Re: [FT] Sensor Range Question

G'day Jerry,

>Actually, MT is kind of weird in which it postulates a larger active
>range than passive range.  Can anybody speak of unclassified projects
>(8-) where this is true?  I always thought that your passive always
>exceeds your active. 

Well I don't know anything about real sensors, but in all the other
sci-fi
books/games we've got they have their passive < then their active (not
so
much an explanation as an excuse I guess, sorry). Derek also just
checked
out his his Harpoon 4 sonar annex and as a rule the sonar systems with
both
active and passive modes have an active range greater than there passive
range, so hopefully we haven't stuffed up too badly. Basically the way
we
thought about it was if you're standing in the dark you don't recieve a
lot
passive info (i.e. not much light so don't see much), but if you start
swinging a torch around (i.e. actively looking then you're more likely
to
see stuff that's further away) - once again hope we didn't screw up too
bad.

>And Beth, what's the difference between passive
>and ESM, aren't they just two sides of the same coin?

Well we looked at it along these lines:

Passive: Just looking for any hint they're there (i.e. looking for
light/heat etc)
Active: Ping someone and work off the radiation reflected back to you
ESM: When you're looking for someone else's ping - so don't detect enemy
ships, but do detect the active sensor scans used by the enemy. Bit like
that torch thing again you can see a torch yonks away, but you can't
see/hear/feel who's using it etc.

>So that gives half a light second passive, 2 light seconds active,
>2.4 light seconds using 'ESM.'  Hmmmm.

And what does that mean? Good Hmmm, bad hmmm, or just hmmmm I 'd rather
be
thinking about something else at lunch? ;)

>I think Laser had a point 

Does that make him a laser pointer (as in the things you use in
seminars) -
OK very sick but I've been at work WAY TOOO long already today.

Cheers

Beth

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Elizabeth Fulton
c/o CSIRO Division of Marine Research
GPO Box 1538
HOBART 
TASMANIA 7001
AUSTRALIA
Phone (03) 6232 5018 International +61 3 6232 5018
Fax (03) 6232 5199 International +61 3 6232 5199

email: beth.fulton@marine.csiro.au