Rigorous Estimation of Local Accuracies

This technical note introduces a rigorous calculation of “local accuracies.” The term local accuracies refers to the relative error between two arbitrary points (uncertainty of one point with respect to the other), expressed in a local horizon three-dimensional reference frame ( e,n,u ) , that were connected using any geodetic-surveying methodology [optical procedures, global positioning system (GPS), etc.]. It is calculated as a function of the full global Cartesian variance-covariance matrix of the ( x,y,z ) coordinates of the points defining the spatial network.