A detailed inquiry into Elite Dangerous Sensor Mechanics / Target Lock Acquisition

[CMDR Mechan]

Greetings fellow CMDRs!

As a science project for the Anti-Xeno Initiative, myself and a few fellow CMDRs (thank you CMDR Bacon_, CMDR fvv2, and CMDR Miraka in particular!) have been studying detailed sensor lock mechanics. And thank you to CMDR Maligno for being enough of a friendly pain-in-the-neck to spur me to create this write-up.

It is well-understood that sensor lock ties to heat - which is why it is known that firing a heatsink will often break target-lock, and some ships (DBS and DBX) are noticeably "stealthy" given their low resting heat (which in turn, is due to a high heat capacity.)

What was not well understood to-date was exactly HOW minimum and maximum ranges were affected by which factors.

The TL;DR answer is:

• Each ship appears to have a "SignatureMultiplier" which can be empirically measured and ties its thermal load to its heat signature; I have mapped these values for a few ships and will keep adding them as I go
  • Please note: We don't know at this stage if "SignatureMultiplier" is an intrisic property of each ship, like for instance minimum heat dissipation, or if it is a derived metric from some other intrinsic ship value; we do know however that it is a single number per ship type
  • If, with further research, we're able to conclusively link what we're calling "SignatureMultiplier" to some other ship intrinsic property, we will eliminate the use of this term and use the derived value instead; however, so far all attempts at establishing a link have failed - hence the empirical nature of this value
• Given the above "SignatureMultiplier", minimum target lock is a simple multiplication of a scanning's ship's sensor Typical Emissions Range ("TER") and the factor above; that is, minimum target lock scales linearly with TER, depends on the targeted ship but not on the targeting ship
• Minimum lock distance is achieved when thermal load equals minimum heat dissipation for a given ship; this typically happens around ~15% heat displayed on hull (this is why ships that can idle below 15% are extremely stealthy)

• Target lock distance then scales quadratically as thermal load increases, following the formula:
  Effective_Lock_Distance = Minimum_Lock_Distance * (1 + (Thermal_Load - Minimum_Heat_Dissipation) / Minimum_Heat_Dissipation)^2

That's it for the TL;DR!

Fly dangerously CMDRs,

CMDR Mechan

** DETAILED WRITEUP FOLLOWS - ONLY FOR CMDRS WHO TRULY CRAVE ALL THE DETAILS

Note: In my equations I use the subscript "TS" to indicate a TARGET SHIP property and the subscript "SS" to indicate a SCANNING SHIP property.

Ship-intrinsic properties

Before we get into the weeds of how sensors work, we need to understand certain key properties that are intrinsic to ships, and others which are module dependent. To begin with, the following properties are intrinsic to each ship (they never vary) and are relevant to our analysis:

• "MinimumHeatDissipation"--> This is the minimum amount of heat units the ship will dump into space, regardless of thermal load (typically at and below ~15% heat.) Any further decrease in heat generation will not further decrease heat dissipation (and thus heat signature) any further
  • EDSY has this value for all ships
  • It is measured in "heat units / s"
• "MaximumHeatDissipation" --> This is the maximum amount of heat units the ship can dump into space (at 66% heat.) Any further increase in heat generation will not further increase heat dissipation (and thus heat signature) any further
  • EDSY has this value for all ships
  • It is measured in "heat units / s"
• "SignatureMultiplier" --> This is a NEW property which we are introducing as part of this analysis, can be empirically measured, and does not appear to correlate with any known ship property (or at least, not with Mass, not with Thermal Capacity, nor any other obvious ones.)
  • EDSY does NOT have this value; I have started a list of measurements and will expand on it
  • It is a dimensionless variable

Module-related ship properties

In addition to ship "intrinsic" properties, there are some ship properties that vary based on modules installed and what is enabled/disabled (and, in the case of thermal load and MW usage, whether hardpoints are deployed or not.) The key properties we care about in this analysis are:

• "MWinUse" --> This represents the number of megawatts that are currently in use in your ship. Please note that this number will vary depending on what modules you turn on/off, whether you deploy hardpoints, and so on
  • EDSY will give you a detailed report on MW consumption if you enable/disable corresponding modules ...
  • ... or you can measure it empirically in-game using by dividing fuel usage (tons / hour) outside of supercruise by 0.08
    • 0.08 is a "magical number" that appears to be hard-coded and appears not to vary by ship type
  • Unsurprisingly, this is measured in ... MW

• "ThermalLoad" --> This represents the number of "heat units" the ship is generating at any point in time per unit of time; it is a factor of many things on a dynamic ship; for the sake of our exercise, we will assume an idle ship in space as that allows us to simplify things a lot
  • For an idle ship, ThermalLoad is simply the product of MWinUse times the ship's powerplant efficiency
  • It is measured in some unnamed "heat unit" per second measure; some people call it "BTU" but that's technically incorrect and I find it confusing, so I'll just use "heat units per second" here

• "Typical Emissions Range" --> This is the ONLY property of the SCANNING ship that comes into the equation
  • You can check this one for yourself in module details, or EDSY will tell you if you ask nicely
  • It is measured in meters (m)

Scanning-specific metrics

Three additional derived metrics are specifically relevant for scanning (and, specifically, lock distance) purposes:

• The MINIMUM distance at which the target ship will be detected by the scanning ship, no matter what (heat sinks, silent running, natural 2% heat, nothing matters below this range - you'll still get a lock)
  • Let us call this value "MinimumLockDistance"
  • This value generally only applies in practice when the target ship is "cold" (below roughly 15% heat) or if you enable silent running
• The ACTUAL distance at which the target ship will be detected by the scanning ship
  • Let us call this value "EffectiveLockDistance"
  • This value depends on scanning ship's sensor and target ship's heat emissions per formulas described below
• The MAXIMUM distance at which the target ship can stay locked by the scanning ship
  • This value depends exclusively on the scanning ships "maximum sensor range" and thus is pretty obvious; we will not be using this value in our analysis

This is how it all works -

• "MinimumLockDistance"

This applies when ThermalLoad <= MinimumHeatDissipation.

So if you want to test it yourself, fly out with a friend, tell them to turn modules off until they are <15% heat, note your own sensors TER, then approach your friend slooooowly back and forth until you can tell exactly what the value where they "appear" on target lock is. Note that Elite "lags" so moving fast (more than 1-2m/s) will prevent you from getting an accurate read.

• "EffectiveLockDistance"

This applies when MaximumHeatDissipation >= ThermalLoad >= MinimumHeatDissipation.

Note the power of two at the end of the formula above. Lock distance scales quadratically with the delta between ThermalLoad and MinimumHeatDissipation.

I derived this formula through a LOT of trial and error through various attempts at regression. Finally found the one that fits all my observations really well.

Equilibrium Heat

Equilibrium heat is broadly irrelevant in and of itself for sensor range calculations (as it is a derived metric). Nevertheless, some folks have asked how it relates to the values above ... and to oblige, here is the formula (credit to CMD Taleden [EDSY] for this one):

The "1.5" divisor is not an oversight. It is a relic of a past era, when 66% heat used to be 100% heat. FD changed it at some point so the old "100%" heat now shows as 150%, but left the mechanics under the hood untouched, hence the 1.5.

But I still want more details!!!!

Here's the spreadsheet we use. Have fun cloning it, messing with it, reverse-engineering it, etc:

ED Sensor mechanics

docs.google.com

OK, but what process did you follow to figure all this out?

Trial and error mostly. A lot of trial. And a lot of error.
If there's sufficient interest I may expand this writeup to describe this as well.

What are known ships SignatureMultiplier values?

This is what I got for ya ...

