Stealth with decoys

[Rich.h (OP)]

Ah that helps a lot more in understanding things and I have done a revision to the decoy.

Missile Size: 2 MSP  (0.1 HS)     Warhead: 0    Armour: 0     Manoeuvre Rating: 10
Speed: 5000 km/s    Engine Endurance: 72.1 hours   Range: 1 297.0m km
Active Sensor Strength: 1.026   Sensitivity Modifier: 180%
Resolution: 500    Maximum Range vs 25000 ton object (or larger): 4 120 000 km
Cost Per Missile: 1.7666

So using the correct formula then the GPS of this missile should be as follows (my current active sensor strength tech is 36)

GPS = 0.1 * 36 * 500 = 1800

Using that to work out it's detection range am I correct with this formula (working on the assumption of an EM sensor component with an EM 11 rating).

11 * 1000 * 1800 = 19,800,000 km

So am I correct then in thinking that if I fired this missile off at a target any ship with an EM sensor with a rating of 11 will detect the missile at 19.8m km?

[bean]

Not quite, because the .1 HS isn't correct.  It's a missile, so only a portion of it is allocated to the sensor.  The active sensor strength (HS*tech) is 1.026 (it's in the stat block), so your GPS is 1.026*500=513 and the counterdetection range is 513*11*1000=5.643 mkm.  (Working backwards, the actual size of the active component is 0.57 MSP, or 0.0285 HS.)
I'd look at turning up and shrinking the engine.  (See http://aurora2.pentarch.org/index.php/topic,5659.0.html for how to make better engines.)  And then make the active bit as big as you can.

[Rich.h (OP)]

So after a lot of shouting and academic debates my engineers have returned with a revised plan they assure me is now functional.

MIL 403 Hermes MK2 - Copy class Recon Frigate    20 000 tons     491 Crew     7604.42 BP      TCS 40  TH 211.2  EM 1560
4400 km/s    JR 3-50     Armour 5-65     Shields 52-300     Sensors 560/180/0/0     Damage Control Rating 31     PPV 21.66
Maint Life 0.11 Years     MSP 2238    AFR 3200%    IFR 44.4%    1YR 19676    5YR 295141    Max Repair 1250 MSP
Intended Deployment Time: 18 months    Spare Berths 1   
Troop Capacity: 1 Company    Magazine 156   

Powedll Class 3 Hyperdrive     Max Ship Size 20000 tons    Distance 50k km     Squadron Size 3
Powedll Class 4 Fusion Drive (2)    Power 880    Fuel Use 22.4%    Signature 105.6    Exp 10%
Fuel Capacity 1 500 000 Litres    Range 60.3 billion km   (158 days at full power)
Alterman Theta Shields (13)   Total Fuel Cost  260 Litres per hour  (6 240 per day)

Chambers-Foster Gauss Turret (2x4)    Range 40 000km     TS: 40000 km/s     Power 0-0     RM 4    ROF 5        1 1 1 1 0 0 0 0 0 0
Chambers-Foster Phalanx (1x8)    Range 1000 km     TS: 25000 km/s     ROF 5       Base 50% To Hit
Muravyov Fire Con MR-48 TS-25k (1)    Max Range: 48 000 km   TS: 25000 km/s     79 58 38 17 0 0 0 0 0 0

Chambers-Foster Size 6 Buoy Launcher (1)    Missile Size 6    Rate of Fire 600
Chambers-Foster Probe Targeting (1)     Range 388.8m km    Resolution 100
Size 6 Decoy Buoy (16)  Speed: 5 000 km/s   End: 691.2m    Range: 207.4m km   WH: 0    Size: 6    TH: 16/10/5
Size 6 Watcheye (10)  Speed: 0 km/s   End: 0m    Range: 0m km   WH: 0    Size: 6    TH: 0/0/0

Muravyov Search Sensor MR-102m R-10 (1)     GPS 1800     Range 102.5m km    Resolution 10
Active Search Sensor MR144-R500 (1)     GPS 18000     Range 144.9m km    Resolution 500
Active Search Sensor MR1448-R500 (1)     GPS 180000     Range 1 449.0m km    Resolution 500
Muravyov TH Sensor 560 (1)     Sensitivity 560     Detect Sig Strength 1000:  560m km
Muravyov EM Sensor 180 (1)     Sensitivity 180     Detect Sig Strength 1000:  180m km
Cloaking Device: Class cross-section reduced to 10% of normal

ECM 30

Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s

This design is classed as a Military Vessel for maintenance purposes

This design carries 16 decoy missiles as below.

