gnss_info

Information about GNSS satellites and their constellations.

Provided C++ libraries

• libsatellite_metadata.so / igs_satellite_metadata.h: General information about satellites downloaded from IGS.
• liborbital_data.so / orbital_data_manager.h: Library that manages downloads of almanac/ephemeris data to support computing satellite orbits. It can also generate a sky view from given place and time.

Nodes

publish_all_satellites

An example node using IGSSatelliteMetadata to construct a list of all GNSS satellites that existed in a given time instant.

Published topics

• satellites (gnss_info_msgs/SatellitesList, latched): The list of satellites.

Parameters

• ~time (float, defaults to ros::Time::now() ): The reference time for which satellites should be looked up.
• ~only_active (bool, default true): Return only satellites active at the reference time.
• ~only_constellations (list of string): If nonempty, limits the published satellites to only those belonging to the listed constellations.
• ~only_signals (list of string): If nonempty, limits the published satellites to only those transmitting at least one of the listed signals.

publish_sky_view

An example node using OrbitalDataManager with EthzSatdbProvider to get approximate locations of satellites.

Published topics

• satellites_positions (gnss_info_msgs/SatellitesPositions, latched): ECEF positions of all satellites from satellites topic for which orbital data are available.
• sky_view (gnss_info_msgs/SkyView, latched): Sky view of all satellites from satellites topic which are visible from the last position received on position topic.

Subscribed topics

• satellites (gnss_info_msgs/SatellitesList): The list of satellites.
• position (geographic_msgs/GeoPoint): Reference position for the sky view.

Parameters

• ~elevation_mask_deg (float, default 5.0°): Minimum elevation of satellites to be considered in the sky view.
• ~refresh_rate (double, default 0.1 Hz): Rate at which updates of the positions should be published and recomputed.

sky_plot

A node turning gnss_info_msgs/SkyView into a plot of satellites.

Published topics

• sky_plot (sensor_msgs/Image): The sky plot.

Subscribed topics

• satellites (gnss_info_msgs/SatellitesList): The list of satellites.
• sky_view (gnss_info_msgs/SkyView): Sky view of some satellites.

Parameters

• ~plot_color (str, default “white”): Background color of the plot. Anything that matplotlib reads (e.g. #ABCDEF00).
• ~show_legend (bool, default True): Whether to show legend in the plot.
• ~show_labels (bool, default True): Whether to show labels of the individual satellites.
• ~show_title (bool, default True): Whether to show title with plot time and reference location.
• ~show_elevation_mask (bool, default True): Whether to show a greyed-out area in masked parts of the plot.
• ~width (int, default 840): Width of the plot in px.
• ~height (int, default 720): Height of the plot in px.
• ~dpi (float, default 120.0): DPI of the plot.
• ~only_constellations (str or list[str], default “”): Either a comma-separated list or a list of string defining which constellations to plot. If empty, everything is plotted.

Possible improvements:

• Get GPS outages from https://www.navcen.uscg.gov/sites/default/files/gps/sof/current_sof.sof .
• Get Galileo outages from NAGUs
  • https://www.gsc-europa.eu/sites/default/files/sites/all/files/UNP_UNUFN.txt
  • https://www.gsc-europa.eu/system-status/user-notifications-archived
• Precise orbits from http://ftp.aiub.unibe.ch/CODE_MGEX/CODE/2023/ (ORB.SP3 files)
  • gnsstk/core/lib/GNSSEph/EphemerisRange.hpp
  • gnsstk/core/lib/Geomatics/PreciseRange.cpp

Changelog for package gnss_info

1.0.2 (2024-02-27)

• Removed catkin_lint buildfarm hacks.
• Do not overwrite test data.
• Fixed CMake compatibility.
• Contributors: Martin Pecka

1.0.1 (2023-11-14)

• Added support for plotting GPSFix messages.
• Added tests.
• Refactored out NavLibraryOrbitalDataProvider.
• Extracted CacheIndex class.
• Extracted cache validity checking.
• Switched to std::filesystem.
• Extracted common functionality.
• Add computation of ECEF position covariance.
• Refactor out gnsstk_ros package.
• Added sky view and sky plot publishers.
• Initial commit
• Contributors: Martin Pecka