GNSS-SDR can read assistance data from Extensible Markup Language (XML) files for faster Time-To-First-Fix, and can store navigation data decoded from GNSS signals in the same format. This folder provides XML Schemas that describe the XML files written by the PVT block. The shared type definitions used by the individual schemas are in common.xsd.

XSD (XML Schema Definition) is a World Wide Web Consortium (W3C) recommendation that specifies how to formally describe the elements in an XML document.

GPS L1 C/A

ephemeris_map.xsd - GPS NAV message ephemeris parameters.
iono_model.xsd - GPS NAV message ionospheric model parameters.
utc_model.xsd - GPS NAV message UTC model parameters.
gps_almanac_map.xsd - GPS NAV message almanac.

GPS L2C and L5

cnav_ephemeris_map.xsd - GPS CNAV message ephemeris parameters.
cnav_utc_model.xsd - GPS CNAV message UTC model parameters.
cnav_iono_model.xsd - GPS CNAV message ionospheric model parameters.

QZSS

ephemeris_map.xsd - QZSS LNAV message ephemeris parameters (the XML root is shared with GPS LNAV).
cnav_ephemeris_map.xsd - QZSS CNAV message ephemeris parameters (the XML root is shared with GPS CNAV).
qzss_iono_model.xsd - QZSS LNAV message ionospheric model parameters.
qzss_utc_model.xsd - QZSS LNAV message UTC model parameters.
qzss_cnav_iono_model.xsd - QZSS CNAV message ionospheric model parameters.
qzss_cnav_utc_model.xsd - QZSS CNAV message UTC model parameters.

Galileo

gal_ephemeris_map.xsd - Galileo ephemeris parameters.
gal_iono_model.xsd - Galileo ionospheric model parameters.
gal_utc_model.xsd - Galileo UTC model parameters.
gal_almanac_map.xsd - Galileo almanac.

GLONASS

gnav_ephemeris_map.xsd - GLONASS GNAV ephemeris parameters.
gnav_utc_model.xsd - GLONASS GNAV UTC model parameters.

BeiDou

bds_dnav_ephemeris_map.xsd - BeiDou D1/D2 DNAV ephemeris parameters.
bds_dnav_iono_model.xsd - BeiDou D1/D2 DNAV ionospheric model parameters, including D2 grid corrections.
bds_dnav_utc_model.xsd - BeiDou D1/D2 DNAV UTC and inter-system time-offset parameters.
bds_dnav_almanac_map.xsd - BeiDou D1/D2 DNAV almanac parameters.
bds_cnav1_ephemeris_map.xsd - BeiDou B-CNAV1 ephemeris parameters.

Validation

The schemas accept current Boost archives and the older archive versions for which GNSS-SDR retains deserialization compatibility. The provided validation utility selects schemas from the standard PVT output filenames. It accepts individual files or directories:

python3 docs/xml-schemas/validate_xml.py ./pvt-output/

The utility requires xmllint, an XML Schema 1.0 validator distributed with libxml2.

Please check https://gnss-sdr.org/docs/sp-blocks/global-parameters/ for more information about the usage of XML files in GNSS-SDR.

You could find useful the utility program rinex2assist for the generation of compatible XML files from recent, publicly available RINEX navigation data files.