GNSS Training 2018

GNSS Precise Positioning and
RTKLIB
Tokyo Univ. of Marine Science and Technology : Nobuaki Kubo

2018-01-23 ~ 2018-01-26 @AIT, Thailand

Receiver used in this training
1. u-blox GNSS receiver (M8P or M8T)
2. Trimble NetR9

u-blox M8T

u-blox M8P
Trimble NetR9

You can purchase M8T• http://www.csgshop.com/product.php?id_product=205

Some Data used in Practice
Static raw data set (24h)- u-blox M8T (ref/rover) + Trimble/NovAtel ant.
- Trimble NetR9 (ref) Trimble ant.
Static raw data set (1h)- u-blox M8P (ref/rover) + Trimble/NovAtel ant.
- Trimble NetR9 (ref/rover) + Trimble/NovAtel ant.
Kinematic raw data set (0.5h)- u-blox M8T (ref/rover) + Trimble/NovAtel ant.
- Trimble NetR9 (ref/rover) + Trimble/NovAtel ant.

RTK DEMO• Both reference station and rover station are installedon the rooftop of our building.
• Using the “RTKLIB” and “internet”, we can check RTK.
• You will learn why the cm-level navigation can beachieved by RTK-GNSS through this class.

u-blox M8P

Trimble NetR9

RTK performance
12h, rooftop, our building

RTK : mm level

Same scale

Carrier-Phase-Based
Positioning with GNSSGNSS Signal Structure
Carriersin(2ft   )
+1

Code

-1

C (t )

+1

Data

-1

D(t )

Signal2PC (t ) D(t ) sin(2ft   )  GNSS Signal Specifications
Carrier Freq (MHz)L1/E1

1575.42L1

1602+0.5625K

L2

1227.60

L21246+0.4375K

L5/E5a1176.45E5b1207.14

E6/LEX

1278.75

Code

Modulation

Data Rate

GNSS

50 bpsGPS, QZSS

250 bpsQZSS (L1-SAIF), SBASC/ABPSK (1)P(Y)

BPSK (10)50 bpsGPS

L1C-d/p MBOC (6,1,1/11)-/100 bps

GPS (III-), Galileo

L1C-d/p BOC (1,1)-/100 bps

QZSS

C/A

BPSK

50 bps

GLONASSP(Y)BPSK (10)50 bpsGPS

L2C

BPSK (1)25 bpsGPS (IIRM-), QZSS

C/A

BPSK

50 bps

GLONASS

L5-I/QBPSK (10)-/100 bps

GPS (IIF-), QZSS

E5a-I/QBPSK (10)-/50 bps

GalileoE5b-I/Q BPSK (10)-/250 bps

GalileoE6-I/QBPSK (5)-/1000 bps

GalileoLEX

BPSK (5)2000 bps

QZSS

Spreading (PRN) CodeGPS C/A Code Generator
G1 Generator
1 2 3 4 5 6 7 8 9 10
PRN Selector

X1 Epoch

Reset
/10

10.23MHzC/A

C (t )

1 2 3 4 5 6 7 8 9 10

G2 Generator

Auto-correlation function

Cross-correlation function11

 (chip)-1T (chip)1

1
R( ) C i (t )C i (t   )dt
T 0

0

1 T i
R( ) C (t )C j (t   )dt (i  j )T 0Carrier/Code Tracking in Receiver
Baseband Processor
CH1
Code NCO

Range

Δt,Δf
DLL

CE,P,L
CDφ

CDφIF

CDI,Q

RFFrontend

φI,Q

Local
Oscillator

Carrier
NCO

Correlator
Correlator

PLL/FLL
Δφ,ΔfPseudorange,
Navi-DataΣ
Carrier-Phase,
Doppler-Freq

Pseudo-range (Code-phase)
Definition:

The pseudo-range (PR) is the distance from thePrs  c  c( tr  t s ) receiver antenna to the satellite antenna including
receiver and satellite clock offsets (and otherbiases, such as atmospheric delays) (RINEX 2.10)(m)

At Satellitet s  tr  Time by Satellite Clock (s)At ReceivertrTime by Receiver Clock (s)Carrier-Phase
Definition:rs   s  r  N(cycle)... actually being a measurement on the beatfrequency between the received carrier ofthe satellite signal and a receiver-generated
reference frequency. (RINEX 2.10)

Received Satellite Carrier: s (t s )Local Reference Frequency:

r (tr )Carrier Beat Frequency:

rs   s  r  NHow about accuracy (Code) ?
Real correlator samples (40MHz)
GPS L1-C/A : 1chip (293m)

With the aid of “loop filtering + correlator characteristic”,
we try to estimate the code measurements
approximately desi-meter level (- 1m).

How about accuracy (Carrier) ?

I phase and Q phase (GPS L1-C/A)

I phase correlation value  Navigation data

With the aid of “loop filtering + correlator characteristic”,
we try to estimate the carrier-phase measurements
approximately mm meter level.

Code vs Carrier-Based Positioning
Standard Positioning(code-based)

Precise Positioning(carrier-based)

Observables

Pseudorange(Code)

Carrier-Phase +Pseudorange

Receiver Noise

30 cm

3 mm

Multipath

30 cm - 30 m

1 - 3 cm

Sensitivity

High (<20dBHz)

Low (>35dBHz)

Discontinuity

No Slip

Cycle-Slip

Ambiguity-

Estimated/Resolved

Receiver

Low-Cost (~$100)

Expensive (~$20,000)

Accuracy(RMS)

3 m (H), 5 m (V) (Single)
1 m (H), 2 m (V) (DGPS)

5 mm (H), 1 cm (V) (Static)
1 cm (H), 2 cm (V) (RTK)

Application

Navigation, Timing, SAR,...

Survey, Mapping, ...

Pseudorange Model(3) Satellite
Clock Bias

Prs  c c( tr  t s )(1) GeometricRange

 c((tr  dt )  (t s  dT s ))   P(4) Ionosphere c(tr  t s )  c(dtr  dT s )   P
 (  rs  I rs  Trs )  c(dtr  dT s )   P
   c(dtr  dT )  I  T   P
s
r

(1)

s

(2)

(3)

s
r

s
r

(4)

(5)

(6)

(5) Troposphere(2) Receiver
Clock Bias

RCV(6) Multipath +Receiver Noise + Other Errors

Carrier-Phase Model (1)Carrier phase measurement isaccumulated Doppler frequency.

Carrier-Phase:rs  r (tr )   s (t s )  N rs   (r ,0  r (t0 ),0s   s (t0 )) ( f (tr  dtr  t0 )  r ,0 )  ( f (t s  dT s  t0 )  0s )  N rs   c(tr  t s ) c(dtr  dT s )  (r ,0  0s  N rs )   (cycle) rs  rs  c(tr  t s )  c(dtr  dT s )   (r ,0  0s  N rs )   
  rs  c(dtr  dT s )  I rs  Trs   Brs  d rs  

Pseudorange:(m)

Carrier-Phase Bias Other Correction Terms

Prs  rs  c(dtr  dT s )  I rs  Trs   P

18

Carrier-Phase Model (2)Carrier-Phase Bias:
Brs  r ,0  0s  Nrs(cycle)N rs : Integer Ambiguity

r , 00s: Receiver Initial Phase: Satellite Initial Phase

Other Correction Terms:





T

s
d rs  d r , pcoT ers,enu  Esatecef d spco ers  d r , pcv  d pcv
 d dispT ers,enu

 d pw  d rel(m)d r, pco : Receiver Antenna Phase Center Offset
d r , pcv : Receiver Antenna Phase Center Variationd spco : Satellite Antenna Phase Center Offsets: Satellite Antenna Phase Center Variation
d pcv
d disp : Site Displacementd pw : Phase Wind-up Effectd rel : Relativistic EffectPhase Wind-up EffectWhat happens in carrier-phase ?

