The First Satellite-Based Open PPP-RTK Service: Operational Experiences and Improvements

Rui Hirokawa, Seigo Fujita, Natsuko Hayase

Abstract: The QZSS Centimeter-Level-Correction Service (CLAS) [1] is the first open satellite-based PPP-RTK service, with operational services for Japan launched in November 2018. Applications of QZSS CLAS include advanced driver assistance systems (ADAS), automatic control of agricultural machinery and drones. PPP-RTK is a new technology, and the challenge is to create an ecosystem for the development of new applications. QZSS CLAS provides an open-source reference implementation [2] and support for receiver manufacturers and application providers. As a result, low-cost multi-frequency GNSS receivers such as u-blox F9P and Septentrio Mosaic-CLAS natively support QZSS CLAS. PPP/PPP-RTK has been challenged by the lack of an industry standard such as the RTCM format. QZSS CLAS defined an effective open format for PPP/PPP-RTK called Compact SSR (CSSR). This format has been adopted as part of the 3GPP LTE Positioning Protocol (LPP) standard [3] and is also used as the basis for format design of other satellite-based open PPP services [4]. This paper presents the operational performance of CLAS, which has been in service for about five years, and describes the challenges it faces in terms of measures to improve performance in urban areas and to cope with ionospheric disturbances. It also presents studies to further increase the number of satellites to be augmented, to authenticate augmentation messages for enhanced security, and to improve compatibility with the national mapping infrastructure, as initiatives to further improve functionality and performance.
Published in: Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023)
September 11 - 15, 2023
Hyatt Regency Denver
Denver, Colorado
Pages: 469 - 482
Cite this article: Hirokawa, Rui, Fujita, Seigo, Hayase, Natsuko, "The First Satellite-Based Open PPP-RTK Service: Operational Experiences and Improvements," Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023), Denver, Colorado, September 2023, pp. 469-482. https://doi.org/10.33012/2023.19213
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