1. T. Sakai, S. Fukushima, N. Takeichi, and K. Ito Electronic Navigation Research Institute, Japan T. Sakai, S. Fukushima, N. Takeichi, and K. Ito Electronic Navigation Research Institute, Japan Augmentation Performance of QZSS L1-SAIF Signal Augmentation Performance of QZSS L1-SAIF Signal ION NTM 2007 San Diego, CA Jan. 22-24, 2007

2. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 1 QZSS will provide augmentation signals:QZSS will provide augmentation signals: –In addition to supplement signals; –L1-SAIF (Submeter-class Augmentation with Integrity Function) on GPS/SBAS L1 frequency and LEX on Galileo E6; –L1-SAIF augmentation signal offers: wide-area differential correction, integrity function, and ranging function. ENRI is responsible for developing L1-SAIF:ENRI is responsible for developing L1-SAIF: –Signal design: identical with SBAS; –Message design is in progress: upper compatible with SBAS. Performance analysis using prototype SBAS:Performance analysis using prototype SBAS: –Submeter accuracy likely achievable; –Most recently, realtime operation trial has been conducted successfully. Introduction

3. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 2 Part 1 Overview of QZSS Program and L1-SAIF Signal

4. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 3 QZS GPS/GEO Signal from high elevation angleSignal from high elevation angle Applicable to navigation services for mountain area and urban canyonApplicable to navigation services for mountain area and urban canyon QZSS Concept Footprint of QZS orbitFootprint of QZS orbit Centered 137ECentered 137E Eccentricity 0.1, Inclination 45degEccentricity 0.1, Inclination 45deg

5. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 4 Supplement signals:Supplement signals: –GPS-compatible L1C/A, L2C, L5, and L1C signals working with GPS; For improving availability of navigation; –With minimum modifications from GPS signal specifications; –Coordination with GPS JPO on broadcasting L1C signal; –JAXA is responsible for all supplement signals. Augmentation signals:Augmentation signals: –Augmentation to GPS; Possibly plus Galileo; –L1-SAIF (Submeter-class Augmentation with Integrity Function): compatible with SBAS; reasonable performance for mobile users; –LEX: for experimental purposes; member organizations may use as 2kbps experimental data channel; –ENRI is working for L1-SAIF and JAXA is developing LEX. QZSS Signals

6. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 5 Frequency Plan SignalChannelFrequencyBandwidth Min. Rx Power QZS-L1CL1CD 1575.42 MHz 24 MHz –163.5 dBW L1CP 24 MHz – 158.4 dBW QZS-L1-C/A 24 MHz – 158.5 dBW QZS-L1-SAIF 24 MHz – 161.0 dBW QZS-L2C 1227.6 MHz 24 MHz – 161.0 dBW QZS-L5L5I 1176.45 MHz 25 MHz – 157.9 dBW L5Q 25 MHz – 157.9 dBW QZS-LEX 1278.75 MHz 42 MHz – 156.0 dBW Find detail in IS-QZSS document.

7. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 6 QZSS will transmit wide-area augmentation signal:QZSS will transmit wide-area augmentation signal: –Called L1-SAIF (Submeter-class Augmentation with Integrity Function); –Developed by ENRI (Electronic Navigation Research Institute), Japan. L1-SAIF signal offers:L1-SAIF signal offers: –Wide-area differential corrections for improving position accuracy; Target accuracy: 1 meter for horizontal; –Integrity function for safety of mobile users; and –Ranging function to improve signal availability. Interoperable with GPS L1C/A and fully compatible with SBAS:Interoperable with GPS L1C/A and fully compatible with SBAS: –Broadcast on L1 freq. with RHCP; Common antenna and RF front-end; –Modulated by BPSK with C/A code; –250 bps data rate with 1/2 FEC; message structure is same as SBAS. L1-SAIF Signal

8. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 7 L1 PRN Assignment PRNSignalSatellite 183QZS-L1-SAIF QZS #1 184QZS-L1-SAIF QZS #2 185QZS-L1-SAIF QZS #3 186QZS-L1-SAIF QZS #4 187QZS-L1-SAIF QZS #5 188 to 192 QZS-L1-SAIF(Reserved) 193 to 197 QZS-L1-C/A QZS #1-5 198 to 202 QZS-L1-C/A(Reserved) Find detail in IS-QZSS document.

9. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 8 Preamble 8 bits Message Type 6 bits Data Field 212 bits CRC parity 24 bits 250 bits MT 0 1 2～52～52～52～5 6 7 9 10 12 17 18 Contents Test mode PRN mask Fast correction & UDRE UDRE Degradation factor for FC GEO ephemeris Degradation parameter SBAS time information GEO almanac IGP mask Interval[s] 6 120 60 6 120 120 120 300 300 300 24 25 26 27 28 63 FC & LTC Long-term correction Ionospheric delay & GIVE SBAS service message Clock-ephemeris covariance Null message 6 120 300 300 120 — MTContentsInterval[s] SBAS Message Structure

10. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 9 L1-SAIF Message (1) Message Type ContentsCompatibilityStatus 0 Test mode SBASFixed 1 PRN mask SBASFixed 2 to 5 Fast correction & UDRE SBASFixed 6UDRESBASFixed 7 Degradation factor for FC SBASFixed 9 GEO ephemeris UnusedFixed 10 Degradation parameter SBASFixed 17 GEO almanac UnusedFixed 18 IGP mask SBASFixed 24 Mixed fast/long-term correction SBASFixed 25 Long-term correction SBASFixed 26 Ionospheric delay & GIVE SBASFixed 12 SBAS network time UnusedFixed 8ReservedUnusedFixed

11. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 10 L1-SAIF Message (2) Message Type ContentsCompatibilityStatus 27 SBAS service message UnusedFixed 28 Clock-ephemeris covariance SBASFixed 29 to 51 (Undefined)—— 52 to 55 (Atmospheric correction) NewTBD 56 Intersignal biases NewTentative 57 (Ephemeris-related parameter) NewTBD 58 QZS ephemeris NewTentative 59 (QZS almanac) NewTBD 60 (Regional information) NewTBD 61ReservedNewTentative 62ReservedSBASFixed 63 Null message SBASFixed

12. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 11 Message Fast Correction Long-Term Correction Ionosphere Troposphere QZS Ephemeris FC Degradation Degradation Parameter PRN Mask IGP Mask C-E Covariance Total Type 2 to 5 25 26 54 and 55 58 7 10 1 18 28 Interval 10 s 60 s 30 s 60 s Messages Required for Constellation 3 4 2 3 1 1 1 1 2 10 Messages per min 18 4 2 3 2 1 1 1 2 10 44 Margin for Other Messages 16 Messaging Capacity

13. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 12 Part 2 Performance Analysis Using Prototype SBAS Prototype SBAS SoftwarePrototype SBAS Software Continuous Daily OperationContinuous Daily Operation Realtime Operation TrialRealtime Operation Trial

14. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 13 Performance analysis method:Performance analysis method: –Typical model-based analysis: modeling (differentially corrected) range domain accuracy and projects it into position domain; –For more reliable analysis of the actual performance, we need to simulate MCS algorithms; For example, generating augmentation message enables evaluation of the actual user error; Error-based analysis; –ENRI has developed the prototype SBAS software for investigation of wide-area augmentation technique; This would be a powerful tool working as an MCS simulator. Performance Analysis Prototype SBAS (MCS simulator) User Receiver SimulatorGPSobservables Position Error Augmentation Message

15. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 14 Actually computer software running on PC or UNIX:Actually computer software running on PC or UNIX: –‘RTWAD’ written in C language (not MATLAB, sorry); –Consists of the essential components and algorithms of WADGPS; –Acts as a simulator of SBAS MCS; Parameters are controllable. Input observables work as monitor stations:Input observables work as monitor stations: –RINEX or raw receiver measurement at any sampling rate; –Requires dual frequency code phase pseudoranges; No carrier phase. Generates the complete SBAS message stream:Generates the complete SBAS message stream: –Outputs one message per second; –250 bps raw message stream before FEC encoding; –Also outputs in NovAtel $FRMA record format is available; for direct input to SBAS user receiver simulator. Prototype SBAS

16. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 15 $FRMA,272,86403.130,183,80811EA4,250,53081FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD FFDFFDFFFBBBBBBBBBBBBAC1CD280*7C $FRMA,272,86404.130,183,80811EA4,250,9A0C1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD FFDFFDFFFBBBBBBBBBBBBB7E76F80*0F $FRMA,272,86405.130,183,80811EA4,250,C661FFDFFDFFDFFDFFDFFFBBBBB880000000 0000000000000000000036CD8A40*70 $FRMA,272,86406.130,183,80811EA4,250,5306FFBFFFF8000000000000000000000000000 000000000000000002B963FC0*0D $FRMA,272,86407.130,183,80811EA4,250,9A091FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD FFDFFDFFFBBBBBBBBBBBB806D3340*77 $FRMA,272,86408.130,183,80811EA4,250,C60D1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD FFDFFDFFFBBBBBBBBBBBB924AAE40*08 $FRMA,272,86409.130,183,80811EA4,250,5361FFDFFDFFDFFDFFDFFFBBBBB890000000 00000000000000000000021FE640*73 $FRMA,272,86410.130,183,80811EA4,250,9A61FFDFFDFFDFFDFFDFFFBBBBB8A0000000 0000000000000000000039994D00*05 $FRMA,272,86411.130,183,80811EA4,250,C60A1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD FFDFFDFFFBBBBBBBBBBBBA6BE8CC0*03 $FRMA,272,86412.130,183,80811EA4,250,530E1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD FFDFFDFFFBBBBBBBBBBBBA99E5040*0A Message Type ID (6 MSBs) Preamble Message Length Satellite PRN Time CRC Message Sample

17. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 16 User Receiver Simulator SBAS user receiver simulator:SBAS user receiver simulator: –Also software running on PC or UNIX; –Processes RINEX observation file with L1 pseudorange; carrier smoothing applied; –Decodes SBAS message stream (NovAtel $FRMA records) and apply them to the observables based on the SBAS standard; –Outputs position solution in ECEF X, Y, Z; –Verified with WAAS and MSAS messages. L1-SAIF message stream generated by the prototype was evaluated by this user receiver simulator:L1-SAIF message stream generated by the prototype was evaluated by this user receiver simulator: –With GEONET observations at some locations as user stations; –Evaluates position accuracies and protection levels of QZSS L1-SAIF.

18. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 17 Standard Configuration At first the prototype generated messages in offline mode with GEONET sites as monitor stations;At first the prototype generated messages in offline mode with GEONET sites as monitor stations; Dual frequency observables sampled every 30 seconds;Dual frequency observables sampled every 30 seconds; 6 monitor stations distributed similar to the MSAS;6 monitor stations distributed similar to the MSAS; 5 user locations for evaluation.5 user locations for evaluation. GEONET for Monitor Stations GEONET for User Stations MSAS Service Area

19. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 18 Line-of-sight component including clock contribution Residual of Corrected Orbit

20. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 19 Ionospheric delay minus IGS/IONEX estimation at each IGP Residual of Iono Correction

21. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 20 User Position Error Example of user positioning error at Site 940058 (Takayama; near center of monitor station network).Example of user positioning error at Site 940058 (Takayama; near center of monitor station network). Period: 22-24 July 2004;Period: 22-24 July 2004; active ionosphere condition. Standalone GPS Augmented by the Prototype HorizontalErrorVerticalError 1.929 m 3.305 m 6.993 m 14.48 m System StandaloneGPS 0.381 m 0.531 m 2.867 m 5.451 m Prototype RMS Max RMS Max

22. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 21 2005/11/14-16 HorVer 2004/7/22-24 HorVer 2004/6/22-24 HorVer 2005/11/14-16MSAS HorVer 0.3541.6950.4182.5170.4322.3180.5664.4550.3972.0470.6024.7170.3811.6590.6312.405 0.3041.4870.4132.1230.3812.8670.5315.4510.4252.6340.6033.4660.5024.8730.7283.700 0.3531.9020.5084.4520.4032.4680.5924.2400.3851.7570.6493.7820.6378.5170.8819.396 940030 940058 940083 0.4533.3020.6476.1580.5862.1430.7645.5090.4912.4150.7764.5740.6403.0120.7302.680950491 1.1326.2661.1025.95808004.4871.3179.2250.7084.5071.0886.5950.9826.2671.0146.61492003 RMSMax RMSMax RMSMax RMSMax RMSMax Site North South Performance Summary Unit: [m]

23. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 22 The prototype has been operated continuously since April:The prototype has been operated continuously since April: –In order to verify the performance of the prototype for long-term; –Standard configuration: 6 monitor stations distributed similar to the MSAS; and ‘Planar Fit’ ionospheric correction; –Observation files are provided from GEONET at daily basis; –Augmentation output is stored as daily files. Evaluation at everywhere, everyday:Evaluation at everywhere, everyday: –Evaluated with GEONET stations at 40 locations; covering the whole Japan for testing integrity; –Position accuracy and integrity function are tested everyday. Messages stored and disclosed at:Messages stored and disclosed at: –URL http://www.enri.go.jp/sat/pro/data/ppwad Continuous Daily Operation

24. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 23 Standard configuration of monitor stations: 6 stations similar to the MSAS;Standard configuration of monitor stations: 6 stations similar to the MSAS; Integrity evaluation stations: 40 stations covering the whole Japan;Integrity evaluation stations: 40 stations covering the whole Japan; So far, no integrity break conditions have been detected.So far, no integrity break conditions have been detected. Monitor Stations Evaluation Stations Integrity Evaluation Sites

25. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 24 Protection Levels vs. Error (1) GEONET 0030 (Oga) 06/4/20 – 06/5/19 (30 days) PPWAD GN/6+S HorizontalVertical

26. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 25 Protection Levels vs. Error (2) GEONET 0083 (Kochi) 06/4/20 – 06/5/19 (30 days) PPWAD GN/6+S HorizontalVertical

27. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 26 User Positioning Accuracy GEONET 3011 (Kawagoe; near Tokyo) 06/6/1 – 06/9/30 (4 months) PPWAD GN/6+S 0.3-0.5m Everyday!

28. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 27 Available at URL http://www.enri.go.jp/sat/pro/data/ppwad From 2006/7/3 (day #184) Archived daily 1 file per day Filename:ppwad_YYDDD.log.gz Archived Message Stream

29. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 28 Realtime Operation Trial Most recently the prototype has capability to run in realtime:Most recently the prototype has capability to run in realtime: –Realtime message generator has been developed; –Realtime input of observables, and realtime output of message stream both via TCP/IP socket connection; –Outputs one message per second each in advance a few seconds to simulate data transmission latency through JAXA-MCS and QZS; –Output message stream is also stored as daily files. Realtime operation trial:Realtime operation trial: –Realtime observables provided by GEONET online; Standard configuration sites (6 monitor stations, 1 Hz); –Trial period: 2007/1/13 – 1/16 (84 hours); –User positioning accuracy was evaluated with GEONET offline RINEX measurements at user locations.

30. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 29 User Position Error (Realtime) Example of user positioning error at Site 940058 (Takayama; near center of monitor station network).Example of user positioning error at Site 940058 (Takayama; near center of monitor station network). Period: 13-16 Jan. 2007 (84 hours);Period: 13-16 Jan. 2007 (84 hours); Realtime mode.Realtime mode. Standalone GPS Augmented by the Prototype HorizontalErrorVerticalError 1.415 m 2.431 m 7.059 m 10.47 m System StandaloneGPS 0.370 m 0.484 m 2.610 m 4.713 m Prototype RMS Max RMS Max

31. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 30 Realtime Performance 2007/1/13-16 (84 hours) HorVer 0.4342.7390.5825.395 0.3702.6100.4844.713 0.3732.7690.6124.584 940030Oga 940058Takayama 940083Kochi 0.7014.5910.9958.042950491Sata 1.3699.9641.24411.5992003Chichijima RMSMax RMSMax RMSMax RMSMax RMSMax Site North South Unit: [m]

32. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 31Conclusion ENRI is developing QZSS L1-SAIF signal:ENRI is developing QZSS L1-SAIF signal: –L1-SAIF augmentation signal on GPS/SBAS L1 frequency; –Signal design: compatible with SBAS; –Message design is in progress: upper compatible with SBAS. Evaluated using prototype SBAS developed by ENRI:Evaluated using prototype SBAS developed by ENRI: –Submeter accuracy likely achievable; –The result of long-term evaluation is promising; The archive of generated messages is available at: http://www.enri.go.jp/sat/pro/data/ppwad –Realtime operation trial has been conducted successfully. Future works will include:Future works will include: –Design of L1-SAIF additional messages improving atmospheric corrections; –Stability test and parameter tuning for realtime operation; –Contact: sakai@enri.go.jp

33. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 32 Backup Slides

34. ION NTM 22-24 Jan. 2007 Sakai, ENRI S LIDE 33 Input format RINEX OBS/NAV NovAtel OEM-3 TrimbleJAVAD Output format Readable Text Binary NovAtel $FRMA record format # of monitor stations ≥ 3 stations (upper limit depends on PC) Message rate 1 Hz Output device File (separated daily) TCP/IP socket connection Sampling rate Any (up to 1Hz) Input device File (offline mode) TCP/IP socket connection (realtime mode) MonitorStationObservables Requires dual frequency pseudoranges and C/N 0 MessageStreamOutput Ionospheric correction Planar fit (identical to WAAS/MSAS) Prototype I/O Features