32.62 min.
204.5 mBasically, “code-carrier” indicates the code multipath errors (+ionosphere effect)
Turn table rotates 33.3333…/min.
It means that the number of rotation was 1077.22.
Converting to “meter” of L1-C/A, 1077.22*0.19… = 204.98 m
204.98/1939 s = 0.1057m / turn have to be compensated in carrier-phase.

After compensation,

You see code multipath…

Antenna Phase Center• The GNSS measurements are referred to the so-called
antenna phase center. The position of the antenna phasecenter is not necessarily the geometric center of the antenna.
Indeed, it is not constant, but it depends on the direction theradio signal coming in.
Source: NavipediaDD (Double Difference)ijΦub  ((ui  bi )  (uj  bj ))
ij
ij
ij
ij
ij
 ub
 c(dtub dTubij )  I ub
 Tubij  Bub
 d ub
 Φ
ij
ij
ij
ij
 ub
 I ub Tubij  N ub
 d ub
 Φ
ij
ij
i
dtub
 dtuij  dtbij  0, dTub dTub
 dTubj  0time difference between u and b
satellite clock changes…

ij
ij
Bub
 (u ,0  0i  Nui )  (b,0  0i  Nbi )  (u ,0  0j  Nuj )  (b,0  0j  Nbj )  Nub(short Baseline and same antenna type)
ij
ij
ij
Φub
 ub
 Nub
 Φ
ij
j
ij
ij
j
i
i
i
Iub
 Iub
 Iub
 0, Tub
 Tub
 Tubj  0, dub
 dub
 dub
0

Satellite i

bi

bj

ui
Receiver uSatellite jujBaseline

Receiver b

Memo for Misra & Enge:
http://gpspp.sakura.ne.jp/
diary200608.htm

Baseline Processing
Nonlinear-LSE:
Parameter Vector:
s3 s1
sm s1 Ts2 s1
x  (ruT , Nub, Nub,..., Nub)
Measurement Vector:y  ( yt1T , yt1T ,..., ytn T )T

Meas Model, Design Matrix:h( x )  ht1 ( x )T , ht 2 ( x )T ,..., ht n ( x )TH  H t1 T , H t 2 T ,..., H t n T



T

T

Meas Error Covariance:R  blkdiag Rt1 , Rt2 ,..., Rtn



Solution (Static/Float):xˆ  x0  ( H T R1H )1 H T R1( y  h( x0 ))s3 s1
s m s1 Ts 2 s1
yt k  ( ub,t , ub,t ,...,  ub,t )kkk  s2 s1   s2 s1  N s2 s1 ub 
 u ,t kb ,t k s3 s1
s3 s1
s m s1 





N
ub
u
,
t
b
,
t

k
k
ht k ( x )   sm s1
s m s1  u ,t  bs,mt s1  N ub

k
k


 s2 s1 T 0  0  eu ,tkT  e s3 s1
0   0H t k   u ,t k








  e sm s1 T 0 0    u ,t k 4 2 2 2  2 2 

 
 
2
2
 2
4  2 2 
Rt k   

 
 
 
 2 2 2 2  4 2 

 
 

rb : Fixed Base-Station Position

It is similar to the single point positioning except for KF

Effect of Baseline Length
BL=0.3 km

BL=13.3 km

RMS Error:
E: 0.2cm
N: 0.6cm
U: 1.0cm
Fix Ratio:
99.9%

RMS Error:
E: 2.2cm
N: 2.4cm
U: 10.6cm
Fix Ratio:
94.2%

BL=32.2 km

BL=60.9 km

RMS Error:
E: 10.0cm
N: 12.0cm
U: 30.2cm
Fix Ratio:
64.3%

RMS Error:
E: 14.0cm
N: 14.8cm
U: 26.7cm
Fix Ratio:
44.4%(24 hr Kinematic: Fixed Solution: Float Solution)

Integer Ambiguity Resolution• Objectives– More accurate than float solutions– Fast converge of solutions• Many AR Strategies– Simple Integer rounding– Multi-frequency wide-lane and narrow-lane generation– Search in coordinate domain– Search in ambiguity domain– AFM, FARA, LSAST, LAMBDA, ARCE, HB-L3, Modified
Cholesy Decomposition, Null Space, FAST, OMEGA, ...

ILS (Integer Least Square Estimation)x  (aT , bT )T , H   A, B y  Hx  v  Aa  Bb  v

Problem:x  arg min ( y  Hx )T Q y 1 ( y  Hx )aZ n ,bR mStrategy:(1) Conventional LSE
Qab  aˆ 
Q
  ( H T Q y H )1xˆ   ˆ   Qx H T Q y 1 y, Qx   a
 Qba Qb b(2) Search Integer Vector with Minimum Squared Residualsa  arg min (aˆ  a )T Qa 1(aˆ  a )aZ n(3) Improve solutionb  bˆ  QbaQa1(aˆ  a )LAMBDA
Teunissen, P.J.G. (1995)
The least-squares ambiguity decorrelation adjustment: a method for fast GPS
integer ambiguity estimation. Journal of Geodesy, Vol. 70, No. 1-2, pp. 65-82.

• ILS Estimation with:– Shrink Integer Search Space with "Decorrelation"– Efficient Tree Search Strategy– Similar to Closest Point Search with LLL Lattice Basis Reduction
Algorithmzˆ  Z T aˆ , Qz  Z T Qa Z

1 ˆ
T


1
T
ˆ
z

arg
min
(
z

z
)
Q
ˆ
ˆ
a  arg min (a  a ) Qa (a  a )z (z  z)
aZ n

zZ n



a  Z T z

Performance of LAMBDA
15

Execution Time (ms): with decorrelation: without decorrelation
10

5

0
5

10

15

20

25

30

35

40

N : Number of Integer Ambiguities(Pentium 4 3.2GHz, Intel C/C++ 8.0)

RTK (Real-Time Kinematic)• Technique with Baseline Processing– Real-time Position of Rover Antenna– Transmit Reference Station Data to Rover via Comm. Link
– OTF (On-the-Fly) Integer Ambiguity Resolution– Typical Accuracy: 1 cm + 1ppm x BL RMS (Horizontal)– Applications:Land Survey, Construction Machine Control, Precision
Agriculture etc.
Reference
StationCommunication Link

Rover
ReceiverRTK Application (1)RTK Application (2)http://www.drotek.com

http://www.emlid.com

Wave Height (m)GNSS TSUNAMI BUOY

Unstable data due to earthquake

South Iwate buoy
• 10km offshore• Depth 200m
14：46 Earthquake
14：53 First detected Tsunami motion
15：12 Tip of Tsunami wave

