In message , Martin Gregorie
writes
The Serbian system used conventional radar transmitters to illuminate
the airspace and a separate set of passive receiver dishes plus a LOT
of computer power to analyze the very weak diffuse reflections, i.e. to
spot an anomaly in the expected RF background where an F117's
anti-radar coating was affecting it. That showed them when one was
coming and where to aim. They knew where to site the missiles because
this system had analyzed the last three day's ops and showed them that
the mission planners had got sloppy and always used the same exit corridor.

Ah. a bistatic system. This method is often touted as the solution,
from a defence point of view, to stealth techniques and also jamming
ones as you can, in theory, subtract all of the conflicting noises and
look at the signal over many separate paths. IIRC the woodpecker was
supposed to be one of these.

Robin
They used optically sighted missiles, which weren't bothered by the
stealth system, to bring down one F-117 and damage a second.

This information was in New Scientist (04 December 1999).



--
Robin Birch