QZSS PPP service
MADOCA / CLAS

Training on GNSS, 8 JAN 2020
12:00-12:30
Kaito Kobayashi
Tokyo University of Marine Science and Technology
TUMSAT GNSS Lab

1Contents
1.

Overview of QZSS2.

PPP service by QZSS

3.

About CLAS

4.

About MADOCA

5.

Evaluation on the ship

6.

Conclusion of the evaluation on ship

7.

Monitoring of MADOCA in Asia

8.

Promotion of MADOCA/CLAS

Download link of this presentation
https://1drv.ms/u/s!AidzfXwz4kDK5TGapdiZGWkcFYQD?e=G5zzbv

TUMSAT GNSS Lab2

1. Overview of QZSSQZSS is Japanese Regional Navigation Satellite System.
4 satellites are available in 2019 and it is planned additional 3 satellite launch until 2023.
Every people in the coverage can use QZSS service freely.

Elevation

QZSS orbit (2019)

QZSS orbit and coverage (2023)
TUMSAT GNSS Lab

31. Overview of QZSSMain objective of QZSS are
1.

More robust navigation to complement other GNSS

2.

High precise positioning service*PNT : Positioning, Navigation, Timing
TUMSAT GNSS Lab42. PPP service by QZSSQZSS provides 2 types of precise point positioning (PPP) service.

CLASMADOCA(centimeter-level augmentation service)(multi-GNSS advanced demonstration tool for orbit and clock analysis)

CLASMADOCA
Single Point Positioning

Single Point Positioning

Service Area of CLAS

Service Area of MADOCAHigh accuracy land-based service
TUMSAT GNSS Lab

Wide coverage PPP service53. About CLAS
CLAS
(centimeter-level augmentation service)
QZSSGNSS

Augmentation data

Up-link station

Ranging signal••••

L6D Signal
Clock error
Orbit error
Ionospheric delay
Tropospheric delay

Control center

Correct error of GNSS
data using L6D Signal
and calculate highaccuracy position

RTK class performance
without base station

Create augmentation data
Continuously Operating Reference Stations (CORS) in Japan

Corrected by L6D signal
GNSS ranging measurement errors
Distance between satellite and receiver

Receiver’snoise

Multipatherror

User side error
TUMSAT GNSS Lab

Troposphericdelay

Ionosphericdelay

propagation delay

Satellite’s
clock error

Satellite’sorbit error

Satellite side error
63. About CLAS
◆SSR corrections include clock, orbit, code bias, phase bias, ionosphere, troposphere correction.

◆Other corrections such as tide correction, receiver PCO/PCV, and phase windup should be correctedby users themselves.

Corrected by L6D signal
GNSS ranging measurement errors
Distance between satellite and receiver

Receiver’snoise

Multipatherror

TUMSAT GNSS Lab

Troposphericdelay

Ionosphericdelay

Satellite’s
clock error

Satellite’s
orbit error

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3. About CLAS
CLAS correction data is created using Japanese local CORS(Continuously Operating ReferenceStations) observation data.

Datacenter

60 km grid of CLAS local correction

1300 reference stations
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3. About CLAS
CLAS receiver get nearest local correction fromL6D signal broadcasted by QZSS.
Thanks to this local atmospheric delay correction,
convergence time is very short than other PPP
service.
QZSS

L6D Signal

Altitude error[m]Just 10 cm error

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93. About CLAS
◆Application of CLAS
• ITS(Intelligent Transportation System)• Agriculture
instead of RTK. Because RTK need network and base station infrastructure.

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4. About MADOCA
MADOCA

Unlike CLAS, MADOCA can’t correct
propagation delay because its
monitoring station is not dense.

(multi-GNSS advanced demonstration tool for orbit and clock analysis)
GPSGLONASS

Galileo

QZSS

Augmentation data

L6E Signal
Ranging signal

Stand-alone PPP where we
can’t use RTKUp-link station

Control center

User in the service area

Create augmentation data

Global monitoring stations(MGM-net)
GNSS ranging measurement errors
Distance between satellite and receiver

Estimated in receiver

Receiver’s
noise

Multipatherror

User side error
TUMSAT GNSS Lab

Troposphericdelay

Ionosphericdelay

propagation delay

Corrected by L6E signal
Satellite’sclock error

Satellite’s
orbit error

Satellite side error
114. About MADOCAWhen L6E signal receiving was interrupted, it needed long time to recover to convergent PPP solution.
This is because atmospheric delay estimation needs some time.

Non-convergent→Don’t use
Altitude error[m]Estimated error Threshold =20cm

6 minutes until convergence
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4. About MADOCA◆Application of MADOCA
Maritime offshore work where RTK can’t use.
High Cost PPP
ServiceDPS (Dynamic Positioning System)
on offshore work

Free MADOCA
Seafloor survey
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4. About MADOCA◆Application of MADOCA
Agriculture where no mobile network service is provided and no cost to install VHF RTK base station.