①青森東岸沖（水深87m）②岩手北部沖（125m）③岩手中部沖（200m）④岩手南部沖（204m）⑤宮城北部沖（160m）⑥宮城中部沖（144m）⑦福島県沖（137m）⑧静岡御前崎沖（120m）⑨三重尾鷲沖（210m）⑩和歌山南西沖（201m）⑪高知西部沖（309m）

①②
③
④
⑤
⑥
小名浜
⑦

八戸
久慈
釜石

⑨
⑩
⑪
上川口

⑧

GPS波浪計
沿岸波浪計

Source: Port and Airport Research InstituteSmart Construction• Computer aided constructionPrecision Farming• Precision farming resolves the issue in decreasing
farm family* Agricultural management* Low cost receiver* Amateur can control* Improvement of harvest* Improvement of quality* Autonomous helicopter

Quality of Big data
• Road condition monitoring• Traffic information in big disasterAccuracy improves the quality of Big data

Autonomous car with precise map* Autonomous car* Smart control

Recent Test : RTK on the wall
E,N series

Monitoring forstructure deformations
Moves antenna close to the wall
Horizontal

Recent Test : Running
Height series

Horizontal

Network RTK (NRTK)• Extension of RTK– RTK without User Reference Station– Sparse Networked Reference Stations– Correction Messages via Mobile-Phone Network– Format: VRS, FKP, MAC, RTCM 2.3, RTCM 3.1– Server S/W: Trimble GPSNet, GEO++ GNSMART, ...
– NTRIP Networked Transport of RTCM via Internet Protocol• NRTK Service in Japan– GEONET: ~1200 Reference Stations by GSI– NGDS, JENOBA, Terasat

Concept of NRTK

Source: GEO++

Relationship between Errors

Several interpolation algorithms

Japanese GEONET(http://terras.gsi.go.jp/ja/index.htm)

Actual Steps of RTK• After this summer school, please check thefollowings regarding the process of RTK todeepen your understanding !
1. Generating “double difference”
2. Finding “integer ambiguities”
3. Baseline processing

1. DD (Double Difference)Φ   ((   )  (   ))
ij
ub

i
u

i
b

j
u

j
b

ij
ij
ij
ij
  ub c(dtub dTubij )  I ub
 Tubij  N ub
 d ubij   Φij
ijij  ub
 I ub Tubij  N ub
 d ubij   Φ
ij
ij
i
dtub
 dtuij  dtbij  0, dTub dTub
 dTubj  0

Without reference station,
it is impossible to remove “receiver
And satellite clock error” completely !
Generate new observation
which means double difference.

ij
ij
Bub
 (u ,0  0i  Nui )  (b,0  0i  Nbi )  (u ,0  0j  Nuj )  (b,0  0j  Nbj )  Nub(short Baseline and same
ij
ij
ij
Φub
 ub
 Nub type)Φantenna
ij
j
ij
ij
j
i
i
i
Iub
 Iub
 Iub
 0, Tub
 Tub
 Tubj  0, dub
 dub
 dub
0

bi

Satellite i

Why do we say thebaseline limitation of RTK ?
(10-100 km or more)
It strongly depends oneach RTK engine !

Satellite j

uj
bj

ui

Baseline
Receiver u

Receiver b
Memo for Misra & Enge:
http://gpspp.sakura.ne.jp/
diary200608.htm

2. Integer Ambiguity Resolution
sv1 _ sv 2
sv1 _ sv 2
sv1 _ sv 2
Prov

r


_ ref
rov_ refp , rov _ refsv1 _ sv 2
rov_ refr

sv1 _ sv 2
rov _ refN

sv1 _ sv 2
rov _ ref

sv1 _ sv 2
 , rov_ ref• Once you can resolve integer N in carrier phase double
difference, you get accurate position about 1 cm.
• It can be imagine that the pseudo-range (code) accuracy isquite important.
• Code-phase is noisy (1 m-) but absolute distance• Carrier-phase is accurate but includes integer ambiguity

3. Test results on the rooftop- double difference of 10 m baseline-

Unit is meter in y axis

Unit is meter in y axis

1. Reference satellite GPS PRN 16
and target satellite is GPS PRN 8
2. Which is code-phase double difference ?
3. If you subtract from right to left, what happen ?
sv1 _ sv 2
sv1 _ sv 2
sv1 _ sv 2
Prov

r


_ ref
rov_ refp , rov _ ref
sv1 _ sv 2
sv1 _ sv 2
sv1 _ sv 2
sv1 _ sv 2
rov

r

N


_ ref
rov _ refrov _ ref , rov_ ref4. (Carrier DD) - (Code DD)

The unit is meter

Divided by wavelength
0.19029 m… (L1)

The unit is cycle

Probably, we guess the integer ambiguity between
PRN16 and PRN8 is about - 40 ?
In fact, the average of this right results was - 41.3

5. What is the correct ambiguity ?
• “Integer least square method” tells us “– 42” in a single
epoch !
• If you know the 3 or more ambiguities, you can estimate
the user position with the level of carrier phase because
only 3 unknowns remains.
• Then, (dx, dy, dz) can be estimated and finally,• (X_user, Y_user, Z_user) = (X, Y, Z) + (dx, dy, dz)
Satellite j

Satellite ibi
sv1 _ sv 2
rov_ refPr

sv1 _ sv 2
rov_ ref

sv1 _ sv 2
p , rov _ ref

sv1 _ sv 2
sv1 _ sv 2
sv1 _ sv 2
sv1 _ sv 2
rov

r

N


_ ref
rov _ refrov _ ref , rov_ refuiReceiver u

uj
bj

Receiver b
Baseline(X_user, Y_user, Z_user) (X, Y, Z)
Reference sta.

6. Test results (dx, dy, dz)

Std. = 2.8 mm

Std. = 4.0 mm

Std. = 3.4 mm

7. Convert to horizontal positions(X, Y, Z)
Reference sta.

Enlarged view of the very small plotshown in the bottom-right corner.

I am repeating myself, RTK tells you only dx, dy, dz.
You have to decide the precise reference positions !

(X_user, Y_user, Z_user)Difference between expensive andlow-cost receiver
Survey-grade receiverLow-cost receiver

Cost＄100,00～$100～

Multiple GNSS

Perfect

BeiDou or Glonass
Other are OK

Multiple Frequency

Perfect

L1/B1/E1/G1 only

Number of channel

400-500--100

RTK (short baseline) + open sky

Perfect

Almost perfect

RTK (over 20 km baseline) + open sky

Almost perfect up to
100 km or more

Impossible

RTK under mid obstructed area (short)

Almost perfect

May be difficult

RTK under dense obstructed area(short)Sometimes not good

DifficultAccuracy of fixed position + openmm→

Accuracy of code position + open

Deci-meter

1-2 meter

PPP (Precise Point Positioning)• Feature– with Single Receiver (No Reference Station)– Efficient Analysis for Many Receivers– Precise Ephemeris– Conventionally Post-Processing• Applications– GPS Seismometer– GPS Meteorology– POD (Precise Orbit Determination) of LEO Satellite– Precise Time Transfer

Static PPP vs Kinematic PPP
Kinematic PPP

Static PPP

Station: IGS CONZ (Chile)

Station: GEONET 0837

Magnitude of 8.6

20cm

2010/2/27 6:28-6:45 GPSTInterval: 1 s

5cm

2009/1/1-2009/12/31
Interval: 1dayPPP Applications

Automated Farming

Tsunami Warning

Mining Machine
Control

Offshore
Construction

Autonomous
Driving

Weather Forecast

RTK vs. PPP
RTKReal-Time PPP

Coverage

Local/Regional(< 1000km)

GlobalTypicalAccuracy

1-3 cm HRMS

2-10 cm, much depending
on orbit/clock quality

Effect of Ref
Movement

Hard to separate ref anduser movement

Less effect by distributed refstations

SystemComplexity

Simple,at least one ref station

Complicated,
need many ref stations

Latency of
Corrections~1s

5 ~ 25 s

BiasesBasically cancelled by DD

Need careful handling

Which is better depends on AP requirement and technology level.
RTKLIB offers both. They are user-selectable by option settings.

