Military.com has an article on a Swedish project to create a radar capable of tracking stealth aircraft (and stealth cruise missiles):
Details of a formerly secret project to defend Swedish airspace against stealthy cruise missiles using a radical but inexpensive radar system were revealed at a conference in Oslo this week. The Associative Aperture Synthesis Radar (AASR) was approaching the hardware-test stage when it was cancelled in 2000 after eight years of work — because there was no imminent cruise-missile threat any more.
The AASR was designed to take advantage of the principle that a target’s bistatic radar cross section — where the radar receiver and transmitter are in different places — may be affected minimally or not at all by stealth measures aimed at conventional radars. In particular, it exploits the “shadow” RCS behind the target, which depends entirely on the target’s geometrical cross-section.