2 6b Fortes

Slide1: 

SIRGAS: Lessons Learned from More Than 10 Years of the Project Luiz Paulo Souto Fortes, PhD President of SIRGAS IBGE, Brazil AFREF Technical Workshop Cape Town, July 10th, 2006

Overview: 

Overview Background Project Structure SIRGAS 1995 Realization SIRGAS 2000 Realization Working Group I: Reference System Working Group II: Geocentric Datum Status of the adoption in the continent Example of an iniative to promote the adoption in Brazil Working Group III: Vertical Datum Next activities SIRGAS Publications Possible reasons for the SIRGAS success Difficulties Final remarks

Slide3: 

Source: Zurich-American Insurance Consequences of using reference systems that are not consistent !

SIRGAS: 

SIRGAS “SIstema de Referencia Geocentrico para América del Sur” “South American Geocentric Reference System” (until February 2001) “SIstema de Referencia Geocentrico para las AméricaS” “Geocentric Reference System for the Americas”

Background: 

Background Before SIRGAS South American countries adopted different reference systems  problems to define borders, for mapping, etc. PSAD56 SAD69 Bogotá Yacaré Campo Inchauspe Classical systems not accurate comparing to GPS Establishment of the SIRGAS Project Conference in October 1993, Assunción, Paraguay Sponsored by IAG, PAIGH and NIMA Objectives To define and establish a geocentric reference system for the continent  ITRF To define and establish a geocentric datum  GRS80 To define and establish a unified vertical datum

Slide6: 

Project Structure

The SIRGAS 95 Realization: 

The SIRGAS 95 Realization First SIRGAS GPS Campaign from May 26 to June 04, 1995 (10 days) 58 principal and 9 eccentric stations established one of the most precise continental networks in the world  < 2 cm Official results presented during the IAG Rio’97 Scientific Assembly WG III “Vertical Datum” created during the same event

Stations Occupied During the SIRGAS 95 GPS Campaign (total of 58): 

Stations Occupied During the SIRGAS 95 GPS Campaign (total of 58)

The SIRGAS2000 Realization: 

The SIRGAS2000 Realization Second SIRGAS GPS Campaign From May 10 to 19, 2000 (10 days) Repetition of first campaign, in order to support computation of velocity for the SIRGAS GPS stations Collection of GPS data for WG III activities Stations at tide gauges to support the link between the classical altimetric systems and the new unified one Stations close to international borders to facilitate the link between national vertical reference systems Participation of North America, Central America and the Caribbean 184 stations occupied in total Official results (coordinates and std.dev.) released in Feb 2003

Stations occupied during the SIRGAS 2000 GPS campaign (total of 184) : 

Stations occupied during the SIRGAS 2000 GPS campaign (total of 184)

Agreement of Individual Solutions with Combined SIRGAS2000 Solution: 

Agreement of Individual Solutions with Combined SIRGAS2000 Solution

SIRGAS2000 Parameters: 

SIRGAS2000 Parameters Densification of ITRF2000 in the Americas ITRF: International Terrestrial Reference Frame GRS80 ellipsoid aGRS80= 6378137 m (= aWGS84) fGRS80 =1/298.257222101 (fWGS84=1/298.257223563) Reference epoch: 2000.4

ITRF x WGS84: 

ITRF x WGS84

Velocity Field of South America (1/2): 

Velocity Field of South America (1/2) The following information was used SIRGAS 1995 GPS Campaign results Referred to ITRF94, epoch 1995.4 SIRGAS 2000 GPS Campaign results Referred to ITRF2000, epoch 2000.4 IGS RNAAC-SIR velocities Results of geodynamic projects in South America (CAP, CASA, SAGA, and SNAPP) Combining least-squares collocation and finite elements solutions Released in November 2003

Velocity Field of South America (2/2): 

Velocity Field of South America (2/2) ITRF 2000

SIRGAS Working Group I: 

SIRGAS Working Group I Responsible for the definition, realization and maintenance of the geocentric reference system Coordinated the two continental GPS campaigns in 1995 and 2000 Current priorities related to the continuous operating GPS stations in the continent which realizes the SIRGAS reference frame Improve the functioning of current stations Improve data transfer to data centers Support the establishment of new stations Set up processing centers in Latin America Current processing center at DGFI, Munich (IGS RNAAC-SIR) University of La Plata (Argentina), IBGE (Brazil), IGAC (Colombia) and INEGI (Mexico) Workshop in August 2006 in Rio de Janeiro

IGS RNAAC-SIR: 

IGS RNAAC-SIR

SIRGAS Working Group II: 

