{
  "version": "quality-rules-0.2.0",
  "publisher": "SatellAItes",
  "reviewed": "2026-10-30",
  "description": "Documentation of the reported-quality classification used in the archived regional snapshots. Not a radio interference detector.",
  "input": "Reported ADS-B navigation quality, position source, position age and emitter category.",
  "rules_in_priority_order": [
    {
      "when": "Emitter category identifies ground vehicle, ground obstacle, or reserved/legacy ground obstacle (C1-C5)",
      "classification": "unknown",
      "excluded_from_gnss_assessment": true
    },
    {
      "when": "Position source is not ADS-B",
      "classification": "unknown"
    },
    {
      "when": "Latitude, longitude or position age is missing",
      "classification": "unknown"
    },
    {
      "when": "Position age is greater than 60 seconds",
      "classification": "unknown"
    },
    {
      "when": "Known integer NACp in [0,11] is below 8, OR known integer NIC in [0,11] is below 7",
      "classification": "quality_degraded"
    },
    {
      "when": "Both NIC and NACp are known valid integers and the previous low-quality rule does not apply",
      "classification": "normal"
    },
    {
      "when": "Otherwise",
      "classification": "unknown"
    }
  ],
  "counts": {
    "contactCount": "Retained, deduplicated contact rows in a snapshot, not unique flights over a day.",
    "degradedCount": "Rows classified quality_degraded.",
    "unknownCount": "Rows classified unknown, including exclusions; do not subtract without examining the source rows.",
    "excludedContactCount": "Rows explicitly excluded from GNSS assessment. An independent counter, not a count of confirmed interference."
  },
  "limitations": [
    "Neither degraded nor normal quality proves the presence or absence of jamming or spoofing.",
    "No direct radio measurement, transmitter attribution, ground-level reception guarantee or regional risk ranking.",
    "Snapshot coverage and provider observation time must accompany any comparison."
  ]
}