TARGET Ship	Signature Multiplier (Empirical)
Anaconda	0.121205357
Chieftain	0.101851852
DBS	0.053639847
DBX	0.056973564
Hauler	0.07291666667

If you dig up more, feel free to add them to the spreadsheet or send them my way


Additional research questions

1. Is a ship's SignatureMultiplier a hardcoded value, or is it a derived metric from some other ship characteristic?
2. What is a Thargoid's interceptor sensors Typical Emissions Range? (of interest to AXI - can be calculated now that we know the mechanics above, with a few "(very) close encounter" experiments)

I'm interested in this research! How can I help?

A few ways:

1. Grab a friend and test additional ships to gather further Signature Multiplier data
2. Run your own tests to see if Signature Multiplier correlates to SOME known ship characteristic, across multiple ships (my tests so far have failed at establishing a link)
3. Sign up with the Anti-Xeno Initiative and join the fight for humanity's future!

And remember ...

*** Edits: Have expanded this article, a lot.
*** More Edits: Fixed a bunch of stuff and typos, including a major typo in a formula above (sorry!)

 

[DNA-Decay]

What’s an MW?

 

[CMDR GRAEME COWELL]

Nice work

 

[Robert Maynard]

What’s an MW?

Mega Watt

 

[galahad2069]

Mega Watt

I thought you were replying to Marty McFly. Or was it gigawatt?

 

[DNA-Decay]

Some of the terms are doing my head in.
Any chance you could do a graphic for this?

Also some clearer names and term definitions.
For example you have a term in your spreadsheet which is "Factor (empirical)"
You don't give a formula for it, but I'm guessing [Thermal Load] x [Factor (empirical)] = [Heat Signature]
I don't get how you work out the [Factor (empirical)] but it's kinda ugly.
Since it turns [Thermal Load] into [Heat Signature] I would call it [Stealth Factor] lower is better.
[Factor (empirical)] = [Stealth Factor]
You could also call it [Thermal Transfer Factor] if Stealth is a different measure.

Another term I'm not getting is [Minimum Target Lock]
Like why is it MINIMUM? Surely you don't break target lock by being too close?
Shouldn't that be [Maximum Target Lock] - ie the farthest distance you can get a target lock?

You definitely should do a graphic that shows how these thing interrelate.
Also Units - Thermal Load is MW is MegaWatts (I think) So what is Heat Signature and how does it relate to the Heat percentage in the HUD?

Good and useful work though - Alec Turner or Ashenfox or someone regular has done a pile of work on Heat previously. You should check their stuff.

 

[Lightspeed]

Interesting analysis.

Sandro Sammarco told us they had made the larger ships more likely to get scanned, ie the bigger the ship the greater the chances. I'm not sure if he meant ship mass or volume, but it would be interesting to see how some of the bigger ships compare in your histogram graph. If it is mass, the Anaconda will stick out as an exception, but if not, then volume is the factor.

Of course, it's possible that bigger ships burn more MWatts, so it could just be that MW output will fit all the ships when correlated with detectability for a scan.

 

[CMDR Mechan]

Interesting analysis.

Sandro Sammarco told us they had made the larger ships more likely to get scanned, ie the bigger the ship the greater the chances. I'm not sure if he meant ship mass or volume, but it would be interesting to see how some of the bigger ships compare in your histogram graph. If it is mass, the Anaconda will stick out as an exception, but if not, then volume is the factor.

Of course, it's possible that bigger ships burn more MWatts, so it could just be that MW output will fit all the ships when correlated with detectability for a scan.

You can see some of the “factors” in the google sheet. It doesn’t appear to be tied to hull mass (else Conda and Chief would be the same), nor total mass - if it is tied to anything, I haven’t figured out what it is. I can say though, those empirically-derived “factors” work extremely well.

 

[CMDR Mechan]

Some of the terms are doing my head in.
Any chance you could do a graphic for this?

I will as I expand the article. For now, I’ve added a couple of charts above.

