Overview

A engineering consulting firm received a project award from bid proposal to design for new retail development. As part of the project bid, the consultant included LiDAR UAS services as part of the surveying operations. Throughout the design and development process site surveyors were given typical allotted deliverables. This began with acquiring an initial layout of the lot and establishing strategic ground control points that would endure throughout the project lifetime.

An initial digital terrain model (DTM) was created, from a 15-minute LiDAR drone flight, for engineering services to design and develop from. The DTM deliverable, derived from initial point cloud data, would typically be acquired through intensive data point gathering. This is commonly done by the surveyors walking the entire site and using GPS & Total Station to acquire precision data and imagery. Which is then organized into a digital model.Routine flights were established in a manner that allowed for consistency and continuity of data gathering and resolution. An elevation of ~200 feet above ground level was determined to offer the best opportunity for effective light return for LiDAR data reliability. A full data set of the lot was acquired in its entirety within about 15 minutes of flight time and 15 minutes of pre-flight setup and procedure. Optimal flight path and flight speed were determined through the flight systems controller software and sensor manufactures recommendations. The flight pattern and payload parameters were then saved in the flight controller system. Thus, to ensure continuity of all future flights.

The precision of the DTM, through the aforementioned flight process, met the standards of best practice that is needed to engineer a design the new development to specification. (Comparative to the previous and more laborious surveying methodology) As typical, if any build progress needed review for design adjustments or later modifications, this same flight process was be repeated. This also allowed site management and stake holders to review and establish progress and modifications to future work scheduling. In addition, and as requested, data deliverables of material volume, asset identification, and visualization of key site locations were generated and added to the digital report.

Method

Routine flights were established in a manner that allowed for consistency and continuity of data gathering and resolution. An elevation of ~200 feet above ground level was determined to offer the best opportunity for effective light return for LiDAR data reliability. A full data set of the lot was acquired in its entirety within about 15 minutes of flight time and 15 minutes of pre-flight setup and procedure. Optimal flight path and flight speed were determined through the flight systems controller software and sensor manufactures recommendations. The flight pattern and payload parameters were then saved in the flight controller system. Thus, to ensure continuity of all future flights.

Utilizing the LiDAR point cloud data series, the UAS operator was able to return to the office, post-process the raw LiDAR dataset to a usable point cloud, which was then applied to a commercial grade geomatic processing system. From there, multiple deliverables could be generated. The typical weekly report included the following:

• Engineering grade DTM datasets to be used in design and development of the overall site.
• Volumetric reports, as requested, of aggregate, overburden, bulk supplies and assets.
• 3D digital terrain modeling and topographical map generation as needed
• Equipment and vehicle asset identification
• Engineering Blueprint / CAD overlay
• Work site progression overlays

Result

By producing a rapid DTM design the engineering consultant firm was able to quickly acquire precision data. This allowed for effective digital modeling without the need to spend extended hours or days onsite to gather the needed data. This added to versatility of scheduling of manpower and surveying resources. Through comprehensive digital documentation, the client had on-demand access to key insights. With various data deliverables available, decisions for design and added development were quickly coordinated and clearly made with stakeholders. Increased productivity and ROI were realized through better time management, more precise scheduling, greater insight to available resources, and overall scrutiny of accurate build site progression.