Missile Size: 6 MSP  (0.3 HS)     Warhead: 0    Armour: 0     Manoeuvre Rating: 10
Speed: 5000 km/s    Engine Endurance: 11.5 hours   Range: 207.4m km
Active Sensor Strength: 4.0734   Sensitivity Modifier: 180%
Resolution: 500    Maximum Range vs 25000 ton object (or larger): 16 390 000 km
Cost Per Missile: 6.8928

My engineers inform me that even a lowly strength 11 EM sensor should pick up this decoy at a little over 22m km away. Since it also moves just slightly faster than the actual vessel, hopes are that when fired at a distant point at a tangent to a current course then it may appear to oncoming vessels as though the ship has light up sensors and made a sharp turn and burn to flee. In the meantime the actual ship can lower engine power and sneak off in the opposite direction to a safe distance where it can take stock of the situation and decide to either continue the mission or escape the system. In addition to these decoys the ship also carries 10 watcheye probes designed to be left at close (100-200m km) range to any colonies we happen to come across. With their EM and TH sensors they would act as a semi permanent spy on what is going on with he colony and any passing ships.

Missile Size: 6 MSP  (0.3 HS)     Warhead: 0    Armour: 0     Manoeuvre Rating: 10
Speed: 0 km/s    Engine Endurance: 0 minutes   Range: 0.0m km
Thermal Sensor Strength: 1.8612    Detect Sig Strength 1000:  1 861 200 km
EM Sensor Strength: 1.863    Detect Sig Strength 1000:  1 863 000 km
Cost Per Missile: 5.9586

Since this class of ship is likely to be operated solely by those working in the intelligence division it has been proposed that a test run be made. A few volunteers will be found who are dedicated to their naval service and have no family ties, these brave few will take a prototype of this class into an NPR home system to first attempt to close within launch distance of the watcheyes. The second stage will be to deliberately provoke a response from the NPR naval forces by allowing the ship to be detected, when conformation of an interception has been made then the decoy will be deployed while the tangent maneuver will be enacted before the ship attempts to escape the system back home. Since the NPR in question are currently on friendly terms with us and these new ship will be of a radical look and always fly without any form of transponder there has been deemed a high chance the NPR could see this as a hostile craft and open fire. In that situation the intelligence division will deny all knowledge of the existence of these craft and those on board will activate a highly effective self destruct device should there be a danger of capture or disablement.

One final question I have about detection with this design is about TCS. The wiki states that "TCS or Target Cross Section, which is the exact class size rounded up to the next whole number and is the value used to detect the ship with active sensors". Does this then mean if you have a ship with zero engine emissions, and is also giving off zero EM emissions, then any ship using an active sensor to detect it will use the TCS value as a replacement for the normal EM/TH value?

In this ships example trying to detect itself with engines powered down, will it be detected at 102m km regardless? It is above the 500 ton amount for the resolution 10 sensor and it has a maximum range against such of 102m km.

[bean]

Your engineers speak correctly this time.
Active sensors always rely solely on TCS for detection.  TH is totally irrelevant.  I believe EM is as well, although I'm not 100% positive of that.  It will detect itself at 102 mkm regardless.  However, it has a much lower cross-section than normal ships of its type, and good enough EM sensors should allow it to avoid most active sensors.
Also, one tip.  Fit a resolution 1 missile defense active.  Otherwise, your gauss turrets are not very useful.
Also, during my own investigation of this, I discovered that missile sensors are capped somewhere around resolution 40000000 by an overflow error.

Code: [Select]

Missile Size: 1 MSP  (0.05 HS)     Warhead: 0    Armour: 0     Manoeuvre Rating: 10
Speed: 12000 km/s    Engine Endurance: 111 minutes   Range: 79.8m km
Active Sensor Strength: 1.6   Sensitivity Modifier: 400%
Resolution: 40000000    Maximum Range vs 2000000000 ton object (or larger): 4,047,710,000 km
Cost Per Missile: 2.71
Chance to Hit: 1k km/s 120%   3k km/s 40%   5k km/s 24%   10k km/s 12%
Materials Required:    0.96x Boronide   1.6x Uridium   0.15x Gallicite   Fuel x250

Development Cost for Project: 271RPBy my math, the detection range for a strength 11 EM sensor is 704,000 mkm.  Yes, that's right.  704 billion km.  27 light-days.  Or, to put it another way, if you fire one of these off in Sol, a moderate-sized DSTS in Alpha Centauri should see it.  Yes, I have a very high-tech game which lets me cram that in to a size 1 missile, but even the most basic tech should be able to build a very good decoy indeed.
(On the other hand, regular actives are capped at resolution 500, so it's better to build a ship that fires decoy missiles than to build a ship that is itself a decoy.)

