Takeyasu Sakai Electronic Navigation Research Institute, Japan Takeyasu Sakai Electronic Navigation...

Takeyasu SakaiElectronic Navigation Research Institute, Japan

Takeyasu SakaiElectronic Navigation Research Institute, Japan

Quasi-Zenith Satellite SystemL1-SAIF Augmentation Signal

Quasi-Zenith Satellite SystemL1-SAIF Augmentation Signal

Munich SatNav SummitMunich SatNav SummitMunich, GermanyMunich, GermanyMarch 25-27, 2014March 25-27, 2014

Munich SatNav Summit 2014 - ENRIMunich SatNav Summit 2014 - ENRI

SSLIDELIDE 22IntroductionIntroduction

• QZSS (Quasi-Zenith Satellite System) programQZSS (Quasi-Zenith Satellite System) program::– Regional navigation service broadcast from high-elevation angle by three or moRegional navigation service broadcast from high-elevation angle by three or mo

re satellites on the inclined geosynchronous (quasi-zenith) orbit and GEO;re satellites on the inclined geosynchronous (quasi-zenith) orbit and GEO;– Broadcast GPS-like supplemental signals on three frequencies and two augmeBroadcast GPS-like supplemental signals on three frequencies and two augme

ntation signals, L1-SAIF and LEX;ntation signals, L1-SAIF and LEX;– The first QZS satellite successfully launched on Sept. 11, 2010.The first QZS satellite successfully launched on Sept. 11, 2010.

• L1-SAIF L1-SAIF (Submeter-class Augmentation with Integrity Function) signal offers(Submeter-class Augmentation with Integrity Function) signal offers::– Sub-meter accuracy wide-area differential correction service;Sub-meter accuracy wide-area differential correction service;– Integrity function for safety of mobile users; andIntegrity function for safety of mobile users; and– Ranging function for position availability; all on L1 single frequency.Ranging function for position availability; all on L1 single frequency.

• ENRI has developed L1-SAIF signal and experimental facilityENRI has developed L1-SAIF signal and experimental facility::– Signal design: SBAS-like signal and message on L1 frequency;Signal design: SBAS-like signal and message on L1 frequency;– Implemented L1-SAIF Master Station (L1SMS) which generates augmentation Implemented L1-SAIF Master Station (L1SMS) which generates augmentation

message stream in realtime and transmits it to the QZSS MCS;message stream in realtime and transmits it to the QZSS MCS;– Conducted experiments of L1-SAIF successfully.Conducted experiments of L1-SAIF successfully.


SSLIDELIDE 33QZSS ConceptQZSS Concept

• Broadcast signal from high elevation angle;Broadcast signal from high elevation angle;

• Applicable to navigation services for Applicable to navigation services for mountain area and urban canyon;mountain area and urban canyon;

• Augmentation signal from the zenith could Augmentation signal from the zenith could help users to acquire other GPS satellites at help users to acquire other GPS satellites at any time.any time.

• Footprint of QZSS orbit;Footprint of QZSS orbit;• Centered at 135E;Centered at 135E;• Eccentricity 0.075, Inclination 43deg.Eccentricity 0.075, Inclination 43deg.

QZSQZSGPS/GEOGPS/GEO


SSLIDELIDE 44

L-band Helical Array Antenna

L1-SAIF Antenna

Laser Reflector

C-band TTC Antenna

Radiation Cooled TWTTWSTFT Antenna

25.3m

Successfully launched on Sept. Successfully launched on Sept. 11, 2010 and settled on Quasi-Z11, 2010 and settled on Quasi-Zenith Orbit (IGSO).enith Orbit (IGSO).

Nickname: “Michibiki”Nickname: “Michibiki”

Space Segment: QZS-1Space Segment: QZS-1

Mass4,020kg (wet) 1,802kg (dry) (NAV Payload： 320kg)

PowerApprox. 5.3 kW (EOL) (NAV Payload: Approx. 1.9kW)

Design Life 10 years


SSLIDELIDE 55Broadcast Ranging SignalsBroadcast Ranging Signals

QZS satellitesQZS satellites

Supplemental Signals by JAXASupplemental Signals by JAXA• GPS-like L1C/A, L2C, L5, and L1C signals (PRN GPS-like L1C/A, L2C, L5, and L1C signals (PRN

193) working with GPS;193) working with GPS;• Improves availability of navigation;Improves availability of navigation;• Minimum modifications from GPS signals.Minimum modifications from GPS signals.

L1-SAIF by ENRIL1-SAIF by ENRI• SBAS-like C/A code (PRN 183) signal on L1 freq.; SBAS-like C/A code (PRN 183) signal on L1 freq.;

Reasonable performance for mobile users;Reasonable performance for mobile users;• Augmentation to GPS; Potentially plus GLONASS Augmentation to GPS; Potentially plus GLONASS

and Galileo.and Galileo.

