There is also
Counter Rocket, Artillery, and Mortar, abbreviated C-RAM or Counter-RAM, is a system used to detect and/or destroy incoming artillery, rockets and mortar rounds in the air before they hit their ground targets, or simply provide early warning.
C-RAM is effectively a land version of weapons such as the Phalanx CIWS radar controlled rapid-fire gun for close in protection of vessels from missiles.
Source:
http://en.wikipedia.org/wiki/Counter-RAM
I know it was developed in 2005, but give the age of Phalanx CIWS I think something could seen in TW 2000 timeline
I think you could see the GAU-8/A Avenger mounted on a make shift frame of some short durring TW 2000, perhaps a Abrams or Bradley?