Acoustics would also struggle to determine friend from foe, if tanks or arty, and then you'd have to deal with dissipation and echoes and other weird effects.

Acoustics would also struggle to determine friend from foe, if tanks or arty, and then you'd have to deal with dissipation and echoes and other weird effects. with a radar you actually can spot the the shell trajectory and turn that into a parabolic arc. then make some rough guesses as to how far they've traveled since then ("shoot and scoot"), and you can map out a firing solution that covers most of a given area. MLRS/rocket arty is great for that since it can fire off a lot of ordinance quickly, at the cost of long reload times. saturate the grid square before their artillery can get away. Radars get you into the EW cat-and-mouse game, tho.