The Soviet S-200 Angara/NATO: SA-5 GAMMON surface-to-air missile (SAM) was a milestone in the development of SAMs, as the first SAM to have its own active radar homing for terminal guidance.  According to Globalsecurity, it was made by Almaz, Grushin with an internal designation of 5V21, although Deagel gives it the internal designation 5V28.  Astronautix.com, however, states it had semi-active radar homing
For reasons never really explained, NATO and the Defense Intelligence Agency reused the SA-5 designation. This is the SA-5 GAMMON. The SA-5 GRIFFON was a completely different missile, the V-1000 anti-ballistic missile.
Threats for which it was designed include air-to-surface missiles preenting new targets, with the ASM becoming a much greater threat than the aircraft carrying it, or finding and engaging that ASM carrier at the extreme range of ground guidance radar. Another application for active guidance was homing in the presence of jamming, the jamming directed at the ground radar systems or at the missile radar itself, which would have very substantial power available in the final attack.
Two sources said it was principally designed against It was also intended to hit aircraft of extreme speed, such as the SR-71 Blackbird, and was exported to the Middle East to be used against reconnaissance aircraft. 
Its propulsion characteristics gave it an unusually long minimum range of 60 km, with a maximum range, against a minimally moving target, of 250 km.
Early warning came from a BIG BACK radar, BACK REST radar, TALL KING radar or BACK TRAP radar. According to Globalsecurity, the target acquisition radar was the BAR LOCK radar, equipped with identification-friend-or-foe. SIDE NET radar gave height information. 
Once acquired, SQUARE PAIR radar provided midcourse guidance.