Quasi-Zenith Satellite System L1-SAIF Augmentation Signal Munich SatNav Summit Munich, Germany March 25-27, 2014 Quasi-Zenith Satellite System L1-SAIF Augmentation Signal Takeyasu Sakai Electronic Navigation Research Institute, Japan

Introduction QZSS (Quasi-Zenith Satellite System) program: Munich SatNav Summit 2014 - ENRI Introduction QZSS (Quasi-Zenith Satellite System) program: Regional navigation service broadcast from high-elevation angle by three or more satellites on the inclined geosynchronous (quasi-zenith) orbit and GEO; Broadcast GPS-like supplemental signals on three frequencies and two augmentation signals, L1-SAIF and LEX; The first QZS satellite successfully launched on Sept. 11, 2010. L1-SAIF (Submeter-class Augmentation with Integrity Function) signal offers: Sub-meter accuracy wide-area differential correction service; Integrity function for safety of mobile users; and Ranging function for position availability; all on L1 single frequency. ENRI has developed L1-SAIF signal and experimental facility: Signal design: SBAS-like signal and message on L1 frequency; Implemented L1-SAIF Master Station (L1SMS) which generates augmentation message stream in realtime and transmits it to the QZSS MCS; Conducted experiments of L1-SAIF successfully.

QZSS Concept Broadcast signal from high elevation angle; Munich SatNav Summit 2014 - ENRI QZSS Concept QZS GPS/GEO Broadcast signal from high elevation angle; Applicable to navigation services for mountain area and urban canyon; Augmentation signal from the zenith could help users to acquire other GPS satellites at any time. Footprint of QZSS orbit; Centered at 135E; Eccentricity 0.075, Inclination 43deg.

Space Segment: QZS-1 L1-SAIF Antenna 25.3m Munich SatNav Summit 2014 - ENRI Space Segment: QZS-1 L-band Helical Array Antenna L1-SAIF Antenna Laser Reflector C-band TTC Antenna Radiation Cooled TWT TWSTFT Antenna 25.3m Successfully launched on Sept. 11, 2010 and settled on Quasi-Zenith Orbit (IGSO). Nickname: “Michibiki” Mass 4,020kg (wet) 1,802kg (dry) (NAV Payload：320kg) Power Approx. 5.3 kW (EOL) (NAV Payload: Approx. 1.9kW) Design Life 10 years

Broadcast Ranging Signals Munich SatNav Summit 2014 - ENRI Broadcast Ranging Signals Supplemental Signals Supplemental Signals by JAXA GPS-like L1C/A, L2C, L5, and L1C signals (PRN 193) working with GPS; Improves availability of navigation; Minimum modifications from GPS signals. QZS satellites L1-SAIF by ENRI SBAS-like C/A code (PRN 183) signal on L1 freq.; Reasonable performance for mobile users; Augmentation to GPS; Potentially plus GLONASS and Galileo. LEX by JAXA For carrier-based experimental purposes; Original CPSK signal on E6 frequency; Member organizations may use LEX as 2kbps experimental data channel. Augmentation Signals

SAIF： Submeter-class Augmentation with Integrity Function Munich SatNav Summit 2014 - ENRI L1-SAIF Signal Ranging Function Error Correction Integrity QZS satellites GPS Constellation Ranging Signal L1-SAIF Signal SBAS-like augmentation signal; Differences are PRN code (183 for L1-SAIF) and Doppler only; Three functions by a single signal: ranging, error correction (Target accuracy: 1m), and integrity; User receivers can receive both GPS and L1-SAIF signals with a single antenna and RF front-end; See IS-QZSS for detail (Available at JAXA HP). User GPS Receivers SAIF： Submeter-class Augmentation with Integrity Function

ENRI L1-SAIF Master Station Munich SatNav Summit 2014 - ENRI ENRI L1-SAIF Master Station L1-SAIF Master Station (L1SMS): Generates L1-SAIF message stream in realtime and transmits it to QZSS MCS developed by and installed at JAXA; Installed at ENRI, Tokyo; 90km from JAXA Tsukuba Space Center; Dual frequency GPS measurements at some locations in Japan necessary to generate L1-SAIF messages are sent from GEONET in realtime. L1SMS GEONET QZS QZSS MCS GNSS Satellites Measure- ments L1-SAIF Message GSI Server (Tokyo) ENRI JAXA TKSC (Tsukuba) L1-SAIF Signal Ranging Signal K-band Uplink

