Without wanting to throw a spanner in the works, did you test with different attitudes tgt ship facing towards, away, sideways? Based on your research it shouldn't matter but, given the amount of variables FDEV use in some of their mechanics I was wondering if it would be a factor, not in reasonable for FDEV to make the rear of a ship more emissive than the front
A detailed inquiry into Elite Dangerous Sensor Mechanics / Target Lock Acquisition
- Thread starter CMDR Mechan
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I sure did. No difference.
Awesome very thorough work mate
Very impressive work indeed.
Physics grad here. Since powerplant efficiency is a dimensionless quantity (a percentage),
ThermalLoad is clearly also expressible in megawatts. Dimensional analysis allows no other conclusion.If your assumption is that powerplant efficiency is a dimensionless variable (a simple %) then you are correct. And, yes, well aware we have MWt and MWe for that very reason.
You don't know that for a fact however. What if it's dimension is "(unspecified heat units) / (megawatt used)?"
And since we have no way of determining that ...
"Heat Units" is easier to deal with than trying to explain and deal with MWe and MWt. The thing is, nowhere in the game are heat units "labeled." Every module that has a thermal load has, just has "Thermal Load: 20" or something. So it's not like the game tells you what those units are. But they are related to heat, so they must be "something" and aren't really dimensionless.
My 2 cents at least.
Very interesting analysis. I was under the impression ships size effected detection ranges. I would be interesting to also test sensor classes (engineered and not) and various ships sizes to expand on these results. Great work so far.
Not quite the size itself, though if you look at the "Signature Multipliers" they are somewhat loosely correlated with size, so to an extent "bigger ships are less stealthy" holds true in practice.
I've tested plenty of sensors, of different classes, engineered or otherwise. Only thing that matters is the sensor's typical emissions range (and, of course, if you go that far away, also their max range)
I think I found a simplification, please can someone check my algebra?
Given:
Renaming more concisely:
Thus:
I hope I got all that right (gulp).
Given:
Code:
Effective_Lock_Distance = Minimum_Lock_Distance * (1 + (Thermal_Load - Minimum_Heat_Dissipation) / Minimum_Heat_Dissipation)^2Renaming more concisely:
Code:
ELD = MinLD * (1 + (TL - MinHD) / MinHD) ^ 2Thus:
Code:
ELD = MinLD * (1 + (TL - MinHD ) / MinHD) ^ 2
= MinLD * (1 + TL / MinHD - MinHD / MinHD) ^ 2
= MinLD * (1 + TL / MinHD - 1) ^ 2
= MinLD * (TL / MinHD) ^ 2I hope I got all that right (gulp).
Sounds about right!
Yay! As a physics grad turned software engineer, I feel the tension between long names (better for understanding the purpose of the code) and shorter names (better for seeing the shape of the algebra).
Updating as we have data on Thargoid's sensor statistics. Thargoid Interceptors appear to use an E-rated Class 5 sensor, with a Typical Emissions Range of 4,640m. That translates into a "cold lock" distance of 473m for a Chieftain, and 249m for a Diamondback Scout.
Hi there. I'm not sure if anybody is still paying attention to this thread, but this is a topic I'm very interested in so I wanted to chime in with my own findings. I'm not sure if we're coming to the same conclusion and presenting it differently, but most of the experimentation I've done looks very different from what you posted at first glance.
So what I've come up with is that every ship has an intrinsic property related to how "stealthy" it is. This is the "Average Emissions" referred to in the Sensor module's description blurb. As far as I can tell this value cannot be changed in any way; I've tried with different ratings and sizes of power plants, different bulkheads, different power distributors, different thrusters, etc and nothing appears to modify this value.
The range at which another ship will detect you (as a resolved contact) is
That's all there is to it.
The Minimum Heat Dissipation shown on EDSY simply corresponds to the auto-resolve distances for the ship in question; which itself depends on the sensor range of the targeting ship.
Some of the Average Emissions that I know of are:
Speaking of the values shown on EDSY, I did read somewhere that the creator of that site said something about having to adjust the heat characteristics shown for each ship because of the re-scaled heat gauge. But I've found this is not actually the case: each ship's heat capacity is still 1.5x what is shown on EDSY. As to how I came to that conclusion, what I did was:
1.) I calculated the Thermal Load of the ship I was in by adding up its power usage and multiplying by the powerplant efficiency
2.) Go into silent running and pop a heat sink.
3.) Once the thermal drain from the heat sink expires, start a stopwatch and stay in silent running
4.) Time how long it takes it get various temperatures.
5.) Calculate the ship's thermal content based on the Thermal Load and the elapsed time
6.) Calculate the ship's heat capacity based on the thermal content from Step 5 and the corresponding Thermal Gauge.
Since silent running traps all heat inside the ship, and I know how much heat the ship is generating, I know how much heat is in the ship at any given time.