SupplementalSupplementalSignalsSignals

AugmentationAugmentationSignalsSignals

LEX by JAXALEX by JAXA• For carrier-based experimental purposes;For carrier-based experimental purposes;• Original CPSK signal on E6 frequency;Original CPSK signal on E6 frequency;• Member organizations may use LEX as 2kbps Member organizations may use LEX as 2kbps

experimental data channel.experimental data channel.


SSLIDELIDE 66L1-SAIF SignalL1-SAIF Signal

User GPSUser GPSReceiversReceivers

• SBAS-like augmentation signal; Differences are SBAS-like augmentation signal; Differences are PRN code (183 for L1-SAIF) and Doppler only;PRN code (183 for L1-SAIF) and Doppler only;

• Three functions by a single signal: ranging, error Three functions by a single signal: ranging, error correction (Target accuracy: 1m), and integrity;correction (Target accuracy: 1m), and integrity;

• User receivers can receive both GPS and L1-SAIF User receivers can receive both GPS and L1-SAIF signals with a single antenna and RF front-end;signals with a single antenna and RF front-end;

• See IS-QZSS for detail (Available at JAXA HP).See IS-QZSS for detail (Available at JAXA HP).

SAIFSAIF ：： Submeter-class Augmentation with Integrity FunctionSubmeter-class Augmentation with Integrity Function

RangingRangingFunctionFunction

ErrorErrorCorrectionCorrection

IntegrityIntegrityFunctionFunction

QZS satellitesQZS satellitesGPS ConstellationGPS Constellation

Ranging SignalRanging Signal

L1-SAIF SignalL1-SAIF Signal


SSLIDELIDE 77ENRI L1-SAIF Master StationENRI L1-SAIF Master Station

• L1-SAIF Master Station (L1SMS):L1-SAIF Master Station (L1SMS):– Generates L1-SAIF message stream in realtime and transmits it to QZSS MCS deGenerates L1-SAIF message stream in realtime and transmits it to QZSS MCS de

veloped by and installed at JAXA;veloped by and installed at JAXA;– Installed at ENRI, Tokyo; 90km from JAXA Tsukuba Space Center;Installed at ENRI, Tokyo; 90km from JAXA Tsukuba Space Center;– Dual frequency GPS measurements at some locations in Japan necessary to geneDual frequency GPS measurements at some locations in Japan necessary to gene

rate L1-SAIF messages are sent from GEONET in realtime.rate L1-SAIF messages are sent from GEONET in realtime.

L1SMSL1SMSGEONETGEONET

QZSQZS

QZSS MCSQZSS MCS

GNSSGNSSSatellitesSatellites

Measure-Measure-mentsments

L1-SAIFL1-SAIFMessageMessage

GSI ServerGSI Server(Tokyo)(Tokyo)

ENRIENRI(Tokyo)(Tokyo)

JAXA TKSCJAXA TKSC(Tsukuba)(Tsukuba)

L1-S

AIF S

ignal

L1-S

AIF S

ignal

Ranging Signal

Ranging SignalRan

ging

Signal

Rangin

g Signa

l

K-band Uplink

K-band Uplink


SSLIDELIDE 88L1-SAIF PerformanceL1-SAIF Performance

• Example of user position error at Site 940058 Example of user position error at Site 940058 (Takayama);(Takayama);

• Realtime operation with MSAS-like 6 referencRealtime operation with MSAS-like 6 reference stations in Japan;e stations in Japan;

• Period: 19-23 Jan. 2008 (5 days).Period: 19-23 Jan. 2008 (5 days).

HorizontalHorizontalErrorError

VerticalVerticalErrorError

1.45 m1.45 m 2.92 m2.92 m

6.02 m6.02 m 8.45 m8.45 m

SystemSystem

StandaloneStandaloneGPSGPS

0.29 m0.29 m 0.39 m0.39 m

1.56 m1.56 m 2.57 m2.57 mw/ L1-SAIFw/ L1-SAIF

RMSRMS

MaxMax

RMSRMS

MaxMax

Note: Results shown here were obtained with geodetic-Note: Results shown here were obtained with geodetic-grade antenna and receivers at open sky condition.grade antenna and receivers at open sky condition.

User location User location for this testfor this test

6 reference6 referencestationsstations

L1-SAIF expe- L1-SAIF experimental arearimental areaStandalone GPS

L1-SAIF Augmentation

GPS Only ResultGPS Only Result


SSLIDELIDE 99Experiment by CarExperiment by Car

• L1-SAIF experimentL1-SAIF experiment::– L1-SAIF is originally planned as an augmentatiL1-SAIF is originally planned as an augmentati

on to mobile users with a certain velocity;on to mobile users with a certain velocity;– Experiment with a car;Experiment with a car;– Location: urban/suburban environment, freewaLocation: urban/suburban environment, freewa

y;y;– Experiment period: Dec. 2010 to March 2011.Experiment period: Dec. 2010 to March 2011.

