OPUS and CSRS Web-Based GNSS services accuracies for data from USA and TURKEY

Abstract

Global Positioning System (GPS), which has entered every aspect of human life since its first appearance, has become widespread with introducing other systems (GLONASS, Galileo, BeiDou, QZSS, IRNSS, etc.). Today, all systems' common name, Global Navigation Satellite Systems (GNSS), continue to exist in our lives. While processing the GNSS data, scientific/academic, commercial software, and web-based applications are being used. Web-based services have become widespread very quickly since their introduction. Web-based services have provided ease of use, free of charge, results in a short period of time for users and eliminated the dependence on licensed software. Today, web-based evaluation services increase their activities, variety and number of users day by day. Research on the accuracy of the location obtained from these services continues. This study determined 42 stations in the United States of America and 18 stations in Turkey (with 10 -day good ionospheric conditions and 6 -day worse ionospheric conditions data sets) OPUS, CSRS web services in (depending on the duration of the session: 1 hour to 24 hours) evaluations were carried out. CSRS web service can evaluate GPS, GLONASS, Galileo data, but OPUS uses only GPS data. As can be seen from both the 1-hour results, it is thought that including GPS + GLONASS data in the evaluation has a positive effect. From the results we obtained, it was determined that 12 hours of observation should be made to good positioning accuracy under one cm using any of these applications. It has been determined that using the web-based GNSS evaluation services, good accurate positioning can be obtained from the data collected with a single receiver. But due to the publication time of precise ephemeris, as soon as the measurement is made, it is not possible to reach the mentioned accuracies. There are similar standards in the global world today and it can be said that a minimum of 2 hours of observation should be made for engineering applications. It has been determined that the web services used can reach the "high precision standard (horizontal 2 -3 mm, vertical 3 -5 mm) "defined by IGS with a minimum of 12 hours horizontally and 24 hours in vertical.