GNSS Applications andQZSS High-Accuracy Services
UTOKYO_ICG GNSS TRAINING
2/12/2024
Nobuaki Kubo (TUMSAT)Table of Contents• Motivation• QZSS high-accuracy service-Static and Kinematic test results in Japan• MADOCA-PPP evaluations at 8 Countries• GNSS applications

Motivation• PPP has been developed by many researchers (manypapers) for a long time and it’s time to put it to practical use.
• Currently, PPP-RTK is becoming popular in the word.
• Japanese CLAS is one of the good example of PPP-RTK.
• We would like to share some test results of these correction
services compared to the conventional RTK.

Correction service (current and future)
Error
Sources

CLAS(PPP-RTK)

DFMCSBAS

MADOCAPPP〇〇〇〇△Instant〇〇〇〇-1 min.

Instant ?

15-30 min.

Code phase

Carrier phase

Code phase

GNSS

GPS/QZSS

GPS/QZSS/GALILEO?

Carrier phase
GPS/QZSS/GLONASS/GALILEO

Coverage

Japan

Japan?

Precise orbit
Precise clock
Ionosphere
Troposphere
Convergence
Measurement

SLAS
Not
separated

Asia, Oceania

All correction services through satellite !
•You don’t need to set up base station.
•You don’t need LTE/4G/5G.
•All you need is receiver and antenna.
•PPP is available within the coverage ofQZSS

Elevation cutoff = 10 degree

Kathmandu

Kathmandu

How you can see elevations for each 4 QZSS (Kathmandu)

At least 3 satellites can be received all the time.

New QZSS will be launched.
7 QZSS constellations in 2024-2025
and 11 QZSS constellations in the future.

Static and Kinematic Test Results
using PPP/CLAS/SLAS Correction
Service through QZSSStatic test results of CLAS/PPP/SLAS at TUMSAT• We started the real-time evaluation of CLAS/PPP/SLAS.
• Reference position is determined by some static PPP solutions in ITRF2014.

4cm50km baseline
National defense academy
and TUMSAT

4cm

1m4cm

CoreAsteRx4

Magellan Systems Japan
MJ-3008-GM4-QZS

u-bloxF9PTrimble
NetR9u-blox
F9P

24h CLAS (static antenna)
June 13, 2021
Topcon Ant.＋CORE AsteRx4
Fix rate：99.6%

24h PPP (static antenna)
June 13, 2021
Trimble Ant. + MSJ receiver24h SLAS (static antenna)
June 13, 2021
Trimble Ant.＋u-blox F9P receiverUseful software !
We can see where
we plowed.

1. Kinematic test at farmer (Iwaki-san)
CLAS/PPP/SLAS based on RTK
Test field (Google)

GPS-703-GGG-HV

Pre-planting soybeans

4 splitter

Base station for RTK
was set up here.

u-bloxF9P(SLAS)

u-bloxF9P(RTK)

Lighthouse (PPP)

https://agri-info-design.com/

Core
AsteRx4(CLAS)
GNSS antenna

Lidar/Camera

Ground Truck Comparisons

RTK(100%)

CLAS(100%)

Test fielddifficult to compare...

PPP

SLAS

Position Errors for CLAS/PPP/SALS
CLAS

PPP

R=12cm
R=5cm

SLAS

R=50cm3. CLAS/PPP demonstration at real construction site• Sand/Soil delivery and fill using dump truck• CLAS/PPP/RTK through same antenna• Position comparisons for about 6 hours

Ground trucks of RTK as a reference
As for ground trucks,
CLAS and PPP are same as RTK.
50mDelivery

Truck height descends slightly
due to fill

Truck height rises slightly
due to delivery

FillRelatively open sky condition but some steep slope of soils

Temporal ENU positions of CLAS

ELunch break
Repetitive operations

NU

9:00(JST)Fix rate：100%

15:00(JST)Comparisons between CLAS and RTK
Very stable positioning
5cm
Here is from RTK

NovAtel Ant.＋CORE AsteRx4
5cm

10cm

Bias in height is due to our mistake (RTK base positions)
10:30(JST)

15:00(JST)Comparisons between PPP and RTK
Several re-convergences were seen.
But stable positioning during most of time.
2m

NovAtel Ant.＋u-blox F9P + Ntrip
2m2m

11:10(JST)

15:00(JST)4. Sendai Airport Test by ENRI
We have gathered GNSS data for 3 days with ENRI.
This is one of the test of 2 hours

RTK : 97.4% FIX except for airfield apron
These positions are used as reference.

