Regional Ionospheric Corrections for High Accuracy GNSS Positioning

Abstract

Centimetre-level accurate ionospheric corrections are required for a high accuracy and rapid convergence of Precise Point Positioning (PPP) GNSS positioning solutions. This research aims to evaluate the accuracy of a local/regional ionospheric delay model using a linear interpolation method across Australia. The accuracy of the ionospheric corrections is assessed as a function of both different latitudinal regions and the number and spatial density of GNSS Continuously Operating Reference Stations (CORSs). Our research shows that, for a local region of 5° latitude ×10° longitude in mid-latitude regions of Australia (~30° to 40° S) with approximately 15 CORS stations, ionospheric corrections with an accuracy of 5 cm can be obtained. In Victoria and New South Wales, where dense CORS networks exist (nominal spacing of ~100 km), the average ionospheric corrections accuracy can reach 2 cm. For sparse networks (nominal spacing of >200 km) at lower latitudes, the average accuracy of the ionospheric corrections is within the range of 8 to 15 cm; significant variations in the ionospheric errors of some specific satellite observations during certain periods were also found. In some regions such as Central Australia, where there are a limited number of CORSs, this model was impossible to use. On average, centimetre-level accurate ionospheric corrections can be achieved if there are sufficiently dense (i.e., nominal spacing of approximately 200 km) GNSS CORS networks in the region of interest. Based on the current availability of GNSS stations across Australia, we propose a set of 15 regions of different ionospheric delay accuracies with extents of 5° latitude ×10° longitude covering continental Australia.

An Observation Density Based Method for Independent Baseline Searching in GNSS Network Solution

“…Different baseline search strategies can be adapted to specific situations. For example, baseline solutions at low latitudes, equatorial and polar regions are usually affected more heavily by ionospheric effects [28,29], especially during a solar maximum period. Thus, more consideration should be given to making the baselines shorter during such periods.…”

Precision Evaluation for Different GNSS Rinex 3 Using Online Services and Open-Source Software PPP-Mans

“…Additionally, the data must be post-processed using specialist or commercial software due to the vulnerability of these methods to these issues. Due to their ease of use and lack of necessity for GNSS post-processing knowledge, online processing services have now supplanted research and commercial software in the processing of GNSS data (Dao et al, 2022).…”

Precision comparison for Different GNSS PPP solution using online services and open-source software processing

“…Real-time kinematic techniques are susceptible to multipath, unstable data links from the reference point, and poor satellite visibility, two GNSS receivers must be used in order to ensure accurate positioning, and the data must also be postprocessed using professional or commercial software. Online processing services have now replaced scientific and commercial software in the processing of GNSS data due to their simplicity of use and lack of need for GNSS post-processing expertise [4].…”