressed up by the crew with all of the correctly placed running lights and
apparently masquraded as a tanker in civil lanes in the Med. The Red force
guys waltzed right by it and didn't think to really check her out. "Port side
watch reports sighting a large tanker, very well..." How do you loose a Nimitz
Class CVN in the Med? Very sneakily....

If a force gets very careful about how much they emit and what they emit, they
can get very "dark" to prying eyes. Add to that in FT we're talking about
using lots of whisker lasers for close by data links, ranging data and lots of
telescopes I suspect.

Obviously when you light some one up with beams, or fire a missile salvo at
them, you've probably just announced for all around that you've got "a Leica
Astrosystems Ranging Laser and Hellseye Mark6 Beam Battery" or "a
GEC-Marconi-Lockheed Aerospace Mark 23 Fire control radar
and a Thiokol-British Aerospace Dynamics Lightingstrike
Salvo Missile launcher".

All of this goes out the window if you can tell the type of plant a ship has
just from its use of a captive singularity irregardless of the drive using
thrust or not. Passive gravitometric emmissions could tell the size and
probably the field used to keep it from hitting the reactor sides and making
the ship go boom. If its just a fancy Fusion plant with a big magnetic bottle
you're going to have to get a lot closer to tell if its a Big Merchant or a
Big Warship, by then you can probably read the hull number with your Graflex,
Inc Catadioptric Telescopes attached to your fire control systems. This all
assumes that the target at 48MU
you're looking at don't thrust at 4MU/sec/sec with enough
engine effulx for a Foch Super Carrier making it obvious its not a 150 Mass
bulk carrier).

So I guess the question is, what kind of drives are they? Thats the first
thing.

Second is how much passive emmissions do the ships give off? You know
something is there. How far beyond 54" do you know? (TK drive emmissions are
another thing, boy this long range sparky stuff gets tricky...)

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> On Tue, 29 May 2001, Ryan Gill wrote:

> On Tue, 29 May 2001, Derk Groeneveld wrote:

Yes. But so is any passive sensor.

> Further, just relying on passive sensors to recognize a

Then again, there's the same risk with active sensors. Also, you;'re
assuming everything CAN be disguised/masked (see below, engines
discussion)

> The above has happened in exercises where a very large CVN

Similarly, a sailing vessel can be given a nimitz-size reflection by
using
a simple retro-reflector...

> If a force gets very careful about how much they emit and

Yes, but you're not going to do much ranging until you've acquired the target,
meaning that EITHER passive sensors were good enough to acquire the target, OR
you had to go active anyhow.

> Obviously when you light some one up with beams, or fire a

Similar to modern passive sonar, where the noise can be related to specific
ships.

> So I guess the question is, what kind of drives are they?

Yup. So what PSB do you want to make up for your desired game effect?;)

Cheers,

> Derk Groeneveld wrote:

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> any case, I wouldn't be surprised if modern day passive sonar has much

The nature of shipbuilding makes it impossible for two vessels of the same
class to be identical, and often minor improvements are worked into the design
as it is built. The chaotic nature of turbulence also has a hand here, so two
nominally identical hulls will have similar, but distinctive flownoises.
Distinguishing between two passive contacts is not that difficult (not that it
is easy), and a tape library of previous encounters enables the listener to
identify a specific vessel. Combine this with some other intelligence (Sonar

> Ryan Gill wrote:

> Further, just relying on passive sensors to recognize a

I had heard that it was the opposite. The plucky brits (possibly aussies) lit
up their vessel as a cruise liner and sailed into the middle of a CVBG (which
couldn't warn off the "civvie" vessel without violating EMCON). [Naval
exercises are never over before the CVN is sunk]

> If a force gets very careful about how much they emit and

EMCON in FT is exacerbated by the problems of maintaining cohesion after a
jump. Everybody's FTL drive being slightly different combined with the fact
that an infinitesimal error multiplied by several light-years is
probably several AU. Unless there is some method of detecting FTL travel at
FTL speeds, invasions are probably on the lines of jump for a point that is
several
light-days away from the target, find everybody else, get together and
do a
short, in-system jump that will only have a small error, so the force
will arrive in some semblance of formation. (assuming that maneuver in
hyperspace is impossible)

> Obviously when you light some one up with beams, or fire a

Not that difficult (depending on how much wizardry is available). Passive
infrared will give a hull temperature and neutrino spectroscopy will give the
powerplant output. These two pieces of information correlate to reveal the
hull surface. It is more difficult if it is not radiating its heat uniformly,
but not as difficult as not radiating heat into space.

