Transcript Augmentation Performance of QZSS L1

ION NTM 2007
San Diego, CA
Jan. 22-24, 2007
Augmentation Performance of
QZSS L1-SAIF Signal
T. Sakai, S. Fukushima, N. Takeichi, and K. Ito
Electronic Navigation Research Institute, Japan
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Introduction
SLIDE 1
• 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:
– Signal design: identical with SBAS;
– Message design is in progress: upper compatible with SBAS.
• Performance analysis using prototype SBAS:
– Submeter accuracy likely achievable;
– Most recently, realtime operation trial has been conducted successfully.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 2
Part 1
Overview of QZSS Program
and L1-SAIF Signal
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 3
QZSS Concept
GPS/GEO
• Footprint of QZS orbit
• Centered 137E
• Eccentricity 0.1, Inclination 45deg
QZS
• Signal from high elevation angle
• Applicable to navigation services for
mountain area and urban canyon
ION NTM 22-24 Jan. 2007 Sakai, ENRI
QZSS Signals
SLIDE 4
• 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 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.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 5
Frequency Plan
Signal
Channel
Frequency
Bandwidth
Min. Rx Power
L1CD
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
24 MHz
– 161.0 dBW
25 MHz
– 157.9 dBW
25 MHz
– 157.9 dBW
42 MHz
– 156.0 dBW
QZS-L1C
1575.42 MHz
QZS-L2C
1227.6 MHz
L5I
QZS-L5
1176.45 MHz
L5Q
QZS-LEX
1278.75 MHz
Find detail in IS-QZSS document.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
L1-SAIF Signal
SLIDE 6
• 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:
– 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:
– 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.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 7
L1 PRN Assignment
PRN
Signal
Satellite
183
QZS-L1-SAIF
QZS #1
184
QZS-L1-SAIF
QZS #2
185
QZS-L1-SAIF
QZS #3
186
QZS-L1-SAIF
QZS #4
187
QZS-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.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 8
SBAS Message Structure
Preamble
8 bits
Message Type
6 bits
Data Field
212 bits
CRC parity
24 bits
250 bits
MT
Contents
Interval
[s]
MT
Contents
Interval
[s]
0
Test mode
6
17
GEO almanac
300
1
PRN mask
120
18
IGP mask
300
Fast correction & UDRE
60
24
FC & LTC
6
6
UDRE
6
25
Long-term correction
7
Degradation factor for FC
120
26
Ionospheric delay & GIVE 300
9
GEO ephemeris
120
27
SBAS service message
300
10
Degradation parameter
120
28
Clock-ephemeris covariance
120
12
SBAS time information
300
63
Null message
2～5
120
—
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 9
L1-SAIF Message (1)
Message Type
Contents
Compatibility
Status
0
Test mode
SBAS
Fixed
1
PRN mask
SBAS
Fixed
Fast correction & UDRE
SBAS
Fixed
6
UDRE
SBAS
Fixed
7
Degradation factor for FC
SBAS
Fixed
8
Reserved
Unused
Fixed
9
GEO ephemeris
Unused
Fixed
10
Degradation parameter
SBAS
Fixed
12
SBAS network time
Unused
Fixed
17
GEO almanac
Unused
Fixed
18
IGP mask
SBAS
Fixed
24
Mixed fast/long-term correction
SBAS
Fixed
25
Long-term correction
SBAS
Fixed
26
Ionospheric delay & GIVE
SBAS
Fixed
2 to 5
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 10
L1-SAIF Message (2)
Message Type
Contents
27
SBAS service message
28
Clock-ephemeris covariance
Compatibility
Status
Unused
Fixed
SBAS
Fixed
—
—
29 to 51
(Undefined)
52 to 55
(Atmospheric correction)
New
TBD
56
Intersignal biases
New
Tentative
57
(Ephemeris-related parameter)
New
TBD
58
QZS ephemeris
New
Tentative
59
(QZS almanac)
New
TBD
60
(Regional information)
New
TBD
61
Reserved
New
Tentative
62
Reserved
SBAS
Fixed
63
Null message
SBAS
Fixed
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 11
Messaging Capacity
Message
Type
Messages Required
for Constellation
Interval
Messages
per min
Fast Correction
2 to 5
3
10 s
18
Long-Term Correction
25
4
60 s
4
Ionosphere
26
2
60 s
2
Troposphere
54 and 55
3
60 s
3
QZS Ephemeris
58
1
30 s
2
FC Degradation
7
1
60 s
1
Degradation Parameter
10
1
60 s
1
PRN Mask
1
1
60 s
1
IGP Mask
18
2
60 s
2
C-E Covariance
28
10
60 s
10
Total
44
Margin for Other Messages
16
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 12
Part 2
Performance Analysis
Using Prototype SBAS
• Prototype SBAS Software
• Continuous Daily Operation
• Realtime Operation Trial
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Performance Analysis
SLIDE 13
• 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.
