On 26/9/21 7:15 am, "Nokes.Name" - greg at nokes.name (via tml list) wrote:
>
> Sent from my iPhone
>
>> On Sep 25, 2021, at 12:10 PM, Alex Goodwin - alex.goodwin at multitel.com.au <xxxxxx@simplelists.com> wrote:
>>
>> Assuming no prior contact or pointers, said contact would be detectable
>> 90% of the time (net kit-modified skill roll of 14) at the following ranges:
>>
>> Beaumont - 10,000 km;
>>
>> Mainwaring - 46,000 km;
>>
>> Jones - 100,000 km;
>>
>> Serafina - 300,000 km.
>>
>> For 50% chance of detection, those ranges expand to:
>>
>> Beaumont - 46,000 km;
>>
>> Mainwaring - 210,000 km;
>>
>> Jones - 460,000 km;
>>
>> Serafina - 1,460,000 km.
>
> My take is
>
> Sensor system X has a detection range of Y. Inside of that range, you have a “blip”. Signal processing systems can refine the “blip” a little bit - higher TL or more advanced systems will get you more data.
>
> The skill comes in when you are 1) refining that “blip” down to a “400 ton Corsair” or 2) when you are operating outside of max range.
>
> So, Beaumont catches a blip, and determines that it’s a medium vessel, with minimal EM signature. They then pass the detection off to the Sr. Watch Officer, Serafina. Serafina trains the PEMS array on the target, and they are able to determine that it’s a 5,000 dTon vessel, running dark. Matching against known signal intelligence, they feel that it’s a Varger light cruiser.
>
> Ops decides to dispatch a drone to investigate.
>
> When the drone goes active near the target, it powers up its AEMS array. After a contested EO skill check with Beaumont, the target able to blind the drone by overwhelming it.
>
> However, Serafina is still on the PEMS array. They feel that there is no way that a Varger light cruiser would have EMS jammers capable of that, so they refine the detection, send it back thru signal, and suspect that it’s a Sword Worlder 10,000 dTon cruiser.
>
> Time for the destroyer to bug out.
>
Greg, thanks for your feedback.

As you have pointed out (and thank you for highlighting my error),
_detection_ by no means implies anything further on its own.

I'm wondering why you're assuming a given sensor has a single effective
range _against all targets of all shapes, sizes, colours, aspects and
emission coatings_?  Simplicity at the table?

Borrowing your tonnages, assuming my initial example was a 400 dton
corsair (if the Terran Confederation Navy before 2300 AD is tangling
with Vargr raiders, something something interesting times something
something) - a 10 kdton battlewagon, ceteris fnordibus, would, per the
hull table on GT:ISW p 189, have an extra +3 size mod.

Neglecting any emission cloaking, this would multiply those ranges I
quoted above by 10 ** ( 3/6 ), or sqrt ( 10 ) - so automagic detection
would be at ~30,000 km, and sensor limit would expand to roughly 6
million km.  Senior Chief Serafina would still have an even chance of
rumbling the bigger contact at ~5.3 million km out.

Detection alone requires succeeding by 0 to 2, per GT:ISW p 221, and
tells the sensor operator(s) that _something_ is out there, with a known
velocity and displacement.  Damned if you know anything more.  
"Something's out there, sir, X distance away, fairly big, and closing at
Y rate."

Detection and recognition requires success by 3-4, adding a fuzzy image
of its general shape to the above.  This can be enough, as you said, to
start refining broad classes of vehicle, correlating with onboard sensor
data libraries, etc.

"Sir, contact is definitely over 5 kilotonnes - either a damned big
freighter or a capital vessel."

Detection and identification requires success by 5+, meaning the object
is resolved to an actual sensor image, and can thus be fed into sensor
libraries for further detail.

 "Sir, contact is identified as the _Legend_-class heavy cruiser TCS
_Fleet Admiral Daniel Dodgie_.  What are they doing way the hell out here?"

Assuming sensor contact is maintained, attempts to upgrade the degree of
success (and thus detail) are rolled at +4 on later attempts (GT:ISW p
227).  If such upgrade attempts fail to improve the degree of detection,
there's no penalty other than time + sensor effort.   I _think_ that
would game-mechanically model the bit you outlined of refining the
contact from the initial blip.

Alex