> So I guess the question is, what kind of drives are they?

That calculation would require specific scientific units applied to ships'
mass,

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> On Tue, 29 May 2001, Richard and Emily Bell wrote:

> The nature of shipbuilding makes it impossible for two vessels of the

Similarly, it's about impossible to rebuild EXACTLY the same frequency control
unit for a new radar etc. So sufficiently advanced ESM should be
able to tell you WHICH SPY-1 that is, once you have identified it
before... And assuming it's switched on.

Cheers,

> At 11:35 PM +0200 5/29/01, Derk Groeneveld wrote:

I'm not sure what you are saying here. Is it that Passives are like the above
ESM? I was essentially talking about Passives.

> > Further, just relying on passive sensors to recognize a

Ahh, but with actives and passives you'll have more information to make your
decision. Passives are using your eyes and ears in a dark room. Active is
using a little pen light to see a specific object. (naturally you know this)

> Similarly, a sailing vessel can be given a nimitz-size reflection by

Reflection against what? Passives? And from what aspect? (Space is 3D, much
harder to predict your aspect) It'll be hard to disguise a sailing vessel from
mm wave radar. A decent mm wave set can pick out what style of rigging one
would have.

The only thing I'd think that mm wave radar would have a hard time
with would be a very well done Q-ship. Besides, the whole principle
of mm-wave radar and its fine resolution is the basis for the ability
of Enhanced and Superior sensors to figure out what the current status of a
vessel is. ("Ok, his drives are down and geeze look at that big hole in his
port side weapons array, he's definately weak on that side sir. His VLS system
looks mostly popped too, so he's not got much fight left in him...")
> Yes, but you're not going to do much ranging until you've acquired the

Ranging can be accomplished with passives too.
Inferometric/stadio-metric triangulation.
I don't see needing Cepheid variables to figure out how far away that Eurie
BDN is...

> Similar to modern passive sonar, where the noise can be related to

I suspect that one would be able to tell what mass/drive power the
ship is by the Main drive/maneuvering drive efflux. Lots of charged
ions and you've got a big ship or a small ship using lots of power. Figure out
the Delta Vee and you've got the Mass and Drive Power at that time Pegged.
That closes your envelope of possible ships by a large margin.

> > So I guess the question is, what kind of drives are they?
;)

Hmm, Captured Singularities by 2180s? I dunno, whats the author say? Jon?

> At 6:02 PM -0400 5/29/01, Richard and Emily Bell wrote:

Hmm, the CVN captain probably turned it round on the Italians, French, and
British in the Med.

> EMCON in FT is exacerbated by the problems of maintaining cohesion

Thats what the fluff in the back says that fleets do. Usually its individual
ships out on their own in the middle of bloody nowhere.

> arrive in some semblance of formation. (assuming that maneuver in

Its my understanding from all of the Fluff that FTL is "you are here *blink*
you are there".

> Not that difficult (depending on how much wizardry is available).
Passive
> infrared will give a hull temperature and neutrino spectroscopy will

> > Second is how much passive emmissions do the ships give off?

Well, I'm looking for more fluff clarification as opposed to a calculation
really. Though I know how hard it is to get Jon to hand down decisions from on
high...:p

I'm inclined to pick something like 105 MU for passives detecting a ship that
has drives doing basic maneuvers, but that seems pretty short really. A large
ship doing thrust 3 and 4 burns would likely show up like a small comet to any
good telescope up to about an Astronomical Unit.

> At 12:19 AM +0200 5/30/01, Derk Groeneveld wrote:

That sounds right, I recall a News group thread now about WOs in Vietnam that
could tell you what batch of Russian Area and Fire control radar's were
operating in North Vietnam, which operator was at it that day and that a tube
was about to blow based on how it was running.

Course thats all passives, looking at active signatures. But again, that's an
excellent system for the day with an excellent operator behind the sensor set.
(Elites running a Superior system, It has to be a good roll)

> At 06:02 29/05/01 -0400, you wrote:

Admiral Sir Sandy Woodward refers to a incident like this in his book 'One
Hundred Days'.

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> On Tue, 29 May 2001, Ryan M Gill wrote:

> At 11:35 PM +0200 5/29/01, Derk Groeneveld wrote:

Okay, I thought you were commenting on ESM in specific.

> > > Further, just relying on passive sensors to recognize a

Of course a combination of the two is the most effective approach. No argument
there.

