@type t() :: %Orbis.GnssConstellation.NavcenStatus{
  active_nanu?: boolean(),
  block_type: String.t() | nil,
  clock: String.t() | nil,
  nanu_subject: String.t() | nil,
  nanu_type: String.t() | nil,
  plane: String.t() | nil,
  prn: pos_integer(),
  slot: String.t() | nil,
  source: map(),
  svn: pos_integer() | nil,
  system: :gps,
  usable?: boolean()
}