Error source mitigation (Typical)
Source/Error

SPP

DGNSS

RTK

PPP

Satellite clock model
1 m (rms)

→

0.0 m

0.0 m

0.01 – 0.1 m

Satellite ephemeris
1 m (rms)

→

0.0 m

0.0 m

0.01 - 0.1 m

Ionospheric delay
2-10 m (zenith)×3 at 5°

1 - 2 m (zenith)0.1 - 0.2 m

0.01 m0.01 mTropospheric delay
2.3-2.5m (zenith)×10 at 5°

0.1 - 0.5 m(zenith)0.1 - 0.2 m

0.01 m0.01 mMultipath (open sky)
Code : 0.5-1 m
Carrier : -1 cm→ Code→ Code→ Carrier→ CarrierReceiver Noise
Code : 0.1-0.5 m
Carrier : 1-2 mm→ Code→ Code→ Carrier→ CarrierFinally…

2-3 m

-1m

- 1 cm- 10 cm

RTK and PPP

Reference station
Continuous communication
Instantaneous position
10-100km limitation

Continuous communication
through satellite
Wait for 5-30 minutes
No limitation

Actual performance…
4

3

PPP
SPP

2

1

DGNSS

After convergence

0
-4

-3

-2

-1

0

1

2

3

4
0.01

-1
0.005

-2

-3

0
-0.01

-0.005

0

0.005

0.01

RTK
-4

-0.005-0.01

Accuracy (95%)
SPP ： 1.36m
DGNSS ： 0.44m
RTK ： 3 mm
PPP : 3.4 cm

Precise Ephemeris• Precise Satellite Orbit and Clock– By Post-Processing or in Real-time– Observation Data of Tracking Stations World-Wide• Format:– Orbit: NGS SP3– Clock: NGS SP3 or RINEX Clock Extension• Contents:– Orbit: ECEF-Positions of Satellite Mass Center– Clock: Clock-biases wrt Time Scale Aligned to GPS Time

IGS: International GNSS Service
Data (GPS/GLONASS
Raw, Ephemeris,...)

Global Data Centers

Analysis Centers (ACs)

SIO

IGN

KASI

CODE

NRCan

ESOC

SIO

GFZ

USNO

ACC

JPL

MIT

NOAA

...

Products(Satellite Orbit/Clock, Station
Pos/Vel, ERP, Atmos,...)...

Tracking Network

CDDIS

GNAACsRegional DCs

RNAACsOper. DCs

IGS Products
Orbit
Accuracy

Ultra-Rapid (IGU)

Final
(IGS)

Rapid
(IGR)

Observed

Predicted~2.5cm~2.5cm~3cm~5cm~100cm~150psRMS~50ps STD

~3ns RMS~1.5ns STD~5ns RMS~2.5ns STD~75ps RMS ~75ps RMS
Clock~20ps STD ~25ps STD

BroadcastLatency

12-18 days

17-41
hours

3-9 hours

realtime

realtime

Updatesevery
Thursdayat 17 UTCdaily

at 03, 09,
15, 21 UTC

at 03, 09,
15, 21 UTC

-

15min

15min

15min

15min

daily

SampleInterval

Orbit
Clock

Sat: 30s
5min
15min
15min
Stn: 5min(2009/8, http://igscb.jpl.nasa.gov/)

daily

IGS Real-time Service• Developed by IGS-RTPP– RTCM v.3 MT1057-1068 (SSR)– Corrections to broadcast ephemeris– Real-time NTRIP stream– Interval: 10 s, Latency: 5 - 10 s
– GPS and GLONASS• Analysis Strategy– Orbit: fixed to IGU or estimated– Clock: estimated with IGS real-timetracking network

http://rts.igs.org

RT-PPP Performance with IGS
BKG: CLK10

BKG: CLK11 (GPS+GLO)

GSOC/DLR: CLK20

RMS: 3.8, 5.5, 7.7cm

RMS: 3.8, 5.0, 7.1cm

RMS: 4.0, 5.2, 6.9cm

ESA/ESOC: CLK31

ESA/ESOC: CLK51

TUW: CLK61

RMS: 14.0, 12.1, 23.4cm

RMS: 5.7, 5.4, 11.6cm

RMS: 23.3, 21.0, 25.0cm

2010/9/18 0:00-23:59, 1Hz, Kinematic PPP, NovAtel OEMV-3+GPS-702, RTKLIB 2.4.1

RTKLIB Practice (1)RTKLIB• An Open Source Software
Package for GNSS Positioning– Has been developed since 2006
– The latest version 2.4.2 p12
distributed under BSD license• Portable APIs and Useful APs– "All-in-one" package for Windows– CLI APs for any environments

http://www.rtklib.com or
https://github.com/tomojitakasu/RTKLIBRTKLIB: Application

Reference
StationY. Ohta et al., Quasi real-time fault model estimation for near-field tsunami forecasting base on
RTK-GPS analysis: Application to the 2011 Tohoku-Oki earthquake (Mw 9.0), JGR-solid earth, 2012

RTKLIB: History••••

2006/4 v.0.0.0
2007/1 v.1.0.0
2008/7 v.2.1.0
2009/1 v.2.2.0• 2009/5 v.2.2.1• 2009/12 v.2.3.0• 2010/8 v.2.4.0• 2011/6 v.2.4.1• 2013/4 v.2.4.2• 2016/12 v.2.4.3

First version for RTK+C program lecture
Simple post processing AP
Add APs, support medium-range
Add real-time AP, support NTRIP,
start to distribute as Open Source S/W
Support RTCM, NRTK, many receivers
Support GLONASS, several receivers
Support PPP Real-time/Post-processing
PPP and Long-baseline RTK (<1000 km)
Support QZSS, JAVAD receiver, …
Support Galileo, Enable BeiDou, …
TBD

RTKLIB: Features• Standard and precise positioning algorithms with:– GPS, GLONASS, QZSS, Galileo, BeiDou and SBAS

• Real-time and post-processing by various modes:– Single, SBAS, DGPS, RTK, Static, Moving-base and PPP• Supports many formats/protocols and receivers:– RINEX 2/3, RTCM 2/3, BINEX, NTRIP 1.0, NMEA0183, SP3,RINEX CLK, ANTEX, NGS PCV, IONEX, RTCA-DO-229, EMS,
– NovAtel, JAVAD, Hemisphere, u-blox, SkyTraq, NVS, …