But as for actives being a little pen light, well, I'm not sure I agree.
Active _tracking_ is a little pen light, but active search sensors are
more like a whopping wide beam.

> >Similarly, a sailing vessel can be given a nimitz-size reflection by

Reflection would be against active sensors, of course.

Mmmm. I guess you can use mm radar in space at a lot longer ranges than on
earth; on earth atmospheric dampening greatly limits mm waves.

> The only thing I'd think that mm wave radar would have a hard time

Sounds sensible.

> >Yes, but you're not going to do much ranging until you've acquired

I'm not familiar with Cepheid variables? As for triangulation, with the ranges
involved with space combat, I doubt you could do it with the sensors on one
ship alone. I'm not familiar with inferometric ranging, so I have no clue how
that'd work for you;)

> >Similar to modern passive sonar, where the noise can be related to

Also, the drives might have unique resonance frequencies etc? Sir, we've seen
this ship before, it's.... Then again, there might be a wartime tuning of this
frequency to a different one than peacetime?

Cheers,

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> On Tue, 29 May 2001, Ryan M Gill wrote:

> At 12:19 AM +0200 5/30/01, Derk Groeneveld wrote:

Then again, they didn't have full auto database-matching, back then...

Cheers,

> At 7:17 AM +0200 5/30/01, Derk Groeneveld wrote:

Thing is, unless you are talking about the SPY Phased array systems, most are
distinct systems. The general search not being very good at
figuring accurate range and height (in the Anti-air role).

> Mmmm. I guess you can use mm radar in space at a lot longer ranges than

Lots less water vapor to absorb your signals.

> I'm not familiar with Cepheid variables? As for

Cepheid variables are stars that pulse regularly and are used to determine how
far objects are. They are a medium sized yard stick. Distances being from
inside our galaxy to the Amdromeda Galaxy or so.

Inferometry is where you use two widely spaced telescopes to give you a much
wider 'virtual' lens. The use of the Very Large Array in the
South Western American desert is an infero-metric array. Larger
arrays have been coordinated by tying the inputs for two (or more) telescopes
on opposite sides of the country or even the world at the same time at the
same targets. In radio telescopes and in opticals it gives you a bigger "lens"
to look through.

This larger lens allows a better clarity of the object. Figure two
ships operating at a great distance 10-20 MU's communicating over
tight whisker beam to coordinate their efforts. They'd get a very good idea of
what's there.

Given a good set of lenses you can determine ranges based on angles between
two prisms space a few meters apart over thousands of meters. The distance of
the Earths orbit (2 AU) has been used to determine distances of stars in our
side of our galaxy over tens of thousands of AU.

Two Telescopes of about 40 inches across on either side of a Vandenberg should
be good for a few tens of thousands of kilometers at least. When I want to
shoot him, I zap him with a ranging laser for final accurate distance and let
fly with my big beams and torps.

In game terms this would be dealt with by two ships adding their passive die
rolls to see what the target is. If you really want to figure it out, but it
uses several ships to figure it out. I wonder if range should play a part.

(there are system now that can track a star and keep tracking a star, why not
a tight comm laser that can track to an object and back, after all NASA
bounces lasers off mirrors on the moon regularly).

> Also, the drives might have unique resonance frequencies etc? Sir,

Yep, witness the way in which magnetic fields of US vessels is manipulated
upon leaving port.

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> On Wed, 30 May 2001, Ryan Gill wrote:

> >At 7:17 AM +0200 5/30/01, Derk Groeneveld wrote:

Accurate _height_ I'll grant you. But with modern multi-beam radar
(which is a bit of a misnomer, since they still use one big transmit fan, only
creating the multibeam in receiving), they get a useful height measurement. As
for figuring accurate range, search radar can give you a range measurement of
approx. 100m resolution. Good enough until you have to direct gunfire. And
then you need a tracker to have a sufficiently high update rate, anyway.

Oh, by the way. SPY sure isn't the only phased array system anymore. And I
think there's interesting challenges for SPY out there, as far as capabilities
go, as well;)

And yes, on most configurations search and tracking radar are seperate
systems. All I'm saying is that actives don't have to be 'little pen lights';
that only applies to actual trackers.

Also, I don't see a reason why a phased array couldn;t make a wider
search-beam; just a matter of different phase shift parameters to your
array on transmission.

