New challenges for exploitation of continuously operating reference GNSS stations during hostilities. Case study of Ukraine

Abstract

The study presents the current state of GNSS Continuously Operating Reference Stations (CORS) networks and their operational characteristics during the ongoing hostilities in Ukraine. Stable GNSS CORS network operation is crucial not only for agricultural, geodetic, and land management tasks but also for military navigation and topography. The aim of this work is to analyze the impact of hostilities in Ukraine's GNSS network, considering factors like temporary occupation of certain territories, power outages due to missile strikes on energy infrastructure, and GNSS signal jamming using radio-electronic methods in front-line regions. Another objective of this study is to highlight examples of incorrect RTK or VRS operation due to potential errors from radio-electronic jamming or GPS spoofing as well as to provide practical recommendations for surveyors. As a result, the research has analyzed changes in the number of properly functioning GNSS stations from 2021 to 2023 using the GeoTerrace and System.NET networks. These networks cover all regions of Ukraine except the temporarily occupied territories by russia. Daily processing of RINEX files with a sampling interval of 30 seconds from CORS GNSS stations was conducted using the Bernese GNSS v.5.2 software package over three years. It was noted that following the large-scale invasion in February 2022 and through the spring of that year, there was a sharp reduction of about 10% in the number of properly functioning active GNSS stations. Scientific novelty and practical importance. The article presents practical recommendations for users, such as surveyors and land managers, performing GNSS measurements in RTK or VRS modes using permanent stations, to assess the influence of radio-electronic jamming or GPS spoofing on observations. CORS network assessment and daily calculated coordinates of GNSS stations from 2021 to 2023 can be used for future geodynamic research in the region.