0. QZSS Observation Data Available to the Public
3rd Asia-Oceania Regional Workshop on GNSS
Nov. 1, Island, South Korea
QZSS Observation Data
Available to the Public
Takeyasu SAKAI
Electronic Navigation Research Institute, Japan

1. Introduction QZSS (Quasi-Zenith Satellite System) program:
Nov Slide 1
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;
Broadcast GPS-like supplement signals on three frequencies and two augmentation signals, L1-SAIF and LEX; ENRI is working for L1-SAIF;
The first QZS satellite successfully launched on Sept. 11, 2010;
Technical verification is ongoing by some research organizations.
Broadcasting ranging signals constantly:
Ranging signals are broadcast constantly and stable; Now no alert flag;
QZS-1 is in the operational phase while technical verification is ongoing;
Now need to promote rapid spread of QZSS capability to consumer equipment.
ENRI just began continuous observation of QZSS:
Measures all signals on triple frequencies except LEX;
We have decided to make observations open to the public for promotion of R&D on QZSS applications;
Daily RINEX files are publicly available for free of charge on the web.

2. QZSS Signals Signal Center Freq. Bandwidth Min. Rcv Power QZS-L1C L1CD
Nov Slide 2
QZSS Signals
Signal
Center Freq.
Bandwidth
Min. Rcv Power
QZS-L1C
L1CD
MHz
24 MHz
–163.0 dBW
L1CP
– dBW
QZS-L1-C/A
– dBW
QZS-L1-SAIF
– dBW
QZS-L2C
MHz
– dBW
QZS-L5
L5I
MHz
25 MHz
– dBW
L5Q
QZS-LEX
MHz
42 MHz
– dBW
Supplement
Signals
(JAXA)
Augmentation
(ENRI)
Supplement Signals: L1C/A, L2C, and L5 are GPS-like (PRN193);
Augmentation Signals: L1-SAIF is SBAS-like (PRN183); LEX is original signal;
For detail, see IS-QZSS. URL:
Augmentation
(JAXA/GSI)

3. Continuous Observation
Nov Slide 3
Continuous Observation
Observation conditions:
ENRI just began continuous observation of L1-SAIF signal for technical verification in October 2011; Also observes other supplement signals;
Observation is available on the web: URL
Range measurements are converted into RINEX format and navigation message is formatted in EMS file; Both are slightly extended for QZSS;
Data files are stored on daily basis.
Receiver
JAVAD ALPHA-G3T
Antenna
Location
ENRI, Tokyo - Top of the tower of No. 6 Building
N E m from ellipsoid
X= Y= Z=
Trimble Zephyr Geodetic 2 (L1/L2/L5)
Target SV
GPS, GLONASS, SBAS, QZSS (incl. L1-SAIF)
Measurements
Code Range, Carrier Range, Doppler, C/N0 (L1, L2, L5)
Note - Sometimes there is missing data due to some reason such as power outage.

4. Equipment Setup JAVAD Rx Linux Trimble Zephyr Geodetic 2 Server
Nov Slide 4
Equipment Setup
JAVAD Rx
Ethernet
Converter
LAN
ANT
Serial
Linux
Server
Trimble Zephyr Geodetic 2
Realtime Data Collection

5. Observation: RINEX Format
Nov Slide 5
Observation: RINEX Format
Extension of existing RINEX format:
The current RINEX format does not support QZSS; SV identifier is not defined for QZSS signals;
Observation is provided in RINEX 2.11 format with an extension;
For supplement signals we use “Jnn” regarding other core systems;
For L1-SAIF augmentation signal, we use “Snn” like SBAS.
Status
System ID
Value of nn
Fixed
GPS
Gnn
PRN
GLONASS
Rnn
Slot Number
SBAS
Snn
PRN-100
Galileo
Enn
COMPASS
Cnn
Our
Extension
QZSS
Jnn
PRN-192
L1-SAIF
For QZS-1
Supplement: J01
L1-SAIF： S83

6. Example of RINEX Observation
Nov Slide 6
Example of RINEX Observation
OBSERVATION DATA G (GPS) RINEX VERSION / TYPE
dat2rnx :16:43UTCPGM / RUN BY / DATE
dat2rnx 1.00 (Oct ) COMMENT
MTKB MARKER NAME
ENRI, JAPAN ELECTRONIC NAVIGATION RES INST, JAPAN OBSERVER / AGENCY
TR_G3TH_ a3_qzss8 Jun,10REC # / TYPE / VERS
TRM ANT # / TYPE
APPROX POSITION XYZ
ANTENNA: DELTA H/E/N
WAVELENGTH FACT L1/2
14 L1 C1 P1 D1 S1 L2 C2 P2 D2# / TYPES OF OBSERV
S2 L5 C5 D5 S # / TYPES OF OBSERV
GPS TIME OF FIRST OBS
GPS TIME OF LAST OBS
END OF HEADER
R23R21G07S37G19G13S29G03R12R22G16G30
G31R10R20G06R11G21G23J01S83 :
Large # of
measurements
21 SVs
Epoch Time
QZSS
GLO
Slot 23
Carrier
C/A code
P/Y code
Doppler
C/N0
GPS
PRN 07
SBAS
PRN 137
L2C code
L5 code
QZS-1
L1 C/A
QZS-1
L1-SAIF

