Protection Level of the Trimble RTX Positioning Engine for Autonomous Applications

Carlos Rodriguez-Solano, Nick Talbot, Gleb Zyryanov, Xiaoming Chen, Ken Doucet, Lorenz Goercke, Stefan Junker, Herbert Landau, Nico Reussner, Diogo Sampaio

Abstract: The Trimble RTX correction service provides state-of-the-art PPP augmentation services in terms of accuracy and fast convergence time. The Trimble RTX technology is based on the estimation of precise satellite orbits, satellite clocks, satellite biases and ionosphere models computed from the data of a worldwide network of GNSS reference stations. This correction data is transmitted to the user via L-band signals from geostationary satellites or the internet. The system supports all current GNSS: GPS, GLONASS, QZSS, BeiDou and Galileo. An accuracy of 2.5 cm (95%) is achieved after a convergence time typically less than 1 minute, by using regional ionospheric and tropospheric models. Since 2019, the corrections also include the integrity functionality required for safety-critical and autonomous applications. For high-integrity applications, the position computed by the end-user needs to provide the protection level at a given integrity risk. The protection level of the combined RTX corrections and positioning engine developed by Trimble, are evaluated in this paper using an integrity risk of 10-7/h. For this purpose, an extensive amount of data is used which includes the following: 1) Static data collected at reference stations, which provide a benchmark for our algorithms under best possible conditions. 2) Real kinematic GNSS data has been gathered from more than 450 test drives using seven different combinations of automotive-grade receivers and antennas and from a variety of highway, urban and rural environments. 3) Simulated observation data, where specific errors have been injected into it in order to stress test the positioning engine. The real- and simulated data have been processed and analyzed to validate the Trimble RTX server and rover positioning technology using only GNSS measurements. Additionally, initial results will be presented including IMU and DMI sensors, which significantly improve the positioning and protection level performance in GNSS challenging environments.
Published in: Proceedings of the 34th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2021)
September 20 - 24, 2021
Union Station Hotel
St. Louis, Missouri
Pages: 1577 - 1595
Cite this article: Rodriguez-Solano, Carlos, Talbot, Nick, Zyryanov, Gleb, Chen, Xiaoming, Doucet, Ken, Goercke, Lorenz, Junker, Stefan, Landau, Herbert, Reussner, Nico, Sampaio, Diogo, "Protection Level of the Trimble RTX Positioning Engine for Autonomous Applications," Proceedings of the 34th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2021), St. Louis, Missouri, September 2021, pp. 1577-1595. https://doi.org/10.33012/2021.17889
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