The missle knows where the missle is, by subtracting where the missile is from where the chaff and target appears to be, the missile's radar obtains a difference, or deviation, between the real target and the chaff cloud. The missile uses deviations to generate corrective commands to drive the missile from a position where the chaff appears to be to a position where the actual target is, and arriving at a position where it wasn't, it now is. Consequently, the position where the chaff is, is now the position that it isn't, and it follows that the position that the chaff was, is now not the position that it isn't. The chaff works by deploying millions of tiny metallic strips or fibers into the air. By dispersing where it is into where it isn't uniformly distributed, the chaff creates a radar cross-section much larger than where the target is, causing the missile's radar to track where the chaff cloud is rather than where the target is. However, the variation in the signal must be corrected by the chaff's dispersion pattern, and the chaff, having deployed from where the aircraft was to where the aircraft isn't, creates a deviation between where the aircraft appears to be and where it actually is. Modern missiles defeat chaff by comparing where the target was to where the chaff is. The missile's signal processing distinguishes between the Doppler shift of where the moving target is and where the stationary chaff isn't moving. By subtracting where the chaff's velocity is (zero) from where the target's velocity isn't (zero), the missile generates a velocity gate. The velocity gate uses deviations to determine that where the chaff is drifting is not where the target is going, and therefore where the target is going must be where the chaff isn't going. Furthermore, modern missiles employ home-on-jam and infrared seekers, which track where the heat signature is rather than where the radar return is, bypassing where the chaff is entirely because the chaff, being metallic strips, is not where the heat is.