Modern military stealth technology is based on the principle that stealthy craft remain invisible to detecting radar and infrared sensors, especially at long ranges.Such technology can be entirely nullified by the detecting radar and/or infrared sensors searching, not for the stealthy craft itself, but for the background behind the stealthy craft. The stealth craft will then show up in the form of a black or blank silhouette in front of the background.
This is much like the way one can pinpoint with extreme accuracy the location of the moon during a solar eclipse, and track its movement with great precision, even though during a solar eclipse one cannot observe the moon itself.
(N.B.: The remainder of this document describes the detailed methods one might use to detect the background behind stealth craft. Thus it is not necessary to read the entire document in order to grasp the principle of Anti-Stealth Technology, though one may of course do so to dispel all scepticism as to its practicability.)Anti Stealth Technology