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This paper discusses the status of the Dual-Frequency Multi-Constellation Satellite-Based Augmentation System (SBAS) trial in Japan. It covers the architecture of SBAS, the history and operation of the MSAS program, the current performance, the future evolution plan, and the introduction of the Dual-Frequency Multi-Constellation (DFMC) SBAS.
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IS-GNSS 2017 Hong Kong, China Dec. 10-13, 2017 The Status of Dual-Frequency Multi-Constellation SBAS Trial by Japan Takeyasu Sakai ElectronicNavigation Research Institute National Institute of Maritime, Port and Aviation Technology, Japan
Introduction • SBAS: Satellite-Based Augmentation System • International standard augmentation system primarily for aviation. • International standard by ICAO (International Civil Aviation Organization). • Transmits Augmentation information from the SBAS satellite. • Augments GPS in terms of accuracy and integrity. • Current standard: Single-frequency SBAS on L1. • US WAAS, Japanese MSAS, European EGNOS, Indian GAGAN. • Japan has been operating its own SBAS called MSAS since 2007. • MSAS: MTSAT-based Augmentation System. • Horizontal navigation service within Japanese airspace. • DFMC SBAS: The Second Generation SBAS • Dual-Frequency Multi-Constellation SBAS using L5 frequency. • Standardization activities ongoing by the ICAO. • ENRI is now conducting DFMC SBAS Experiment. • The First DFMC SBAS experiment with live L5 signal from the space.
SBAS Architecture SBAS Satellite GNSS Satellites GNSS Signals SBAS Signal Users Uplink Station Ground Monitor Network • Monitors consistency of GNSS signals on the ground. • Transmits differential correction and integrity information via SBAS satellite.
MSAS Program • MSAS: SBAS Program by Japan • JCAB (Japan Civil Aviation Bureau) decided the development of its own SBAS in 1993. • The system named MSAS, or MTSAT Satellite-based Augmentation System, was originally planned to be operational in 2000. • Launch of the MTSAT-1 was unfortunately failed in 1999. • MSAS GEO Satellites • MTSAT (Multi-functional Transport Satellite): Aviation and weather missions. • MTSAT works for AMSS and SBAS services for aviation. • MTSAT-1R and MTSAT-2 were launched in 2005 and 2006, respectively. • Beginning of Operation • Broadcast test signal since summer 2005. Certification activities for 2 years. • Finally, MSAS began its operation in September 27, 2007. • Available for Enroute to NPA (non precision approach) flight modes.
MTSAT Coverage (Fukuoka FIR) Decommissioned in 2015 MTSAT-1R @140E MTSAT-2 @145E FIR: Flight Information Region
Current Configuration MTSAT-2 GPS Satellites Ranging Signals Augmentation Signals 6 GMS in Japan PRN137 Sapporo GMS PRN129 Users Kobe MCS (and GMS) Fukuoka GMS Hitachi-Ota MCS (and GMS) Tokyo GMS Ground Network MSAS Monitor Stations Naha GMS • 1 GEO, 2 MCS (Master Control Station) and 4 GMS (Ground Monitor Station); • MCS also has GMS function; MSAS has 6 domestic monitor stations. • MTSAT-2 is broadcasting 2 signals from 2 MCS (PRN129 and PRN137).
Performance GPS only GPS only Horizontal 0.722m RMS Horizontal 0.717m RMS MSAS PRN129 MSAS PRN137 GEONET 940058 (Takayama) 16/8/8-12 (5 days) PRN129 and PRN137 Broadcast Signal
Continuous Operation • Current status: • MTSAT-1R decommissioned in 2015. MTSAT-2 will be in 2020. • 2 MRS sites decommissioned in 2015. • The ground facilities need to be upgraded: It is difficult to maintain 20-year old equipment. • Replacement in 2020: • MSAS continues operation with 1 GEO and 6 GMS until 2020. • In 2020, MSAS will continue operation with a GEO of the QZSS. • QZSS (Quasi-Zenith Satellite System): Japanese regional satellite navigation system with IGSO and GEO satellites. • The L1Sb signal of QZS-3 (GEO) will be used for MSAS service. • MCS equipment will also be fully replaced at the same time. • 7 GMS will be added: Totally 13 GMS domestic. • Performance will be similar with the current MSAS: Horizontal only.
