MGA Webinar Series : 1
Very Cheap RTK Receivers:
Changing the Landscape of Positioning Services
Dinesh ManandharCenter for Spatial Information Science
The University of Tokyo
Contact Information: dinesh@iis.u-tokyo.ac.jp
25th May 2018
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp1Webinar Information• Webinar ID : MGA Webinar # 1• Webinar Topic :• Very Cheap RTK Receivers: Changing the Landscape of Positioning Services• Date :• 11th MAY 2018 Friday, Time : 18:00 (JST) 09:00 (UTC)• Duration : 45min + 15min (Q/A)• Resource Person :• Dinesh Manandhar, Associate Professor, The University of Tokyo• Registration : https://gnss.peatix.com• Further Information:• http://www.csis.u-tokyo.ac.jp/~dinesh/WEBINAR.htm
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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Quiz
• What is the Price of a GNSS Receiver?

• $10? $100? $500 $1,000 $3,000 $10,000 or more?

• What is the Accuracy that you can get from a GNSS receiver?
• mm, cm, dm, few meters or 10 – 30m• But,• What is your budget?
• What Accuracy do you need?
• What type of applications are you using?
• How do you log the data?
• Static Mode on a Tripod• Dynamic Mode on a Car?

• Real-Time or Post-Processing
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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High-End Survey Grade Receivers
L5/E5/B2/L3

L2

L6/E6/B3

L1/E1/B1• Multi-frequency• L1/L2/L5/L6• G1/G2• E1/E5/E6• B1/B2/B3• Multi-system• GPS, GLONASS, GALILEO, BeiDou,
QZSS, NAVIC, SBAS etc• Price varies from $3, 000 to $30,000
or moreDinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

4Low-Cost Receivers

L1/E1/B1*• Multi-System• GPS, GLONASS, GALILEO, BeiDou, QZSS, SBAS etc• Basically Single Band

• L1-Band• Very soon: Multi-System, Multi Frequency, L1/L2 or L1/L5• Some chip makers have already announced Multi-System, MultiFrequency GNSS Chips for Mass Market• Low Cost:• Less than $300 (Multi-GNSS, L1 Only) including Antenna and allnecessary Hardware, Software• The price of module itself is less than $100
*Note: Only one signal type from each system is processed
e.g. GPS has L1C/A and L1C in L1, ,but only L1C/A is used in Low-Cost Receiver
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

5Our Definition of Low-Cost Receiver• Price• Accuracy• Weight: $100 or less
: Better than 100cm: Within 100gm$100x100cmx100gm
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

6New Emerging Applications• ITS• Timing Application• ITS-Station (infra on the road side)• ADAS• V2X, V2I• Public Transport Monitoring• Traffic Congestion• Public Safety and Security• Driver’s Behavior Monitoring• Toll Charge• ERP (Electronic Road Pricing)• Precise Agriculture• Drone Mapping• Direct Geo-referencing• Internet• Financial Institutes• Power Grids• Logistics Services• Emergency Services• eCall / ERA GLONASS• SAR (Search And Rescue)• Construction Management and Monitoring• Aviation• SBAS• Marine• VMS, AIS
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

7Many Applications require
Low-Cost, Small-Size & Low-Power
Receiver System
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

8But, is it possible to get
High-Accuracy with Low-Cost
Receivers?
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp9How Accurate is GPS?
Verticle Accuracy : 3.872m @ 95%CI @ Location A

Horizontal Accuracy : 1.891m @ 95%CI @ Location A

Global Accuracy Standard:
Better than 12.8m at 95% CI Global Average URE
Better than 30m at 99.94% CI Global Average URE
URE: User Range Error  Pseudorange Accuracy
Ref: https://www.gps.gov/technical/ps/2008-SPS-performance-standard.pdf
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

10Question?

Though the Normal Accuracy of GPS is about 10m,
why can we get Centimeter Level Accuracy?

