1. Experiments and Potential Applications
ICG WG-B APP-SG
Munich, Germany
March 4, 2018
DFMC SBAS
Experiments and Potential Applications
Takeyasu Sakai
Electronic Navigation Research Institute
National Institute of Maritime, Port and Aviation Technology, Japan

2. Introduction SBAS: Satellite-Based Augmentation System
ICG WG-B APP-SG, March 2018
Introduction
SBAS: Satellite-Based Augmentation System
International standard augmentation system.
Transmits Augmentation information from the SBAS satellite.
Augments GNSS in terms of accuracy and integrity.
Current standard: Single-frequency SBAS on L1 transmitted by GEO.
US WAAS, Japanese MSAS, European EGNOS, Indian GAGAN.
DFMC SBAS: The Second Generation SBAS
Dual-Frequency Multi-Constellation SBAS using L5 frequency.
Robust navigation augmented via GEO and non-GEO SBAS satellites.
ENRI has been conducting DFMC SBAS experiment via QZSS L5S signal.
Potential Applications of DFMC SBAS
Robust navigation service everywhere in the coverage.
Not influenced by the ionosphere activities even in the low latitude regions.
Could be transmitted by non-GEO SBAS satellite like QZSS IGSO.
Possible solution for applications where GEO signal is likely blocked.

3. SBAS Architecture Monitors consistency of GNSS signals on the ground.
ICG WG-B APP-SG, March 2018
SBAS Architecture
SBAS Satellite
GNSS
Satellites
Ground Monitor Network
Users
Uplink
Station
GNSS Signals
SBAS Signal
Monitors consistency of GNSS signals on the ground.
Transmits differential correction and integrity information via SBAS satellite.

4. DFMC SBAS DFMC (Dual-Frequency Multi-Constellation) SBAS
ICG WG-B APP-SG, March 2018
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.
Robust navigation service everywhere in the coverage.
Could be transmitted by non-GEO SBAS satellites like QZSS IGSO.
Possible solution for applications where GEO signal is likely blocked.
Standardization activities ongoing by the ICAO.
ENRI is now conducting DFMC SBAS Experiment
The First L5 SBAS experiment with live 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.
Contributes to standardization activities by the ICAO.

5. Real Time Experiment Monitor Stations
ICG WG-B APP-SG, March 2018
Real Time Experiment
Monitor Stations
GPS+Galileo+QZSS
Dual Frequency (L1+L5)
DFMC L5 SBAS
Location:
GEONET (Wakayama)
Period:
2017/11/13 01: :00 (6H)
Evaluation of L5 SBAS message generated in real time.
Supporting GPS, Galileo, and QZSS in L1/L5 dual-frequency mode.
Confirmed that L5 SBAS augments multi-constellation of GPS+Galileo+QZSS.

6. ICG WG-B APP-SG, March 2018
Non-GEO SBAS Concept
Tyler Reid, ION GNSS+ 2015
GEO
IGSO
DFMC SBAS could be transmitted by non-GEO satellites like QZSS IGSO.
Improves availability of augmentation signals where GEO signal is blocked.
Arctic/Nordic regions, mountain area, urban canyon,…

7. Visibility from Nordic Region
ICG WG-B APP-SG, March 2018
Visibility from Nordic Region
Elevation angles computed from QZS-1/2/4 almanacs.
QZSS IGSO satellites are visible in Nordic region; Higher elevation than EGNOS GEO at some location.

8. Discussion DFMC (Dual-Frequency Multi-Constellation) SBAS
ICG WG-B APP-SG, March 2018
Discussion
DFMC (Dual-Frequency Multi-Constellation) SBAS
Augments GNSS in terms of accuracy and integrity.
Eliminates ionospheric effects thanks to dual-frequency operation.
Could be transmitted by non-GEO SBAS satellites like QZSS IGSO.
Possible Applications
Dual frequency operation: Robust navigation with integrity.
Service at the Equatorial regions.
SBAS service by combination of GEO and non-GEO satellites.
Improves signal availability in the urban canyon and mountain areas.
Enables navigation with integrity in the Arctic and Nordic regions.
Ongoing Standardization Activities
Recognize advantage of non-GEO SBAS and support its standardization.
Collaborate to develop applications realized by QZSS IGSO.

9. Conclusion SBAS: International Standard Augmentation System
ICG WG-B APP-SG, March 2018
Conclusion
SBAS: International Standard Augmentation System
Augments GNSS in terms of accuracy and integrity.
The standardization of DFMC SBAS is ongoing by the ICAO.
Using L5 SBAS signal instead L1.
Eliminates ionospheric effects thanks to dual-frequency operation.
Could be transmitted by non-GEO SBAS satellites like QZSS IGSO.
ENRI has been conducting DFMC SBAS experiment via QZSS L5S signal.
Potential Applications of DFMC SBAS
Robust navigation service not influenced by the ionospheric activities.
Possible solution for urban canyon, mountain area, and Arctic/Nordic regions.
Contact for more discussion:
Dr. Takeyasu Sakai
Electronic Navigation Research Institute
National Institute of Maritime, Port and Aviation Technology, Japan