Multi-GNSS Ionospheric SSR Corrections for Enhanced GNSS Positioning Performances in South America
Creators: name: de Oliveira Jr., Paulo Sergio
name: Fabricio, dos Santos Prol
name: Lucas, dos Santos Bezerra
Publisher: name: Zenodo
Year: 2024
Subjects: GNSS
ionosphere
Space-State-Representation

description: The Global Navigation Satellite System (GNSS) has established itself as a transformative technology, playing an important role in an array of economic activities that rely on geospatial information. Precision agriculture, environmental monitoring, fleet management, mapping, air navigation, Internet of Things (IoT), and smart cities are some of the sectors that benefit from the potential of GNSS technology to optimize their operations. However, the accuracy and reliability of GNSS positioning are influenced by various systematic errors that can compromise the utility of the technology in critical applications. One advanced approach that holds promise for mitigating these systematic errors is the State Space Representation (SSR) concept. SSR allows for the individual modeling and correction of these errors in GNSS observables, significantly improving the accuracy of positioning. Real-time Precise Point Positioning (RT-PPP) is a positioning method that extensively relies on the SSR concept, using highly precise products like satellite orbits and clocks. Such products are also crucial for relative positioning when the distances between reference and rover are larger than 100 km. The integration of SSR corrections, particularly for ionospheric effects and hardware biases, can substantially enhance the GNSS positioning performances in both scenarios, even for post-processing applications. One critical aspect in the quest for improved SSR corrections is the effective utilization of multiple GNSS constellations, commonly referred to as Multi-GNSS. The integration of these constellations, including the Galileo constellation, offers significant potential for refining SSR correction generation, especially in regions where ionospheric effects have a pronounced impact on positioning accuracy, such as in South America. The central objective of this study is to investigate the effectiveness of the generation of Multi-GNSS SSR corrections, with a particular focus on modeling ionospheric effects. By exploring the Multi-GNSS SSR corrections, this research aims to enhance positioning and navigation solutions, especially in scenarios requiring centimeter-level accuracy. This aligns with the goals of the Joint Study Group 1 (JSG1) of the focus area on Geodetic Space Weather Research (GSWR), which is currently targeting precise ionospheric solutions for geodetic positioning. Our research revealed that incorporation of multiple GNSS constellations introduces redundancy and diversity, which not only contributes in robust positioning but also improves the resilience of the system against signal degradation and obstructions. It is important to acknowledge that while Multi-GNSS SSR corrections offer substantial advantages, they also introduce the challenge of accounting for additional systematic errors, particularly the inter-system biases that may arise from the integration of multiple constellations. In summary, our research innovation lies in two aspects: 1) the integration of Multi-GNSS SSR corrections introduces redundancy and diversity, providing robust positioning in challenging environments and substantially reducing the time needed for centimeter-level accuracy; 2) our research investigates the mitigation of ionospheric effects in regions of intense ionospheric perturbations (e. g., scintillation), a persistent challenge in GNSS positioning.