Also some clearer names and term definitions.
For example you have a term in your spreadsheet which is "Factor (empirical)"
You don't give a formula for it, but I'm guessing [Thermal Load] x [Factor (empirical)] = [Heat Signature]
I don't get how you work out the [Factor (empirical)] but it's kinda ugly.
Since it turns [Thermal Load] into [Heat Signature] I would call it [Stealth Factor] lower is better.
[Factor (empirical)] = [Stealth Factor]
You could also call it [Thermal Transfer Factor] if Stealth is a different measure.

The “empirical factor” I calculated is what ties a given (target) ship minimum target lock range, to a scanning ship’s sensor Typical Emissions Range.

So it goes:
(Minimal target lock range) = (Scanning ship’s sensor Typical Emission Range) * (Target ship “empirical factor”)

Another term I'm not getting is [Minimum Target Lock]
Like why is it MINIMUM? Surely you don't break target lock by being too close?
Shouldn't that be [Maximum Target Lock] - ie the farthest distance you can get a target lock?

You definitely should do a graphic that shows how these thing interrelate.

Minimum Target Lock distance is the distance you will acquire the target, no matter the target’s heat. Doesn’t matter if they are silent running, popping a heatsink, or running at 2% heat naturally - you will ALWAYS detect a target ship at that range.

Also Units - Thermal Load is MW is MegaWatts (I think) So what is Heat Signature and how does it relate to the Heat percentage in the HUD?

Good and useful work though - Alec Turner or Ashenfox or someone regular has done a pile of work on Heat previously. You should check their stuff.

Thermal Load is not expressed in MW. Thermal Load is expressed in some “unnamed heat unit” (some people call it BTU, but that’s not an in-game term, and also not accurate technically). Thermal Load, for an idle ship, is simply the product of your MW_in_use times your power plant’s heat efficiency (it gets more complicated for a ship that’s moving, but that’s beyond the point here.)

I haven’t defined “heat signature” but if you were to define it, I would use my formula i.e., “heat signature”=(1+(thermal_load-min_heat_dissipation)/min_heat_dissipation)^2. Multiply that value times the target ships minimum target lock range, and you get the actual target lock value at the given thermal load.

How thermal load links to heat% you see on the HUD is a bit complicated as it is a quadratic, not a linear, relationship. The exact formula is: heat%=sqrt(thermal_load/max_heat_dissipation)/1.5

 

[CMDR GRAEME COWELL]

Interesting analysis.

Sandro Sammarco told us they had made the larger ships more likely to get scanned, ie the bigger the ship the greater the chances. I'm not sure if he meant ship mass or volume, but it would be interesting to see how some of the bigger ships compare in your histogram graph. If it is mass, the Anaconda will stick out as an exception, but if not, then volume is the factor.

Of course, it's possible that bigger ships burn more MWatts, so it could just be that MW output will fit all the ships when correlated with detectability for a scan.

I think Sandro meant the chance(% if you like) of getting scanned ie npc's attempting a scan as opposed to a scan being successful I get scanned (roughly should probably log some data) 2.5 times as often in my T9 as I do in an eagle given the same parameters ie mission type cargo onboard

 

[777Driver]

I think Sandro meant the chance(% if you like) of getting scanned ie npc's attempting a scan as opposed to a scan being successful I get scanned (roughly should probably log some data) 2.5 times as often in my T9 as I do in an eagle given the same parameters ie mission type cargo onboard

All of that has nothing to do with the OP. You are talking about NPC behaviour and their attempts to investigate and scan you (Authority ships at stations) Paint wear is also tied into the chance of being scanned, a ship with degraded paint also has a higher chance of being investigated and scanned. All of that can be offset by becoming allied with the station you are operating into or smuggling into.

The OP is detailing sensor resolve distances and it's link to heat output.

 

[CMDR GRAEME COWELL]

All of that has nothing to do with the OP. You are talking about NPC behaviour and their attempts to investigate and scan you (Authority ships at stations) Paint wear is also tied into the chance of being scanned, a ship with degraded paint also has a higher chance of being investigated and scanned. All of that can be offset by becoming allied with the station you are operating into or smuggling into.

