Introduction to MADOCA

Hideshi Kakimoto
Global Positioning Augmentation Service Corporation

1. What is MADOCA ?
MADOCA : A processing tool developed by JAXA to estimate precise satellite orbit and clock
Centimeter Level
Augmentation Servicefor Experiment

Satellite Image: http://qzss.go.jp

Cabinet Office,
Government of Japan

QZS-2/3/4
L6E

Quasi-Zenith Satellite
System Services Inc.

Augmentation Message
for Precise Positioning
MADOCA
Processing Tool

Commercial
Distribution Serviceby the Internet

Precise Positioning Users
Reference of GNSS Receiver: http://www.magellan.jp

 GPAS is providing a service to distribute augmentation messages processed by MADOCA The augmentation messages are distributed by QZSS and the Internet© 2020 Global Positioning Augmentation Service Corporation

22. Why we need MADOCA?
Benefits of MADOCA No location restrictions to be used
i.e. RTK requires a continuous GNSS station (CORS) within 30 km
Note: CORS within 30 km is required to save the initial convergence time of MADOCA (see p.6).

 No communication devices except GNSS receiver are required by receiving QZSS service
Note: To use GPAS's internet service or Local Augmentation (see p.6) , a device to access tothe internet is required
Centimeter LevelAugmentation Servicefor Experiment
Commercial
Distribution Service
by the Internet

QZS-2/3/4
L6E
Satellite Image: http://qzss.go.jp

QZSS Service Area :Visible range of QZSS (see p. 8)

Internet Service Area :World Wide

Precise positioning is possible
only with a GNSS receiver© 2020 Global Positioning Augmentation Service Corporation

33. Principles of GNSS Augmentation by MADOCA
Augmentation Principles
The accuracy of satellite positioning can be improved up to 10 centimeters by applying MADOCA
augmentation composed of satellite-side corrections (State Space Representation) .
(2) Satellite Clock(1) Satellite Orbit

General satellite positioning(3) Signal Biases(4) Ionosphere(5) Troposphere
Factors causing signal delay(6) Multipath / NoiseError Sources

Corrected by(1) Satellite OrbitMADOCA(2) Satellite ClockMADOCA(3) Signal Biases

MADOCA(4) Ionosphere

Positioning Process(5) Troposphere

Positioning Process(6) Multipath / Noise

N/AFig. 1 Error Sources on Satellite Positioning

Positioning Error:
1 meter or more
Augmented positioning by MADOCA

Positioning Error:
10 centimeters
Fig. 2 Image of GNSS Augmentation
by MADOCA

Notice: Positioning accuracy is affected not only by MADOCA performance, but also by receiver
performance or by the performance of user's positioning algorithm.
© 2020 Global Positioning Augmentation Service Corporation44. PPP/PPP-AR Positioning[ PPP: Precise Point Positioning ]Positioning with 10cm accuracy is available using MADOCA augmentation message and GNSS
receiver that supports dual frequencies (L1/L2) . This method is so called "PPP".
PPP Processing
Software (*1)

Augmentation Message

Observation Data(*1) GNSS Receivers with built-in PPP processing software are commercially available.
Fig. 3 Configuration of PPP

GNSS Receiver / Antenna(supports L1/L2)(Reference) https://www.magellan.jp/english[ PPP-AR: PPP with Ambiguity Resolution ]Positioning accuracy can be further improved by ambiguity resolution using phase bias (FCB)
correction in augmentation message.
1.0
0.5
0-0.5
-1.0
0.5
0-0.5
-1.0
0.5
0-0.5 Initial-1.0 Convergence
05:00
05:30

Float

Ambiguity Fixed

Initial Convergence Timeapprox. 30 minutes

Since ionosphere and troposphere errors are
estimated by the Kalman filter after the start ofpositioning, the positioning requires "initialconvergence time" to reach 10 cm accuracy.

RMS 3.3 cm

Positioning Accuracy

RMS 4.1 cm

Less than 10 cm

After the initial convergence, the positioning
accuracy is less than 10 cm.
Time to First Fix (TTFF)RMS 6.0 cm
06:00

06:30

Fig. 4 Example of PPP-AR result© 2020 Global Positioning Augmentation Service Corporationapprox. 10 minutes

In this case, it takes approx. 10 minutes from the
07:00 start of positioning to the ambiguity resolution.

