Author Topic: How do you know what sensor strength to go for? Are there rules of thumb?  (Read 1145 times)

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Offline Iestwyn (OP)

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How do you know what sensor strength to scale your passive sensors up to? I know that thermal detects engines and EM detects shields (and that signatures for both can be found in the summaries for those components), but I don't really know anything else. Do you guys have to do calculations based on enemy (or friendly) tech every time you make sensors? Or are there shortcuts, like the "resolution 100 for ships, resolution 1 for missiles" rule?

Thanks in advance!
 

Offline TheTalkingMeowth

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I sort of do calculations based on what signal I expect from my enemies. Really, it depends on what I want a ship (or, really, the formation that includes the ship) to be able to do.

All my warships get size 1 passives of both kinds, both for RP and because it avoids nasty surprises. Dedicated sensor ships get larger passives. How much larger? For ships I want to send in with my navy to help spot aliens, I go as big as I can manage while keeping enough anti-missile defense I can be comfortable sending them away from the main body. I've learned the hard way that spreading your ships out to expand your sensor envelope leads to missiles in short order. EM sensors could probably be smaller than thermal ones, since interesting EM signatures are so big. But I often go symmetric just because tracking enemy fleets via their EM emissions is so much longer ranged than any other means.

The calculations really come in for spy ships. I want them to be able to detect particular targets (populations and known enemy active sensors) from beyond the range they are likely to be spotted, and I usually know the strengths I am looking for. That makes the calculation straightforward, though there is some guesswork in figuring out the actual range of an active sensor. I haven't been too successful there, to be honest.
 

Offline Iestwyn (OP)

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All excellent stuff; thanks!

One thing I've been wondering: the various signatures ships produce scale at the same time that sensors grow more sensitive. Does that mean that there are relatively standard sizes of sensors that work at most tech levels?
« Last Edit: November 13, 2020, 04:58:29 PM by Iestwyn »
 

Offline TheTalkingMeowth

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I'm not sure what you mean....

Military ships will generally get thermally louder as tech improves, since they are getting faster and (often) larger. But this is thoroughly divorced from sensor improvements.

Active sensor EM signatures DO increase as they get more sensitive, since an upgrade in grav pulse strength means a louder sensor in exchange for greater range.

Overall, increasing tech causes detection to happen at larger and larger ranges: ships run hotter, shout louder, and are being searched for by increasingly sensitive passives and increasingly powerful actives.

As such, if you want to maintain a fixed detection range you can actually start decreasing sensor sizes. But why would you? Knowledge is power, and higher tech results in increased engagement ranges too.
 

Offline Iestwyn (OP)

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Yeah, I made that comment when I was in the store trying to shepherd my 1.5 year old daughter. Once I got in the car, I realized I'd gotten the engine thermal signature the wrong way around; I thought the higher tech led to smaller signatures. Now I remember that only works with the emission shielding.

I guess I'm still curious about whether you use standard sizes for your passives. You use size 1 sensors on your warships; your other "roles" seemed to have really variable sensor sizes (as large as possible on your sensor escorts and tailored to your enemies for spies/scouts). Do you tend to default to specify sizes in general, though?
 

Offline Iceranger

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Related to this topic, I did some math before and under the C# sensor model, assume you have the same EM tech as the opponent, then you need a ~5.1HS passive EM sensor to detect your opponent's RES1 active outside its sensor range. ~2.4HS for a RES10, ~1.1HS for a RES100. This is irrelevant to their active tech nor the size of their active sensors.

If the opponent has a better EM tech than yours, the above numbers go up, and otherwise go down. I really need to find that piece of napkin where I wrote my math :D
 
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Offline Iestwyn (OP)

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Related to this topic, I did some math before and under the C# sensor model, assume you have the same EM tech as the opponent, then you need a ~5.1HS passive EM sensor to detect your opponent's RES1 active outside its sensor range. ~2.4HS for a RES10, ~1.1HS for a RES100. This is irrelevant to their active tech nor the size of their active sensors.

