• Precision Values: These values tell the processing algorithm how ‘correct’ the values from the GPS are. This helps the algorithm with better defining the geo-coordinate system, for performing better auto-calibration (if needed), and for improving accuracy of the project. These entered precision values are one-sigma values (that is the expected value falls within this range 62% of the time).
• The default values for Camera Station geo-coordinate precision are based on an assumption that the UAV taking the photos was a multi-rotor style UAV with standard GPS and barometric altitude sensor and storage. This generally means that the altitude / height of the UAV is relatively constant, and this leads to a small precision value default for Elevation or Z. As well, the standard GPS unit on the UAV (and not a high accuracy one) leads to the larger default values for precision in Plan or XY (or NE).
• See the Camera Station Geographic Precision section for reasonable values in different circumstances. The settings are also described on the Global Geo-coordinate Precisions Dialog.