> >Mmmm. I guess you can use mm radar in space at a lot longer ranges

Yup. I'm just trying to remember whether there are other factors that would
reduce mm radar performance, other than absorbtion.

> >I'm not familiar with Cepheid variables? As for

Ah, ok:)

> Inferometry is where you use two widely spaced telescopes to give you

Okay; sound spretty much like what we do with phased arrays over here;
even if that's a whole lot of small transmit/receive antenna's spaced
not-all-that-far-apart.

> This larger lens allows a better clarity of the object. Figure two

Does it allow for better 'clarity', or for more resolution at
cross-angles? Mmm.If this works anything like phased array, though,
you'd need position info on your friendly ships, in the order of magnitude of
your sensor wavelength, or is this not as sensitive to phase shifts?

> > Given a good set of lenses you can determine ranges based on angles

But tens of thousands of kilometres isn't very far, in space?

> In game terms this would be dealt with by two ships adding their

Mmm. I'd allow it for actives, as well.. More complicated, but not impossible
:)

> (there are system now that can track a star and keep tracking a star,

Not a problem.

> >Also, the drives might have unique resonance frequencies etc? Sir,

Isn't this degaussing against magnetic mines? If not, I've learnt something
new again:)

Cheers,

> At 9:18 AM +0200 5/30/01, Derk Groeneveld wrote:
And I
> think there's interesting challenges for SPY out there, as far as

I'll grant you that and then some.

> And yes, on most configurations search and tracking radar are seperate

> Yup. I'm just trying to remember whether there are other factors that

Sounds like we need to take a walk over to sci.military.moderated....
> Okay; sound spretty much like what we do with phased arrays over here;

It gives you in effect a much larger telescope. A larger telescope can resolve
smaller objects more easily and with greater detail. By combining the data
from the two widely spaced receivers you see more details. This has been done
by Astronomers for years. Military folks are just now trying it against
stealthy aircraft if I understand correctly. I think the real trick is that
you need a lot of coordination. The internet was enough for the Astronomers to
do it though.

> But tens of thousands of kilometres isn't very far, in space?

Not really. Not on the System wide scale. Remember, we're talking about ships
that zip in and out of systems to the FTL points on the fringes (gotta get
some distance between you and those gravity wells before you throw the switch
for the TK drives.)

> Mmm. I'd allow it for actives, as well.. More complicated, but not

Oh aye. Single actives, smaller passive dies but they can stack their efforts.

> Isn't this degaussing against magnetic mines? If not, I've learnt

Helps against magnetic mines, but I'll bet you the navy does it to the subs
too. Probably helps reduce their magnetic signature. I suspect they won't even
breathe about it though.

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> On Wed, 30 May 2001, Ryan Gill wrote:

> At 9:18 AM +0200 5/30/01, Derk Groeneveld wrote:

It does, doesn't it? Or dive for Skolnik's book on radar tech;)

> >Okay; sound spretty much like what we do with phased arrays over

Okay, I can see how that works, since resolution is a direct result of your
antenna diameter and signal wavelength.

> By

Maybe, but in a way, it's what phased array radars do at much smaller
distances.

> I think the real trick is that you need a lot of

Right. Including good information on eachother's relatikve position, speed,
etc. Mmm. Time bases might also be a problem, if speeds near relatavistic;)

> >But tens of thousands of kilometres isn't very far, in space?

Yup.

> >Isn't this degaussing against magnetic mines? If not, I've learnt

Damn, they'll have to kill you now.

Cheers,

> Ryan M Gill wrote:

> At 11:35 PM +0200 5/29/01, Derk Groeneveld wrote:

ESM is a catch-all that includes most (all?) radar/radio spectrum.

> > > Further, just relying on passive sensors to recognize a

A big plastic balloon enclosing a tinfoil shape of a carrier will fool the mm
radar set, and if it incorporates chilled/heated surfaces, it can also
fool passive infrared. The deception is easily blown at firing ranges, but if
you are that close to the decoy, it is too late to get back to where the enemy
REALLY is.

> The only thing I'd think that mm wave radar would have a hard time

This is heavily dependent on how big an mu is. If it is thousands of
kilometers, you may have difficulty resolving two closely spaced ships (less
than 500m apart). Passive sensor will let you know when you have vented
compartments to space from the gas cloud itself, and the missing insulation
(ship will lose more heat through the hole).

> >

True, but you do need to have collected a large number of Eurie BDN records to
be certain, or the sneaky devil will change the emissivity to fool you into
thinking that he is nearer/closer than he really is.