GPS
observables
Prototype SBAS
(MCS simulator)
User Receiver
Simulator
Augmentation Message
Position Error
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Prototype SBAS
SLIDE 14
• 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:
– RINEX or raw receiver measurement at any sampling rate;
– Requires dual frequency code phase pseudoranges; No carrier phase.
• 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.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Message Sample
SLIDE 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
Time
$FRMA,272,86410.130,183,80811EA4,250,9A61FFDFFDFFDFFDFFDFFFBBBBB8A0000000
Message Type ID
0000000000000000000039994D00*05
CRC
Satellite PRN
(6 MSBs)
$FRMA,272,86411.130,183,80811EA4,250,C60A1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD
FFDFFDFFFBBBBBBBBBBBBA6BE8CC0*03
Preamble
Message
$FRMA,272,86412.130,183,80811EA4,250,530E1FFDFFDFFDFFDFFDFFDFFDFFDFFDFFD
Length
FFDFFDFFFBBBBBBBBBBBBA99E5040*0A
ION NTM 22-24 Jan. 2007 Sakai, ENRI
User Receiver Simulator
SLIDE 16
• 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:
– With GEONET observations at some locations as user stations;
– Evaluates position accuracies and protection levels of QZSS L1-SAIF.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Standard Configuration
SLIDE 17
GEONET for Monitor Stations
GEONET for User Stations
MSAS Service Area
• At first the prototype generated
messages in offline mode with
GEONET sites as monitor stations;
• Dual frequency observables
sampled every 30 seconds;
• 6 monitor stations distributed
similar to the MSAS;
• 5 user locations for evaluation.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Residual of Corrected Orbit
Line-of-sight component including clock contribution
SLIDE 18
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Residual of Iono Correction
Ionospheric delay minus IGS/IONEX estimation at each IGP
SLIDE 19
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 20
User Position Error
Standalone GPS
Augmented by the Prototype
• Example of user positioning error at
Site 940058 (Takayama; near center
of monitor station network).
• Period: 22-24 July 2004;
active ionosphere condition.
