New Multi-Constellation, Multi-Frequency PPP-AR Service – Design Considerations and Operational Results

Leos Mervart, Zdenek Lukes, Paul Alves

Abstract:	In 2020, Hexagon announced a breakthrough in global Precise Point Positioning (PPP), demonstrating significant reductions in convergence time with global RTK From the Sky™ technology. This technology has since been incorporated into Hexagon’s TerraStar™ services, for production use in global applications. These advancements were the result of an end-to-end modernization of Hexagon’s global correction services technology, from reference station hardware and software to the positioning rover algorithms. At the heart of the TerraStar service is the Orbit and Clock Determination System (OCDS). This paper will explore OCDS and how it is at the core of what makes global RTK From the Sky technology possible. The expansion of the constellations from dual-frequency to triple-frequency or quad-frequency means that there is more information available to improve the network processing performance, but it comes at the cost of processing time and complexity. A creative software design was used to integrate the new signals into the processing and accommodate the very high computation requirements a creative software design is used. The OCDS corrections (precise satellite orbits and clocks, and satellite-specific biases for individual signals, also referred to as “State Space Representation”) are used by PPP with Ambiguity Resolution (PPPAR) positioning algorithms. The design of these corrections allows for one-way, mass-distribution of correction data via satellite or Internet broadcast. The OCDS system supports the commercial TerraStar, Oceanix, and Apex Correction Services used across land, near-shore and marine applications, respectively. The improved performance due to the evolution of the OCDS system enables new applications and significant advances in traditional markets. This paper will highlight some of these applications and demonstrate how the software design and implementation changes impact the application performance. Performance metrics and results will be shown highlighting the improvements that this new system design, with its additional signals, provides over the legacy, dual-frequency system.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	1293 - 1307
Cite this article:	Mervart, Leos, Lukes, Zdenek, Alves, Paul, "New Multi-Constellation, Multi-Frequency PPP-AR Service – Design Considerations and Operational Results," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 1293-1307. https://doi.org/10.33012/2022.18534
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In