See Sidereon.ILS.bounded_ils_search/5.

See Sidereon.GNSS.RTCM.decode/1.

See Sidereon.GNSS.RTCM.decode_frame/1.

See Sidereon.GNSS.RTCM.decode_message/1.

See Sidereon.GNSS.RTCM.decode_stream/1.

@spec doppler(Sidereon.Elements.t(), DateTime.t(), ground_station(), number()) ::
  {:ok,
   %{range_rate_km_s: float(), doppler_hz: float(), doppler_ratio: float()}}
  | {:error, term()}

Compute Doppler shift for a satellite-ground link.

Propagates the TLE, transforms to GCRS, and computes the range rate and Doppler shift at the given carrier frequency.

The station is a map: %{latitude: deg, longitude: deg, altitude_m: meters}.

Returns {:ok, %{range_rate_km_s: float, doppler_hz: float, doppler_ratio: float}}.

Example

station = %{latitude: 40.0, longitude: -74.0, altitude_m: 0.0}
{:ok, d} = Sidereon.doppler(tle, datetime, station, 437.0e6)
d.doppler_hz  # => ~10_000.0

@spec eclipse(Sidereon.Elements.t(), DateTime.t(), Sidereon.Ephemeris.t()) ::
  {:ok, :sunlit | :penumbra | :umbra} | {:error, term()}

Check whether a satellite is in Earth's shadow (eclipse) at a given time.

Propagates the TLE, transforms to GCRS, fetches the Sun position from the ephemeris, and returns the eclipse status.

Returns {:ok, :sunlit | :penumbra | :umbra} or {:error, reason}.

Example

{:ok, eph} = Sidereon.Ephemeris.load("de421.bsp")
{:ok, status} = Sidereon.eclipse(tle, datetime, eph)

See Sidereon.GNSS.RTCM.encode/1.

See Sidereon.GNSS.RTCM.encode_frame/1.

See Sidereon.Conjunction.find_tca_candidates/7.

See Sidereon.Conjunction.find_tca_conjunctions/8.

See Sidereon.GNSS.Constellation.from_celestrak_json/2.

See Sidereon.GNSS.Constellation.from_celestrak_json_lenient/2.

See Sidereon.GNSS.Constellation.from_celestrak_omm_lenient/2.

@spec geodesic_direct(number(), number(), number(), number()) ::
  {:ok, Sidereon.Geodesic.direct_result()}
  | {:error, Sidereon.Geodesic.GeodesicError.t()}

Solve the WGS84 direct geodesic problem.

See Sidereon.Geodesic.direct/4 for details.

@spec geodesic_inverse(number(), number(), number(), number()) ::
  {:ok, Sidereon.Geodesic.inverse_result()}
  | {:error, Sidereon.Geodesic.GeodesicError.t()}

Solve the WGS84 inverse geodesic problem.

See Sidereon.Geodesic.inverse/4 for details.

@spec geodetic(Sidereon.Elements.t(), DateTime.t()) ::
  {:ok, Sidereon.Geodetic.t()} | {:error, term()}

Compute geodetic coordinates (lat/lon/alt) for a satellite at a given time.

Propagates the TLE, transforms TEME -> GCRS -> ITRS, and converts to WGS84.

Returns {:ok, %{latitude: deg, longitude: deg, altitude_km: km}}.

Example

{:ok, tle} = Sidereon.parse_tle(line1, line2)
{:ok, geo} = Sidereon.geodetic(tle, datetime)
geo.latitude  # => 51.23

@spec ground_track(Sidereon.Elements.t(), [DateTime.t()], keyword()) ::
  {:ok, [Sidereon.Geodetic.t()]} | {:error, term()}

Compute the ground track (sub-satellite points) for a satellite over a list of times.

For each datetime the satellite is propagated and reduced through TEME -> GCRS -> ITRS -> WGS84 geodetic, yielding the point on the ellipsoid directly beneath the satellite. This is the batch companion to Sidereon.geodetic/2.

Options

• :opsmode - SGP4 operation mode, :afspc (default) or :improved. The satellite is built with this opsmode, so the track is consistent with Sidereon.geodetic/2 and Sidereon.predict_passes/5 under the same opsmode.