• Supports real-time communication via:
– Serial, TCP/IP, NTRIP and file streams

RTKLIB: GUI APs
RTKNAVI
RTKPLOTSTRSVRNTRIPSRCBROWSRTKPOST

RTKGETRTKCONVRTKLIB: CLI APs• RNX2RTKP (rnx2rtkp)
Post-processing Positioning• RTKRCV (rtkrcv)
Real-time Positioning• CONVBIN (convbin)
RINEX Translator• STR2STR (str2str)
Stream Server• POS2KML (pos2kml)
Google Earth Converter
CLI Command Reference

RTKLIB: Package Structure
rtklib_2.4.2.zip
/src

/rcv
/bin
/data
/app
/rtknavi/strsvr/rtkpost/rtkpost_mkl/rtkplot/rtkconv/srctblbrows/rtkrcv/rnx2rtkp/pos2kml/convbin/str2str/appcmn
/icon
/mkl
/test
/util
/doc

: Source programs of RTKLIB libraries: Source programs depending on GPS/GNSS receiv.
: Executable binary APs and DLLs for Windows: Sample data for APs: Build environment for APs: RTKNAVI (GUI): STRSVR (GUI): RTKPOST (GUI): RTKPOST_MKL (GUI): RTKPLOT (GUI): RTKCONV (GUI): NTRIP source table browser (GUI): RTKRCV (console): RNX2RTKP (console): POS2KML (console): CONVBIN (console): STR2STR (console): Common routines for GUI APs: Icon data for GUI APs: Intel MKL libraries for Borland environment: Test program and data
: Utilities: Document files

RTKLIB: APIs/* matrix and vector functions */mat(),imat(),zeros(),eye(),dot(),norm(),matcpy(),matmul(),matinv(),solve(),lsq(),filter(),smoother(),matprint(),matfprint()/* time and string functions */str2num(),str2time(),time2str(),epoch2time(),time2epoch(),gpst2time(),time2gpst(),timeadd(),timediff(),gpst2utc(),utc2gpst(),timeget(),time2doy(),adjgpsweek(),tickget(),sleepms()/* coordinates functions */ecef2pos(),pos2ecef(),ecef2enu(),enu2ecef(),covenu(),covecef(),xyz2enu(),geoidh(),loaddatump(),tokyo2jgd(),jgd2tokyo()/* input/output functions */readpcv(),readpos(),sortobs(),uniqeph(),screent()/* positioning models */eph2pos(),geph2pos(),satpos(),satposv(),satposiode(),satazel(),geodist(),dops(),ionmodel(),ionmapf(),tropmodel(),tropmapf(),
antmodel(),csmooth()/* single-point positioning */pntpos(),pntvel()/* rinex functions */readrnx(),readrnxt(),outrnxobsh(),outrnxnavh(),outrnxnavb(),uncompress(),convrnx()/* precise ephemeris functions */readsp3(),readsap(),eph2posp(),satposp()/* receiver raw data functions */getbitu(),getbits(),crc32(),crc24q(),decode_word(),decode_frame(),init_raw(),free_raw(),input_raw(),input_rawf(),input_oem4(),
input_oem3(),input_ubx(),input_ss2(),input_cres(),input_oem4f(),input_oem3f(),input_ubxf(),input_ss2f(),input_cresf()/* rtcm functions */init_rtcm(),free_rtcm(),input_rtcm2(),input_rtcm3(),input_rtcm2f(),input_rtcm3f()/* solution functions */readsol(),readsolt(),outsolheads(),outsols(),outsolexs(),outsolhead(),outsol(),outsolex(),setsolopt(),setsolformat(),outnmea_rmc(),outnmea_gga(),outnmea_gsa(),outnmea_gsv(),/* SBAS functions */sbsreadmsg(),sbsreadmsgt(),sbsoutmsg(),sbsupdatestat(),sbsdecodemsg(),sbssatpos(),sbspntpos()/* integer least-square estimation */lambda()/* realtime kinematic positioning */rtkinit(),rtkfree(),rtkpos()/* post-processing positioning */postpos(),postposopt(),readopts(),writeopts()/* stream data input/output */strinitcom(),strinit(),strlock(),strunlock(),stropen(),strclose(),strread(),strwrite(),strsync(),strstat(),strsum(), strsetopt(),
strgettime()/* stream server functions */strsvrinit(),strsvrstart(),strsvrstop(),strsvrstat()/* rtk server functions */rtksvrinit(),rtksvrstart(),rtksvrstop(),rtksvrlock(),rtksvrunlock(),rtksvrostat(),rtksvrsstat() ...

RTKLIB: Supported Receivers
Data Message Types
GLONASS
ION/UTC
Ephemeris Parameters

Format

GPS Raw
Meas Data

GLONASS
Raw Meas

GPS
Ephemeris

RTCM v.2.3

Type 18, 19

Type 18, 19

Type 17-

RTCM v.3.1

Type 1002,
1004

Type 1010,
1012

Type 1019

Type 1020

NovAtelOEM4/V,
OEMStar
NovAtelOEM3

RANGEB,RANGEB,
GLORANGECMPB RANGECMPB RAWEPHEMB EPHEMERISB

NovAtelSuperstar II
u-blox
LEA-4T,
LEA-5T
Hemisphere
Crescent,
EclipseSkyTraq
S1315F

Antenna
Info

SBAS
Messages

Others-Type 3, 22-

Type 1, 9,
14, 16-

Type 1005,
1006, 1007,
1008, 1033-

SSR
corrections

IONUTCB-

RAWWAASFRAMEB

-

RGEB,
RGED

-

REPB

-

IONB, UTCB

-

FRMB

-

ID#23

-

ID#22

-

-

-

ID#67

ID#20,#21

UBX
RXM-RAW-UBXRXM-SFRB-UBX
RXM-SFRB-UBX
RXM-SFRB-bin 96-bin 95-bin 94-bin 80--

msg 0xE0
(224)

-

-

[NE],[LD][IO],[UO],
[GD]

-

[WD]

msg 0xDC(220)[~~],[::],[RD],[SI],[NN],[TC],QZSS Data,
Galileo Data-

msg 0x26-

msg 0x03

msg 0xDD
msg 0xE0
(221)
(224)
[R*],[r*],[*R], [R*],[r*],[*R],JAVAD[*r],[P*],[p*], [*r],[P*],[p*], [GE],[GD],(GRIL/GREIS) [*p],[D*],[*d], [*p],[D*],[*d],[gd][E*],[*E],[F*] [E*],[*E],[F*]Furunomsg 0x08
msg 0x24
GW10 II

msg 0x20

Multi-GNSS Support
GPS (12)
GLONASS (8)Galileo (4)QZSS (1)BeiDou (10)SBAS (4)2013-06-12 10:20 GPST
Visibility at Tokyo by RTKPLOT# Total (39)
(El>10deg)

RTKLIB: References

rtklib_2.4.2/doc/manual_2.4.2.pdf

http://www.rtklib.com

RTKLIB Practice (1)• Install RTKLIB• Setup Receivers and Antennas• Use RTKLIB in Post Processing Mode
• RTKLIB in Real-Time Mode (demo)

RTK Practice
Reference
StationCommunication Link

Rover
Receiver• Post processing: Observation and Navigation
data are required (RINEX).
• Real-Time: Communication link anddifferential data reception are required(RTCM/NTRIP).