If the opponent has a better EM tech than yours, the above numbers go up, and otherwise go down. I really need to find that piece of napkin where I wrote my math :D

See, this is the sort of fascinating stuff I live for: someone else doing incredibly complex math that boils down to really easy results I can use without thinking. XD It even answers my question: now I have standard sizes for when I think the enemy will be pinging for missiles, fighters, or ships.

Don't suppose you have anything as magical for thermal sensors? ;) I don't know how you could, since I can't think of anything standard you'd be detecting, but it doesn't hurt to ask.
 

Offline Iceranger

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Related to this topic, I did some math before and under the C# sensor model, assume you have the same EM tech as the opponent, then you need a ~5.1HS passive EM sensor to detect your opponent's RES1 active outside its sensor range. ~2.4HS for a RES10, ~1.1HS for a RES100. This is irrelevant to their active tech nor the size of their active sensors.

If the opponent has a better EM tech than yours, the above numbers go up, and otherwise go down. I really need to find that piece of napkin where I wrote my math :D

See, this is the sort of fascinating stuff I live for: someone else doing incredibly complex math that boils down to really easy results I can use without thinking. XD It even answers my question: now I have standard sizes for when I think the enemy will be pinging for missiles, fighters, or ships.

Don't suppose you have anything as magical for thermal sensors? ;) I don't know how you could, since I can't think of anything standard you'd be detecting, but it doesn't hurt to ask.

Unfortunately there is nothing similiar for TH sensors.

The EM sensor size was derived like this.

We have:

Code: [Select]
Active Sensor Range = SQRT((Racial Sensor Strength * HS * Racial EM Sensitivity * (Resolution ^ (1/1.5)) / PI) * 1,000,000 km
Active Sensor Strength = Racial Sensor Strength * HS * Resolution
Passive Detection Range = SQRT(Passive Sensor Strength * Target Signature ) * 250,000 km
Passive Sensor Strength = Racial EM Sensitivity  * HS

Let's use the following notation:
Opponent's racial sensor strength -> Ao
Opponent's EM sensitivity -> Eo
Opponent's active size -> So
Opponent's active resolution -> Ro

Own racial EM sensitivity -> E
Own EM size -> S

So as a EM source, the opponent's active sensor's signature = Ro * So * Ao
Your passive EM's range to pick up that signature = (E * S * Ro * So * Ao)^(1/2) * 250kkm
Opponent's active sensor range = (Ao * So * Eo / PI) ^(1/2) * Ro^(1/3) * 1000kkm

We want our EM sensor to pick up opponent's active before they pick us up, so (E * S * Ro * So * Ao)^(1/2) * 250kkm >  (Ao * So * Eo / PI) ^(1/2) * Ro^(1/3) * 1000kkm
Note that (Ao * So)^(1/2) cancels each other, so (E * S * Ro)^(1/2) > (Eo / PI)^(1/2) * Ro^(1/3)*4
Take square on both sides, E * S > Eo / PI * Ro (-1/3) * 16
So we have S > Eo * Ro (-1/3) * 16 / E / PI

Thus when Eo = E, S > Ro (-1/3) * 16 / PI
Take Ro = 1 then S > 16 / PI ~= 5.093
Ro = 10 then S > 16 / PI * 10 ^ (-1/3) ~= 2.364
Ro = 100 then S > 16 / PI * 100 ^ (-1/3) ~= 1.097

When the opponent has better EM tech than your tech, you can take Eo / E to scale up the above results. With a 50HS EM sensor with mere EM sensitivity 8 tech, you are able to detect any active sensor outside its range even if the opponent has end game tech.
« Last Edit: November 13, 2020, 07:56:17 PM by Iceranger »
 
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Offline Michael Sandy

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A lot depends on whether you are talking about player vs AI strategy or player vs player run empire, or versus AI but with RP considerations.

The AI isn't capable of deliberate deceptions, or restraint for the purpose of luring someone out of position to attack.  The AI also isn't really capable of being bluffed out when its scouts are shut down.

I generally go with a spectrum for my scouts, from 1.6 HS minimalists which are fast, expendable to 6 HS fighters with 1 HS sized sensors and a lot of speed, to 10 HS fighters with a 2.5-3 HS sensor suite.  1000 ton fast sensor boats are pretty easy to customize, as retooling such small shipyards is very fast.

