IBGE - The Brazilian Institute of Geography and Statistics makes available on its web site (www.ibge.gov.br) the PPP (Positioning by Precise Point), a free online service which processes data generated through GPS (Global Positioning System), in order to inform the latitude, longitude and altitude of points in the Brazilian territory.

The system will allow users of topographic and geodetic GPS equipment -  mainly used by professionals in the fields of engineering and surveying – to obtain high-precision coordinates in the Geocentric Reference System for the Americas (SIRGAS), the reference system officially used in Brazil. The software for coordinate processing is available on www.ppp.ibge.gov.br.

There are currently three categories of GPS equipment at use: recreational (or navigator), topographic and geodetic, and, except in the first one, it is necessary to process data before using them.

By launching the service, IBGE now provides, for the first time in Latin America, a processing tool for GPS data which will allow users without deep technical knowledge to obtain high-precision coordinates. Another advantage of PPP-IBGE is that professionals who make use of GPS for their activities will not need to buy a data processing software. With the system offered by the institute, little information will need to be sent in order that the procedure is done free of charge.

Once the coordinates calculated by IBGE are referred to in the Geocentric Reference System for the Americas (SIRGAS2000), the data obtained by users will be in accordance with the official pattern. 

The IBGE-PPP processes GPS data which have been collected in topographic or geodetic equipment, either moving or static ones. In order to use this service, the user must send IBGE information as described below:

1.    GPS data preferably zipped (to reduce receiving time of information by the system)

2.      The type and altitude of the antenna used in the survey.

The results will be sent in a few minutes, through the e-mail provided by the user at the submission of data for processing.

Only data collected after February 25, 2005 will be accepted, since on this date was SIRGAS officially adopted in Brazil. The data must be sent by users 48 after the end of collection.

IBGE-PPP makes use of the processing software CSRS-PPP, developed by the Geodetic Division of NRCan (Natural Resources of Canada). The license for using the system was made available to IBGE, for use in the national territory, through the National Geospatial Framework Project (PIGN), and object of cooperation between IBGE and the University of New Brunswick, in Canada, supported by the Canadian Agency of International Development (CIDA) and by the Brazilian Cooperation Agency (ABC).

See the three types of GPS equipment available

GPS for recreation or navigation is the one found in mobile telephones, cars, handheld computers, vessels, etc. It provides coordinates with lower precision, of approximately 9 meters for latitude and 15 meters for longitude. The results are obtained few moments after the appliance is turned on, without the need of any additional procedure.

It is the most common type of GPS nowadays, because it is low-cost and can be used in a big variety of activities. The topographic GPS is the one used by professionals in the field of engineering and surveying – for example, a topographer who needs to know the perimeter of a rural property. In this case, the topographer stops for some minutes at each point defining the perimeter, and the GPS collects data during this period. The data collected must be later processed in order to provide the points of interest. The expected accuracy in the use of this type of GPS may range from 20 to 50 cm.

There is also the geodetic GPS, which is even more precise. It is used by professionals of civil engineering and surveying for surveys which require precision of few centimeters (less than 10 cm) in coordinates, in applications such as the control of settling on a dam or bridge, measurement of the movements in the earth’s crust, etc. In order to obtain the coordinates, in this case, it is also necessary to provide the data collected.  

Know more about SIRGAS 2000

On February 25, 2005, the Geocentric Reference System for the Americas (SIRGAS2000), compatible with GPS, was officially adopted as a new reference for the Brazilian Geodetic (SGB) and for the National Cartographic System (SCN).

This means that, from 2014 on, after a transition period of 10 years, only information produced based the SIRGAS200 geodetic system will be considered valid. Such a decision was made in the realm of the

Project of Geodetic Referential Change, created in 2000, controlled by IBGE and formed by work groups with representatives of private and governmental institutions, universities and users who deal with georeferenced information.

A geodetic reference system is a coordinate system, used to represent earth characteristics, either physical or geometric. In practical terms, it is important for obtaining coordinates (latitude, longitude and altitude), which make it possible to represent and find any element of the earth’s surface on a map.

The fundamental difference between SIRGAS2000 and the referential previously used in Brazil is that the previous ones have a topocentric orientation, that is, the point of origin and orientation of systems is in the Earth’s surface; SIRGAS2000 has a geocentric orientation, that is, it adopts as the origin of the reference a point located in the center of Earth. By adopting the geocentric reference, it is possible to make direct use of GSP technology, an important tool in the update of maps, control of transporting company fleets, air, sea and land navigation at real time. Besides, the use of this system by Latin America will contribute to the end of a series of problems originated in the discrepancy between geographic coordinates presented by the GPS system and those found in the maps currently used in the continent.

Between the coordinates produced by previous references and SIRGAS2000 there is a spatial difference of dozens of meters, depending on the place where it is located.