Returns {:ok, [%Sidereon.Geodetic{}]} (one per datetime, in order) or {:error, reason}.

Example

now = DateTime.utc_now()
times = for s <- 0..600//60, do: DateTime.add(now, s, :second)
{:ok, track} = Sidereon.ground_track(tle, times)
hd(track).latitude  # => 12.34

See Sidereon.ILS.lambda_ils_search/3.

See Sidereon.GNSS.RINEX.Clock.load/1.

See Sidereon.GNSS.RINEX.Clock.load_lossy/1.

@spec look_angle(Sidereon.Elements.t(), DateTime.t(), ground_station(), keyword()) ::
  {:ok, Sidereon.LookAngle.t()} | {:error, term()}

Compute the look angle (azimuth/elevation/range) from a ground station to a satellite at a given time.

The station is a map: %{latitude: deg, longitude: deg, altitude_m: meters}.

Returns {:ok, %{azimuth: deg, elevation: deg, range_km: km}}.

Options

• :opsmode - SGP4 operation mode, :afspc (default) or :improved. The satellite is built with this opsmode, so the look angle is consistent with Sidereon.predict_passes/5 run under the same opsmode.

Example

station = %{latitude: 40.0, longitude: -74.0, altitude_m: 0.0}
{:ok, look} = Sidereon.look_angle(tle, datetime, station)
look.elevation  # => 25.7

@spec moon_angle(vec3(), vec3()) :: float()

Compute the angle between satellite nadir and the Moon direction.

See Sidereon.Angles.moon_angle/2 for details.

@spec ocean_tide_loading(
  vec3(),
  integer(),
  integer(),
  integer(),
  number(),
  [[number()]],
  [[number()]]
) ::
  {:ok, vec3()} | {:error, term()}

Compute ocean tide loading station displacement in metres, ECEF.

See Sidereon.GNSS.RINEX.Clock.parse/1.

See Sidereon.GNSS.RINEX.Clock.parse_lossy/1.

@spec parse_tle(String.t(), String.t()) ::
  {:ok, Sidereon.Elements.t()} | {:error, String.t()}

Parse a Two-Line Element set.

Returns {:ok, %Sidereon.Elements{}} or {:error, reason}.

Examples

iex> {:ok, el} = Sidereon.parse_tle(
...>   "1 25544U 98067A   18184.80969102  .00001614  00000-0  31745-4 0  9993",
...>   "2 25544  51.6414 295.8524 0003435 262.6267 204.2868 15.54005638121106"
...> )
iex> el.catalog_number
"25544"

@spec parse_tle_file(String.t()) ::
  {:ok,
   %{
     satellites: [%{name: String.t(), tle: Sidereon.Elements.t()}],
     skipped: non_neg_integer()
   }}

Parse a multi-record TLE file (CelesTrak / Space-Track style) into named satellites.

Handles bare two-line sets, three-line name+line1+line2 sets, and CelesTrak 0 NAME markers, tolerating blank lines and CRLF. Returns {:ok, %{satellites: [%{name: name, tle: %Sidereon.Elements{}}], skipped: n}}, where each tle is ready for propagate/2, look_angle/3, etc., and skipped counts records that failed SGP4 initialization.

Examples

iex> text = """
...> ISS (ZARYA)
...> 1 25544U 98067A   18184.80969102  .00001614  00000-0  31745-4 0  9993
...> 2 25544  51.6414 295.8524 0003435 262.6267 204.2868 15.54005638121106
...> """
iex> {:ok, %{satellites: [sat], skipped: 0}} = Sidereon.parse_tle_file(text)
iex> sat.name
"ISS (ZARYA)"

@spec predict_passes(
  Sidereon.Elements.t(),
  Sidereon.Passes.ground_station(),
  DateTime.t(),
  DateTime.t(),
  keyword()
) :: {:ok, [Sidereon.Pass.t()]} | {:error, Sidereon.Passes.predict_error()}

Predict visible passes of a satellite over a ground station.