RTCM• The standard for differential global navigation
satellite system was defined in RTCM Special
Committee 104 and its current version is
Version 3. RTCM standard for differential global
navigation satellite services are communication
protocols between reference stations andmobile receivers which allow very high accurate
positioning, when compared with positioning
system without augmentation.

NTRIP• The NTRIP was also defined in the RTCM
Special Committee 104. NTRIP stands for“Networked Transport for RTCM via Internet
Protocol”. It is based on Hypertext transfer
Protocol version 1.1 and the intention is todisseminate differential correction data
through the internet.

https://igs.bkg.bund.de/index/index

Install RTKLIB• Copy the following directory and files in the USB
memory to your laptop PC.
School_RTK_2017\RTKLIB_bin-master.zip\u-centersetup_v8.26.zip\rawdata\car (u-blox, NetR9, POSLVX)\rooftop (u-blox, SkyTraq, NetR9)
You can refer to the latest update:https://github.com/tomojitakasu/RTKLIB

u-blox NEO-M8P

https://www.u-blox.com/en/product/neo-m8p

Setup u-blox Receiver/u-center• Install Support S/W to your laptop PC– u-blox u-center(u-centersetup_v8.26.zip)
u-bloxu-center v8.26

u-blox NEO-M8P-2
Mini-EVK Card + antenna
micro
USB

your Laptop PC

Connection• Start u-center and select Receiver->Port• You will see COM*. You can check your COM port inyour laptop’s devise manager• If you have any difficulties(win10), please catch us.

Firmware Check• View->Message View->UBX->MON->VER

Baud rate Check• View->Message View->UBX->CFG->PRT• Please change from 9600 to 115200

If you want to change the rate…
• View->Message View->UBX->CFG->RATE• Please change the measurement periodIf you want to save the raw-data…
• View->Message View->UBX->RXM->”RAWX”
and “SFRBX”• Right click->Enable Message

u-center (my desktop movie)• Connection• Single point positioning• RTK was valid using NTRIP of base station,(via same antenna, perfect condition)• Switch from GPS/QZS/GLO to GPS/QZS/BEI
Please check them by yourself after you go back to home.
If you need an information how to set the reference station,please refer to the website (GNSS TUTOR).
http://www.denshi.e.kaiyodai.ac.jp/gnss_tutor/experiment.html

RTKCONV• When you post-process of GNSS raw data, RINEX format isquite popular.
• You can convert u-blox/SkyTraq raw data to RINEX format
using rtkconv.exe.
• In the case of Trimble T02 file, you can use “Convert To RINEX”
which is available in the Trimble website.

Use RTKLIB (1)• Execute RTKLAUNCH.
RTKLIB_bin-master\bin\rtklaunch.exe

RTKPLOT STRSVR NTRIPBRS RTEGETRTKCONV RTKPOST RTKNAVI

Use RTKLIB (2)• Execute RTKPOST by
RTKLAUNCH• Execute Menu of RTKPLOT:
rawdata\rooftop\
netr9_ref.17o and netr9_ref.nav• Click here

1h data was obtained on 20th July 2017 using NetR9 on the rooftop.
2017/7/20 5:00:00-5:59:59 (GPST)

Use RTKLIB (3)Satellite ID
G: GPS
R: GLO
E: GAL
J: QZS
C: BEI

Use RTKLIB (4)Skyplot# of Visible Satellites and DOPUse RTKLIB (5)RTKPLOT - Options

OBS Data Options

Solution Data Options

Common Options

Use RTKLIB (6)RTKPOST - Options
Setting1

OutputSingle Point Positioning

Coordinate Origin
If you change the coordinate origin
as a precise reference position,(35.66633461, 139.7922008, 59.741)
you see bias like below.

DGNSS• Precise rover position(LAT/LON/HGT):
35.66627025 139.79226723 59.33

RTK-GNSS2 receivers were set simultaneously• Trimble NetR9 with Trimble antenna• u-blox M8P with YOKOWO antenna• For the equal comparison, same settings wereapplied.
• GPS/BEI + Instantaneous.

Similar test using u-blox

Or, netr9_rov.17ou-blox M8P results

NetR9 results

RTKLIB (my desktop movie)• Connect u-blox M8P• Execute RTKNAVI• RTK was valid using NTRIP of base station(NetR9) via the same antenna under perfectcondition (GQB).
• GQR was also valid but GLONASS ambiguity
resolution is set OFF.
Please check them by yourself after you go back to home.
If you need an information how to set the reference station,please refer to the website (GNSS TUTOR).
http://www.denshi.e.kaiyodai.ac.jp/gnss_tutor/experiment.html

How to connect (my desktop)

Internet

u-center / RTKLIBInternet

Base station(Ntrip server)

Rover station
Correction data is received via internet
GNSS raw data is received via USB-Serial
You can switch Desktop to Laptop/Pad/Raspberry Pi

RTKNAVI - Options
If you set GQR and it doesn’t fix, please try it again
by changing the setting of Integer Ambiguity Res “OFF”.

u-blox M8P DGNSS (GB)Code-phase accuracy is quite
important for RTK performance

Limited Coverage of RTK• Normally, the coverage of RTK is 10-20km. It strongly
depends on the ionospheric activity.
• But, the recent commercial RTK engine can cover up
to 50-100km.
• Also, you can use VRS/FKP correction service. The
commercial company produces real-time correction
data (Ntrip) using several base stations.
• QZSS will provide similar correction data throughthe L6 signal (inside Japan). It is challenging because
message bit-rate is 2Kbps.

PPP does not have limitation in area
• PPP provides precise orbit and clock of GNSS.
• It means that you have to remove
ionospheric/tropospheric errors as much as
possible. It takes 5-30 minutes and depends
on the ionosphere model you have.
• QZSS is going to test PPP correction data
through the L6 signal. In fact, we have tested
it for serval years by JAXA (MADOCA).

RTKLIB Practice (2)Car data and field test
• Car data is post-processed using RTKLIB• Homework• RTK field test using u-blox M8P (8 groups)

Car data• 2017/7/19 8:24:20 – 8:57:20 (GPST)• Total 9900 epochs in 5Hz• Near university campus (normal urban)• u-blox M8T and Trimble NetR9 for both Roverand reference station• You can compare these two receivers• Single-frequency or dual-frequency ?
• What is the best setting ?

Settings of u-blox M8P

PLOT

Q=1

If you set minimum C/N0 ,28074635

If you remove QZS ,46354103

If you use NetR9 ,46356810

If you use dual-frequency ,68108477

Comparing two POS files (RTKPLOT)

Previous test result

POSLVX result(Post-processed RTK/IMU/Speed)
Just drug and drop of “poslvx.pos” into RTKPLOT

What happens if you click “1-2” ?

RTKPLOT 1-2

6-7 epochs were over 20-30 cm
in horizontal direction

Homework• Please try to find the best setting of RTKLIB using theu-blox data (both ref and rover).
• “Best” means highest number of fixes within 30cm
based on POSLVX file.

