Exploring Absolute GNSS for Positioning without Internet Connectivity: Evaluating SPP and PPP Performance for High Accuracy Applications

This study investigates the accuracy of offline Global Navigation Satellite System (GNSS) in remote areas where there are no internet connectivity. The research focused on offline Single Point Positioning (SPP) and Precise Point Positioning (PPP) techniques, comparing their accuracy and assessing the impact of observation duration on offline SPP accuracy. The instruments used include Hi Target v30 GNSS receiver and its accessories, Hi-Target Geomatics office software. The offline SPP data were obtained using the Hi-Target Geomatics office software. The PPP data were obtained using the offline SPP data that were converted to RINEX file and uploaded to CSRS-PPP online platform. Observations were carried out in 1 hour and 2 hours on different points respectively. The comparisons were done and the various charts were plotted as well to analyze the process. The results showed that offline SPP achieves higher accuracy with error ranges of 0.36m to 1.18m when observations last for 2-hour and between 1.67m to 3.48m for when observations last for 1-hour. The study demonstrates that longer observation periods improve offline GNSS SPP accuracy thereby reducing noise and multipath effects. The findings have significant implications for surveying and mapping applications in remote areas, where accurate positioning is crucial but without internet services.