See Sidereon.Passes.predict/5 for full documentation.

@spec propagate(Sidereon.Elements.t(), DateTime.t()) ::
  {:ok, Sidereon.TemeState.t()} | {:error, Sidereon.SGP4.propagation_error()}

Propagate orbital elements to a specific datetime, returning TEME position and velocity.

Returns {:ok, %Sidereon.TemeState{}} with position in km and velocity in km/s, or {:error, reason}.

Examples

iex> {:ok, el} = Sidereon.parse_tle(
...>   "1 25544U 98067A   18184.80969102  .00001614  00000-0  31745-4 0  9993",
...>   "2 25544  51.6414 295.8524 0003435 262.6267 204.2868 15.54005638121106"
...> )
iex> {:ok, teme} = Sidereon.propagate(el, ~U[2018-07-04 00:00:00Z])
iex> {x, _y, _z} = teme.position
iex> x > 3000 and x < 4000
true

See Sidereon.GNSS.RINEX.Clock.to_rinex_string/1.

See Sidereon.GNSS.RTCM.derive_lli/4.

See Sidereon.GNSS.RTCM.lli_bits/0.

See Sidereon.GNSS.RTCM.message_number/1.

See Sidereon.GNSS.RTCM.minimum_lock_time_ms/2.

See Sidereon.GNSS.RTCM.msm_epoch_dt_ms/3.

See Sidereon.GNSS.RTCM.msm_lli/1.

See Sidereon.GNSS.RTCM.msm_signal_rinex_code/2.

See Sidereon.Conjunction.screen_tca_candidates/7.

See Sidereon.Conjunction.screen_tca_conjunctions/8.

@spec solid_earth_pole_tide(
  vec3(),
  integer(),
  integer(),
  integer(),
  number(),
  number(),
  number()
) ::
  {:ok, vec3()} | {:error, term()}

Compute solid-earth pole tide station displacement in metres, ECEF.

@spec solid_earth_tide(
  vec3(),
  integer(),
  integer(),
  integer(),
  number(),
  vec3(),
  vec3()
) ::
  {:ok, vec3()} | {:error, term()}

Compute solid-earth tide station displacement in metres, ECEF.

See Sidereon.GNSS.PrecisePositioning.solve_ppp_fixed/4.

See Sidereon.GNSS.PrecisePositioning.solve_ppp_float/4.

See Sidereon.GNSS.RTK.solve_rtk_fixed/1.

See Sidereon.GNSS.RTK.solve_rtk_float/1.

@spec sun_angle(vec3(), vec3()) :: float()

Compute the angle between satellite nadir and the Sun direction.

See Sidereon.Angles.sun_angle/2 for details.

@spec sun_moon_ecef([integer()]) ::
  {:ok, %{sun: [vec3()], moon: [vec3()]}} | {:error, term()}

Compute Sun and Moon ECEF vectors for UTC Unix microsecond epochs.

@spec sun_moon_eci([integer()]) ::
  {:ok, %{sun: [vec3()], moon: [vec3()]}} | {:error, term()}

Compute Sun and Moon ECI vectors for UTC Unix microsecond epochs.

@spec teme_to_gcrs(
  Sidereon.TemeState.t() | gcrs_state(),
  DateTime.t() | tuple(),
  keyword()
) ::
  gcrs_state()

Convert a TEME state vector to GCRS (Geocentric Celestial Reference System).

Set skyfield_compat: true to reproduce the committed Skyfield oracle vectors used by the validation suite. The default is sidereon's native path.

Example

gcrs = Sidereon.teme_to_gcrs(teme, datetime)
gcrs = Sidereon.teme_to_gcrs(teme, datetime, skyfield_compat: true)

Fixed inter-system time offset to - from, in seconds, for the atomic scales.

See Sidereon.GNSS.Time.timescale_offset/2 for the scale names and the epoch-required/unsupported error cases.

Leap-aware inter-system time offset to - from, in seconds, at utc_jd.

See Sidereon.GNSS.Time.timescale_offset_at/3.

See Sidereon.GNSS.RINEX.Clock.write/2.