From: mikkelhaaheim@gmail.com   
      
   Le lundi 26 septembre 2016 01:19:13 UTC+2, Rick Pikul/Chakat Firepaw a   
   écrit :   
      
   > >> Nope, not false.  Your later simply shows that you still don't   
   > >> understand how a sensor system like this would work.   
   > >>    
   > >> (Hint:  Think about why radar dishes move and why they can get away   
   > >> with not constantly staring at things.)   
   > >    
   > > Nope, still false. You can get away with terrestrial radar scanning   
   > > because the gaps created during military radar sweeps are generally not   
   > > large enough to slip aircraft through, at least not at the ranges where   
   > > you have reliable detection.   
   >    
   > And the gaps in an interplanetary sensors sweeps are not large enough for    
   > ships to slip through.   
      
   There are quite a few different kinds of "gaps" that stealth can take   
   advantage of. A sensor platform requires accumulation of RELIABLE signal   
   input. Platforms acquire input through signal source strength, detector   
   sensitivity, spatial signal    
   accumulation (collector area), and temporal signal accumulation (exposure   
   time). RELIABILITY is established through detection amplitude, signal duration   
   and/or repetition, signal contrast, multiple detection sites, etc. It is NOT   
   enough to simply detect    
   a signal. You must also rule out false positives  (energy discharges produced   
   by the sensor equipment, localised discharge events, routine deviations in   
   known sources --you can't just eliminate a signal as a known target, because   
   intensities of    
   background sources tend to vary naturally as a product of physical activity in   
   the deep space environment, so you end up throughing out legitimate positives   
   as well-- , unmapped natural sources, etc.   
   Just considering the spatio-temporal gaps... sure, a spacecraft is not going   
   to move very far in terms of angular resolution during the duration of the   
   gap. Unfortunately, the ratio of gap to signal means that scanning can be   
   easily defeated by simple    
   pulsed emissions. Sure, occasional pulses might be detected, but without   
   repeated pulses at fixed intervals, you never know if you actually have a   
   single vessel track, or if you have numerous incidental detections of natural   
   sources (sunlight reflecting    
   off a smaller asteroid, etc). So, you say that you will just dedicate sensors   
   to each possible "ping"... but this can easily be defeated by increased volume   
   of "legitimate" transport activity.   
   Among the other gaps:   
   signal emission vector- it doesn't do any good to have the most sensitive   
   detectors if they are not placed in the path of the emitted energy;   
   signal wavelength- sensitive detectors tend to achieve sensitivity by   
   concentrating on specific bands of wavelength, which are useless if other   
   bands are being emitted instead;   
   low contrast- there is A LOT of background "static" out there, so you will be   
   virtually invisible if your emission is within the normal variation of   
   background signal intensities... difficult with a torchship at full burn, not   
   so difficult if you are    
   limiting emissions to even a few dozen kW (WISE can detect as little as 50 to   
   100 watts, RADIATED IN THE DIRECTION OF THE DETECTOR).   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)