Predicted Orbits and Clocks for Enhanced Position Accuracy

Aaron Boda, Vijaykumar Bellad, Sudha Vana

Abstract:	This paper presents Rx Networks’ StarCourse (RxN SC) technology, which delivers predicted Global Navigation Satellite Systems (GNSS) ephemerides consisting of satellite orbit and clock data and is accessible over the internet in RINEX, SP3, and binary formats. The predictions are available by default for seven days, with the first 24 hours achieving accuracy comparable to broadcast ephemeris (BCE) real time performance. This capability challenges the traditional concept of realtime assisted GNSS (A GNSS) and avoids the need for continuous wireless network connectivity, which is valuable for consumer devices. Recent enhancements to RxN SC’s orbit and clock prediction have further improved accuracy, opening the possibility of replacing BCE altogether. Using one month of data from October 2024, we evaluated RxN SC performance against the Center for Orbit Determination in Europe (CODE) Final products, quantifying signal-in-space ranging error (SISRE) and positioning accuracy across 40 globally distributed International GNSS Service (IGS) stations using L1 GPS, Galileo, and BeiDou observations. RxN SC SIS4D errors after 24 hours were 0.6 m for GPS and Galileo and 1.2 m for BeiDou, increasing after seven days to 3.0 m for GPS, 3.5 m for Galileo, and 6.2 m for BeiDou, all reported at the 68th percentile. Horizontal positioning errors at the 68th percentile were 1.4 m after 24 hours, 2.4 m after three days, and 5.8 m after seven days. Vertical positioning errors at the 68th percentile were 2.3 m after 24 hours, 3.8 m after three days, and 8.1 m after seven days. These results confirm that RxN SC can match BCE accuracy for the first 24 hours while maintaining reasonable accuracy for up to seven days, offering significant benefits for low-power and intermittently connected devices.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	1164 - 1175
Cite this article:	Boda, Aaron, Bellad, Vijaykumar, Vana, Sudha, "Predicted Orbits and Clocks for Enhanced Position Accuracy," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 1164-1175. https://doi.org/10.33012/2025.20321
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In