SIRGAS Working Group II Responsible for the establishment of the geocentric datum, for the promotion of the national geodetic networks´ connection to it as well as for the coordination of the densification of the SIRGAS reference frame in each member country Adoption of SIRGAS recommended by the 7th and 8th United Nations Regional Cartographic Conferences for the Americas (New York, Jan 2001 and June 2005, respectively) Many Latin American countries officially introduced SIRGAS as their national reference frame

Status of adoption of SIRGAS in the Americas: 

Status of adoption of SIRGAS in the Americas

Slide20: 

Its objetive is to collaborate and assist Brazilian efforts to promote the national adoption of a geocentric coordinate system (SIRGAS2000) compatible with modern satellite technologies. Project activities include technical issues, understanding the impacts caused by the adoption of this new coordinate system, and establishment of strong communication links with the user community. Products will be made available to users at the end of the project. National Geospatial Framework Project

Working Group III: 

Working Group III Responsible for the establishment of a unified vertical reference system in the continent, including the modernization of the existing height systems through their link to the new system Two types of heights Ellipsoidal (Geometric) Based on geopotential numbers (Physical) Current activities Continue to apply gravity corrections to spirit leveling data in order to compute geopotential numbers to be adjusted in the continent Continue to tie the vertical networks between neighboring countries Compute the reference geopotential W0 Improve the geoid/quasi-geoid using gravity information from terrestrial and satellite data Occupy tide gauges with GPS

SIRGAS Publications: 

SIRGAS Publications Edited by the Central Bureau (IBGE, Brazil) Two versions: Portuguese/Spanish and English Newsletter #1: Sep 1994 #2: Dec 1994 #3: Dec 1995 #4: Dec 1996 #5: Feb 1998 #6: Feb 2002 #7: Dec 2002 #8: Feb 2005 #9: Apr 2006 SIRGAS Final Report, Working Groups I and II Sep 1997, released during the IAG Rio’97 Statute Publications and official results available at the new SIRGAS webpage http://sirgas.igm.gov.ar

Possible Reasons for the SIRGAS Success (1/2): 

Possible Reasons for the SIRGAS Success (1/2) Establishment of a project structure with: An Executive Committee, responsible for all project decisions, composed by an official representative – principal and alternate - of each participating country, The appointment of the representatives demanded great effort (from Oct 93 to Sept 94!) After the majority of countries were participating, the remaining ones wanted to join the project! Small working groups composed by people – not countries´ representatives - with a great commitment to work! Participation of foreign scientific institutions supporting the project activities Some amount of regular annual financial resources ($$$) to organize meetings PAIGH and IAG

Possible Reasons for the SIRGAS Success (2/2): 

Possible Reasons for the SIRGAS Success (2/2) Only two official languages spoken in most of Latin America countries (Spanish and Portuguese) - inter-understandable Project implemented in steps: From 1993 to 2001 establishing a successful structure in South America Since 2001, including the remaining countries of Americas, especially from Latin America Frequent publishing of project results and information to all participants and other people/institutions across the world Creation of a network of contacts in the continent, useful for other initiatives Individual countries can have budget restrictions, but a group of them, working together, form a strong and powerful organization Cooperation, Cooperation, Cooperation !!!

Difficulties: 

Difficulties Changes of the people involved in the project, especially in military institutions Difficult to keep track of the contact person and to keep the continuity of the initiatives in the corresponding country Restricted resources of Latin American countries in general, especially for field work and international traveling Need for help from international/foreign partners and institutions, like IAG, PAIGH, DGFI, NGA, University of Hannover, BEK, IGS, etc. Dedicated participants need to accumulate their regular work activities with lots of extra work brought by the project Technically speaking, the establishment of the continental 3-D geometric framework was very successful due to the availability of GNSS technology; however, with respect to the physical heights, the work is even more challenging and runs in a much slower pace, considering the classical methodology involved

Final Remarks: 

Final Remarks The SIRGAS project encompasses all activities necessary to establish a modern geodetic framework in the continent, compatible with the most accurate positioning techniques currently available The adoption of an accurate and unified reference frame in the continent as the first layer of Spatial Data Infrastructures guarantees the consistency of information between countries Nowadays WGS84 can be considered coincident with SIRGAS2000  GPS results automatically referred to SIRGAS2000 SIRGAS has been very successful 12 project meetings held during the past 13 years One of the most successful international projects carried out under the umbrella of the International Association of Geodesy (IAG) SIRGAS activities are also carried out under the scope of IAG Commission 1 on Reference Frames, Subcommission 1.3b for Central and South America Especial efforts are being carried out in order to get Central America and Caribbean countries involved in the project

Slide27: 

SIRGAS fixes the problem !