> > > So I guess the question is, what kind of drives are they?

This gets to the heart of the problem. If you kept the same scale between the
detection and combat phases of a fleet engagement (and had REALLY small figs),
playing out the detection phase on a table would let you play the combat phase
on a postage stamp. The only adequite treatment I have seen of this situation
is GDW's Star Cruiser. The detection ranges are seldom above 30 mu. Long

> Ryan M Gill wrote:

> I'm inclined to pick something like 105 MU for passives detecting a

The quick and dirty method is too define the detection range for a ship with
one (1) mass factor of drives as X. The detection range of every other other
starship that is no more, or less, stealthy than the reference vessel is the
square root of its drive mass * X. So the Bonaparte, with 48 mass factors of
main drive, is

OK, I'm going to do my standard "Sensors as they affect game play".

If you are going to have sensors that only work insystem and give you full
info at greater than 36" you might as well not even bother.

Why?

Campaign: I jump insystem. We play all kinds of nifty sensor games. We get
outside weapons range, realize one force is superior, the inferior force jumps
out.

Non-campaign: Obvious, there is no point.

Net result in both cases: No affect from the sensors, I might as well have
twiddled my thumbs.

In message <ML-3.4.991398730.6838.books@babinga.dms.state.fl.us>
> Roger Books <books@mail.state.fl.us> wrote:

> OK, I'm going to do my standard "Sensors as they affect game play".

Well, I did have the idea for the 'really simple sensors system' -
designed largely for pick-up and tormanent games:

Player with relatively superior sensor assets can set up after everyone else
(all players must still set up in their designated areas, however).

ECM equipped ships don't need to be set up until the players with superior
sensors does, however.

Slightly more complexity: most tormanents I've played in have a maximum
starting velocity - allow player with superior sensor assets 1 free turn
of main drive burn if desired (warning - this could be worth a lot - and
will make costing sensors difficult).

No idea if it is balanced - or even worth the bother :-)

> At 8:32 AM -0400 6/1/01, Roger Books wrote:

> Why?

What if the Superior force is attacking an inferior force that must defend.
The inferior force is going to want to do as much as they can do deny the
superior force information.

I'm concerned with sensors more due to much reading of the Honor Harrington
books plus accounts of naval battles where you don't know all of what is
there. Greater than 36" sensor range lets you know something is there, but
what?

> On 1-Jun-01 at 16:32, Ryan M Gill (rmgill@mindspring.com) wrote:

With beyond 36" sensors I will just run into non-spoof range and
look. I don't care much what you show me unless you want to divide your forces
and let me defeat you in detail.

> I'm concerned with sensors more due to much reading of the Honor

I really like that suggestion a lot!

I've always thought that once you got into tactical range (i.e. the tabletop),
you had already detected the enemy (save possible stealth type craft). I'd
figured that once you got into the scope of what Full Thrust handles, you'd
already played the sensor detection games, found the enemy, and the engagement
had begun.

I like the idea of giving the side with superior detection some advantage in
setup.

I'm not sure about the starting thrust rating, but it does follow that a group
of vessels that may not have detected the attackers until after the attackers
had begun their run could have a lower starting thrust. It may not be 100%
realistic, but I think it would play well.

This could also encourage players to include scout-type ships in their
fleets with dedicated sensing equipment, since every little bit of advantage
goes a long way.

George

[quoted original message omitted]

> At 4:53 PM -0400 6/1/01, Roger Books wrote:

True, on a small table that is quite easy. Also as most games are run, its not
much use. But one of my wishes is to work up a means of having campaigns that
take place on spaces larger than the table. Effectively a system battle that
is more than the table top. When you consider the size of a system even just
ours, its very far from the orbit of a planet like earth to the orbit of say
Jupiter.

Some base distances for scale:

Its one Astronomical Unit from Earth to the Sun. 1.5 AU separate Mars from the
Sun. Jupiter is 5 AU, Saturn 9. Going further you have more gas giants.

My thoughts on what makes for a good battle (like taking the Soloman Islands,
or the battle of Midway, or Dogger Bank say) requires more than one tables
worth of play area. Even if its just task groups represented on a map, there
would be smaller groups of scouts, Cruisers and DDs playing cat and mouse
before the main battle lines join.

Being able to have the major force in the right place at the right time is
what makes for a major victory. I like the idea of introducing that big
question of what battle are you going to fight into the game.

