GNSS Constellation Catalogs

Orbis.GNSS.Constellation 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.GNSS.Constellation.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.GNSS.Constellation.from_celestrak_omm(celestrak_omms)
{:ok, navcen} = Orbis.GNSS.Constellation.parse_navcen_html(navcen_html)
records = Orbis.GNSS.Constellation.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.GNSS.Constellation.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.GNSS.Constellation.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.GNSS.Data.sp3(Orbis.GNSS.Data.mgex_sp3(:gfz, ~D[2026-06-04]))
report = Orbis.GNSS.Constellation.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.