[DIT_grue]

Rich.h: I thought you claimed they would "always fly without any form of transponder"? (Meaning, why did you mount screamers on the vessel itself? Remember that you can't control sensors below the level of an individual ship, so either all its actives are on, or all of them are off.) For a stealth ship, being unable to get exact scan details of enemy shipping, or even to shoot down missiles, without announcing your presence to the entire universe could be a slight handicap.

Okay, examining it more carefully, at least you appear to carry a single CIWS, which mitigates one issue slightly (since that doesn't require a separate AS lock). On the other hand, not only do you mix CIWS with gauss turrets (duplicating support systems without exploiting the independence of CIWS), the tracking speed of your FC looks to be crippling your turrets (and presumably does the same for your CIWS). And you have substantial shields as well - generally, trying not to be noticed is best done by not making lots of noise! Not to mention that all that deadweight slows you down, requiring stronger (hotter) engines, and bloats your TCS. On the whole, I'd say that either your engineers are trying to conduct history's most expensive assassination of an intel weenie, or they haven't quite grasped what you're asking for.

[Rich.h (OP)]

Ah yes well spotted on the missing missile detection sensor, well it wouldn't be Aurora if at least one essential component was missing from a design before it launches. Also interesting information about the missile resolution, I wrong assumed that since a ship based sensor was limited to a resolution of 500 so would be a missile sensor. With that in mind I have managed to reduce the missile to size 1 and vastly increase it's detection range along with speed. Hopefully it will work to keep ships chasing it now for far longer and thus further away from the actual recon vessel.

To address the other issue about some parts of this design, the CIWS, gauss turrets and shields are not there with the intention of being used ever. In the same way you do not slap on armour to a ship with the intention of getting shot, but it is there as a backup should you get hit. The systems on this ship are what has been deemed as the bare minimum it might need to survive a combat situation against a small number or lightly armed foe for just long enough to make an escape through a jump point. If the situation arrived where this ship was detected and it was clear the decoys had failed then and only then would shields be raised, and the active sensor be activated (afterall by that point the game is up so you may as well get all the information you can). The ship will make for the nearest escape point at full speed and if anyone got close enough the gauss turrets would be deployed.

Since the design spec for this craft was a 20k ton vessel then the engines required to reach this speed at my current tech level will always give a TH signature of around this figure. The 20k ton figure was chosen as I needed a small stealth ship that could carry the required sensor package, be able to self jump, cloak, and carry both decoy and defensive armaments. The problem around the FC speed is one that at this time cannot be resolved as my current TS tech is 6250km/s, so using the maximum possible X4 on design will only ever let me track at 25,000km/s. Unless there is a bug in my current game then the same issue applies to the CIWS as it is using that TS base.

[83athom]

CIWS is its own self contained unit. It does not rely or use any other component. It could be classified as a passive defense (like armor) as it doesn't produce detectable emissions and will function normally. And any speed above a FC's or turret's (CIWS included) tracking speed is taken off in the chance to hit, it can still hit but at a reduced chance to. So in a fleet doctrine like this, I would honestly forego most of the sensor and the FCs/gauss in favor of more CIWS and armor (more or less shields is debatable so should be decided class by class).

[Rich.h (OP)]

CIWS is its own self contained unit. It does not rely or use any other component. It could be classified as a passive defense (like armor) as it doesn't produce detectable emissions and will function normally. And any speed above a FC's or turret's (CIWS included) tracking speed is taken off in the chance to hit, it can still hit but at a reduced chance to. So in a fleet doctrine like this, I would honestly forego most of the sensor and the FCs/gauss in favor of more CIWS and armor (more or less shields is debatable so should be decided class by class).

The biggest issue there though is that would mean I only have any offensive capability against missiles with CIWS. The two gauss turrets are there to either allow this ship to properly attack a very small number of FAC that get too close, or to try to strike against a larger craft that gets in range also. Now I fully understand how that might seem futile at this time since the gauss only have a 40k range, however there I am stuck with a tech limitation. When my tech has moved on a little these turrets will be switched out for most likely a meson based system or perhaps even a small laser one. For the current time though things like defensive turrets are the last addition to this design after all other considerations have been put in place. Sadly using anything other than gauss pushes the craft over the 20k ton spec limit unless I make it so they are totally useless against missiles, which then leaves me with just armour, shields and a single CIWS.

