PROCESSING EVALUATION OF PROCESSING EVALUATION OF SIRGASSIRGAS--CON NETWORK BY IBGE CON NETWORK BY IBGE

ANALYSIS CENTERANALYSIS CENTERSonia Maria Alves Costa

Alberto Luis da SilvaJhonnes Alberto Vaz

IAG2009 04/09/2009 – Buenos Aires / Argentina

ContentContent

� Motivation

� SIRGAS-CON Network

� SIRGAS Analysis Centres

� Processing Strategy� Processing Strategy

� Results

� Time Series of Coordinates

� Summary and Future Work

MotivationMotivation

� IBGE is responsible for the definition, maintenance and

provide the access to the National Spatial Reference System

���� Brazilian Geodetic System - SGB ;

� 1997: Started the establishment of the active geodetic

network ���� Brazilian Network for Continuous Monitoring of

GNSS (RBMC) ���� The main Reference Frame in the country

� 2005: Adoption of Geocentric Reference System for the

Americas – SIRGAS, SIRGAS2000

� 2006: Network expansion from 24 to 66 (july 2009)

SIRGAS Processing CenterSIRGAS Processing Center–– IBGEIBGE

� The network maintenance and control is done through the

daily data processing.

� Monitoring the temporal variation of the coordinate s

together with the data quality;

� Data processing since January 2003 (GPS week 1199);

� Software: Bernese GPS Software 5.0 – BPE;

� Results: Daily and weekly (combined) loosely constrained

solutions in SINEX format (IBG wwww 7.SNX).

SIRGASSIRGAS--CON NetworkCON Network

� Currently, SIRGAS Reference Frame is realized by a

network of continuously operating GNSS stations with

high precision coordinates (associated to a specific

reference epoch) and their changes over time (station

velocities)velocities)

� Composed of more than 190 stations, (46 are part of the

IGS network).

� SIRGAS Analysis Centers: american institutions with the

task to provide control of the permanent stations and

maintenance of SIRGAS Reference Frame;

SIRGAS Analysis CentersSIRGAS Analysis Centers

�Local Processing Centers:

� Instituto Brasileiro de Geografia e Estatística - IB GE;

� Instituto Geográfico Agustín Codazzi – IGAC;

� Instituto de Geodésia e Geodinâmica da Universidade

Nacional de Cuyo, IGG -CIMA;Nacional de Cuyo, IGG -CIMA;

�IGS Regional Analysis Center – IGS-RNAAC-SIR:

� Deutsches Geodätisches Forschungsintitut – DGFI;

�Combination Centers:

� Instituto Brasileiro de Geografia e Estatística – IB GE;

� Deutsches Geodätisches Forschungsintitut – DGFI;

SIRGASSIRGAS--CON NetworkCON Network

� Due to the increasing number of SIRGAS-CON stations, it

was divided in two levels :

� (1) SIRGAS-CON-C ����Core network, the densification of the

ITRF in Latin America, with stable fundamental stations tha t

guarantee the consistency and precision of SIRGAS over

time.

� (2) SIRGAS-CON-D ���� a network composed of several

national densifications, including the reference station s of

SIRGAS-CON-C.

� SIRGAS-CON Realization

(status : August 2009)

Source: www.sirgas.org www.sirgas.org

SIRGAS Analysis Centers (2/2)SIRGAS Analysis Centers (2/2)

�Experimental Processing Centers:

� Serviço Geográfico Militar do Uruguai – SGM-UY;

� Laboratório de Geodésia Física e Satelital, Univers idade

de Zulia – LGFS-LUZ;

� Instituto Geográfico Militar do Equador, IGM -Ec;� Instituto Geográfico Militar do Equador, IGM -Ec;

� Instituto Nacional de Estatística e Geografia, INEG I

(México)

� Instituto Geográfico Nacional da Argentina (IGN-Ar)

� > 100 stations:

31 IGS stations

> 70 regional stations

Currently Processed Stations - IBGE

Zenith delay estimated each 2 hours (12 daily corrections p/station)

Zenith delay estimated each 2 hours (12 daily corrections p/station)

Troposphere

Niell dry componentNiell dry componentA priori troposphere model

IGS final - IGS05EOP week

IGS final - ITRF2000/IGb00EOP week

Orbits/EOP

SHORTESTSHORTESTBaseline formation strategy

03º10ºElevation angle

30 sec30 secSampling rate

Bernese 5.0 ( BPE mode)Bernese 5.0 ( BPE mode)Software used

Double DifferenceDouble DifferenceObservations

After week 1400Week 1199 to 1400Processing Date

Processing Strategy

All stations constrained (σσσσ=±±±±1m)OUTPUT FILES: SINEX

4 IGS stations - (BRAZ, LPGS, RIOG and SANT) are used to constrain the weekly solution(σσσσ=±±±±1mm)OUTPUT FILES: SINEX

Weekly solutions

Constraint all the stations (σσσσ=±±±±1m)OUTPUT FILES: SINEX

Constraint solution in station BRAZ (σσσσ=±±±±1mm)OUTPUT FILES: SINEX

Daily solutions

IGS05_RIGSb00Coordinates and Velocities

Absolute (IGS_05)Absolute (IGS_05) and RelativePhase Center Variation

FES2004GOT00.2Ocean Loading Model

QIF strategy with GIM from CODEQIF strategy with GIM from CODEAmbiguity

daily corrections p/station)A priori sigmas applied with respect to prediction model Niell(wet component)-first parameter +/- 5 m absolute and +/-5 cm relative

daily corrections p/station)A priori sigmas applied with respect to prediction model Niell(wet component)-first parameter +/- 5 m absolute and +/- 5 cm relative