• Experiment setup:Experiment setup:– Reference: GPS+IMU sensor;Reference: GPS+IMU sensor;– Post-processing with GEONET stations (20- 3Post-processing with GEONET stations (20- 3

0 km separation) for accurate reference;0 km separation) for accurate reference;– GPS/L1-SAIF receiver and PC in cabin;GPS/L1-SAIF receiver and PC in cabin;– Receives L1-SAIF signal on PRN 183;Receives L1-SAIF signal on PRN 183;– Applies L1-SAIF corrections in realtime and ouApplies L1-SAIF corrections in realtime and ou

tputs position fix.tputs position fix.

GPS+IMUGPS+IMU

GPS/L1-SAIF RxGPS/L1-SAIF Rx


SSLIDELIDE 1010On the FreewayOn the Freeway

• On Dec. 14, 2010; QZS near the Zenith;On Dec. 14, 2010; QZS near the Zenith;• About 10 km drive at the Kofu Basin on Chuo Freeway going About 10 km drive at the Kofu Basin on Chuo Freeway going

westward from Tokyo;westward from Tokyo;• Plain ground with less bridges across the Freeway.Plain ground with less bridges across the Freeway.

Plan View of the RoutePlan View of the Route Typical SituationTypical Situation

2 kmGEONETGEONETNakamichiNakamichi

GEONETGEONETIchinomiyaIchinomiya


SSLIDELIDE 1111Freeway: GPS No AugmentationFreeway: GPS No Augmentation

1.2m1.2m

15min15min

Hor

izon

tal P

ositi

on E

rror

, m

Chuo Freeway: GPS without Augmentation

UTC Time 1:22:08 to 1:37:08


SSLIDELIDE 1212Freeway: L1-SAIF AugmentedFreeway: L1-SAIF Augmented

0.5m0.5m

15min15min

Hor

izon

tal P

ositi

on E

rror

, m

Chuo Freeway: L1-SAIF Augmentation

UTC Time 1:22:08 to 1:37:08


SSLIDELIDE 1313In Tsukuba CityIn Tsukuba City

• On Dec. 16, 2010; QZS near the Zenith;On Dec. 16, 2010; QZS near the Zenith;• About 6 km drive in West part of Tsukuba City in Ibaraki Pref.;About 6 km drive in West part of Tsukuba City in Ibaraki Pref.;• Road on the ground level with less tall buildings around.Road on the ground level with less tall buildings around.

Plan View of the RoutePlan View of the Route Typical SituationTypical Situation

1 km

GEONETGEONETTsukuba 1Tsukuba 1


SSLIDELIDE 1414Tsukuba: GPS No AugmentationTsukuba: GPS No Augmentation

2.0m2.0m

15min15min

Hor

izon

tal P

ositi

on E

rror

, m

Tsukuba: GPS without Augmentation

UTC Time 5:30:01 to 5:45:01


SSLIDELIDE 1515Tsukuba: L1-SAIF AugmentedTsukuba: L1-SAIF Augmented

0.6m0.6m

15min15min

Hor

izon

tal P

ositi

on E

rror

, m

Tsukuba: L1-SAIF Augmentation

UTC Time 5:30:01 to 5:45:01


SSLIDELIDE 1616ConclusionConclusion

• ENRI has developed QZSS L1-SAIF signalENRI has developed QZSS L1-SAIF signal::– Signal design: SBAS-like C/A code signal (PRN 183) on L1 frequency;Signal design: SBAS-like C/A code signal (PRN 183) on L1 frequency;

– Planned as an augmentation to mobile users;Planned as an augmentation to mobile users;

– Implemented L1-SAIF Master Station (L1SMS) which generates augmentation messImplemented L1-SAIF Master Station (L1SMS) which generates augmentation message stream in realtime and transmit it to QZSS MCS.age stream in realtime and transmit it to QZSS MCS.

• QZSS satellite “Michibiki”QZSS satellite “Michibiki”::– The first satellite for QZSS, “Michibiki”, was successfully launched in 2010;The first satellite for QZSS, “Michibiki”, was successfully launched in 2010;

– Continuously broadcasting navigation signals just as planned.Continuously broadcasting navigation signals just as planned.

• L1-SAIF ExperimentsL1-SAIF Experiments::– ENRI has conducted L1-SAIF experiments successfully and confirmed submeter-claENRI has conducted L1-SAIF experiments successfully and confirmed submeter-cla

ss accuracy as originally planned;ss accuracy as originally planned;

– Currently investigations are in progress on usage of Multi-GNSS with GLONASS, duCurrently investigations are in progress on usage of Multi-GNSS with GLONASS, dual frequency augmentation, and application in short message service;al frequency augmentation, and application in short message service;

– Information is available at: Information is available at: http://www.enri.go.jp/sat/qzss_e.htmhttp://www.enri.go.jp/sat/qzss_e.htm

Takeyasu Sakai Electronic Navigation Research Institute, Japan Takeyasu Sakai Electronic Navigation...

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