55. Local Augmentation
Initial convergence time and TTFF can be saved by estimating ionosphere/ troposphere errors using
continuous GNSS observation station (Local Station).

IonosphereTroposphere<Factors causing signal delay>
Local Station
Continuous Estimation on
Ionosphere / Troposphere
Within 30 km (*1)
TTFF: 1-5 minutes

Augmentation Message(by MADOCA)(*1) State of iono./tropo will be different
between long distance points (over 30 km).

Fig. 5 Image of Localized Augmentation

1.0Float
Ambiguity Fixed
0.5
Without Localized Augmentation
Initial Convergence Time approx. 1 minute0
Initial convergence time is shortened to 1 minute-0.5
by applying "Local Augmentation".
-1.00.50
Positioning AccuracyLess than 10 cm-0.5
Positioning accuracy is the same as no localized-1.0
augmentation.
0.5
0Time to First Fix (TTFF)
approx. 1 minute-0.5
TTFF is also shortened to 1 minute.
-1.0
05:00
05:30
06:00
Fig. 6 Example of PPP-AR result with Localized Augmentation© 2020 Global Positioning Augmentation Service Corporation

66. Demonstration
Case 1 : PPP-AR

Station 93026

Augmentation Message(by MADOCA)

Station 93032

PPP-AR Processing

14.2 km
PPP-AR Result

Station 93032
Acknowledgement : Station 93026/95032 are operated byGSI as a part of GEONET.

Case 2 : PPP-AR with Local Augmentation

Station 93026
Receiver

TOPCON NETG5

Antenna

TRM59800.80 GSIContinuous Estimation
on Iono./Trop.
<Locali Augmentation>

Position

Lat 35.563402508 N
Lon 139.67335861 E
Hgt 47.537 m

Augmentation Message(by MADOCA)

Station 93026

Station 93032
ReceiverTrimble NetR9

Antenna

TPSCR.G5 GSI

Position

Lat 35.436484221 N
Lon 139.65375210 E
Hgt 70.615 m

Station 93032

PPP-AR Processing

PPP-AR Result
Fig. 7 Configuration of the Demonstration© 2020 Global Positioning Augmentation Service Corporation77. GNSS Augmentation Service for Experiment with QZSSGNSS augmentation messages generated by MADOCA are being distributed from QZSS*1
as an experiment service on L6E channel.
*1 ) Distributed from QZS-2, 3, 4 (excluding QZS-1)
QZSS visibility<Sample Configuration for Utilization>
QZS-2/3/4
L6E

Augmentation
Message

GNSS Receiver / Antennacompatible with MADOCA

Reference of GNSS Receiver: http://www.magellan.jp
Satellite Image: http://qzss.go.jp© 2020 Global Positioning Augmentation Service Corporation

88. GNSS Augmentation Service by GPAS
Global Positioning Augmentation Service (GPAS) is commercially distributing GNSS augmentation
messages through the Internet.
Service Menu

Please visit GPAS's website to apply for user registration :http://www.gpas.co.jp<Sample Configuration for Utilization>
AugmentationMessage
via Internet

Observation Data
in RTCM

Positioning Software "GSOK"&PC

GNSS Receiver / Antenna

Augmentation
Message
via Internet
GNSS Receiver / Antennacompatible with MADOCA
Reference: http://www.magellan.jp© 2020 Global Positioning Augmentation Service Corporation

99. Specifications of Augmentation Message
The augmentation messages conform to RTCM SSR standard format stage-1 and stage-2
proposed in 2013-2014. Supported satellites are GPS, GLONASS, and QZS-1*1.
*1 ) QZS-2,3,4 and Galileo will be supported by October 2022.

