{
  "disc_radius": {
    "value": 20015,
    "unit": "km",
    "how_derived": "V45 derivation from southern route distances",
    "supersedes": "10000 km (V1)"
  },
  "firmament_height": {
    "value": 9086,
    "unit": "km",
    "how_derived": "V48 parallax and telluric resonance",
    "supersedes": "5000 km (V1)"
  },
  "polaris_height": {
    "value": 6500,
    "unit": "km",
    "how_derived": "Elevation angle triangulation",
    "supersedes": "None"
  },
  "sun_altitude": {
    "value": 5733,
    "unit": "km",
    "how_derived": "V48 triangulation",
    "supersedes": "None"
  },
  "moon_altitude": {
    "value": 2534,
    "unit": "km",
    "how_derived": "V48 triangulation",
    "supersedes": "None"
  },
  "saa_africa_cell_lon": {
    "value": 0.0,
    "unit": "deg",
    "how_derived": "CHAOS-7 observational 2025 node",
    "supersedes": "None"
  },
  "saa_sa_cell_lon": {
    "value": 300.0,
    "unit": "deg",
    "how_derived": "CHAOS-7 observational 2025 node",
    "supersedes": "None"
  },
  "magnetic_gravity_coupling": {
    "value": 1.67,
    "unit": "nT/uGal",
    "how_derived": "V48 from BOU 2017 & Mohe 1997 ratio",
    "supersedes": "None"
  },
  "field_decay_rate": {
    "value": 28,
    "unit": "nT/yr",
    "how_derived": "Global network average",
    "supersedes": "None"
  },
  "north_pole_deviation": {
    "value": -18.06,
    "unit": "deg",
    "how_derived": "NOAA NP.xy exponential asymptote deviation at 120E",
    "supersedes": "None"
  }
}