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  • Writer's pictureWTS Sacramento

Recap - August 2021 Lunch Program

On Tuesday, August 24th, WTS Sacramento welcomed Joe Feyder, PLS from R.E.Y. Engineers, Inc. for a presentation on Advanced Surveying Technologies. During his presentation, Joe covered the different technologies that R.E.Y. Engineers has to offer including mobile LiDAR scanning, UAV drone LiDAR scanning, bathymetric surveying, and a combination of the technologies.

Mobile LiDAR point cloud deliverable of a highway

The benefits of mobile LiDAR scanning include enhanced safety, time savings, cost savings, completeness and accuracy. The initial output of a mobile LiDAR scan is a point cloud that is made up of a comprehensive spray of data points that form a complete “picture” of the project site. Topographic survey information can then be extracted from the point cloud to develop a more traditional looking topographic survey file. Data collection using mobile LiDAR technology doesn’t require lane closures and the need for traffic control is minimal. Utilizing the mobile LiDAR point cloud to extract topographic survey information with computer software greatly reduces the exposure of field staff to hazardous traffic conditions. The saturation of the point cloud goes beyond the project area and scope and having the point cloud deliverable makes it easy to accommodate changes to the scope without revisiting the site. R.E.Y. Engineers focuses on acquiring and delivering data to survey grade accuracy, which can be obtained while traveling at highway speeds using the mobile LiDAR system. To increase the functionality of the mobile LiDAR unit, it can be mounted to different types of vehicles to fit the needs of the project. Aside from their typical scan truck, R.E.Y. Engineers has mounted the unit to ATVs for off-road use, their bathymetric survey vessel to scan along rivers or other bodies of water, and to high rail vehicles to scan rail corridors.

The point cloud from a scan that utilized the mobile LiDAR unit while attached to R.E.Y.’s bathymetric survey vessel. The points shown in blue are from underwater bathymetric survey technologies and the topside data was collected using the mobile LiDAR unit.

The heavy lift UAV drones that R.E.Y. Engineers uses to perform UAV aerial scans can carry both a LiDAR scanner and a camera so both scan data and digital imagery can be acquired simultaneously. For all LiDAR scans, data can be captured on anything within the field of view of the scanner. A large benefit of the UAV drone is that it can get to a vantage point with a large unobstructed view. The scanner can even get data returns through areas of vegetation. If sunlight can penetrate to the ground through the vegetation, the UAV drone can get ground returns in that location as well.

R.E.Y. Engineers’ Heavy lift UAV drone with lightweight scanner and camera.

Joe shared a recent project that R.E.Y. Engineers completed for LA Metro to make renovations and expand rail capabilities near Union Station. A major challenge of this project was that a 1,900 foot long portion of the rail was encased in twin 18’ diameter subterranean tunnels. The team mounted the mobile LiDAR system to a rail vehicle and was able to perform 360-degree scans of the tunnels. The mobile LiDAR system usually relies on GPS, but without sky visibility, the survey team got creative with the project control and was able to surpass the accuracy tolerances needed to complete the project.

The point cloud showing of one of the LA Metro tunnels with traditional topographic survey line and curve data extracted from the data

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