[TheDeadlyShoe]

intriguing concept.

You could do a TH decoy using a small ship built entirely out of maximum multiplier engine.  A fighter perhaps, although a fighter probably cant generate enough signature to compare to a 20kt ship.

[Rich.h (OP)]

intriguing concept.

You could do a TH decoy using a small ship built entirely out of maximum multiplier engine.  A fighter perhaps, although a fighter probably cant generate enough signature to compare to a 20kt ship.

I did consider that as my first idea but as you say getting a fighter to generate enough TH compared to a stealth 20kt ship is hard. In addition the detection range is far and below the distance these decoys are picked up at. Finally there is the issue of size, since this vessel currently carries some 20 odd decoys would mean probably increasing beyond the 20kt limit if I used fighters, and each of the decoys would be far too valuable in terms of ship resources to use until the last minute.

[Veneke]

I've attempted similar designs on and off for a while but mine are usually much smaller.  It's a really cool idea, and I hope it works when you take it out for trials!
 
I'm curious though what the intention is of the multiple active sensors.  It's a stealth ship right? So it shouldn't need any actives except for anti-missile work (and it doesn't even need that if you only use CIWS).  IIRC you can dumb-fire your missiles at waypoints without an active sensor, you just need a fire control.
 
I presume that you're playing with maintenance off? The maintenance life is much too low if not.
 
The company is cool, and I like to put one on myself for ships that are on extended detached duty, but it's not a great design choice.

[83athom]

you can dumb-fire your missiles at waypoints without an active sensor, you just need a fire control.

The missiles would need built in actives for that to work. (not criticizing, just expanding)

[Rich.h (OP)]

I've attempted similar designs on and off for a while but mine are usually much smaller.  It's a really cool idea, and I hope it works when you take it out for trials!
 
I'm curious though what the intention is of the multiple active sensors.  It's a stealth ship right? So it shouldn't need any actives except for anti-missile work (and it doesn't even need that if you only use CIWS).  IIRC you can dumb-fire your missiles at waypoints without an active sensor, you just need a fire control.
 
I presume that you're playing with maintenance off? The maintenance life is much too low if not.
 
The company is cool, and I like to put one on myself for ships that are on extended detached duty, but it's not a great design choice.

The bigger active sensor is there partly as I had space for it after meeting all other design demands, and also as a last ditch system. From an RP standpoint that sensor is an entire intel suite, it includes an advanced sensor net along with space magic subspace narrowband communications, along with an advanced AI. Should it ever become obvious that the decoys have failed and one of these ships are going to get some very close company with a guarantee of hostilities, then this sensor pack is turned on. It quickly scans all ships in ranges and makes a deep analysis of the details of them, it then encrypts and compresses all data before firing it off towards the nearest receiver beacon so that HQ will at least have some idea of what happened and the capabilities of the vessels in that area.

Part of my design doctrine for this game is to include things that mechanically don't make much sense as I like ships that can handle a few different roles to some degree. You are correct about the maintenance though as I find it a micromanagement nightmare sometimes, so I am playing without it until 7.2.

[Rich.h (OP)]

Well the intended test run of this design has been a total failure, somehow a senator who has constantly opposed all intelligence missions and detests anything approaching black operations got wind of the design. After tracing some data logs it seems this senator sent full details of the both the entire ship design and missions it was intended for over to a diplomat from the Worrell Commonwealth. This leak was not discovered until the prototype of this class was already in Sirius and had gone communications dark. Upon returning the ship captain reported that the vessels of the Worrell Commonwealth paid no attention at all to them, they fired off a couple of decoys with no luck, to make matters worse it seems a virus had got into the sensor suite and shortly after the second decoy had been launched the entire sensor pack activated lighting up the vessel for all to see. However it was still totally ignored and so the captain brought her home to report.

Well it seems that once you reach a certain friendly status with an NPR they no longer seem to mind you buzzing a 20kt ship around their home system for a couple of weeks. I can only guess that is why they ignored me as I tried everything I could to make sure I was spotted and they simply did not react. Seems this concept is just going to have to wait until I find a new NPR or a spoiler.

[bean]

I made a brief test last week with a spoiler (the one that tends to swarm everywhere).  The issue was that I had quite a few ships in the system, including one with an active sensor that dwarfed even my decoy in power.  I had a couple of vessels operating near one of their motherships, and had one of them fire a decoy off.  It didn't go for the decoy, and ended up heading home instead.  I'll have to try again later.