There are a number of systems to deal with RPGs and similar threats, such as the US and Israeli active protection systems that shoot down incoming rounds, the slat armor used to predetonate HEAT rounds (shown, top), the cloth based TARIAN armor also used to predetonate armor (shown, Bottom), and now Textron has come up with the Tactical Rocket Propelled Grenade (RPG) Airbag Protection System (TRAPS), which uses sensors to detect an incoming round, and than uses an airbag to detonate the warhead far enough away from the hull to minimize damage. (no pictures, sorry)

There are a number of reasons that I am dubious.

The first is that it combines all the disadvantages of a passive system (single use) with those of an active system (expensive sensors), and also because it would appear to be particularly vulnerable to the tandem round system used in the RPG-30. (bottom 2 pictures)

I would also note that it does seem to suffer the same problem as all such systems developed under the Aegis^* of the Pentagon:

The progress of TRAPS has not been as fast as one might expect. It was first unveiled at an Army trade show back in October 2006, after spending $3.5 million in Pentagon cash the previous year. Phase II testing is still to take place, and an operational system will be some way down the line. Janes notes the timing of the latest tests –- Textron is bidding to be part of the Army’s new Joint Light Tactical Vehicle (JLTV) program.

It’s running late, and it appears to be over budget.