You can't manage what you don't measure.
Imagine the value of having 3D data for site planning with data only a day old. Small Unmanned Arial Systems (sUAS) along with processing software provide the capability to do ad hoc site mapping. Using base data layers of high resolution ortho imagery and colorized 3D point clouds, a wide range of analytic information can be quickly produced. For example, areas of containment ponds along with shoreline contour models can be directly extracted from the sUAS collected data. Ingress road slopes can be measured for equipment movement planning. Water drainage modeling can be conducted for both planning and maintenance. These are just a few examples of the wide range of use of sUAS collected site mapping data.
A small unmanned aerial system (sUAS) is equipped with an inexpensive camera. The area of interest is programmed into the sUAS flight control system and the sUAS automatically flies the area, collecting a large number of overlapping images. Following the flight, a fairly new software algorithm called “Structure from Motion” is used to generate a dense 3D model from the collected images as well as a mosaic of the images. Finally, an analytic software application is used to compute volumes, generate contours, and create cross sections and other derived data such as gridded elevation models.
Ground Control Points are markers placed on the ground as either permanent marks (recommended for repetitive operations such as quarries) or temporary paint markings. The precise location of these markers is then determined using standard survey techniques. The marks show in the acquired images and are used to provide scale and precise location to the computed models.
The collection of data is accomplished by flying the drone, we reccommend a camera-equipped multirotor platform, over the quarry or stockpile site. Under the control of a mission plan uploaded to the drone, the fight is fully automatic. The drone flies a pattern of lines, automatically triggering the camera at the appropriate locations. The drone then self-lands and shuts down.
The images and flight log are transferred from the drone to a computer by a USB cable. The images are then processed in an image processing application that generates both a 3D model (as a dense collection of very accurate points) as well as an image map (an orthophoto mosaic) of the site. The ground control points are used to provide precise orientation to a reference coordinate system.
The point cloud and ortho generated in the previous step are analyzed in our application software, LP360. This application allows you to view the site in three dimensions, perform any necessary data cleaning and generate analytic products. Volumetric analysis can be performed by simply drawing a line around the base of a stockpile. The volume computation is then automatically performed. In addition to volume computations, you can do linear distance measurements, generate contour maps, measure area, and create cross-sections and other products. Data can be exported into standard formats such as LAS, Shape and TIF for use in downstream engineering software applications.