The OP is detailing sensor resolve distances and it's link to heat output.

Understand that (have read OP including the excellent work further quantifying the variables involved in detection distance vs heat) I was replying to the earlier an earlier post that mentioned Sandro's comments and pointing out that likelyhood of attempted scan is not the same as chance of scan being successful just like simply replying to a thread Is not the same as reading and understanding it

 

[CMDR GRAEME COWELL]

Nice work @Astyrrean your data re heat vs power use correlates closely with @Frenotx earlier work

 

[CMDR Mechan]

All of that has nothing to do with the OP. You are talking about NPC behaviour and their attempts to investigate and scan you (Authority ships at stations) Paint wear is also tied into the chance of being scanned, a ship with degraded paint also has a higher chance of being investigated and scanned. All of that can be offset by becoming allied with the station you are operating into or smuggling into.

The OP is detailing sensor resolve distances and it's link to heat output.

You are correct sir. Also, did a major upgrade of the opening post with a lot more detail in the writeup.

 

[CMDR Mechan]

Nice work @Astyrrean your data re heat vs power use correlates closely with @Frenotx earlier work

Credit to CMDR Taleden from EDSY - I'm using his edsy.js formulas for heat. They work really well!

 

[Winterwalker]

Awesome, awesome work. Bookmarking to read thoroughly later. o7

 

[777Driver]

Understand that (have read OP including the excellent work further quantifying the variables involved in detection distance vs heat) I was replying to the earlier an earlier post that mentioned Sandro's comments and pointing out that likelyhood of attempted scan is not the same as chance of scan being successful just like simply replying to a thread Is not the same as reading and understanding it

Sorry mate, my original post came across way more blunt than I intended, morning coffee and all that!

 

[Maligno]

Now this is the sort of writeup I wanted you to put together from the beginning =). I think we're all gonna have a jolly good time adding data to it.

Here are some suggestions and comments:

1) In the TL;DR : "Given the above "SignatureMultiplier", minimum target lock is a simple multiplication of a scanning's ship's sensor Typical Emissions Range ("TER") and the factor above; that is, minimum target lock scales linearly with TEM, depends on the targeted ship but not on the targeting ship"

the TEM acronym...do you actually mean TER?

2) ""MinimumHeatDissipation"--> This is the minimum amount of heat units the ship will dump into space, regardless of heat (typically at and below ~15% heat.) Any further decrease in heat generation will not further decrease heat dissipation (and thus heat signature) any further"

I think you want to say "regardless of heat generation" or "regardless of thermal load"

3) ""SignatureMultiplier" --> This is a NEW property which we are introducing as part of this analysis, can be empirically measured, and does not appear to correlate linearly with any known ship property (or at least, not with Mass, not with Thermal Capacity, nor any other obvious ones.)"

I would delete the word "linearly" since we don't know if there's a correlation at all. It could be non-linear, but we don't know so I think it's best to drop the word "linearly".

4) "0.08 is a "magical number" that appears to be hard-coded and appears not to vary by ship type"

I think for now it's safe to assume it's hard-coded and doesn't change. But I think in the future we want to make sure that is the case for all ships in the game. Maybe we don't have to make 10 measurements per ship, but at least one or two measurements just to make sure it holds. I know you noted this further down in the writeup, but I think you should make a quick note right there next to that sentence.

5) "In is measured in some unnamed "heat unit" per second measure; some people call it "BTU" but that's technically incorrect and I find it confusing, so I'll just use "heat units per second" here"

I think you wanted to say "And" instead of "In"

6) "This value generally only applies in practice when the target ship is "cold" (below roughly 15% heat)"

I suppose it also applies when the target is engaged in Silent Running.

