Zero Base-length Data Processing
Post-Processing Kinematic (PPK) for
High-Accuracy Position Data
Dinesh Manandhar
CSIS, The University of Tokyo, Japandinesh@csis.u-tokyo.ac.jp
JAN 2020
1Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

Observation Data
• Base Station Data

• Receiver: Trimble NetR9
Multi-frequency, Multi System• Data Format: T02 Trimble format• Data Conversion: Convert to RINEX Format• Antenna: Zephyr 2• Rover Data

• Receiver: U-Blox M8T• Data Format : UBX• Data Conversion : Convert to RINEX Format using RTKLIB

2Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

Zero Base-Length PPK
GNSS Antenna
NETR9GNSS, Receiver
Base-Station
X0Y0Z0

M8T
GNSS, ReceiverROVER

3XbYbZb

XrYr
Zr

Zero Base-Length = Distance between Base and Rove is ZeroBoth receivers are sharing the same antenna with a splitterThus, {X0}, {Xb} and {Xr} must be the same.
However, due to various errors and signal processing techniques inside the receivers,
the position data fro {Xb} and {Xr} might be different.
A good test to see receiver performance
PPK  RTK in Post-Processing Mode

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

Zero Base-Length PPK Results

Check theresults ofX0, Xb and Xr

4Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

X0
Y0
Z0

Xb
YbZb

Xr
YrZr

Compute Base Station Antenna Coordinate• Observer Data for 24 hour
• Convert to RINEX 2.12 Format• Use Online PPP Service• Use Software provided by maker (If available) for PPP• Use RTKLIB for PPP• Use RTK Processing with the nearest base-station

5Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

Post-processing using RTKLIB

6Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Select Rover andBase Files

7

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Setting 1 Menu

8Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Setting 1 Menu
Processing Options

9Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Setting 2 Menu

10Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Output Menu

11

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Positions Menu

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Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTKLIB
Processing Running

13

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP : NetR9 (High-End Receiver)14

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP : NetR9 (High-End Receiver)15

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP : U-blox (Low-Cost Receiver)16

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP : U-blox (Low-Cost Receiver)17

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP : u-blox vs NetR9SPP Output
Red: u-blox (Low-Cost)
Violet: NetR9 (High-End)

18

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

DGPS

19

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

DGPS

20

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTK

21

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTK

22

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTK

23

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP vs RTK

24

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP vs RTK

25

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

SPP vs RTK

26

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

Output Data from SPP and PPK• Compute CEP for SPP• Compute CEP for PPK

27

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

RTK Exercise
GNSS RoverAntenna

GNSS Base-Station
Antenna

yd1

d2

yx

X0
Y0
Z0
28

d3

Question:
If we move antenna exactly by x-cm
and/or y-cm, do we also get the same
shift in GPS data for x and y?
Example:We move the antenna by 10cm in x
direction, do we see a change in 10cm
in GPS data?

xx

GNSS, Receiver
Base-Station

GNSS, Receiver
ROVERXbYbZbXrYrZr

Dinesh Manandhar, The University of Tokyo, Japan, dinesh@csis.u-tokyo.ac.jp

Is vector d2 = vector (d1 + x)?
Is vector d3 = vector (d2 + x)?