Brazilian Network for Continuous Monitoring of the GNSS Systems - RBMC

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Description

Set of geodetic stations, equipped with high-performance GNSS (Global Navigation Satellite Systems) receivers, which provide observations to establish coordinates once a day or in real time.

Warning

The RBMC has been making available, since January 1, 2020, 1-second tracking interval files in the RINEX 3 format. Detailed information about the publication and instructions for editing these files can be found below at Information on data with 1 second. The data with tracking interval of 15 seconds in the RINEX 2 and RINEX 3 formats from all RBMC stations remain available in the same way, unchanged, using HATANAKA compression and in the RINEX 3 format, only for stations with multi-constellation equipment.

Information on one-second data

In the context of the RBMC Improvement and Modernization Project, the RBMC made available on January 1, 2020 data with tracking interval of 1 second, in the RINEX 3 format, from the stations listed below:

  • BELE (Belém/PA)
  • BOAV (Boa Vista/RR)
  • BRAZ (Brasília/DF)
  • MGBH (Belo Horizonte/MG)
  • POAL (Porto Alegre/RS)
  • POLI (São Paulo/SP)
  • POVE (Porto Velho/RO)
  • SALU (São Luis/MA)
  • SAVO (Salvador/BA)
  • TOPL (Palmas/TO)
  • UFPR (Curitiba/PR)

The project also foresees the gradual improvement of the stations with data in 1 second.

The data are organized into files of 15 minutes, due to the storage size, and are published every 15 minutes on the IBGE ftp server  ftp://geoftp.ibge.gov.br/informacoes_sobre_posicionamento_geodesico/rbmc/
dados_RINEX3_1s/
. The structure of the directories and the step by step for joining the files, as well as the conversion into the RINEX 2 version can be accessed here.

The data with tracking interval of 15 seconds in RINEX 2 and RINEX 3 from these stations and from the other RBMC stations remain available in the same way, unchanged, using HATANAKA compression, and in the RINEX 3 format, only for stations with multi-constellation equipment.

Information about the Hatanaka compression

Since December 21, 2017, the RBMC has made available all the observables tracked by the receivers, that is, depending on the model of the receiver, the observation file may contain all the observables tracked from the GPS, GLONASS, GALILEO and SBAS constellations, improving the post-processing service with respect to the number of observations and constellations. Thus, in order to reduce the size of the files and facilitate the download, we now use the HATANAKA compression format.

The HATANAKA compression algorithm was developed by Japanese researcher Yuki Hatanaka, from the Geospatial Information Authority of Japan (GSI). Its strategy consists of joining redundant information, thus allowing a significant reduction in the file size.

With the introduction of new GNSS constellations and the addition of new observable information implemented in the modernization of the systems, the observation files tend to significantly increase in size over the next years.

Therefore, we describe the major advantages of using Hatanaka:
1. Space saving in the storage devices;
2. Performance gains in the download;
3. Possibility of a larger time series of data online.

To decompress the file, the CRX2RNX program should be downloaded from the GSI page (http://terras.gsi.go.jp/ja/crx2rnx.html). Aiming at helping the users in the conversion, we made also available a step by step to carry out the procedure.

The CRX2RNX software made available by the GSI is freeware. Users are expected to notice what is described in the LICENSE.txt file.

Learn more about Hatanaka at https://www.unavco.org/software/data-processing/preprocessing/preprocessing.html#hatanaka 

Information about RINEX 3

The RINEX 3 format supports all the signals from the GPS, GLONASS, Galileo, BeiDou, IRNSS, QZSS and SBAS constellations. Therefore, the RBMC stations equipped with multi-constellation GNSS receivers, those able to track constellations other than GPS and GLONASS, started having their data made available in the RINEX 3 format as of August 30, 2018.

The files are made available daily with a interval of 15 seconds at ftp://geoftp.ibge.gov.br/informacoes_sobre_posicionamento_geodesico/rbmc/dados_RINEX3/, with double compression, Hatanaka (.crx) and gzip (.gz).

The navigation file is published apart in the /ano/orbitas/ directory.

The nomenclature of the files follows the universal structure described below:

tracking data file in the RINEX 3 format:
XXXX00BRA_R_AAAADDDHHMM_01D_15S_MO.crx.gz

XXXX00BRA – Station name, station type and country code;
R – File generated by a GNSS receiver;
AAAADDD0000 – Year, day of the year, hour and minute;
15S – tracking interval;
MO – Indicates it is an observation file;
crx – Hatanaka compression;
gz – Gzip.

Navigation file in the RINEX 3 format:
BRDC00WRD_R_AAAADDDHHMM_01D_MN.rnx.gz

MN – Indicates it is a navigation file

More information about the RINEX 3 format at https://kb.igs.org/hc/en-us/articles/201096516-IGS-Formats

Access to RINEX 3 data - ftp://geoftp.ibge.gov.br/informacoes_sobre_posicionamento_geodesico/rbmc/dados_RINEX3/

 

To access the RBMC-IP page, click here.

To access the RBMC Twitter, click here.