7) Up in the TL;DR you have the master equation written as: " Effective_Lock_Distance = (1 + Thermal_Load / Minimum_Heat_Dissipation)^2 * Minimum_Lock_Distance"

But down in the detailed section you have it written a little different.

8) "Note the power of two at the end of the formula above. Lock distance scales quadratically with the delta between ThermalLoad and MinimumHeatDissipation."

I think "ratio" is more appropriate than "delta" because you are dividing the two numbers not taking their difference. But that's just a minor semantic point =)

 

[CMDR Mechan]

Now this is the sort of writeup I wanted you to put together from the beginning =). I think we're all gonna have a jolly good time adding data to it.

Here are some suggestions and comments:

1) In the TL;DR : "Given the above "SignatureMultiplier", minimum target lock is a simple multiplication of a scanning's ship's sensor Typical Emissions Range ("TER") and the factor above; that is, minimum target lock scales linearly with TEM, depends on the targeted ship but not on the targeting ship"

the TEM acronym...do you actually mean TER?

Yup, good catch, fixed.

2) ""MinimumHeatDissipation"--> This is the minimum amount of heat units the ship will dump into space, regardless of heat (typically at and below ~15% heat.) Any further decrease in heat generation will not further decrease heat dissipation (and thus heat signature) any further"

I think you want to say "regardless of heat generation" or "regardless of thermal load"

Yup, edited.

3) ""SignatureMultiplier" --> This is a NEW property which we are introducing as part of this analysis, can be empirically measured, and does not appear to correlate linearly with any known ship property (or at least, not with Mass, not with Thermal Capacity, nor any other obvious ones.)"

I would delete the word "linearly" since we don't know if there's a correlation at all. It could be non-linear, but we don't know so I think it's best to drop the word "linearly".

Agreed - done.

4) "0.08 is a "magical number" that appears to be hard-coded and appears not to vary by ship type"

I think for now it's safe to assume it's hard-coded and doesn't change. But I think in the future we want to make sure that is the case for all ships in the game. Maybe we don't have to make 10 measurements per ship, but at least one or two measurements just to make sure it holds. I know you noted this further down in the writeup, but I think you should make a quick note right there next to that sentence.

Maybe ... although this one seems a pretty safe one.

5) "In is measured in some unnamed "heat unit" per second measure; some people call it "BTU" but that's technically incorrect and I find it confusing, so I'll just use "heat units per second" here"

I think you wanted to say "And" instead of "In"

Yup, TY sir

6) "This value generally only applies in practice when the target ship is "cold" (below roughly 15% heat)"

I suppose it also applies when the target is engaged in Silent Running.

Yessir - hence the generally, but maybe worth calling it out.

7) Up in the TL;DR you have the master equation written as: " Effective_Lock_Distance = (1 + Thermal_Load / Minimum_Heat_Dissipation)^2 * Minimum_Lock_Distance"

But down in the detailed section you have it written a little different.

Will standardize; I find the latter easier to read, also this one missed a term - fixed.

8) "Note the power of two at the end of the formula above. Lock distance scales quadratically with the delta between ThermalLoad and MinimumHeatDissipation."

I think "ratio" is more appropriate than "delta" because you are dividing the two numbers not taking their difference. But that's just a minor semantic point =)

Not exactly ... I am dividing the delta from a number, by the number itself, hence it's a delta% ... still a delta .
Thing is ... there was a typo in the formula ( / instead of - ) thanks for helping me catch it!

 

[Lightspeed]

Greetings fellow CMDRs!

As a science project for the Anti-Xeno Initiative, myself and a few fellow CMDRs (thank you CMDR Bacon_, CMDR fvv2, and CMDR Miraka in particular!) have been studying detailed sensor lock mechanics. And thank you to CMDR Maligno for being enough of a friendly pain-in-the-neck to spur me to create this write-up.

It is well-understood that sensor lock ties to heat - which is why it is known that firing a heatsink will often break target-lock, and some ships (DBS and DBX) are noticeably "stealthy" given their low resting heat (which in turn, is due to a high heat capacity.)