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

11GPS Position Accuracy: From few meters to centimeter
centimeter

meter

50 cm grid

50 cm grid

5 cm grid

SPP (Single Point Position)

DGPS (Differential GPS)RTK (Real Time Kinematic)

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp12Errors in GPS Observation (L1C/A Signal)
Error Sources

One-Sigma Error , mSatellite Orbit
Satellite Clock

Total
2.0
2.0

DGPS
0.0
0.0

Ionosphere Error
Troposphere Error
Multipath

4.0
0.7
1.4

0.4
0.2
1.4

Receiver Circuits

0.5

0.5

Comments
Common errors are
removedCommon errors are
reducedIf we can remove common errors, position accuracy can be increased.
Common errors are: Satellite Orbit Errors, Clock Errors and Atmospheric Errors (within few km)
Values in the Table are just for illustrative purpose, not the exact measured values.
Table Source : http://www.edu-observatory.org/gps/gps_accuracy.html#Multipath
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp13How to Remove or Minimize Common Errors?
Use Differential Correction
30[X]error = [X]known – [X]measured

Send Correction Data to RoverFor Real-Time Position

Rover
For RTK, both rover and base receivers
need to use the same satellites
Antenna is installed at aUser in the Field
Base-station Antenna position
known-position(Either fixed or moving)
shall be known in advanceBase-Station

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

14How to Remove or Minimize Common Errors?
Principle of QZSS MADOCA and CLAS Services
QZSS

GPS

Correction Data:
Satellite Orbit Error of GPS and Other Satellites
Satellite Clock Error of GPS and Other Satellites

Correction data for other satellites
will also be provided
Rover

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp15

Low-Cost Receiver System : Type A
Real-Time or Post-Processing RTK, Base and Rover Mode
GNSS Antenna RoverBT

TabletRasPi
APP
Ver. : 1.0

Raspberry Pi 3B

GNSS Receiver

WiFi

U-blox M8T

Send RTCM Correction
data for RTK to Receiver

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

NTRIP
Caster16

Low-Cost Receiver System: Type B
Post-Processing RTK, Rover Mode Only
GNSS Antenna Rover
Raspberry Pi Zero w/WiFi&BT

GNSS Receiver

U-blox M8T

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

17Low- Cost Receiver System : Type C
Real-Time or Post-Processing RTK, Rover Mode Only
GNSS Antenna Rover

GNSS Receiver

U-blox M8T

Tablet
RTKDroid
APP
Ver. : 1.0

Send RTCM Correction
data for RTK to Receiver
WiFi(Internet)

NTRIP
CasterDinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp18Low-Cost Receiver System : Type D
Real-Time or Post Processing PPP, Rover Mode Only
GNSS Antenna Rover

GNSS
Receiver

TBD

Tablet
MADROID
APP
Ver. : 1.0

RTCM and/or SSR
PPP-RTK
e.g. MADOCA Service

WiFi

MADOCA
Correction
ServerDinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

19Low-Cost High-Accuracy Receiver System
TYPE A Type A: Low-Cost, High-Accuracy Receiver System

TYPE B Type B: Low-Cost, High-Accuracy Receiver System

Real-Time and Post-Processing, Base and Rover Mode
GNSS Antenna RoverBT

For Post-Processing & Rover Mode Only

TabletRasPi
APP
Ver. : 1.0

GNSS Antenna Rover
Raspberry Pi Zero w/WiFi&BT

Raspberry Pi 3B

WiFi

GNSS Receiver
U-blox Neo-M8T

TYPE C

RTCM for
RTK

NTRIP
CasterType C: Low-Cost, High-Accuracy Receiver System
Real-Time and Post-Processing, Rover Mode Only

TYPE D

GNSS Antenna Rover

Type D: Low-Cost, High-Accuracy Receiver System
Real-Time and Post-Processing, Rover Mode Only