For example, let's say I'm in a Keelback and its Thermal Load is 5.67. After doing the heat sink test I get the following results (this is just a sample of the results):
From this I concluded that 37.422 is 12% of the ship's heat capacity, 70.308 is 22% of the ship's heat capacity, and 101.493 is 32% of the ship's heat capacity. That corresponds to Heat Capacities of 311.85, 319.582, and 317.17; taking the average of those to smooth out rounding and UI errors, and I get a value of 316.2. Almost exactly 1.5x as much as the 215 shown on EDSY.
In the same post about EDSY, I think I also remember them saying something about the cooling rates being higher than what was anticipated. I don't think it was mentioned which ship they were looking at, but from what I've seen EDSY appears to assume that every ship has a cooling coefficient of 0.3. During testing, however, I've found that the cooling rate for each ship is an intrinsic value that could be as low as 0.2 or as high as 0.3 (I haven't tested every ship, though). Like Average Emissions, nothing seems to modify this value.
As for what this coefficient refers to, its the "A" in the following formula:
This formula refers to the rate at which your ship dissipates heat, and is how you figure out what to put in for the "Heat Dissipation" term in the ship detection formula from above.
This is something that Frenotx posted about a few years ago, although he did assume that the coefficient is always 0.2. As an example of ships that have a greater value for this coefficient, the Krait Phantom has a coefficient of 0.25 and the Federal Corvette has one of 0.3.
So let's look at a few examples to see how all of this fits together. First we need some information:
Let's say that all 3 ships are sitting at 20% thermal gauge, and a ship with a (unengineered) 4C Sensor with a TER of 5,600 m is trying to target them. Each ship's heat dissipation would be Cooling Coefficient * 20%^2 * Heat Capacity and the sensor lock range would be:
So those are the major points for how I think it all works. Other things I think you should be aware of are the different sources of heat in the game (beyond just powering modules). These include:
1.) Recharging/Regenerating shields through SYS capacitor. Thermal Load for that is:
2.) Thruster thermal load, which depends on Acceleration, NOT Speed. If your speed is constant, or more accurately your velocity vector is not changing in any way, thermal load from thrusters is zero. Thermal Load for when you are accelerating is the ship's thrust percentage (which you can control in FA Off) multiplied by the listed thermal load on your ship's thruster module information page. If you are using more than one directional thruster (forward and lateral, for example) Thermal Load is proportional to whichever thrust percent is greatest.
There is also some evidence to suggest that angular acceleration generates thruster thermal load. But this is hard to test, so I just assume it works the same way as the thermal load from linear acceleration.
3.) Boosting generates heat, as everyone knows. The amount of heat generated is 3x PD Draw. This is in addition to the Thruster thermal load due to acceleration noted above.
4.) Being near hot objects, like stars, increases thermal load. I worked out a pair of formulas to describe this thermal load but I don't have it handy at the moment. One thing to note about them, is that the thermal load doesn't actually depend on the temperature of the star; only its radius and your distance from it. The formulas were also only valid for main sequence stars and only when you are in supercruise; you get much lower values once you drop down into normal space, I've noticed.
That's all I've got for now.
So what I've come up with is that every ship has an intrinsic property related to how "stealthy" it is. This is the "Average Emissions" referred to in the Sensor module's description blurb. As far as I can tell this value cannot be changed in any way; I've tried with different ratings and sizes of power plants, different bulkheads, different power distributors, different thrusters, etc and nothing appears to modify this value.
The range at which another ship will detect you (as a resolved contact) is
Code:
(Heat Dissipation/Average Emissions)^2 * Typical Emissions RangeThat's all there is to it.
The Minimum Heat Dissipation shown on EDSY simply corresponds to the auto-resolve distances for the ship in question; which itself depends on the sensor range of the targeting ship.
Some of the Average Emissions that I know of are:
| Ship | Average Emissions |
| Federal Corvette | 9.1 |
| Imperial Cutter | 8.1 |
| Krait Mk2 | 8 |
| Alliance Crusader | 7.5 |
| Type 9 | 7.8 |
| Keelback | 6.3 |
| Any Human SLF | 3.4 |
| Vulture | 7 (I think I have to redo this one) |
Speaking of the values shown on EDSY, I did read somewhere that the creator of that site said something about having to adjust the heat characteristics shown for each ship because of the re-scaled heat gauge. But I've found this is not actually the case: each ship's heat capacity is still 1.5x what is shown on EDSY. As to how I came to that conclusion, what I did was:
1.) I calculated the Thermal Load of the ship I was in by adding up its power usage and multiplying by the powerplant efficiency
2.) Go into silent running and pop a heat sink.
3.) Once the thermal drain from the heat sink expires, start a stopwatch and stay in silent running
4.) Time how long it takes it get various temperatures.
5.) Calculate the ship's thermal content based on the Thermal Load and the elapsed time
6.) Calculate the ship's heat capacity based on the thermal content from Step 5 and the corresponding Thermal Gauge.