> Charles Taylor wrote:

> Well, I did have the idea for the 'really simple sensors system' -

Another simple idea: (okay, not so simple)

All units are set up as "unknown objects", and both sides get to add extra
UO's as decoys (possibly two or three per ship). A decoy has a thrust of two.
A player may inspect one UO for each ship that has at least one level of
better sensors, and an additional UO for each ship that has the two levels of
better sensors. UO's that are ships or fighter squadrons pretending to be
decoys are replaced with the ship or fighter squadron. Decoys are removed from
play. Ships with normal sensors can only inspect a UO by replacing its UO
marker with an "unidentified ship" marker. It can then inspect one UO with
each firecon it posesses. The number of firecons, is obviously revealed. A
fighter squadron may inspect one UO if it is within 6mu (the squadron is
revealed as such.).

Inspections are done in the orders phase. Units that fire are immediately
replaced with their model. If the UO takes damage, decoys are destroyed,

> Ryan M Gill wrote:

> At 4:53 PM -0400 6/1/01, Roger Books wrote:

> Richard and Emily Bell wrote:

        Prefect is indeed a really good source of information -- it's a
pity that the game doesn't live up to the sourcebook (after devoting pages to
vector-based interceptions and spheres of manuver, your tactics on the
map are 'place ships wherever you want them to be' with no actual interception
at all). The unfortunate part about Prefect is that the sensors they suppose
are less capable than current sensors when it comes
to detecting ships. A 100-ton space fighter could NOT manuver at
multiple G's with a reaction drive for hours without being picked up, as they
suggest, even going against 20th century sensors. I don't believe that our
technology will have devolved in the interim. Their interstellar detection
method is extremely interesting, albeit possibly not applicable to FT. It also
offers one of the best (IMO, essentially the ONLY good) justifcation for
having both battleships and fighters in the same game....

True.

FB indicates in the flavor text the SHORTEST turn-arround-time between
jumps is 6 hours. I would suggest making this a little random (as some ships
are not as efficient as others and some are need a little longer do to service
wear). I would suggest 6-8 hours (5 hours + 0.5(1d6) rounded up).

Using 15 minutes per turn this would be 24-32 turns before the tug could
jump out of the system. Using 7.5 minute turns it would be 48-64 turns.

If jumping in, dropping the stingships, jumping out, recharging, jumping in,
picking up the stingships and jumping back out. It would be a minimum of 96
turns (192 turns using 7.5).

-----
Brian Bell
-----

> -----Original Message-----
unless,
> they

From: Thomas Barclay <kaladorn@fox.nstn.ca>

> Does a diceless sensor system have no appeal whatsoever?

> Well, I can only speak for myself, but I'm not

The risk here is forcing a space combat game folloe known realities of
Earthbound combat in order not to offend those sensibilities.

> There is no range at which things are

There's also no absolute range limit for a beam weapon to hit. If we wanted to
be hyper accurate, you should roll some exponential falloffprobability beyaond
36" for Class 3 beams. You dont in FT because of the granularity of the game.
Same sauce for sensors.

> This has

Exactly the same with wepon fire, but we abstract that out. I think that
that knd of fiddling belongs _more_ to weapon fire than sensors. I
likely
won't play with sensor rules if it's going to at 50+% more time to a
given
turn. Show be a diced system that is tuly simple and fast. - Beth's
system proposed a couple posts later souds like a good start.

But I'll still push diceless. I've seen no comelling argument yet to say that
we need to add another round of rolling anything. Fixed ranges with
variations add quite enough of the flavor for me. I _don't_ want a
submarine or sniper game.

...

> Similarly, in FT, there is no stealth or subterfuge

You want that, you need to retool the cloaking rules, not the sensor rules.
Or, as you say later expand the scope of the game and play hide-and seek
on the strategic level.

Later:
> 2) sensors should be part of hull (thus you

That's another reason never to make small ships. You don't even need scouts
.

> 3) tying them to firecons makes a DN more like

And tying them to mass is better than that? How much better a scout is a
mass 150 DN vs. a mass 8 souct with Mass-based sensing?

> On 18-Jun-01 at 01:23, Derek Fulton (derekfulton@bigpond.com) wrote:

But now we are odering off the internet and they have the capability of
pictures.

Not to be harsh, but if a company doesn't put pictures of what they are
selling on the net I feel safe making the assumption they don't want to show
me their product. If they don't want me to see it I don't want to buy it.

Please Forgive, my earlier post on this subject was not meant for this list.
Please disregard.