GNSS Antenna Rover
TabletRtkDroid
APP
Ver. : 1.0

GNSS Receiver
U-blox Neo-M8T

GNSS Receiver
U-blox Neo-M8T

Tablet
MADROID
APP
Ver. : 1.0

RTCM for
RTK
WiFi
NTRIP
CasterGNSS Receiver
U-blox Neo-M8T

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

RTCM and/or SSR
PPP-RTK
e.g. MADOCA Service

WiFi

MADOCA
Correction
Server20

Low-Cost Receiver Systems
Type

Type A2018 Q3
Beta Ver.
Available

Type B2018 Q3
Beta Ver.
Available

Type C2018 Q3
Beta Ver.
Available

Type D2018 Q4
Development
in Pipeline

Receiver System

RTK
Processing
EngineReal-time RTK
Base and Rover Setting

Log Raw Data for Postprocessing RTK

UsageReal-time RTK
Simultaneous Log of
Raw Data

Real-time PPP
Based on MADOCA
Correction Data fromInternet

Mode

User
Interface

BaseStation
Data

Correction
Data Format

Raspberry Pi 3B

Base orRover

Android
Device
APP: RTKPI

NTRIP
Server or
VRS (future)

RTCM 3Raspberry Pi
Zero/WiFi&BT
Option:RaspberryPi
CameraRover Only

None

Postprocessing

RINEX
User Defined

Rover Only

Android
DeviceAPP:RTKDROID

NTRIP
Server or
VRS (future)

RTCM 3

Rover Only

APP:
MADROID

MADOCA
Correction
Data Server

MADOCA
FormatFuture: CLAS

Android Device

Android Device

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp21Low-Cost High Accuracy System : Type A
Base-Station
GNSS Antenna

Rover Unit (User)

Internet

Internet

Raspberry Pi 3B

GNSS Rover Unit USB Cable(User in the Field)

RasPi APP for RTK
SW Maps for GIS
Data Input

TabletRasPi
APP
Ver. : 1.0

NTRIP
Caster

WiFi
GNSS Receiver
U-blox M8T

GNSS Antenna

GNSS
ReceiverBTNTRIP Caster

GNSS Base-Station

Low-Cost RTK System
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp22RTK-Pi APP for Low-Cost RTK System

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp23Board Computer for Low-Cost RTK System
Raspberry Pi 3B for
Raspberry Pi Zero w/WiFi & BT
Real-time and Post-processing RTK
for Post-processing RTK

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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Accuracy from Low-Cost RTK System
GNSS Antenna RoverBT

TabletRasPi
APP
Ver. : 1.0

Raspberry Pi 3B

WiFi
NTRIP
CasterRover-Station:
Receiver: u-blox M8T
Antenna: Zephyr 2Computer: RaspberryPi 3B+
Distance between Base and Rover : about 12Km

5cm

GNSS Receiver
U-blox Neo-M8T

5cm

Base-Station:
Receiver: Trimble NetR9
Antenna: Zephyr 2
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp25Data from Low-Cost RTK System

Raw Data from Receiver
Pseudorange, Carrier Phase, Doppler etc

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp26Data from Low-Cost RTK System

Navigation Data from Receiver
Includes Satellite Ephemeris Data, Satellite Clock Data etc

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp27

Low-Cost RTK Field Survey Data
Static, Tokyo

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp28

One Hour RTK Post-processing, Static, Tokyo

Base
Rover

: NetR9 (high): NetR9 (high)Show only
RTK FIX Data

50cm Grid

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

1cm Grid

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One Hour RTK Post-processing

Base
Rover

: NetR9 (high): U-bloxM8P (low)Show only
RTK FIX Data

50cm Grid

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

1cm Grid

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One Hour RTK Processing

Base
Rover

: U-bloxM8P (low): U-bloxM8P (low)Show only
RTK FIX Data

50cm Grid

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

1cm Grid31

Low-Cost RTK Field Survey Data
Dynamic (Car), Tokyo

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp32

RTK Survey in Tokyo by Car

1

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RTK Survey in Tokyo by Car

1

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp34NN_03
Base : High-End
Rove : High-End
GPS+GALILEO+BEIDOU+QZSSGreen Dot : RTK Fix Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp35

NU_03
Base : High-End
Rove : Low-Cost
GPS+GALILEO+BEIDOU+QZSSGreen Dot : RTK Fix Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp36

NU_03
Base : High-End
Rove : Low-Cost
GPS+GALILEO+BEIDOU+QZSSGreen Dot : RTK Fix Solution
Yellow Dot : RTK Float Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp37

