Precise Point Positioning on the Reliable Detection of Tropospheric Model Errors

Abstract

Precise point positioning (PPP) is one of the well-known applications of Global Navigation Satellite System (GNSS) and provides precise positioning solutions using accurate satellite orbit and clock products. The tropospheric delay due to the neutral atmosphere for microwave signals is one of the main sources of measurement error in PPP. As one component of this delay, the hydrostatic delay is usually compensated by using an empirical correction model. However, how to eliminate the effects of the wet delay during a weather event is a challenge because current troposphere models are not capable of considering the complex atmosphere around the receiver during situations such as typhoons, storms, heavy rainfall, et cetera. Thus, how positioning results can be improved if the residual wet delays are taken into account needs to be investigated . In this contribution, a real-time procedure of recursive detection, identification and adaptation (DIA) is applied to detect the model errors which have the same effects on both phase and code observables; e.g., the model error caused by the tropospheric delay. Once the model errors are identified, additional parameters are added to the functional model to account for the measurement residuals. This approach is evaluated with Global Positioning System (GPS) data during two rainfall events in Darwin, Australia, proving the usefulness of compensated residual slant wet delay for positioning results. Comparisons with the standard approach show that the precision of the up component is improved significantly during the periods of the weather events; for the two case studies, 72.46 % and 64.41 % improvements of root mean squared error (RMS) resulted, and the precision of the horizontal component obtained by the proposed approach is also improved more than 30 % compared to the standard approach. The results also show that the identified model errors are concentrated at the beginning of both heavy rainfall processes when the front causes significant spatial and temporal gradients of the integrated water vapor above the receiver.

Tropospheric Delay Parameter Estimation Strategy in BDS Precise Point Positioning

“…With the continuous improvement of these meteorological empirical models, some scholars have combined meteorological empirical models with zenith tropospheric delay models, such as the GPT3 + Saastamoinen method, which calculates the average deviation of ZTD at more than 16,000 global stations over 10 years at around −0.99 cm [26]. At present, some scholars have also combined numerical reanalysis data with tropospheric delay models and have achieved good results in improving the accuracy of prior values in precise models and in improving the positioning accuracy as well [7,[27][28][29][30][31][32][33][34].…”

Investigating the effect of observation interval on GPS, GLONASS, Galileo and BeiDou static PPP

“…Precise point positioning (PPP) (Zumberge et al 1997) has received significant attention over recent decades. PPP is a powerful tool for many scientific research, such as atmospheric and ionospheric studies (Ge et al 2021a;Ma and Verhagen, 2020;Wang et al 2020), monitoring of deformation, tectonic and earthquake activities (Vazquez-Ontiveros et al 2020;Alcay et al 2019;Mendoza et al 2012), geophysical studies (Geng et al 2017) and, time transfer (Ge et al 2020). One of the most important aspects of PPP compared with the precise differential positioning is that positioning accuracy of mm to cm can be obtained using a single receiver in the static and kinematic modes, respectively (Yigit et al 2021;Yigit et al 2014;Alcay and Turgut 2021).…”

Impacts of Arc Length and ECOM Solar Radiation Pressure Models on BDS-3 Orbit Prediction

“…BDS-3 can provide global services, such as positioning, velocity, and timing with accuracies of 10 m, 0.2 m/s, and 20 ns, respectively. Since the satellite orbit is the foundation for high-precision services and applications of BDS-3 [2], any global navigation satellite system (GNSS) error will directly affect the accuracy of navigation and positioning solutions, e.g., the emergence of real-time precise point-positioning real-time kinematic (PPP-RTK) technology [3], realtime atmospheric monitoring [4,5], early GNSS-based earthquake warning, and other technologies [6][7][8][9]. Therefore, precise real-time GNSS satellite orbits are urgently required for scientific and industrial communities.…”