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Autonomous UAVs using SLAM to navigate without GPS
I have just spent an incredible three days in Houston at the SPAR3D 2017 conference. There is so much going on right now in the 3D world with several key technologies just coming to fruition and finding broad application in the real world.
One of them is Simultaneous Localization and Mapping (SLAM) technology. In 2012 a company called GeoSLAM, which was a joint venture with Australia's National Science Agency (CSIRO), began marketing a SLAM-based solution developed by CSIRO. I blogged about a backpack solution for indoor mapping that Avideh Zakhor from the University of California Berkeley had developed for navigating inside a building, generating floor plans, distinguishing rooms, identifying staircases, texture mapping surfaces, identifying windows, finding heat sources such as computers and human occupants, identifying lights, and even estimating plug load lower consumption - all automatically.
At this year's SPAR3D conference Stefan Hrabar from CSIRO described a project he has been working on that combines autonomous navigation with LiDAR-based SLAM to enable drones to safely navigate autonomously without GNSS in areas with complex geometrical structures. This enables missions that the UAV can do with no pilot intervention. Some examples that have been implemented include rainforest surveys - looking for invasive species, telco (cell phone) tower inspection and mapping, construction site monitoring including inside buildings, and underground mine mapping, especially, vertical, hard to access shafts called stopes. For example, Stefan showed a demonstration of telco tower mapping where the UAV was placed near a telco tower, a button pushed to initiate the flight, and the drone mapped the tower without any human intervention.
Hovermap is the CSIRO application that provides a SLAM-based 3D LiDAR mapping payload for small UAVs. It provides omnidirectional collision avoidance, advanced autonomy, and the ability to operate in GNSS-denied areas. Hovermap uses a rotating LiDAR to produce a virtual spherical shield around the UAV. Real-time SLAM makes it possible for the drone to navigate in complex geometric environments without GPS, while the on-board autonomy makes possible mission execution without human intervention. Some aplications include construction site mapping (inside buildings and outside), underground mine mapping and transmission line mapping and monitoring.