L1-SAIF Performance GPS Only Result Horizontal Error Vertical 1.45 m Munich SatNav Summit 2014 - ENRI L1-SAIF Performance Standalone GPS L1-SAIF Augmentation GPS Only Result 6 reference stations User location for this test L1-SAIF expe- rimental area Horizontal Error Vertical 1.45 m 2.92 m 6.02 m 8.45 m System Standalone GPS 0.29 m 0.39 m 1.56 m 2.57 m w/ L1-SAIF RMS Max Example of user position error at Site 940058 (Takayama); Realtime operation with MSAS-like 6 reference stations in Japan; Period: 19-23 Jan. 2008 (5 days). Note: Results shown here were obtained with geodetic-grade antenna and receivers at open sky condition.

Experiment by Car L1-SAIF experiment: Experiment setup: GPS+IMU Munich SatNav Summit 2014 - ENRI Experiment by Car L1-SAIF experiment: L1-SAIF is originally planned as an augmentation to mobile users with a certain velocity; Experiment with a car; Location: urban/suburban environment, freeway; Experiment period: Dec. 2010 to March 2011. Experiment setup: Reference: GPS+IMU sensor; Post-processing with GEONET stations (20- 30 km separation) for accurate reference; GPS/L1-SAIF receiver and PC in cabin; Receives L1-SAIF signal on PRN 183; Applies L1-SAIF corrections in realtime and outputs position fix. GPS+IMU GPS/L1-SAIF Rx

On the Freeway Plan View of the Route Typical Situation Munich SatNav Summit 2014 - ENRI On the Freeway 2 km GEONET Nakamichi Ichinomiya Plan View of the Route Typical Situation On Dec. 14, 2010; QZS near the Zenith; About 10 km drive at the Kofu Basin on Chuo Freeway going westward from Tokyo; Plain ground with less bridges across the Freeway.

Freeway: GPS No Augmentation Munich SatNav Summit 2014 - ENRI Freeway: GPS No Augmentation Chuo Freeway: GPS without Augmentation Horizontal Position Error, m 1.2m UTC Time 1:22:08 to 1:37:08 15min

Freeway: L1-SAIF Augmented Munich SatNav Summit 2014 - ENRI Freeway: L1-SAIF Augmented Chuo Freeway: L1-SAIF Augmentation Horizontal Position Error, m 0.5m UTC Time 1:22:08 to 1:37:08 15min

In Tsukuba City Plan View of the Route Typical Situation Munich SatNav Summit 2014 - ENRI In Tsukuba City 1 km GEONET Tsukuba 1 Plan View of the Route Typical Situation On Dec. 16, 2010; QZS near the Zenith; About 6 km drive in West part of Tsukuba City in Ibaraki Pref.; Road on the ground level with less tall buildings around.

Tsukuba: GPS No Augmentation Munich SatNav Summit 2014 - ENRI Tsukuba: GPS No Augmentation Tsukuba: GPS without Augmentation Horizontal Position Error, m 2.0m UTC Time 5:30:01 to 5:45:01 15min

Tsukuba: L1-SAIF Augmented Munich SatNav Summit 2014 - ENRI Tsukuba: L1-SAIF Augmented Tsukuba: L1-SAIF Augmentation Horizontal Position Error, m 0.6m UTC Time 5:30:01 to 5:45:01 15min

Conclusion ENRI has developed QZSS L1-SAIF signal: Munich SatNav Summit 2014 - ENRI Conclusion ENRI has developed QZSS L1-SAIF signal: Signal design: SBAS-like C/A code signal (PRN 183) on L1 frequency; Planned as an augmentation to mobile users; Implemented L1-SAIF Master Station (L1SMS) which generates augmentation message stream in realtime and transmit it to QZSS MCS. QZSS satellite “Michibiki”: The first satellite for QZSS, “Michibiki”, was successfully launched in 2010; Continuously broadcasting navigation signals just as planned. L1-SAIF Experiments: ENRI has conducted L1-SAIF experiments successfully and confirmed submeter-class accuracy as originally planned; Currently investigations are in progress on usage of Multi-GNSS with GLONASS, dual frequency augmentation, and application in short message service; Information is available at: http://www.enri.go.jp/sat/qzss_e.htm