Ground control is highly beneficial, but not required.
When client-supplied ground control is available, it is possible to measure the vertical accuracy of a survey. With a single ground control point (GCP), we can align the survey vertically (z). When more GCPs are available, we can perform additional refinements.
The Survey Project Report will include an accuracy statement. If enough suitable ground control points were supplied, your Survey Project Report will also include the vertical accuracy, including the root mean square error (RMSE) and the linear error 90% (LE90).
Some factors that influence survey accuracy include:
Availability of client-supplied ground control
Quality and distribution of client-supplied ground control
Convergence angle between satellite stereo images
Specifications of the satellite used
Ground control makes it possible to measure and improve the horizontal accuracy of a survey. With a single GCP, we can align the survey horizontally (x,y). When more GCPs are available, we can confirm the geolocation of the survey and perform additional refinements.
Surveys produced from WorldView satellite imagery have a relative accuracy of ~20 cm over 5 km, independent of ground control.
High relative accuracy is particularly important for calculating volume changes in leach pads, stockpiles, waste dumps, and tailings facilities.
The satellite used to acquire satellite imagery is one of the factors that influences the accuracy of an elevation survey or map (DEM).
Since 2004, PhotoSat has conducted dozens of accuracy studies to demonstrate the capabilities of commercial satellites for producing high-quality topography.