7. Navigation Message: EMS File
Nov Slide 7
Navigation Message: EMS File
Extension of EMS File Format:
Navigation messages broadcast on L1C/A-equivalent ranging signals are decoded and archived in the extended EMS Format;
EMS format is used in EGNOS Data Archive Service (EDAS); Originally contains only EGNOS broadcast messages;
Our extension: Including GPS/GLONASS/QZSS navigation messages additionally.
Format
PRN YY MM DD HH MM SS TT data…
Parameter
PRN
PRN number by which the message is broadcast
YY MM DD
Date
HH MM SS
Time (Transmission of the first bit of the message) TT
GPS/QZSS: Subframe ID (1 to 5)　 bits = Every 6s
GLONASS: String ID (1 to 15)　　　 bits = Every 2s
SBAS/SAIF: Message Type (0 to 63) 250 bits = Every 1s
data…
Message contents (Hexadecimal; The first bit of the message is stored as MSB of the first char)

8. Example of EMS File SBAS/L1-SAIF GLONASS GPS QZSS L1C/A
Nov Slide 8
Example of EMS File
A DFA7FBFF B00 (64 chars)
AFC (64 chars)
ACA06292A06079C2421E D00 (64 chars)
BC1BA68F4C024B5D6992CE0
BC1BA68F4C024B5D6992CF0 :
BC1BA68F4C024B5D6992C00
C608DFFC009FFDFFC003FFDFFD (64 chars)
C609DFFC011FFDFFC013FD5FFD...D000 (64 chars)
C6CE03B79FB824827D84B7D AC0 (64 chars)
CDFFC005FFDFFC00DFFFFF7...7D00 (64 chars)
EDFFC011FFDFFC011FFC (64 chars)
CE8477D878477BFF85D007F (64 chars)
B8AC6957F0A00C0F7D592CE0
B8AC6957F0A00C0F7D592CF0
B8AC6957F0A00C0F7D592C00
B09E8E8E1029C09E90002DEA1...8D00　(76 chars)
B09E8E8E1029C09E90002DEA1...F800 (76 chars)
B09E8E8E1029C09E90002DEA1...3CC0　(76 chars)
B09E8E8E1029C09E90002DEA1...4A00　(76 chars)
A11DFFDFFFFF7FF1FFFFEBFDD...9C00　(64 chars)
A12DFFDFFC007FFDFFFFE3FD1...3B00 (64 chars)
B000048E10217C9EA (76 chars)
A081FFDFFC001FFDFFFFF9FFD...B500 (64 chars)
C67308C963CF A FE00 (64 chars)
C67308CB63EF D BD00 (64 chars)
C60C1FFDFFC001FFDFFC005FFC (64 chars)
SBAS/L1-SAIF
GLONASS
GPS
QZSS L1C/A
Order of completion of message decoding
Epoch Time
PRN
Msg ID
Data

9. Discussion Is RINEX appropriate for data publication?
Nov Slide 9
Discussion
Is RINEX appropriate for data publication?
So far, RINEX seems most commonly used data exchange format;
Option: BINEX and RTCM 3.0 could be used (also for realtime?).
Some applications are not capable of large # of measurements:
Need degraded version of observation, for example, 2-frequency version?
Is RINEX navigation message file necessary? (Is EMS file enough?)
RINEX navigation file (*.YYn) is easily applicable to QZSS L1-C/A;
L1-SAIF message: Ephemeris message may be stored in RINEX file (*.YYh); But other messages have little option other than EMS (or similar) format;
An idea: Store L1-SAIF messages in RINEX observation file using comment record.
Does anyone need realtime distribution?
ENRI is ready for realtime distribution;
Data collection is performed in a realtime manner;
Communication line available for realtime distribution may be less capacity.
ENRI is also collecting data at some locations inside Japan.

10. Conclusion QZSS needs promotion: ENRI’s contribution: Proposal:
Nov Slide 10
Conclusion
QZSS needs promotion:
QZS-1 is in the operational phase while technical verification is ongoing;
Need promotion for rapid spread of QZSS capability to consumer equipment.
ENRI’s contribution:
Began continuous observation of QZSS and data publication;
Measures all signals on triple frequencies except LEX;
Daily RINEX files are publicly available for free of charge on the web.
URL
Proposal:
SV identifier for RINEX observation:
For supplement signals, use “Jnn” (J01 for QZS-1) regarding other core systems;
For L1-SAIF augmentation signal, use “Snn” (S83 for QZS-1) like SBAS.
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