15cm PhotoSat Surveying Accuracy
To ensure 15cm survey accuracy, PhotoSat needs approximately 100 ground survey control points per 100km² of survey area.
PhotoSat routinely produces survey data accurate to 15cm in elevation on mine sites and oil and gas projects.
PhotoSat processing with no ground survey points produces 20cm relative and 3m global survey accuracy
PhotoSat applies a number of corrections to the stereo satellite photos prior to applying the ground survey data. These preliminary corrections usually bring the relative PhotoSat survey accuracy to 20cm in elevation over horizontal distances of 10km. The global accuracy prior to applying ground survey data is usually better than 3m in x, y and z.
PhotoSat surveying using ground survey points produces better than 15cm survey accuracy
Referencing to 100 or more ground survey points per 100 km2 PhotoSat routinely achieves better than 15cm accuracy using stereo WorldView-1, 2 or 3 satellite photos. The ground survey points used in the PhotoSat processing are usually existing survey points. On mining projects these points already exist as built survey data. The points may be derived from existing LiDAR surveys. On oil and gas projects these survey points are usually seismic survey source and receiver x, y, z coordinates. Two examples are shown below.
PhotoSat absolute survey accuracy of 30cm is achieved using three ground survey points per 100km2. This is discussed in the 30cm accuracy page. Better than 20cm survey accuracy is achieved with ten ground survey points per 100km2. This is discussed in the 20cm accuracy page.