Optimisation of an Automatic Online Post-Processing Service for Static Observations as Realised in the Polish ASG-EUPOS System

Abstract

The paper presents an assessment of the accuracy and precision of point positioning using a currently available online service for automatic post-processing (APPS) of GNSS observations made by the Polish Active Geodetic Network—European Position Determination System (ASG-EUPOS). The ASG-EUPOS network is part of the national EUPOS project and was selected for the study because of its substantial spatial reach in Europe. A modification to the current APPS algorithm is proposed to limit the number of baseline vectors used in positioning and change the method for adjusting post-processing results. Currently, the APPS of the ASG-EUPOS determines point coordinates based on the method for adjusting direct and equally accurate observations with the least-squares method (equally accurate method, EAM). The modification proposes to determine the coordinates based on post-processing results adjustment using the unequally accurate observations method (unequally accurate method, UAM). Our analysis diagnoses the uncertainty of the ASG-EUPOS’s APPS, and the modification optimises the adjustment. The proposed modification facilitates a much lower standard deviation of positioning in relation to reference positions. It is demonstrated that, if modified, the ASG-EUPOS service can provide automatic post-processing for 1 h GPS observations with a 1 s interval at 0.03 m accuracy for 99% of cases.