MSAS Evolution Plan • Replacement in 2020: MSAS V2 • MSAS continues operation with 1 GEO and 6 GMS until 2020. • In 2020, MSAS will continue operation with a GEO of the QZSS. • QZSS (Quasi-Zenith Satellite System): Japanese regional satellite navigation system with IGSO and GEO satellites. • The L1Sb signal of QZS-3 (GEO) will be used for MSAS service. • 7 GMS will be added: Totally 13 GMS domestic. • Supporting vertical guidance: MSAS V3 • Vertical guidance: LPV and LPV-200 operation. • Will be supported in accordance with introduction of the 2nd GEO in 2023. • Dual-Frequency operation: MSAS V4 • Eliminates ionospheric effects dramatically. • Robust vertical guidance (LPV and LPV-200) in the whole coverage area. • QZSS GEO will have L5 SBAS signal for dual-frequency operation.
MSAS Evolution Plan • L5 SBAS trial since 2017. • Replacement to the new QZSS-based system in 2020. • LPV/LPV-200 upgrade in 2023 and L5 SBAS implementation after that.
DFMC SBAS • DFMC (Dual-Frequency Multi-Constellation) SBAS • The second generation SBAS following L1 SBAS. • Using L5 SBAS signal instead L1. • Eliminates ionospheric effects thanks to dual-frequency operation. • Vertical guidance service everywhere in the coverage. • Standardization activities ongoing by the ICAO. • ENRI is now conducting DFMC SBAS Experiment • The First L5 SBAS experiment with real L5 signal from the space. • Using QZSS L5S signal transmitted from GEO (QZS-3) and IGSO (QZS-2/4). • Prototype DFMC SBAS for the experiment has been developed. • GPS/GLONASS/Galileo-capable dual-frequency SBAS. • Compliant with the draft standards of DFMC SBAS being discussed at ICAO. • Began the experiment on 23 Aug. via L5S signal of QZS-2 IGSO. • Expects transmission from QZS-3 GEO by end of this year. • Contributes to standardization activities by the ICAO.
Configuration QZSS #2, #3, and #4 GLONASS GPS Galileo GEO (QZS-3) + IGSO (QZS-2/4) Ranging Signal Uplink L5S Signal L5S Signal BeiDou Measured OBS L5 SBAS Message GEONET ENRI L5 SBAS Prototype QZSS C&C GSI (Shinjuku, Tokyo) ENRI, MPAT (Chofu, Tokyo) QZSS MCS (Hitachi-Ota, Ibaraki) • Supports DFMC • Provides observation in real time • Operates in real time • Dual-Frequency • Supports GPS, GLONASS, and Galileo • Uplink L5 SBAS message stream for transmission
Prototype DFMC SBAS 13 Monitor Stations • Dual Frequency • DFMC L5 SBAS • Location: • GEONET 950369 • (Wakayama) • Period: • 2016/12/15 (24H) • SBAS corrections improve position accuracy in both modes of GPS and GPS+GLONASS. • SBAS messages are generated by the prototype DFMC SBAS developed by ENRI in accordance with the draft DFMC L5 SBAS standards.
Prototype DFMC SBAS w/o augmentation w/ augmentation Horizontal Accuracy Vertical Accuracy • Evaluated long-term performance using archive data at GEONET 950369 Wakayama. • Confirmed stable performance for a year; Horizontal ~0.5m and Vertical ~1m.
Real Time Experiment 5 GPS No GLONASS Clock/Orbit Correction 7 Galileo Position Solution 2 QZSS Monitored Satellites Galileo SV-8 Satellites in Sky Output Message Stream
Conclusion • SBAS: International Standard Augmentation System • Augments GNSS in terms of accuracy and integrity. • Available: US WAAS, Japanese MSAS, European EGNOS, Indian GAGAN. • Japan has been operating its own SBAS called MSAS since 2007. • The standardization of DFMC SBAS is ongoing by the ICAO. • DFMC SBAS Experiment Using QZSS L5S Augmentation Signal • The First L5 SBAS experiment with real L5 signal from the space. • ENRI has developed the prototype SBAS for experiments. • GPS/GLONASS/Galileo-capable dual-frequency SBAS. • Compliant with the draft standards of DFMC SBAS being discussed. • The experiment has been conducted since 23 August, 2017. • Contact for more information: Dr. Takeyasu Sakai <sakai@mpat.go.jp> Electronic Navigation Research Institute National Institute of Maritime, Port and Aviation Technology, Japan