About 30 years ago a small aerospace company developed an artillery and mortar countermeasure. It detected an incoming round and then broadcast a signal to the fuze telling it the round was at the right height to detonate. The round would do so well before it was supposed to, rendering it much less harmful.
That depends entirely on the fuse. It would be useless vs a mechanical fuse (the vast majority). It may work on a proximity airburst fuse.