RTK field test using M8P/M8T(Post-processed)• Please check your memory obtained through this class.
It is not difficult.
• All you need is two observation files (base and rover) +navigation file.
• Probably, Netr9 can be used as a base station. You
need to obtain the observation data at rover.
• You bring your laptop with ublox receiver and antenna.
you need to check the configuration of your ublox.
Then, please just click record in the u-center. Or you
can also use RTKLIB to record the raw-data.

Simultaneous data is required
You need to prepare the raw-data at base station
to include your period at rover.
Base
time

Rover
You recorded your raw-data for this period

timeFish !

Any questions ?
nkubo@kaiyodai.ac.jp

Following pages are complements of GNSS
and more details about precise positioning
especially PPP including MADOCA.

Time Systems• Time Systems– TAI: International Atomic Time– UTC: Coordinated Universal Time– Local Time (JST, EDT, ...)
– UT0, UT1, UT2: Universal Time
– GMST: Greenwich Mean Sidereal Time
– GPS Time
– GLONASS Time– ...

Time System Conversion
TAI to UTC:

tUTC  tTAI  (UTC  TAI )UTC to UT1:

tUT1  tUTC  (UT1  UTC)UT1 to GMST:

UTC-TAI (s)-25

1990/1/1--30

1996/1/1--26

1991/1/1--31

1997/7/1--27

1992/7/1--32

1999/1/1--28

1993/7/1--33

2006/1/1--29

1994/7/1--34

2009/1/1-

GMST0h UT 1  24110.54841 8640184.812866T 'u 0.093104T 'u 2 6.2  106 T 'u 3
GMST  GMST0h UT 1  r (tUT 1  t0h UT 1)

r  1.0027379093
50795 5.90061011T 'u 5.9 1015T 'u 2

T 'u  d 'u / 36525 d 'u : number of days elapsed since 2000 Jan 1, 12h UT1GPS Time to TAI:tTAI  tGPST  19 s

GPS Time to UTC:

tUTC  tGPST  (tLS  A0  A1(tGPST  tot ))Coordinate Systems• ECEF: Earth-Centered Earth-Fixed– ITRF– WGS 84: US (GPS)– PZ90: Russia (GLONASS), ...

Reference
Pole

z

Earth
Center• ECI: Earth-Centered Inertial– ICRF: International Celestial
Reference Frame• ECI-ECEF Connection– Precession/Nutation Model– EOP: Earth Orientation Parametersyx

Reference
meridian

ECEF

ITRF
• International Terrestrial Reference Frame– A "Realization" of Maintained by IERS
– GPS, VLBI, SLR, DORIS Site Position/Velocity List
– ITRF2005, ITRF2000, ITRF97, ITRF96, ...
VLBI: Very Long Baseline Interferometry
ITRS: International Terrestrial Reference System
SLR: Satellite Laser Ranging
IERS: International Earth Rotation Service
DORIS: Doppler Orbit determination and Radiopositioning Integrated on Satellite

http://itrf.ensg.ign.fr/ITRF_solutions/2005/ITRF2005.php

ECEF to ECI Transformation
IRP

Z

ECEF
(ITRF)

Z

IRP

yP



P



A

A

CEP

CEP

-xP

CEP

Z

Y

'

Ecliptic of date
180E
90W

IRM

Mean of
Mean equator
Dateof dateTrue equatorof date

X

O

O


'

Y
90E

Y

A

0E
X

Z

Z

(2)

CEP

(1)
True of
Date

Mean equatorof dateTrue equatorof date


Y

GST
X

Ecliptic at epoch
J2000.0

Ecliptic of dateO

P : Precession

PJ2000

P

(3)

IRP
IRM

N : NutationXJ2000O

J200090°A'

Ecliptic ofdate

W : Polar MotionX

90°+zA

GST  GMST   cos A
 0". 00264sin  0". 000063sin 2

Amean equator
at epoch
J2000.0Y

ECI(ICRF)

reci  PNRz (GST)Wrecef

 RZ ( A ) RY ( A ) RZ ( z A ) RX ( A ) RZ ( ) RX ( A   ) RZ (GST) RX ( yP ) RY ( xP )recef

(3)

(2)

(1)

EOP: Earth Orientation Parameters
Earth Rotation Angle:
UT1-UTC

Yp(mas)UT1-UTC (ms)Polar Motion:
Xp, Yp3m
Xp (mas)

1960

1970

1980

IERS C04 Series (1962/1/1-2009/8/11)

1990

2000

Ellipsoid and Datum
GRS 80

WGS 84a (m)63781376378137f

1/298.257222
101

1/298.257223
563

GM(m3/s2)3986005.000
x 1083986004.418
x 108

Ellipsoid:rr  ( x, y, z )T

z

b

h

a(1  e )x,y plane

r

2

'

N


a

Lat/Lon/Height to ECEF:
e2  f (2  f )N

 ' : Geocentric Latitude  : Longitude
 : Geodetic Latitude
h : Ellipsoidal Heighta
1  e 2 sin2  ( N  h) cos cos  
rr   ( N  h) cos sin   ( N (1  e 2 )  h) sin GeoidH : Geodetic Height

Geopotential:



 n
n

GM 
a


V (r , ' ,  )   (CnmYnmc  SnmYnms ) Geoid
1 
r 
r

 n  2 m 0  

EGM96 Geoid ModelhEllipsoidSpherical Harmonics
Spherical harmonic functions:
Yn0  Yn0c
Ynmc  Pnm (sin ' ) cos mYnms  Pnm (sin ' ) sin m

Legendre function:
Pnm  N nmPnm , P00 ( x)  1, P10 ( x)  x
Pn 1, n ( x)  0,
Pnn ( x)  (2n  1)(1  x 2 )1/ 2 Pn 1, n 1 ( x)Pnm ( x) 

(2n  1) xPn 1, m ( x)  (n  m  1) Pn  2, m ( x)nm

2n  1N nm   2(2n  1)(n  m)!
(n  m)!
(m  0)(m  0)Coordinates Transformation
Helmert Transformation (A to B): x T1 
 1
 
 

 y    T2   (1  D) R3
z
 
 R
  B  T3 
 2

 R3
1
R1

R2  x  
 R1  y 
1  z  A

- T1, T2, T3 : Translation along coordinate axis
-D
: Scale factor- R1, R2, R3 : Rotation of coordinate axis
CoordinatesA
ITRF2005

B

T1
(mm)

T2
(mm)

T3
(mm)

D
(10-9)

R1
(mas)

R2
(mas)

R3
(mas)

0.1

-0.8

-5.8

0.40

0.00

0.00

0.00

-0.2/y0.1/y-1.8/y0.08/y 0.00/y 0.00/y 0.00/y

ITRF2000(Epoch 2000.0)

Ionospheric Delay
Ionospheric Delay Model:
n2  1 

n

X
YT 2
1  iZ 2(1  X  iZ )

 1  X  1  f N2 / f 2 ( L  band)YT 44(1  X  iZ )2

 YL 2: Appleton-Hartree Formula
N ee 2

1  f N2 / f 2  1  f N2 / 2 f 2  1  40.30Ne / f 2

f N2 



TEC: Total Electron Content

I rs  40.30Ne / f 2dl  40.30  1016TEC / f 2

4  0me2: plasma frequency

Electron Density (Ne):

IRI-2007 model: 2009/7/31 0:00 Tokyo (http://modelweb.gsfc.nasa.gov/models/iri.html)

