UAV-Based LiDAR Can Measure Shallow Water Depth

The topography and bathymetry payload for UAV

2 min read

World's first small-scale topographic and bathymetric scanning LiDAR

ASTRALiTe's edge™ is the world's first small-scale topographic and bathymetric scanning LiDAR that can detect small underwater objects, measure shallow water depth, and survey critical underwater infrastructure from a small UAV platform.

The edge™ can see beneath the water surface at depths from 0-5 meters and is completely self-contained with its own Inertial Navigation System with GNSS, battery, and onboard computer. It weighs about 5 kg and is designed for deployment on UAV systems for faster, safer, and more accurate bathymetric surveys. This patented 2-in-1 topographic and bathymetric LiDAR offers a centimeter-level depth resolution. There are numerous possible applications for this LiDAR, such as coastal mapping and surveying, infrastructure inspection, or even military logistics.


Importance of geo-referencing and motion stabilization

“We needed a motion and navigation solution for our LiDAR. Our requirements included high accuracy along with low size, weight, and power" explains Andy Gisler, Director of Lidar Systems with ASTRALiTe. In addition, the system needed to be able to apply Post-Processing Kinematic (PPK) corrections to the LiDAR data to provide higher accuracy results to ASTRALiTe's customers.

The LiDAR provides a comprehensive point cloud that needs to be motion-compensated and geo-referenced to be usable. Two methods can be used to reach the centimeter-level accuracy requested by surveyors. The first one is Real-Time Kinematic (RTK), which makes use of corrections obtained from a base station or a base station network in real-time thanks to a radio or a GSM link. The second one is used after the mission using a PPK software. This software will apply the same correction as RTK, but it will also re-compute all the inertial data and raw GNSS observables with a forward-backward-merge algorithm to correct all the trajectories, fill any loss of position, and greatly improve the overall accuracy.

ASTRALiTe chose SBG Systems' dual antenna Ellipse2-D inertial navigation system which provides motion, RTK, and PPK. The weight of the INS/GNSS solution was especially important to ASTRALiTe as they were designing a system to be flown on most UAVs, where light payload capacities are required for UAV compatibility. The possibility to use two antennas was a key element to consider, as they required a robust heading even during slow-speed flights. In addition to this INS, they also use Qinertia, SBG Systems' in-house post-processing software.

This PPK software gives access to offline RTK corrections from more than 7,000 base stations located in 164 countries and is designed to help UAV integrators get the best of their GNSS or INS/GNSS solution.


About SBG Systems INS/GNSS

SBG Systems is an international company which develops Inertial Measurement Unit with embedded GNSS, from miniature to high accuracy ranges. Combined with cutting-edge calibration techniques and advanced embedded algorithms, SBG Systems manufactures inertial solutions for industrial & research projects such as unmanned vehicle control (land, marine, and aerial), antenna tracking, camera stabilization, and surveying applications.

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How the U.S. Army Is Turning Robots Into Team Players

Engineers battle the limits of deep learning for battlefield bots

11 min read
Robot with threads near a fallen branch

RoMan, the Army Research Laboratory's robotic manipulator, considers the best way to grasp and move a tree branch at the Adelphi Laboratory Center, in Maryland.

Evan Ackerman

This article is part of our special report on AI, “The Great AI Reckoning.

"I should probably not be standing this close," I think to myself, as the robot slowly approaches a large tree branch on the floor in front of me. It's not the size of the branch that makes me nervous—it's that the robot is operating autonomously, and that while I know what it's supposed to do, I'm not entirely sure what it will do. If everything works the way the roboticists at the U.S. Army Research Laboratory (ARL) in Adelphi, Md., expect, the robot will identify the branch, grasp it, and drag it out of the way. These folks know what they're doing, but I've spent enough time around robots that I take a small step backwards anyway.

The robot, named RoMan, for Robotic Manipulator, is about the size of a large lawn mower, with a tracked base that helps it handle most kinds of terrain. At the front, it has a squat torso equipped with cameras and depth sensors, as well as a pair of arms that were harvested from a prototype disaster-response robot originally developed at NASA's Jet Propulsion Laboratory for a DARPA robotics competition. RoMan's job today is roadway clearing, a multistep task that ARL wants the robot to complete as autonomously as possible. Instead of instructing the robot to grasp specific objects in specific ways and move them to specific places, the operators tell RoMan to "go clear a path." It's then up to the robot to make all the decisions necessary to achieve that objective.

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