Horizontal Errors of CLAS and SLAS

R=2mR=10cm

CLAS : 92.0%(RTK & CLAS)

SLAS : 96.5%(RTK & SLAS)MADOCA PPP Performance evaluationin Asia and Oceania

MADOCA PPP Performance evaluationin Asia and Oceania• The first objective is to evaluate real
MADOCA PPP performance in several
countries in Asia and Oceania.
• The second objective is to find thepotential users of PPP in these countries.
+GalileoEvaluation• Receiver is multi-GNSS receiver
manufactured by Magellan SystemsJapan.
• Locations are 1 in Japan and 7 inforeign countries.
• Errors in each station are evaluatedbased on true position(ITRF2014)→suitable for moving
platform in global.
• GNSS receiver for MADOCA-PPP is
prepared as a chip (ASIC).

13cm×9cm

True position is given by several
software based on ITRF2014

NMEA(PPP)Outline of locations
Locations (Time)TUMSAT JAPAN（August 2019）
Chula Thailand（August 2019）
UOP Philippine（August 2019）
MJIIT Malaysia（Nov. 2019)
Curtin Australia（Nov. 2019）
UOI Indonesia（Dec. 2019）
Singapore（Feb. 2021）
Vietnam（March 2023）

Horizontal 95% values at all countries in 2022

http://www.denshi.e.kaiyodai.ac.jp/gnss_tutor/madoca.html

Short Summary• Performance evaluation of PPP/CLAS/SLAS for both static andkinematic were introduced.
• Static (95%): PPP 10cm (aft conv.), CLAS 3cm, SLAS 1m• Kinematic (95%): PPP 15cm (aft conv.), CLAS 3-4cm, SLAS 1m• CLAS can be used instead of RTK to some degree.
• PPP will be useful for monitoring stations because the basestation of RTK moves due to the crustal movement.
• PPP is updated for PPP-AR and short convergence.

GNSS Applications

Robot-car demonstration• We set up several waypoints at ground.
• Students developed the small semi-autonomous robot-car.
• Once started, the robot car will automatically pass throughmultiple waypoints and finally stop.
• It is not expensive ($500+MADOCA receiver) and goodlearning tool for students.

Automatic Waypoints Runs
STOPSTARTMonitoring base station (station) using PPP

Hitachi Zosen : GNSS Ocean Buoy
Furuno : GNSS Automatic Displacement Measurement System

RTK has been used for these applications. As for buoy, PPP will be better selection.
For monitoring the base station of RTK, PPP can be used to monitor the base station itself.

Monitoring base stations（GEONET:GNSS Earth Observation Network System)
Geospatial Information Authority of Japan

About 1,300 stations
CLAS uses part of these stations.
This is a very sophisticated system.
PPP might be used for this purpose.

Movements MAP
Geospatial information authority of Japan

Results of MADOCA-PPP after big Noto Peninsula Earthquake

Differences between GSI
and student’s analysis
using MADOCA-PPPPrecise positioning anywhere in the worldSimple survey in campus

Install a cm-level receiver and antenna onthe bicycle. Go around in a proper circle
and generate a map of altitude

Unit is m
0.4m

You can clearly see thatthe area around thebaseball mound is high.
Latitude (m)

10cm
-0.1m

Longitude (m)Precise 3D map generation by GNSS/IMU/Speed/LidarDepth Surveying by Small Boat

Depth Survey Results at Campus Pond

Questions and Comments
nkubo@kaiyodai.ac.jp

You can also see the exact slope of the road.

50㎝0㎝

2. CLAS during 100㎞ expressway

Approx. 100㎞
100km

Core AsteRx4 CLAS
79.5%FIX

Softbank RTK
94.5%FIX

Mostly within 10cm

Mostly within 3cm
Hakozaki interchange

5,Nov,2023,real time

HUST, Vietnam

GNSS Meteorology