The idea is that with the different sizes, I am more likely to find a window that allows me to track the enemy from beyond the range that they can target my scout.  Maybe they can detect it, but they can't catch it or shoot it with missiles without closing.

But using small scouts for sensor security, you need to be much more proactive with them, sending them billions of km ahead of the fleet in some cases.  As far as 'rules of thumb', I could go into a LOT on my scouting philosophy. ;)  No one ship can do all scouting missions.

Basic scout roles:
Fleet scout  Fast, endurance between 2 weeks and 6 months, sensor payload between 15% and 25% HS.  Speed keeps it alive, and everything is stripped down to reduce its sensor profile.  A scout pared down to the absolute minimum size may be able to track without being tracked, but might not be able to stay on station long enough to do its mission.

Rock checker, LONG endurance, perhaps with a single ship jump engine, has a res 1 active sensor capable of detecting the smallest enemy presence at 10,000 km, but not really great beyond that.  60-100 billion km range.  Emphasis is on economical exploration.  Survivability of the ship is minimal, but because it operates with other ships, survivability of the DATA is high.  Rock checkers are MUCH cheaper than survey ships, and go in ahead of the survey fleet, looking for enemy presence.

Picket, long crew and maintenance endurance, but perhaps with a very short range.  Role is to monitor a jump point or a planet of interest, and shadow contacts. A survey support carrier can drop it off at a jump point, and pick it up several years later.

Fleet security, MASSIVE sensor.  The biggest you can research and install.  Unfortunately, sensor tech advances render it obsolescent, and large sensors are both expensive to research and prohibitive to refit.  Speed isn't as much of an issue as it is in the heart of the fleet.  Unsubtle as hell when a 50 HS res 100 sensor PINGS the system.  I found it useful to build PDCs with active sensors back in VB6, because there wasn't an issue of tooling required.  Sensor advancements would just make the sensor smaller, which isn't that much of a consideration for a PDC, it would still cost about the same.

Scouts generally are not armed, but they could be paired with variants that strip out the sensor and perhaps some range for a weapon system, and then would operate with the scouts to seek out and destroy enemy scouts.  They wouldn't need much armament to be effective, just a beam weapon and enough speed and initiative to close.

So start your design process from the mission.  Figure out the speed you need, the sensor range vs cross-section, and then figure out how much endurance you can have and still do the mission reliably.
 
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Offline Iestwyn (OP)

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Out of curiosity, could you go into the rock checker role a bit more? I thought you were referring to geosurvey ships, but it doesn't look like it.
 

Online nuclearslurpee

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Out of curiosity, could you go into the rock checker role a bit more? I thought you were referring to geosurvey ships, but it doesn't look like it.

"Rock checker" usually means a ship which flies between planets and other likely locations for an alien presence and pings them with active sensors. Small ship with enough speed and endurance to fly around a star system and a small sensor to do the basic pinging duties, so it's more expendable than your big fancy survey ships. If it finds an alien presence or gets blown up, you know where your survey ships need to be careful.
 
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Offline Michael Sandy

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What nuclear slurpee said.

I designate fighter sized ships that can independently transit a jump point "pinnaces".  I first got into using them a lot when I decided that I wanted to make use of fighter factories before box launchers were available, and discovered that I really liked the versatility of them.

I like having 3-5 year endurance on the rock checkers, even if their fuel endurance is significantly less than that, because they spend a lot of time waiting for survey fleets to discover jump points for them to probe, and while their morale is not of critical importance, their engineering life IS.  Pinnaces proved useful in that immediately after developing the minimal technology for jump engines, I could start probing.  Saves a lot on tooling and a lot on research not having to research an efficiency 4 jump engine, only to have to replace it in a year.

Performance isn't as critical for rock checkers, but having more endurance means somewhat less micromanagement needed to cycle them back for maintenance.

Btw, I STRONGLY recommend having a small survey support carrier with your survey fleets, 1000-2000 hangar tonnage, for scouts, deployable sensor platforms with 1 HS sensors so they can qualify as commercial for maintenance purposes, jump point probes, and maybe a small fast parasite warship for dealing with unarmed enemy scouts.  You don't necessarily need to update the engines of the support carrier, but you can update its complement.