Low-Cost High-Accuracy GNSS Receiver
Dinesh ManandharCenter for Spatial Information Science
The University of Tokyo
Contact Information: dinesh@iis.u-tokyo.ac.jp
Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

Slide : 1

High Accuracy Receivers are Expensive• High-Accuracy Survey Grade Receivers are multi-frequency
and multi-system receivers• L1/L2/L5, G1/G2, B1/B2/B3 etc• GPS, GLONASS, BGALILEO, BeiDou, QZSS etc• Price varies from $5,000 to $30,000 or more.

• However, Low Cost Receivers are also capable of• Multi-System: GPS, GLONASS, GALILEO, BeiDou, QZSS, SBAS etc• Currently only in L1-Band Frequency• Low Cost: $300
• Very soon: Multi Frequency, L1/L5• Broadcom already announced production of L1/L5 GNSS chip
Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

2Slide : 2

How accurate is GPS Position?

50 cm grid

50 cm grid

5 cm grid

SPP (Single Point Position)

DGPS (Differential GPS)RTK (Real Time Kinematic)

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

3Slide : 3

Errors in GPS Observation (L1C/A Signal)
Error Sources
Satellite Orbit
Satellite Clock
Ionosphere Error
Troposphere Error

One-Sigma Error , mTotal
DGPS
2.12.1
4.0
0.7

0.0
0.0
0.4
0.2

Comments
Common errors are
removedCommon errors are
reducedMultipath
1.4
1.4
Receiver Circuits
0.5
0.5
If we can remove common errors, position accuracy can be increased.
Common errors are: Satellite Orbit Errors, Clock Errors and Atmospheric Errors (within few km)
Table Source : http://www.edu-observatory.org/gps/gps_accuracy.html#Multipath

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

4Slide : 4

Principle of Differential Correction
30

Send Correction Data to RoverFor Real-Time Position

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

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

5Slide : 5Principle of QZSS MADOCA / CLAS Service
QZSSGPSCorrection Data:
Satellite Orbit Error of GPS and Other Satellites
Satellite Clock Error of GPS and Other Satellites
Rover
Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

6Slide : 6

Low-Cost High Accuracy System
GNSS Antenna
GNSS Antenna

InternetInternet

Raspberry Pi 3B

GNSS Receiver
U-blox Neo-M8T

NTRIP
CasterWiFi
GNSSReceiver

USB Cable

GNSS Rover Unit(User in the Field)

RasPi APP for RTK
SW Maps for GIS
Data Input

GNSSBase-Station

BT

TabletRasPi
APP
Ver. : 1.0

NTRIP Caster

GNSS Base-Station

Low-Cost RTK System
Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

Slide : 7

RtkPi APP for Low-Cost RTK System

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

8Slide : 8

Board Computer
forLow-Cost
RTKSystemRaspberry Pi 3B for
Raspberry Pi Zero w/WiFi & BT
Realtime and Postprocessing RTK

for Post-processing RTK

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

9Slide : 9

Accuracy from Low-Cost RTK System
GNSS Antenna RoverBT
GNSS Receiver
U-blox Neo-M8TTablet
RasPi
APP
Ver. : 1.0

Raspberry Pi 3B

WiFi

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

5cm

NTRIP
Caster5cm

Base-Station:
Receiver: Trimble NetR9Antenna: Zephyr 2Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

10Slide : 10

Data from Low-Cost RTK System

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

11Slide : 11

Data from Low-Cost RTK System

Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

12Slide : 12

Type – R1: GNSS Receiver with RaspberryPi-3

GNSS Antenna Rover
Raspberry Pi 3B

BT

TabletRasPi
APPVer. : 1.0

GNSSReceiver
WiFi

Base-Station
Data for RTK

NTRIPCasterType R1:
Base or Rover Mode
Real-Time and Post-Processing RTK
Based on RTKLIB Engine
2019/1/14 Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

13

Slide : 13

Type – R2: GNSS Receiver with RaspberryPi-Zero/W
Raspberry Pi Zerow/WiFi&BT

GNSS Antenna Rover

GNSS ReceiverType R2:
Rover ModeSPS + Post-Processing RTKLog Necessary Raw Data for Post-processing RTK
Based on RTKLIB Engine
Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

14Slide : 14

Type – A1: GNSS Receiver with Android Device

GNSS Antenna Rover

GNSS
Receiver

TabletRtkDroid
APP
Ver. : 1.0

RTCM forReal-time
RTK

WiFi

Type A1:
Rover Mode
Real-Time or/and Post-Processing RTK
Based on RTKLIB Engine
Real-time processing in Android Device
APP: RTKDroid

NTRIP
CasterGNSS Receiver Module

2019/1/14 Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

15Slide : 15

Type – W1: GNSS Receiver + WiFi + BT

GNSS Antenna
For Post-Processing
Just power-on the device
Data will be logged to SD Card

SDCardSPI

GNSS
ReceiverFor Real-Time Processing
Connect to an Android Device via BT

UART

CPU +WiFi / BT

TabletRtkDroid
APP
Ver. : 1.0

Base-Station
Data for RTKWiFi
NTRIPCaster2019/1/14 Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

16Slide : 16

Type - M1: MADOCA Network + Android Device + F9 Board (MAF)
GNSS
Antenna

F9 - Board
Multi-Band
Receiver

WiFi / BTAndroid
Device
MADROID
APP
Ver. : 1.0

MADOCA
Correction Data

WiFi
NTRIP
Caster2019/1/14 Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

17Slide : 17

Type - M3: MADOCA Network + Android Device (MA)

MADOCA
Correction Data
NTRIP
CasterInternetAndroidDevice withMulti-Band
GNSS Receiver
MADROID
APP
Ver. : 1.0

GNSS L1, L2, L5/E5e. g. Xiomi Mi8

2019/1/14 Training on GNSS – Course (T151-30), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 14 – 18 JAN 2019
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

18Slide : 18