Evaluation of Trimble Centerpoint RTX correction service for real-time GNSS monitoring: a field-based comparison with RTK positioning

Nowadays, real-time geodetic monitoring has applications in a wide range of areas in the geosciences and beyond, such as monitoring active volcanoes and critical engineering structures, and developing early warning systems for earthquakes, tsunamis and landslides. This study evaluates the effectiveness of Trimble Inc.'s patented CenterPoint Real Time eXtended (RTX) Global Navigation Satellite System (GNSS) correction service through a comparative analysis with the traditional single-baseline Real-Time Kinematics (RTK) approach, using a series of field tests. The tests were specifically designed to assess the applicability of the RTX technique for real-time geodetic monitoring of seismic and volcanic active areas or landslides, and engineering structures, with a focus on the amplitude and rate of displacement. A geodetic GNSS antenna was connected to two receivers operating in RTX and RTK modes. A micrometric sled and a telescopic rod were used to induce 3D controlled displacements of the antenna. A total of 108 measurement sessions were collected, resulting in 286,116 one-second observations. The performance of the RTX and RTK methodologies was assessed in terms of precision and accuracy using various statistical metrics. The RTX service consistently demonstrated performance that was either competitive with or superior to RTK, particularly for vertical displacements (< 1 cm for RTX and > 1.5 cm for RTK) and rapid deformation scenarios, where precision and accuracy errors remained within a few centimetres. Our field tests demonstrate the reliability and robustness of the RTX technique for precise real-time displacement monitoring, potentially paving the way for its application in geohazard mitigation.