UU_03
Base : Low-Cost
Rove : Low-Cost
GPS+GALILEO+BEIDOU+QZSSGreen Dot : RTK Fix Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp38NN_13
Base : High-End
Rove : High-End
GPS OnlyGreen Dot : RTK Fix Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp39

NU_13
Base : High-End
Rove : Low-Cost
GPS OnlyGreen Dot : RTK Fix Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp40

UU_13
Base : Low-Cost
Rove : Low-Cost
GPS OnlyGreen Dot : RTK Fix Solution
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp41NN_03 vs. NN_13
Base : High-End
Rove : High-End
GPS+GALILEO+BEIDOU+QZSS vs. GPS Only

RTK Fix Solution
Green Dots: GPS+GALILEO+BEIDOU+QZSSBlue Dots: GPS Only

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

42Future of Low-Cost GNSS Receiver Systems

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

43Future of Low Cost GNSS Receiver System• IoT, ITS, UAV and many other location data related markets
are driving the receiver manufacturers to produce low-cost,high-accuracy and better performance receiver systems evenin difficult environments.
• Manufacturers are also moving towards low-cost, highaccuracy and better performance receivers systems to meetthe demand from location business.

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp44L5/E5/B2/L3

L2

L6/E6/B3

L1/E1/B1

L2

L6/E6/B3

L1/E1/B1

Why Manufacturers are going for LowCost, Dual-Frequency Systems?
• The figure shows that many GNSS signals are crowded
either in L1 or L5 bands.
• All GNSS have at least one signal either in L1 or L5 band
• L5 signals are stronger than L1 signals by few dBs• L5 signals performs better than L1 signals in difficult
environment like urban area, forest or semi-indoor• L5 frequency spectrum is reserved and protected for RNSS
• All these may lead receiver designers to focus on L1/L5
Dual Frequency Receiver rather than L1/L2 receiver

Source: http://www.navipedia.net/index.php/File:GNSS_All_Signals.png
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

4545

Source : Broadcom
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

46Broadcom already announced Dual-Frequency GNSS chip

Source : Broadcom
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

47

Multi-Band GNSS Receiver from u-Blox

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp48

Trimble’s Catalyst System
Trimble provides low-cost hardware
But, you have to pay for Subscription-based Software Service

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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Smart-Phone GNSS for High-Accuracy Position• Android Smart-Phone devices provide GNSS Raw Data

• Android OS Nougat (7.0) and higher output GNSS Raw Data

• GNSS Raw Data are necessary for RTK Processing• Pseudorange, Carrier Phase, Doppler etc.
• It’s possible to do RTK with Smart-Phone device• The only problem is Antenna• An accuracy within One Meter from Smart-Phone device will
revolutionize Location Business
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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GNSS raw data on Android devices opens up
a range of possibilities and opportunities

Source: https://developers.google.com/location-context/
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp51

Some Useful Softwares

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp52Useful Software for GNSS• RTKLIB• Software for RTK Data Processing•••

Real-Time or Post-Processing
Data Format Conversion
Evaluation and Analysis of Data

• www.rtklib.com• Please Joint Next Webinar on 1st June and 8th June to learn details about RTKLIB• Registration at https://gnss.peatix.com (Free)• SW Maps• An Android APP useful for GNSS Data Logging for GIS Applications• Basically, a GIS data input App. More than 50,000 downloads• https://play.google.com/store/apps/details?id=np.com.softwel.swmaps&hl=en_US• RTKDroid• Android APP used for RTK with u-blox M8T or M8P receiver•

Connect u-blox receiver to an Android device using a OTG cable• Will be provided to webinar participants if they would like to test and evaluate• u-Center• Software from u-blox to log GNSS data in Windows or Android OS• Can be used with non-u-blox receivers as well to log data
• Very useful to log GPS data in Android device
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp53Additional Information
Please visit websites
For Webinar: http://www.csis.u-tokyo.ac.jp/~dinesh/WEBINAR.htm
https://gnss.peatix.com
Contact:
dinesh@iis.u-tokyo.ac.jp

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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