# `Sidereon.GNSS.Positioning.SourcedSolution`
[🔗](https://github.com/neilberkman/sidereon-ex/blob/main/lib/sidereon/gnss/positioning.ex#L190)

A single-point-positioning solution paired with the provenance of the
ephemeris that produced it.

Returned by `Sidereon.GNSS.Positioning.solve_with_fallback/5`. `solution` is
the usual `Sidereon.GNSS.Positioning.Solution`; `source` records which source
produced the fix and how it related to the requested epoch, so a degraded or
substituted source is never reported silently:

  * `{:precise, %Sidereon.GNSS.Staleness.StalenessMetadata{}}` - a precise SP3
    product produced the fix. The metadata `kind` is `:exact` (zero staleness,
    the product covered the epoch) or `:nearest_prior` (a stale-but-within-cap
    product was used), with its source epoch and staleness.
  * `{:broadcast, {:precise_unavailable, selection_error}}` - the precise
    selection was declined outright (no precise products, none covering or
    preceding the epoch, or the nearest beyond the cap), so broadcast produced
    the fix. `selection_error` is the typed
    `t:Sidereon.GNSS.Staleness.selection_error/0` reason.
  * `{:broadcast, {:precise_degraded_unusable, staleness, spp_reason}}` - a
    stale-but-within-cap precise product was selected but could not serve the
    requested epoch (its coverage ends before it), so broadcast produced the
    fix. `staleness` is the tried product's
    `Sidereon.GNSS.Staleness.StalenessMetadata`, and `spp_reason` is the
    precise solve error that triggered the fallback.

# `source`

```elixir
@type source() ::
  {:precise, Sidereon.GNSS.Staleness.StalenessMetadata.t()}
  | {:broadcast,
     {:precise_unavailable, Sidereon.GNSS.Staleness.selection_error()}}
  | {:broadcast,
     {:precise_degraded_unusable, Sidereon.GNSS.Staleness.StalenessMetadata.t(),
      term()}}
```

# `t`

```elixir
@type t() :: %Sidereon.GNSS.Positioning.SourcedSolution{
  solution: Sidereon.GNSS.Positioning.Solution.t(),
  source: source()
}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*