Swepos online GNSS post processing service: a comprehensive overview and practical guide

The SWEPOS Post Processing Service (SWEPOS-PPS), developed by Lantmäteriet, the Swedish mapping, cadastral and land registration authority, is an online tool that provides high-precision GNSS positions in the SWEREF 99 and ITRF reference frames, facilitating geodetic surveying, infrastructure projects, and cadastral applications. This paper describes the system’s technical setup, how it processes GNSS data, and its practical uses. It also outlines improvements made between 2023 and 2025, including a modular architecture, the use of Bernese GNSS Software 5.4, adoption of updated antenna models (IGS20.ATX), and extended support for RINEX file versions 3.x and 4.x. The service now works with multiple GNSS systems (GPS, GLONASS, Galileo), and an updated troposphere model helps improve height accuracy, especially in difficult conditions. Data quality is checked using the Anubis software, which filters out bad RINEX files and issues warnings. Users can also request detailed RINEX quality reports. Tests show that for sessions lasting 2–3 h, the service reaches about 1–2 cm horizontal and 2–3 cm vertical accuracy, with longer observation times enabling sub-centimeter precision. When compared with the SWEPOS Network RTK service (SWEPOS-NRTK), SWEPOS-PPS performs better for static measurements longer than 4 h, while SWEPOS-NRTK is more suitable for faster tasks with lower accuracy needs. SWEPOS-PPS supports accurate positioning and helps implement reference frames, contributing to GNSS-based work in Sweden.