What was not well understood to-date was exactly HOW minimum and maximum ranges were affected by which factors.

The TL;DR answer is:

• Each ship has a "SignatureMultiplier" which can be empirically measured and ties its thermal load to its heat signature; I have mapped these values for a few ships and will keep adding them as I go
• Given the above "SignatureMultiplier", minimum target lock is a simple multiplication of a scanning's ship's sensor Typical Emissions Range ("TER") and the factor above; that is, minimum target lock scales linearly with TER, depends on the targeted ship but not on the targeting ship
• Minimum lock distance is achieved when thermal load equals minimum heat dissipation for a given ship; this typically happens around ~15% heat displayed on hull (this is why ships that can idle below 15% are extremely stealthy)

View attachment 163356

• Target lock distance then scales quadratically as thermal load increases, following the formula:
  Effective_Lock_Distance = Minimum_Lock_Distance * (1 + (Thermal_Load - Minimum_Heat_Dissipation) / Minimum_Heat_Dissipation)^2

View attachment 163357

That's it for the TL;DR!

Fly dangerously CMDRs,

CMDR Mechan

** DETAILED WRITEUP FOLLOWS - ONLY FOR CMDRS WHO TRULY CRAVE ALL THE DETAILS

Note: In my equations I use the subscript "TS" to indicate a TARGET SHIP property and the subscript "SS" to indicate a SCANNING SHIP property.

Ship-intrinsic properties

Before we get into the weeds of how sensors work, we need to understand certain key properties that are intrinsic to ships, and others which are module dependent. In particular, the following properties are intrinsic to each ship (they never vary) and are relevant to our analysis:

• "MinimumHeatDissipation"--> This is the minimum amount of heat units the ship will dump into space, regardless of thermal load (typically at and below ~15% heat.) Any further decrease in heat generation will not further decrease heat dissipation (and thus heat signature) any further
  • EDSY has this value for all ships
  • It is measured in "heat units / s"
• "MaximumHeatDissipation" --> This is the maximum amount of heat units the ship can dump into space (at 66% heat.) Any further increase in heat generation will not further increase heat dissipation (and thus heat signature) any further
  • EDSY has this value for all ships
  • It is measured in "heat units / s"
• "SignatureMultiplier" --> This is a NEW property which we are introducing as part of this analysis, can be empirically measured, and does not appear to correlate linearly with any known ship property (or at least, not with Mass, not with Thermal Capacity, nor any other obvious ones.)
  • EDSY does NOT have this value; I have started a list of measurements and will expand on it
  • It is a dimensionless variable

Module-related ship properties

In addition to ship "intrinsic" properties, there are some ship properties that vary based on modules installed and what is enabled/disabled (and, in the case of thermal load and MW usage, whether hardpoints are deployed or not.) The key properties we care about in this analysis are:

• "MWinUse" --> This represents the number of megawatts that are currently in use in your ship. Please note that this number will vary depending on what modules you turn on/off, whether you deploy hardpoints, and so on
  • EDSY will give you a detailed report on MW consumption if you enable/disable corresponding modules ...
  • ... or you can measure it empirically in-game using by dividing fuel usage (tons / hour) outside of supercruise by 0.08
    • 0.08 is a "magical number" that appears to be hard-coded and appears not to vary by ship type
  • Unsurprisingly, this is measured in ... MW

View attachment 163445

• "ThermalLoad" --> This represents the number of "heat units" the ship is generating at any point in time per unit of time; it is a factor of many things on a dynamic ship; for the sake of our exercise, we will assume an idle ship in space as that allows us to simplify things a lot
  • For an idle ship, ThermalLoad is simply the product of MWinUse times the ship's powerplant efficiency
  • It is measured in some unnamed "heat unit" per second measure; some people call it "BTU" but that's technically incorrect and I find it confusing, so I'll just use "heat units per second" here

