This article by Chuck Boyer, Director of Geospatial Solutions, at Aerial Services, Inc. is an excellent introduction to the importance of ground control in supporting lidar missions.
When discussing LiDAR accuracy, the most important statement a LiDAR consultant can end their sentence with is “with proper ground control”. Without proper ground control, the measurable and definable accuracy of LiDAR point cloud data cannot be known. In capable hands of a professional mapper, accuracy can be inferred, but without ground control it cannot be objectively measured.
Airborne LiDAR sensors fire pulses of light up to 500,000 or more times per second. These pulses then hit the ground, reflect back to the sensor and are recorded as distances. In a typical mapping mission, there are billions and billions of points collected and form what we refer to as a “point cloud”. Each point in the cloud has an associated 3D coordinate. It is a marvel of modern science that an aircraft moving at high rates of speed can emit then capture so many points of reflected light every second and that each point can be accurately determined where it came from.
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