ProductEstimation
Interval (sec)

Message
Interval (sec)

RTCM Message Type #GPS

GLONASSQZSS<QZSS Service: Centimeter Level Augmentation Service for Experiment>
Orbit Correction

3030

1057

1063

1246

High-Rate Clock Correction

121062

1068

1251

User Range Accuracy (URA)

130

1061

1067

1250

10800

30

1059

1065

1248

Code Bias<Internet Service: Commercial Service by GPAS>

Orbit Correction

30

11057

1063

1246

Clock Correction

1110581064

1247

High-Rate Clock Correction

111062

1068

1251

User Range Accuracy (URA)

11106110671250

Code Bias

10800

1105910651248

Phase Bias (FCB)

900111--13

For details, please see our website:
https://www.gpas.co.jp/service_madoca.php© 2020 Global Positioning Augmentation Service Corporation

1010. Technical Features on PPP/PPP-AR compared to RTK
MADOCA-PPP/PPP-AR

RTK

Horizontal Positioning
Accuracy

10 centimeters

Centimeter-level

Convergence Time<Without Local Augmentation>
About 10-30 minutes<With Localized Augmentation>
Few minutes

Less than 1 minute

Service Coverage*1<Without Local Augmentation>
Worldwide<With Local Augmentation>
LimitedLimited

Coordinate System*2

Absolute(ITRF)

Relative(Depends on Reference Station)*1) Local augmentation and RTK require reference GNSSstation(s) within 30 km, which limits coverage.
MADOCA (w/o L.A.) is available worldwide regardlessof location of reference station.
Reference Station(CORS)

RTK andMADOCA (w/ L.A.)

MADOCA (w/o L.A.)© 2020 Global Positioning Augmentation Service Corporation*2) PPP/PPP-AR calculates absolute coordinates ofuser, and RTK calculates relative coordinates from areference station. This difference will be advantage
or disadvantage depending on application.
For example, relative coordinates are useful forlocal surveys. On the other hand, absolutecoordinates can clarify the crustal movement or
amplitude caused by an earthquake.

~30km

1111. MADOCA Utilization Activities with QZSS Experimental Signal ServicePurpose
Widely use of high-precision positioning service from QZSS (MADOCA) inAsia-Oceania region

Scheme of the Activity
Act. 1 : Establishing monitoring stations and continuous evaluation
 Establish monitoring stations in Asia-Oceania region, and continuouslyevaluate the positioning accuracy as a reference MADOCA performance.
Act. 2 : Promotion and Enhancement Enhancement of low-cost MADOCA receiver system
 Promote GNSS and QZSS/MADOCA technology through webinars, trainings,lectures, and pilot projects

Framework
Cabinet Office,Government of Japan
Mitsubishi ElectricCorporation

Secretariat
Continuous Monitoring

QZSS Services Inc.
(QSS)The University ofTokyo

Tokyo University of Marine
Science and Technology

GPAS

Organizing seminars, Establishing stations
MADOCA
Receiver development
Continuous evaluation message provider

MGA

Cooperative labs in Asia-Oceania region© 2020 Global Positioning Augmentation Service Corporation

1212. Status of Continuous Monitoring
Monitoring Stations

BangkokTokyoPerthMonitoring Station (7)Country/Region City

Planning (1)InstitutionJapanTokyo

Tokyo University of Marine Science andTechnology

Philippines

ManilaUniversity of the Philippines

Thailand

Bangkok

Chulalongkorn University

Malaysia

Kuala Lumpur

Malaysia-Japanese International Instituteof Technology

Indonesia

Jakarta

University of Indonesia

Australia

PerthCurtin University

Singapore

Singapore

Nanyang Technological University

VietnamHo Chi Minh

Ho Chi Minh City International University

Monitoring Availability in FY2021/H1

Available

City
Availability
Tokyo
80.3%
Manila83.1%
Bangkok
71.0%
Kuala Lumpur
77.0%
Jakarta
59.0%
Perth85.2%
Singapore
15.3%

JuneApril© 2020 Global Positioning Augmentation Service Corporation

May

Unavailable

JulyOutage of MADOCA

AugustSeptember

1313. Positioning Accuracies on Each Monitoring Station
Horizontal RMS (m)
April

May

JuneRMS(m)0.4TokyoK.L.
July

ManilaBangkok
Singapore
Jakarta
PerthAugust
September

15 days outage of MADOCA

0.3
0.2
0.1

0.0

Vertical RMS (m)
April

May

June

July

AugustSeptember

RMS(m)

0.4
0.3
0.2
0.1
0.0

Accuracy deterioration due to few minutes outage of MADOCA© 2020 Global Positioning Augmentation Service Corporation

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Hideshi Kakimoto
Global Positioning Augmentation Service Corporation
Emailkakimoto@gpas.co.jp
Phone +81-3-6278-7881
Website http://www.gpas.co.jp/en© 2020 Global Positioning Augmentation Service Corporation

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