Solar Cycle
International Sunspot Number (ISN): 1700-2009
20 21 22 23

by SIDC (Solar Influences Data Analysis Center) in Belglum (http://sidc.oma.be)Solar Cycle Prediction: Cycle 24
23

24

24

by NOAA SWPC (Space Weather Prediction Center) (http://www.swpc.noaa.gov/SolarCycle)

LC: Linear CombinationC  a1  b2  cP1  dP2 (1  11, 2  22 )L1

L1 Carrier-Phase

1

0

0

0

Wave Ionos Typical
Length Effect Noise(cm) wrt L1 (cm)
19.0
1.0
0.3

L2

L2 Carrier-Phase

0

1

0

0

24.4

1.6

0.3

LC/L3

Iono-Free Phase

C1

C2

0

0

-

0.0

0.9

1

-1

0

0

-

0.6

0.4

LC

LG/L4 Geometry-Free Phase

Coefficients
a

b

c

d

WL

Wide-Lane PhaseW / 1 W / 2

0

0

86.2

1.3

1.7

NL

Narrow-Lane PhaseN / 1 N / 2

0

0

10.7

1.3

1.7

MW

Melbourne-Wübbena W / 1 W / 2 N / 1 N / 2

86.2

0.0

21

MP1

L1-Multipath

2C2  1

2C2

1

0

-

0.0

30

MP2

L2-Multipath

2C1

2C1  1

0

1

-

0.0

30

C1  f12 /( f12  f 22 ), C2   f 22 /( f12  f 22 ), W  1/(1/ 1  1/ 2 ), N  1/(1/ 1  1/ 2 )

Single Layer Model
Ionospheric Delay Model:I

40.30  1016
f2

1 40.30  1016
TEC 
 VTEC(t , pp ,  pp )2
cos z '
f

Satellite

IPP Position/Slant Factor:z  π/ 2  El
z'  arcsin

Re sin z, α  z  z'
Re  H ion

 pp  arcsin(cosα sin  sinα cos cos Az)
λ pp  λ  arcsin

sinα sin Az

 pp

IPP: Ionospheric
Pierce Point
z'
Hion

z
Ionosphere

ReceiverEarthRe

Ionospheric TEC Grid

2009/7/31 0:00

2009/7/31 2:00

2009/7/31 4:00

2009/7/31 6:00

2009/7/31 8:00

2009/7/31 10:00

2009/7/31 12:00

2009/7/31 14:00

2009/7/31 16:00

2009/7/31 18:00
2009/7/31 20:00(IGS TEC Final, GPS Time)

2009/7/31 22:00

Tropospheric Delay
Tropospheric Delay Model:
T  mh ( El)ZHD  mw ( El)ZW D
ZHD 

0.0022768p
1  0.00266cos 2  2.8  107 H: Zenith Hydrostatic Delay (m)ZW D : Zenith Wet Delay (m)mh (El) : Hydrostatic Mapping Function
mw (El) : Wet Mapping Function

ZenithDelay

ZWD to PWV (Precipitable Water Vapor):Tm  70.2  0.72T
PW V 

1  105mk 
Rv  k2  k1 v  3 
md Tm Rv  461, k1  77.6,
ZW D k2  71.98, k3  3.754 105

mv  18.0152, md  28.9644

Slant
El DelayMapping Function
a

1
1

m( El) sin(El) 

b
1 c
a

sin(El) bsin(El)  ca, b, c : Mapping Function
Coefficients

NMF, GMF, VMF1
Hydrostatic

Wet(2006/1/1-2007/12/31, TSKB, El=5deg)

Antenna Phase Center 1
Receiver Antenna
Phase Center:

Antenna
Phase
CenterAntenna Phase Center Variation (PCV)
Choke-Ring Type
Zero-Offset Typed r , pcv

L1d r, pco
Antenna
Reference
Point (ARP)

Antenna Phase
Center Offset

L2
z (U)
x (E)
y (N)

IGS Absolute Antenna Model (IGS05.PCV)

Antenna Phase Center 2
Satellite Antenna
Phase Center:

Mass Center ofSatellite

Antenna Phase
CenterAntenna Phased s pco Center Offset
Nadir Angle

s

d pcv
Earth

Satellite Coordinate to ECEF:
Esatecef  (e s x , e s y , e s z )esz  es y 

rs

rs, es 

es z  esse z  essrsun  r

s

Sun

es y

rsun  r s,esx  es y  esz

Satellite

y

x

esz

esx

z

Site Displacement• Displacement of Ground-Fixed Receiver– Solid Earth Tide
– Ocean Tide Loading (OTL)– Pole Tide
– Atmospheric Loading• Tide Model– IERS Conventions 1996/2003/2010– Ocean Loading: Schwiderski, GOT99.2/00.2, CSR 3.0/4.0,
FES99/2004, NAO99.b– M2,S2,N2,K2,K1,O1,P1,Q1,M1,Mm,Ssa

Earth Tides
Earth Tides Model

IERS Conventions 1996 + NAO99.b, 2007/1/1-1/31, TSKBPhase Wind-up Effect• Relative rotation between satellite and receiver antennas
effect to the measured phase of RHCP signal.


s
D

D

r / 2  N 
d pw   sign(ers  ( D s  Dr )) arccos

s
D Dr





D s  e xs  eus (eus  e xs )  eus  e sy : Dipole Vector of Satellite Antenna

Dr  er , x  ers (ers  er , x )  ers  er , y : Dipole Vector of Receiver Antenna
Eecef enu  (er , xT , er , yT , er , zT )T : ECEF to ENU Transformation Matrix

ers

N: LOS Vector from Receiver to Satellite Antenna: Integer Ambiguity

Relativistic Effects• Satellite/Receiver:– Frequency Shift by Earth Gravity (General Rel.)– Frequency Shift by Sun/Moon Gravity (General Rel.)– Second-Order Doppler-Shift by Motion (Special Rel.)• Signal Propagation:– Sagnac Correction (Rotating Coordinates)– Shapiro Time Delay Effect– Lense-Thirring Drag
Satellite Clock Bias/Rate Correction
2r s  v s
d rel  
+ Periodic Term:c2

Real-Time PPP via QZSS LEXGPS GLONASS

Galileo QZSSLEX Signal~ 1.7 Kbit/s

Reference
Stations

MADOCA

MGM-NetPreciseOrbit/Clock
Estimation

PPP Users

MADOCA (1)Multi-GNSS Advanced Demonstration toolfor Orbit and Clock Analysis• For real-time PPP service via QZSS LEX– Many (potential) applications over global area

• Precise orbit/clock for multi-GNSS constellation– Key-technology for future cm-class positioning• Brand-new codes developed from scratch– Optimized multi-threading design for recent CPU– As basis of future model improvements

MADOCA (2)Data Interfaces
MGM
-Net

Parameter Estimator

Data Interfaces

MGRTE
RDS

LMG

EKF

RTCM,
BINEX,
Javad

IGS
etc

QZSS MCS

Offline
DL

LEX
MT 12

MGEST
LSQ

RINEX,
SP3, ERPMGPLOT

MADOCA API

MADOCA (3)MADOCA (4)• QZSS-MS • MGM-Net • IGS • MGEX