Ground Stations

Represents a location on the surface of a celestial body.

Parameters:

• frame

  –

  Body-fixed frame as Frame or str (e.g. "IAU_EARTH", "ITRF").

• longitude

  –

  Geodetic longitude as Angle.

• latitude

  –

  Geodetic latitude as Angle.

• altitude

  –

  Altitude above the reference ellipsoid as Distance.

• ellipsoid

  –

  Reference ellipsoid, overriding the one conventionally paired with the frame.

Examples:

>>> darmstadt = lox.EllipsoidLocation(
...     "IAU_EARTH",
...     longitude=8.6512 * lox.deg,
...     latitude=49.8728 * lox.deg,
...     altitude=0.108 * lox.km,
... )

Methods:

• altitude –

  Return the altitude above the reference ellipsoid.

• body_fixed_position –

  Return the body-fixed Cartesian position as a numpy array in m.

• coordinates –

  Return the geodetic coordinates as a (longitude, latitude, altitude) tuple.

• ellipsoid –

  Return the reference ellipsoid the coordinates are referenced to.

• frame –

  Return the body-fixed frame the coordinates are referenced to.

• latitude –

  Return the geodetic latitude.

• longitude –

  Return the geodetic longitude.

• observables –

  Compute observables to a target state.

• origin –

  Return the central body (origin).

• rotation_to_topocentric –

  Return the rotation matrix from body-fixed to topocentric frame.

altitude() -> Distance

body_fixed_position() -> ndarray

coordinates() -> tuple[Angle, Angle, Distance]

ellipsoid() -> Ellipsoid

frame() -> Frame

latitude() -> Angle

longitude() -> Angle

observables(
    state: Cartesian,
    provider: EOPProvider | None = None,
    frame: str | Frame | None = None,
) -> Observables

origin() -> Origin

rotation_to_topocentric() -> ndarray

A reference ellipsoid, defined by its equatorial radius and flattening.

Parameters:

• equatorial_radius

  –

  Semi-major axis as Distance.

• flattening

  –

  Flattening factor in [0, 1).

Examples:

>>> lox.Ellipsoid.WGS84
>>> lox.Ellipsoid(6378137.0 * lox.m, 1 / 298.257223563)

Methods:

• equatorial_radius –

  Return the equatorial radius.

• flattening –

  Return the flattening factor.

equatorial_radius() -> Distance

flattening() -> float

A measured horizon profile for visibility analysis.

A horizon mask captures the physical skyline around a ground station as elevation over azimuth. Visibility additionally honours the station's operational min_elevation floor; detection tests elevation against the maximum of both.

Parameters:

• azimuth

  –

  Array of azimuth angles in radians. The values are normalised to [-π, π) and sorted, so any convention works: [0, 2π), [-π, π], unsorted data, and profiles that do or do not repeat their wrap-around point. The mask is periodic, with the segment between the last and the first point spanning the seam at ±π.

• elevation

  –

  Array of horizon elevations in radians.

Raises:

• ValueError –

  If the arrays have different lengths, if they are empty, or if two points normalise to the same azimuth but carry different elevations.

Examples:

>>> mask = lox.HorizonMask(azimuth, elevation)

Methods:

• azimuth –

  Return the azimuth grid in radians, normalised to [-π, π) and sorted.

• elevation –

  Return the horizon elevations in radians.

• elevation_at –

  Return the horizon elevation at the given azimuth.

azimuth() -> list[float]

elevation() -> list[float]

elevation_at(azimuth: Angle) -> Angle

Observation data from a ground station to a target.

Parameters:

• azimuth

  –

  Azimuth angle as Angle.

• elevation

  –

  Elevation angle as Angle.

• range

  –

  Distance to target as Distance.

• range_rate

  –

  Rate of change of range as Velocity.

Methods:

• azimuth –

  Return the azimuth angle.

• elevation –

  Return the elevation angle.

• range –

  Return the range (distance).

• range_rate –

  Return the range rate.

azimuth() -> Angle

elevation() -> Angle

range() -> Distance

range_rate() -> Velocity

Represents a visibility pass between a ground station and spacecraft.

A Pass contains the visibility interval (start and end times) along with observables computed at regular intervals throughout the pass.

Methods:

• interpolate –

  Interpolate observables at a specific time within the pass.

• interval –

  Return the visibility interval for this pass.

• observables –

  Return the observables at each time sample.

• times –

  Return the time samples during this pass.

interpolate(time: Time) -> Observables | None

interval() -> Interval

observables() -> list[Observables]

times() -> list[Time]