Originally posted by 38:
[b]Tripwire, thanks for detailed reply, no bad feeling
here...
Sorry for the topic, just want to hijack the thread a little bit
more.. and have some more to discuss with u:
Regarding the E-2 can detect an aeroplane 200km away, doesnt mean
it can subsequently detect the Astro rocket size target in 90km.
The APS-145 detective range is only got sth to do with the RCS and
the speed of the target. Just as u mentioned, the rocket actual
size is comparable to that of MRAAM. A common MRAAM RCS is 0.1-0.2
m2, but a F15 size plane is 10-15m2. So the E2 can track the
10-15m2 RCS target in 200kms but much short for it to track sub-1m2
target. Considering the E-2 has to track so many targets in the sky
and sea and land at same time, how it can realize in time, the
rockets r not AAM towards itself or sth else? On the other hand,
the rocket flies at such high speed, it takes only a few minutes to
cover its 90km range. Do u think the E2 tracking practice is not a
joke in reality?
When we watching Hollywood war movies like Topgun/ Behind the enemy
line or so, usually, the fighter jet pilot realize the AAM only by
their alarm, but not via their onboard radar.
[/b]
no hard feelings at all... ...
with regard to your question... i would like to point out afew
points...
1.. RCS isnt determined solely by the size of the object... the
shape, material used and even the paint used are far more
important.
so you cannot equate the ASTRO rocket RCS to that of a MRAAM just
like that unless the design of both the ASTRO and the AMRAAM is
identical and the only difference is size.
2.. RCS isnt constant across the entire object... unless the object
is round... the concept is best explain by using a pencil... your
ability to see the pencil in my hand at a distance, is dependent on
how i hold the pencil... directly pointing the pencil lead at your
eye or holding the pencil straight up before your eye.
3.. the E-2 scanned its area of responsibility top down... thus the
RCS of the astro rocket would appear much bigger to the E-2... as
it more resembles seeing a pencil held vertically towards your eye
then a pencil held pointing straight at your pupil.
4.. Astros fire in salvos... the more rockets are launched
simultaneously.. the bigger the overall RCS.. something similar to
the concept of radar response due to migratory birds flying in a
flock.
5.. speed do not determines the radar detection and tracking
capability... afterall... most military radars have to cope with
high speed fighters flying in excess of mark 2 and SAMs and AAMs
flying as fast as mach 4 or more. AStro would never attain such a
comparable speed.
6 Rockets are unlike missiles... after firing.. their speed rapidly
rises at a constant rate as long as the it has fuel... once the
fuel is burnt out... its speed begins to rapidly drop at a constant
rate as well, in proportion to the air resistance its facing. its
angle also changes and with that... its altitude would begin to
fall... like a simple parabolic arc.
based on the characteristics of rockets.. its easy to write up a
computer program that would automatically alert the radar operator
to the presence of such a radar contact... thereby ensuring a
successful lock on the initial source of where these contacts are
from. .. that is how the ARTHUR artillery alert radar system
work.
with regard to hollywood... its hollywood... .hehehee
sorry...
normally a fighter plane's radar is in its nose (anyone knows of a
fighter plane radar installed in its ass? hehee), as such.. most of
the time the radar is looking forward, not sideway and certainly
NOT backward.....
to alert planes against enemies to its rear... RWR (radar warning
recievers) are installed on the rear tail wing of all fighters...
they warn pilots of possible enemy fighters presence by picking up
radar waves emmitted from the enemy fighter's forward radar.
before a missile is fired... the radar wave changes... the radar
waves frequency used by the plane to search for enemy fighters is
different from the radar waves frequency that is used to "paint"
the target... thus the RWR can pick up this second "unique"
painting radar waves and warn the pilot that he HAS BEEN LOCKED
ON.
another thing about approaching missiles not appearing on the
fighter pilots radar is because its coming straight at the fighter
plane, or using the pencil analogy... the pencil is point straight
at your pupil with the minimum RCS.
