Drones Accurately Reading RFID Tag Positions

MIT figured out a better way for drones to use RFID technology
With a clever hack  by Dani Deahl  @danideahl  in TheVerge

" .... MIT’s new solution, called Rfly, allows a drone to read RFID tags without strapping a giant reader to it. Instead, the drone is equipped with a tiny relay, which acts like a Wi-Fi repeater. The drone receives the signal sent from a remote RFID reader and then forwards it to read tags nearby. Since relays are small, this means more compact drones with plastic parts can be used — ones that can fit in narrower spaces and don’t pose a danger of injuring people.

Rfly-outfitted drones make up for not having a physical RFID reader by taking several readings of each tag as they fly by. But, that isn’t enough to determine the tag’s exact location. The drone’s constant movement creates a signal delay, so the reader can’t accurately determine the drone’s location relative to the tag its scanning. MIT solved that by also affixing the drone with its own RFID tag, which is about the size of a grain of rice. The drone alternates between relaying the reader’s signal and pinging back information from its own RFID tag. This allows the system to triangulate the drone’s position, and then locate the tag being scanned to within a few inches.  ... "