Cars of the future will be heavily reliant on their suite of sensors for proper functioning; vehicles today already pack a ton of cameras, ultrasound and radar arrays, but they mostly use these for non-core driver assistance and other features, and if they weren’t working, it wouldn’t be the end of the road because the human driver’s built-in sensors are the real fall-back.

That might not always be the case, and so Ford has filed for a new patent (via CNET) that could provide another kind of backup for onboard vehicle sensors. This is key because autonomous vehicles, and Level 5 vehicles in particular, won’t be able to fall back as easily or at all on human intervention. Ford’s patent gets around this by having a drone dock with a car whose sensors are failed or throwing errors, lending the vehicle its own onboard sensor suite as a failsafe substitute.

It’s actually a super-clever workaround that adds extravehicular redundancy to highly automated vehicles — kind of like an off-site backup for the sensory component of our future autonomous virtual drivers.

This system is, for the moment, just a patent application, which means it’s likely many steps removed from being something that you could actually see working in the real world. But there’s plenty of time for Ford to work out the kinks — truly mass market highly automated vehicles are likely at least a decade away, if not more.