GNSS Constellation Catalogs

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Orbis.GnssConstellation builds identity tables for GNSS satellites and checks them against loaded GNSS products. The first supported system is GPS.

The base GPS source is CelesTrak's public gps-ops OMM/JSON feed, which carries the current NORAD catalog id and a PRN in OBJECT_NAME. NAVCEN's GPS constellation page can be merged as a status overlay for SVN and active NANU usability.

# Live fetch: CelesTrak gps-ops plus NAVCEN status overlay.
{:ok, records} = Orbis.GnssConstellation.fetch_gps()

record = hd(records)
{record.system, record.prn, record.svn, record.norad_id, record.sp3_id}
# {:gps, prn, svn_or_nil, norad_cat_id, "Gxx"}

For reproducible workflows, fetch bytes elsewhere and parse explicitly:

{:ok, records} = Orbis.GnssConstellation.from_celestrak_omm(celestrak_omms)
{:ok, navcen} = Orbis.GnssConstellation.parse_navcen_html(navcen_html)
records = Orbis.GnssConstellation.merge_navcen(records, navcen)

NAVCEN rows are merged by PRN only when the NAVCEN block type is compatible with the CelesTrak object name. If a PRN is in transition and NAVCEN still carries a NANU for an older vehicle, the row is kept in record.source.navcen_conflict instead of being used as the normalized SVN.

Export the compact CSV used by many GNSS workflows:

csv = Orbis.GnssConstellation.to_csv(records)

# prn,norad_cat_id,active,sp3_id
# 1,62339,true,G01
# ...

Validate the catalog before using it in a downstream pipeline:

report = Orbis.GnssConstellation.validate(records)

report.duplicate_prns
report.duplicate_norad_ids
report.inactive_unusable_prns

Compare active, usable catalog IDs against a loaded SP3 product:

{:ok, sp3} = Orbis.GnssData.sp3(Orbis.GnssData.mgex_sp3(:gfz, ~D[2026-06-04]))
report = Orbis.GnssConstellation.validate_sp3(records, sp3)

report.missing_sp3_ids
report.extra_sp3_ids

The catalog layer only reports data consistency. It does not change solver selection, infer cross-correlation, or apply application-specific satellite health policy.