PPPH-VA: an open-source software for real-time multi-GNSS variometric approach using single- and dual-frequency observations

Variometric approach (VA) technique has been introduced as an alternative to real-time kinematics and real-time precise point positioning techniques. As the ability of the variometric approach to detect short-term dynamic behaviors in real-time mode in applications such as Global Navigation Satellite Systems (GNSS)-seismology and structural health monitoring is demonstrated, the demand for open-source VA software is increasing. However, open-source software that is capable of VA processing in real-time mode based on single- and dual-frequency multi-GNSS observations is scarce. In view of this fact, we have developed an open-source VA processing software called PPPH-VA that can evaluate single- and dual-frequency multi-GNSS observations in real-time mode. PPPH-VA is developed in the MATLAB environment, and it can simultaneously process GPS, GLONASS, Galileo, BeiDou-2, and BeiDou-3 data with the VA technique in real-time mode, employing both single- and dual-frequency observations. We evaluated PPPH-VA using shake table experiments based on real data, and the results demonstrate that it provides high accuracy in terms of detection of dynamic displacements. Toolbox can successfully detect the dominant frequencies of short-term dynamic behaviors and is capable of determining the amplitude values corresponding to the peak frequency at the sub-mm level. Moreover, in the time domain, it can obtain dynamic behaviors with an accuracy of millimeters.