Horizontal
Error
Vertical
Error
Standalone RMS
GPS
Max
1.929 m
3.305 m
6.993 m
14.48 m
RMS
0.381 m
0.531 m
Max
2.867 m
5.451 m
System
Prototype
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 21
Performance Summary
2005/11/14-16
Site
2004/7/22-24
2004/6/22-24
2005/11/14-16
MSAS
Hor
Ver
Hor
Ver
Hor
Ver
Hor
Ver
940030
RMS
Max
0.354
1.695
0.418
2.517
0.432
2.318
0.566
4.455
0.397
2.047
0.602
4.717
0.381
1.659
0.631
2.405
940058
RMS
Max
0.304
1.487
0.413
2.123
0.381
2.867
0.531
5.451
0.425
2.634
0.603
3.466
0.502
4.873
0.728
3.700
940083
RMS
Max
0.353
1.902
0.508
4.452
0.403
2.468
0.592
4.240
0.385
1.757
0.649
3.782
0.637
8.517
0.881
9.396
950491
RMS
Max
0.453
3.302
0.647
6.158
0.586
2.143
0.764
5.509
0.491
2.415
0.776
4.574
0.640
3.012
0.730
2.680
92003
RMS
Max
1.132
6.266
1.102
5.958
0800
4.487
1.317
9.225
0.708
4.507
1.088
6.595
0.982
6.267
1.014
6.614
North
South
Unit: [m]
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Continuous Daily Operation
SLIDE 22
• 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:
– 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:
– URL http://www.enri.go.jp/sat/pro/data/ppwad
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Integrity Evaluation Sites
SLIDE 23
Monitor Stations
Evaluation Stations
• Standard configuration of
monitor stations: 6 stations
similar to the MSAS;
• Integrity evaluation stations: 40
stations covering the whole
Japan;
• So far, no integrity break
conditions have been detected.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Protection Levels vs. Error (1)
Horizontal
Vertical
GEONET 0030 (Oga)
06/4/20 – 06/5/19 (30 days)
PPWAD GN/6+S
SLIDE 24
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Protection Levels vs. Error (2)
Horizontal
Vertical
GEONET 0083 (Kochi)
06/4/20 – 06/5/19 (30 days)
PPWAD GN/6+S
SLIDE 25
ION NTM 22-24 Jan. 2007 Sakai, ENRI
User Positioning Accuracy
SLIDE 26
GEONET 3011
(Kawagoe; near Tokyo)
06/6/1 – 06/9/30
(4 months)
PPWAD GN/6+S
0.3-0.5m Everyday!
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Archived Message Stream
From 2006/7/3 (day #184)
Archived daily
1 file per day
Filename:
ppwad_YYDDD.log.gz
Available at URL http://www.enri.go.jp/sat/pro/data/ppwad
SLIDE 27
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Realtime Operation Trial
SLIDE 28
• 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 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.
ION NTM 22-24 Jan. 2007 Sakai, ENRI
User Position Error (Realtime)
SLIDE 29
Standalone GPS
Augmented by the Prototype
• Example of user positioning error at
Site 940058 (Takayama; near center
of monitor station network).
• Period: 13-16 Jan. 2007 (84 hours);
• Realtime mode.
Horizontal
Error
Vertical
Error
Standalone RMS
GPS
Max
1.415 m
2.431 m
7.059 m
10.47 m
RMS
0.370 m
0.484 m
Max
2.610 m
4.713 m
System
Prototype
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Realtime Performance
2007/1/13-16
(84 hours)
Site
North
South
Hor
Ver
940030
Oga
RMS
Max
0.434
2.739
0.582
5.395
940058
Takayama
RMS
Max
0.370
2.610
0.484
4.713
940083
Kochi
RMS
Max
0.373
2.769
0.612
4.584
950491
Sata
RMS
Max
0.701
4.591
0.995
8.042
92003
Chichijima
RMS
Max
1.369
9.964
1.244
11.59
Unit: [m]
SLIDE 30
ION NTM 22-24 Jan. 2007 Sakai, ENRI
Conclusion
SLIDE 31
• 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:
– 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:
– Design of L1-SAIF additional messages improving atmospheric corrections;
– Stability test and parameter tuning for realtime operation;
– Contact: [email protected]
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 32
Backup Slides
ION NTM 22-24 Jan. 2007 Sakai, ENRI
SLIDE 33
Prototype I/O Features
Input format
Monitor
Station
Observables
Sampling rate
Input device
Message
Stream
Output
RINEX OBS/NAV
NovAtel OEM-3
Trimble
JAVAD
Requires dual frequency
pseudoranges and C/N0
Any (up to 1Hz)
File (offline mode)
TCP/IP socket connection (realtime mode)
Output format
Readable Text
Binary
NovAtel $FRMA record format
Message rate
1 Hz
Output device
File (separated daily)
TCP/IP socket connection
# of monitor stations
Ionospheric correction
≥ 3 stations (upper limit depends on PC)
Planar fit (identical to WAAS/MSAS)