Many of us will have watched TV or movie dramas where a bunch of luckless travellers get totally lost in a dense forest. They hear the unmistakable sound of a helicopter nearby and start waving frantically.
Most often, the rescuers will fail to see them and the life-threatening adventure starts anew. Being unable to spot hikers under a thick canopy is a very real problem though, but fleets of autonomous drones might offer some hope.
Researchers from MIT and NASA’s Langley Research Centre have been modifying quadrotor drones to allow a fleet to work together to zip through the trees of a thick forest without the need for GPS navigation, talking to each other wirelessly as they fly.
Each drone is equipped with LiDAR to create detailed maps of the area. Noting that individual trees are much of a muchness to drones using this system, the researchers instructed the fleet to look for clusters of trees and register unique patterns, and then tap into algorithms to determine if an area has already been searched or is yet to be searched. Onboard path-planning software tells each drone to head for yet-to-be-searched areas.
The mapping information from each drone can be stitched together using simultaneous localization and mapping software at a ground station for monitoring by human search teams. In this three-dimensional map, the trees are represented by blue and green blocks and unexplored zones are at first dark, but turn grey as they’re being mapped.
Source: MIT News