MADOCA receiver and antenna

Wide area,
networkless farm

Agriculture Machinery
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5. Evaluation on the ship
We evaluated CLAS and MADOCA on the training ship of ouruniversity.
We show two voyage result near Tokyo bay area.

7/24/2019
6 h, 53.7 km
Training ship Shioji-Maru

Test voyage 1
TUMSAT GNSS Lab

7/25/2019
5 h, 87.3 km
Test voyage 215

5. Evaluation on the ship (CLAS)◆ Fix rate of voyage 2 was good.
◆ Accuracy almost satisfied the official performance standard on land.
Longitude error[m]Latitude error[m]Altitude error[m]Error plot of Voyage 1

Error plot of Voyage 2

TUMSAT GNSS Lab◼ Fix : Reliable cm-level solution◼ Float : Corrected by CLAS but
not reliable solution◼ SPP : CLAS is not used16

5. Evaluation on the ship (CLAS)◆ Fix rate of voyage 2 was good.
◆ Accuracy almost satisfied the official performance standard on land.

Cumulative frequency graph (only Fix solution)

CLAS
Fix rate Horizontal 2DRMSE
7/24 Voyage1
62.80% 9.06cm
7/25 Voyage2
93.60% 13.26cm

Vertical 2DRMSE
25.76cm
34.78cmTUMSAT GNSS Lab

Official performance standard
Horizontal : <12cm
Vertical : <24cm* RMSE : Root Mean Squared Error
175. Evaluation on the ship (CLAS)
In voyage 2, the ship cruised with quick maneuver and Fix solution could not be calculated during thehigh COG rotation. This reason is assumed that L6D signal from QZS-3 was blocked by the mast.
When we changed L6 tracking selection mode to “Auto” (select good condition satellite automaticallyfrom QZS-1~QZS-4), the Fix rate was improved to 91.7% from 62.8%.

Relation ship between L6D signal S/N (Signal to Noise ratio) and positioning mode.
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5. Evaluation on the ship (MADOCA)◆MADOCA solution includes large error that caused by interruption of L6E correction data receiving.
◆ Availability was high, but accuracy was worse than CLAS.
Longitude error[m]Latitude error[m]Altitude error[m]Error plot of Voyage 1

Error plot of Voyage 2

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5. Evaluation on the ship (MADOCA)◆ MADOCA solution includes large error that caused by interruption of L6E correction data receiving.
◆ Availability was high, but accuracy was worse than CLAS.

Cumulative frequency graph (only PPP solution)

MADOCA
PPP rate Horizontal 2DRMSE
7/24 Voyage1
98.80% 58.07cm
7/25 Voyage2
99.80% 62.92cm

Vertical 2DRMSE
127.44cm
116.46cm

TUMSAT GNSS Lab* RMSE : Root Mean Squared Error

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6. Conclusion of the evaluation on ship
CLAS
◆Accuracy satisfied expectation and it was better than MADOCA.
◆There is no accuracy and availability degradation in the coastal area 5~10km away.

◆Mast or other object on the ship blocked L6 signal and it caused low fix rate.
We should consider antenna install position or more robust L6 tracking selection algorithm.

MADOCA◆By monitoring estimated error, we can use 40cm level position solution constantly in the wide
QZSS coverage area.
◆Influence by ship object is lower than CLAS.
◆Future tasks are➢ conduct more evaluations in different regions and environments.
➢ Performance improvement to achieve faster solution convergence and eliminate vertical bias.
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7. Monitoring of MADOCA in Asia
Now, we are monitoring MADOCA-PPP accuracy
and reliability in some university in Asia andOceania.

TokyoHo Chi Minh
ManilaBangkok
Kuala Lumpur
Singapore
Jakarta

Already monitoring
Planned to install in 2020

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Perth22

7. Monitoring of MADOCA in Asia

Operation ofQZSS(+launch)
Developmentof correction
service

Customersatisfaction(people use)
Competitivein the world
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7. Monitoring of MADOCA in Asia
Real time MADOCA-PPP solution in each station.
ManilaTokyo

Bangkok

Kuala Lumpur

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7. Monitoring of MADOCA in Asia
Real time MADOCA-PPP solution in each station.
Jakarta

PerthTUMSAT GNSS Lab

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7. Monitoring of MADOCA in Asia
Bangkok
0.4

0.2

0051015202530202530

Kuala Lumpur
0.20.10051015

Perth0.2

0.1005101520

TUMSAT GNSS Lab

2530- Average of thehorizontal error- Standard deviation of thehorizontal error

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8. Promotion of MADOCA/CLAS
Consumer receiver release was started nowadays.
Mitsubishi (CLAS)

Magellan Systems Japan (CLAS,PPP)

Core (CLAS,PPP?)

JRC (CLAS)TUMSAT GNSS Lab

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8. Promotion of MADOCA/CLAS
We hope more QZSS use in Asia region.
Please let us know if you are interested in MADOCA-PPP. We will help you solve your problem by
QZSS-PPP service.

QZSS official home page : https://qzss.go.jp/en/Prof.Kubo : nkubo@kaiyodai.ac.jp
Kaito Kobayashi : d650efrmm@outlook.com
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