East

6

8

10

(mm

)

North

0

2

4

6

8

10

1495

1497

1499

1501

1503

1505

1507

1509

1511

1513

1515

1517

1519

1521

1523

1525

1527

1529

1531

1533

1535

GPS week

(mm

)

Residuals RMS (weekly solutions) – IBGE X IGS05

North

East

1 mm

Up

0

2

4

6

8

10

1495

1497

1499

1501

1503

1505

1507

1509

1511

1513

1515

1517

1519

1521

1523

1525

1527

1529

1531

1533

1535

GPS week

(mm

)

0

2

4

6

1495

1497

1499

1501

1503

1505

1507

1509

1511

1513

1515

1517

1519

1521

1523

1525

1527

1529

1531

1533

1535

GPS week

(mm

)

Up

2 mm

5 mm

Residuals RMS (weekly solutions) – IBGE X DGFI

Weekly Root Mean Square ���� IBGE X DGFI

North

East

2 mm

Up

GPS week

2 mm

4 mm

Residuals RMS (weekly solutions) – IBGE X CIMAWeekly Root Mean Square ���� IBGE X CIMA

North

East

2 mm

2 mm

Up

GPS week

2 mm

4 mm

Residuals RMS (weekly solutions) – IBGE X IGAC

Weekly R oot M ean Square ���� IBGE X IGAC

North

East

2 mm

GPS week

Up

2 mm

4 mm

Estimated VelocitiesEstimated VelocitiesRIOD

SANT

Estimated VelocitiesEstimated Velocities�IBGE X VEMOS:

What is our interest ?What is our interest ?

�Seasonal movements;

�Local behavior (monument stability);

�Discontinuities or jumps in the coordinates time se ries;�Discontinuities or jumps in the coordinates time se ries;

Time Series – station POAL

Horizontal difference before and after antenna change = 1,7 cm

Time Series – station VARG

North

East

Horizontal difference First jump ~ 2,5 cm

Second jump ~ 4,4 cm

GPS week

East

Up

?

Time Series – station UBAT

North

East

Horizontal difference First jump ~ 4 cm

?Up

GPS week

Time Series – station NAUS

East

North

Up

East

GPS week

Distance between two stations

����

13 km

����

13 km

GPS

-4,0

-3,0

-2,0

-1,0

0,0

1,0

2,0

3,0

4,0

5,0

28/12/2005 28/06/2006 28/12/2006 28/06/2007 28/12/2007 28/06/2008 28/12/2008

Var

iaçã

o (c

m)

Linígrafo

-800,0

-600,0

-400,0

-200,0

0,0

200,0

400,0

600,0

800,0

28/12/2005 28/06/2006 28/12/2006 28/06/2007 28/12/2007 28/06/2008 28/12/2008

Var

iaçã

o (c

m)

Time Series – NAUS x hydrometric station

28/12/2005 28/06/2006 28/12/2006 28/06/2007 28/12/2007 28/06/2008 28/12/2008

Data

28/12/2005 28/06/2006 28/12/2006 28/06/2007 28/12/2007 28/06/2008 28/12/2008

Data

Linígrafo x GPS

28/12/2005 28/06/2006 28/12/2006 28/06/2007 28/12/2007 28/06/2008 28/12/2008

Data

Var

iaçã

o (c

m)

Linígrafo

GPS

Linígrafo x GPS - (Normalizado entre 1 e -1)

-1,0

-0,6

-0,2

0,2

0,6

1,0

28/12/2005 28/06/2006 28/12/2006 28/06/2007 28/12/2007 28/06/2008 28/12/2008

Data

Var

iaçã

o (c

m)

Linígrafo

GPS

~ 13 km

∆h ~ 8 cm / ano

Time Series – NAUS x hydrometric station

∆N ~ 12 m / ano

ResultsResults :: ftp://geoftp.ibge.gov.br/SIRGAS/

EXPERIMENTALEXPERIMENTAL

GraficosGraficos

CombinacaoCombinacao

Plots of the stations ´́́́time series and velocity

estimation

weekly report

weekly report from the combination

RelatoriosRelatorios

ResultadosResultados

SINEX (loosely)

CombinacaoCombinacaoProcessamentoProcessamento

CombinacaoCombinacaoProcessamentoProcessamento

SINEX (loosely and constrained)

weekly report

annual report

SummarySummary

� GPS processing is essential for the reference frame control

and maintenance;

� Results are consistent with the other processing centers;

� The velocity vectors and the temporal behavior of each

station will be better defined and reliable, due to thestation will be better defined and reliable, due to the

increasing number of processed weeks

FutureFuture WorkWork

�New processing strategy (ambiguities resolution)�website;

Thank you for your attention!Thank you for your attention!

For more information: ibge@ibge.gov.brFor more information: ibge@ibge.gov.br

www.ibge.gov.br

IAG2009 04/09/2009 – Buenos Aires / Argentina