Abstract: The Global Navigation Satellite System (GNSS) radio occultation (RO) technique plays a pivotal role in collecting data for meteorological and space weather prediction. The accuracy of neutral atmosphere bending angle estimations in GNSS RO processing, a key metric of the technique's sensitivity, can be greatly enhanced by precise determination of GNSS satellite clock offsets. This study builds upon the findings of [1], demonstrating that employing GNSS satellite clock products with a 2-second interval, as opposed to the conventional 30-second interval, significantly reduces uncertainty in bending angle measurements at elevations above 50 km, notably in GLONASS RO processing [2]. Through collaboration with the COSMIC Program at the University Corporation for Atmospheric Research (UCAR), we developed a post-processing method utilizing high-rate GNSS clock products. A script was created to download, merge, and/or decimate 1-second RINEX data from 50 worldwide ground stations, and the GINAN [3] software was used to generate high-rate clock products. These were validated against International GNSS Service (IGS) final clock products. The experiment aims to assess the impact of 30-second and high-rate clock products on bending angle calculations for the GPS and GLONASS constellations in one month of COSMIC-2 mission data [4]. Preliminary results suggest significant improvements in the accuracy of bending angle retrievals, promising enhanced performance in atmospheric research applications.

[1] Jian Yao, Jan-Peter Weiss, and Teresa VanHove, “Impacts of high rate GNSS satellite clock estimation on radio occultation bending angle retrievals: preliminary report,” Proceedings of the 2023 Institute of Navigation International Technical Meeting (ITM), pp. 995 – 1001, 2023.
[2] Jan P. Weiss, Sergey Sokolovskiy, Bill Schreiner, and Yoke Yoon, “GNSS clock interpolation impacts on radio occultation bending angle retrieval,” IGS Workshop, 2017.
[3] Rupert Brown, “GINAN project overview,” 2022.
[4] Yao-Chun Ko, Jian Yao, Jan-Peter Weiss, and Teresa VanHove, “Impacts of High Rate GNSS Satellite Clock Estimation on Radio Occultation Bending Angle Retrievals: Updated Report” https://www.ion.org/itm/abstracts.cfm?paperID=13030

Adviser: Haonan Chen
Co-Adviser: Jian Yao
Non-ECE Member: Christine Chiu
Member 3: N/A
Addional Members: N/A

Publications:
N/A

Program of Study:
ECE-578-001
ECE-556-001
ECE-571-001
ECE-575-L01
ECE-579-001
MATH-569A-401
MATH-569B-001
MATH-569C-001