Since silent running traps all heat inside the ship, and I know how much heat the ship is generating, I know how much heat is in the ship at any given time.
For example, let's say I'm in a Keelback and its Thermal Load is 5.67. After doing the heat sink test I get the following results (this is just a sample of the results):
| Elapsed Time (seconds) | Thermal Content (elapsed time x thermal load) | Thermal Gauge (%) |
| 6.6 | 37.422 | 12% |
| 12.4 | 70.308 | 22% |
| 17.9 | 101.493 | 32% |
In the same post about EDSY, I think I also remember them saying something about the cooling rates being higher than what was anticipated. I don't think it was mentioned which ship they were looking at, but from what I've seen EDSY appears to assume that every ship has a cooling coefficient of 0.3. During testing, however, I've found that the cooling rate for each ship is an intrinsic value that could be as low as 0.2 or as high as 0.3 (I haven't tested every ship, though). Like Average Emissions, nothing seems to modify this value.
As for what this coefficient refers to, its the "A" in the following formula:
Code:
A * (Thermal Gauge)^2 * Heat CapacityThis formula refers to the rate at which your ship dissipates heat, and is how you figure out what to put in for the "Heat Dissipation" term in the ship detection formula from above.
This is something that Frenotx posted about a few years ago, although he did assume that the coefficient is always 0.2. As an example of ships that have a greater value for this coefficient, the Krait Phantom has a coefficient of 0.25 and the Federal Corvette has one of 0.3.
So let's look at a few examples to see how all of this fits together. First we need some information:
| Ship | Heat Capacity | Cooling Coefficient | Average Emissions |
| Federal Corvette | 498 | 0.3 | 9.1 |
| Krait Phantom | 450 | 0.25 | 8 |
| Keelback | 316 | 0.2 | 6.3 |
| Ship | Heat Dissipation | Sensor Lock Range (TER of 5600 m) |
| Federal Corvette | 5.976 | 2415.05 |
| Krait Phantom | 4.5 | 1771.875 |
| Keelback | 2.528 | 901.70 |
1.) Recharging/Regenerating shields through SYS capacitor. Thermal Load for that is:
Code:
PD Draw * Regen Rate2.) Thruster thermal load, which depends on Acceleration, NOT Speed. If your speed is constant, or more accurately your velocity vector is not changing in any way, thermal load from thrusters is zero. Thermal Load for when you are accelerating is the ship's thrust percentage (which you can control in FA Off) multiplied by the listed thermal load on your ship's thruster module information page. If you are using more than one directional thruster (forward and lateral, for example) Thermal Load is proportional to whichever thrust percent is greatest.
There is also some evidence to suggest that angular acceleration generates thruster thermal load. But this is hard to test, so I just assume it works the same way as the thermal load from linear acceleration.
3.) Boosting generates heat, as everyone knows. The amount of heat generated is 3x PD Draw. This is in addition to the Thruster thermal load due to acceleration noted above.
4.) Being near hot objects, like stars, increases thermal load. I worked out a pair of formulas to describe this thermal load but I don't have it handy at the moment. One thing to note about them, is that the thermal load doesn't actually depend on the temperature of the star; only its radius and your distance from it. The formulas were also only valid for main sequence stars and only when you are in supercruise; you get much lower values once you drop down into normal space, I've noticed.
That's all I've got for now.
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You've got me thinking about the dolphin post patch as a potential megaship data/cargo pirate. I've found it to be far cooler than it used to be, and with the expanded cargo relative to the dbx, it might fit nicely in this niche with appropriate engineering. I play mostly solo in Open, so I don't have a partner to test the dolphin with...
That’s cool, I guess? I skimmed most of it; and read about the FA Off stuff and Salome’s obituary, mostly..
But what does any of it have to do with what I or Astyrrean posted? Are you guys going to release an article about sensor mechanics in the next issue?
How can this information be used in practical flying/ship builds?
I like to build extremely cold vessels, and have a DBX that flies at 9-10% heat with icy canopy most of the time. Have not been able to get below 11% in a Dolphin.
What is the typical distance to maintain from an enemy ship to gain an advantage? What would the advantage actually be? Does the size of enemy sensor matter? Does the grade matter?
Does heat matter in Supercruise?
I've been interdicted, submitted and sat still- only to observe pirate ships drop in and just sit there. It seems that they not only cannot target lock, but cannot see me at all. Escaping is as easy as toggling off FA, applying a quick burn and drifting away.
I like to build extremely cold vessels, and have a DBX that flies at 9-10% heat with icy canopy most of the time. Have not been able to get below 11% in a Dolphin.
What is the typical distance to maintain from an enemy ship to gain an advantage? What would the advantage actually be? Does the size of enemy sensor matter? Does the grade matter?
Does heat matter in Supercruise?
I've been interdicted, submitted and sat still- only to observe pirate ships drop in and just sit there. It seems that they not only cannot target lock, but cannot see me at all. Escaping is as easy as toggling off FA, applying a quick burn and drifting away.