View attachment 163440

• "Typical Emissions Range" --> This is the ONLY property of the SCANNING ship that comes into the equation
  • You can check this one for yourself in module details, or EDSY will tell you if you ask nicely
  • It is measured in meters (m)

Scanning-specific metrics

Three additional derived metrics are specifically relevant for scanning (and, specifically, lock distance) purposes:

• The MINIMUM distance at which the target ship will be detected by the scanning ship, no matter what (heat sinks, silent running, natural 2% heat, nothing matters below this range - you'll still get a lock)
  • Let us call this value "MinimumLockDistance"
  • This value generally only applies in practice when the target ship is "cold" (below roughly 15% heat) or if you enable silent running
• The ACTUAL distance at which the target ship will be detected by the scanning ship
  • Let us call this value "EffectiveLockDistance"
  • This value depends on scanning ship's sensor and target ship's heat emissions per formulas described below
• The MAXIMUM distance at which the target ship can stay locked by the scanning ship
  • This value depends exclusively on the scanning ships "maximum sensor range" and thus is pretty obvious; we will not be using this value in our analysis

This is how it all works -

• "MinimumLockDistance"

View attachment 163441

This applies when ThermalLoad <= MinimumHeatDissipation.

So if you want to test it yourself, fly out with a friend, tell them to turn modules off until they are <15% heat, note your own sensors TER, then approach your friend slooooowly back and forth until you can tell exactly what the value where they "appear" on target lock is. Note that Elite "lags" so moving fast (more than 1-2m/s) will prevent you from getting an accurate read.

• "EffectiveLockDistance"

View attachment 163463

This applies when MaximumHeatDissipation >= ThermalLoad >= MinimumHeatDissipation.

Note the power of two at the end of the formula above. Lock distance scales quadratically with the delta between ThermalLoad and MinimumHeatDissipation.

I derived this formula through a LOT of trial and error through various attempts at regression. Finally found the one that fits all my observations really well.

Equilibrium Heat

Equilibrium heat is broadly irrelevant in and of itself for sensor range calculations (as it is a derived metric). Nevertheless, some folks have asked how it relates to the values above ... and to oblige, here is the formula (credit to CMD Taleden [EDSY] for this one):

View attachment 163446

The "1.5" divisor is not an oversight. It is a relic of a past era, when 66% heat used to be 100% heat. FD changed it at some point so the old "100%" heat now shows as 150%, but left the mechanics under the hood untouched, hence the 1.5.

But I still want more details!!!!

Here's the spreadsheet we use. Have fun cloning it, messing with it, reverse-engineering it, etc:

ED Sensor mechanics

docs.google.com

OK, but what process did you follow to figure all this out?

Trial and error mostly. A lot of trial. And a lot of error.
If there's sufficient interest I may expand this writeup to describe this as well.

What are known ships SignatureMultiplier values?

This is what I got for ya ...

TARGET Ship	Signature Multiplier (Empirical)
Anaconda	0.121205357
Chieftain	0.101851852
DBS	0.053639847
DBX	0.056973564

If you dig up more, feel free to add them to the spreadsheet or send them my way




Additional research questions

1. Is a ship's SignatureMultiplier a hardcoded value, or is it a derived metric from some other ship characteristic?
2. What is a Thargoid's interceptor sensors Typical Emissions Range? (of interest to AXI - can be calculated now that we know the mechanics above, with a few "(very) close encounter" experiments)

I'm interested in this research! How can I help?

A few ways:

1. Grab a friend and test additional ships to gather further Signature Multiplier data
2. Run your own tests to see if Signature Multiplier correlates to SOME known ship characteristic, across multiple ships (my tests so far have failed at establishing a link)
3. Sign up with the Anti-Xeno Initiative and join the fight for humanity's future!

And remember ...

*** Edits: Have expanded this article, a lot.
*** More Edits: Fixed a bunch of stuff and typos, including a major typo in a formula above (sorry!)

A lot of work ! Thankyou for making this public