Active protection and the top-attack era
Trophy, Afghanit, Arena — and the drones that ignore them.
Soft kill vs hard kill
Soft-kill APS blinds or decoys a missile (smoke, lasers, IR jammers). Hard-kill APS fires a interceptor — a shotgun blast, an explosively formed fragment — at the incoming warhead a few metres out. Trophy (Israel, now on some Abrams and Leopard 2) is the combat-proven hard-kill system. Arena-M and Afghanit are the Russian counterparts; public combat evidence is thinner.
What APS does not do
Most current systems are built against ATGMs and RPGs arriving from a limited elevation. A cheap FPV diving at 70° can miss the radar envelope. A tandem warhead may still have a residual jet. And APS has a magazine: after two or three intercepts a sector is empty. Infantry walking beside the tank must also survive the interceptor fragments.
The combined answer
No serious army treats APS as a substitute for armor. The stack is: doctrine (don’t go alone), infantry overwatch, smoke, composite + ERA, APS, and a recovery plan. Ukraine since 2022 is the open-air classroom for that stack — and for how fast it fails when any layer is missing.