Constellation

class dsns.constellation.OrbitalCenter(name: str, position: ndarray = array([0., 0., 0.]))

Orbital center class. Used to represent a body around which satellites orbit.

__init__(name: str, position: ndarray = array([0., 0., 0.]))

Initialize the orbital center with a fixed position.

Parameters:

  • name – Name of the orbital center.

  • position – Position of the orbital center (m).

update(time: float)

Update the orbital center.

Parameters:

time – Time in seconds since the epoch.

class dsns.constellation.PlanetOrbitalCenter(name: str, center: ndarray | tuple[float, float, float] | OrbitalCenter, radius: float, rotation_period: float, angle_offset: float = 0.0)

Orbital center class for a planet with a fixed rotation period. We assume the orbit is a perfect circle centered on the origin, in the x-y plane.

__init__(name: str, center: ndarray | tuple[float, float, float] | OrbitalCenter, radius: float, rotation_period: float, angle_offset: float = 0.0)

Initialize the orbital center.

Parameters:

  • name – Name of the orbital center.

  • center – Center of the orbit (m).

  • radius – Radius of the orbit (m).

  • rotation_period – Rotation period of the planet (s).

  • angle_offset – Initial angle of the planet (degrees).

update(time: float)

Update the orbital center.

Parameters:

time – Time in seconds since the epoch.

class dsns.constellation.Satellite(name: str, sat_id: int, constellation_name: str, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Satellite class. Used to represent a satellite in a constellation.

__init__(name: str, sat_id: int, constellation_name: str, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)
class dsns.constellation.Satellites(satellites: list[Satellite])

List of satellites, with helper functions for lookup by name/ID.

__init__(satellites: list[Satellite])
property ids: list[int]

Get a list of all satellite IDs.

property names: list[str]

Get a list of all satellite names.

append(satellite: Satellite)

Add a satellite to the list.

Parameters:

satellite – Satellite to add.

extend(satellites: Self | list[Satellite])

Add multiple satellites to the list.

Parameters:

satellites – List of satellites to add.

index(satellite: Satellite) → int

Get the index of a satellite in the list.

Parameters:

satellite – Satellite to get the index of.

Returns:

Index of the satellite.

by_id(sat_id: int) → Satellite | None

Get a satellite by its ID.

Parameters:

sat_id – ID of the satellite to get.

Returns:

Satellite with the given ID, or None if no satellite with that ID exists.

by_name(name: str) → Satellite | None

Get a satellite by its name.

Parameters:

name – Name of the satellite to get.

Returns:

Satellite with the given name, or None if no satellite with that name exists.

class dsns.constellation.ISLHelper

Base class for ISL (Inter-Satellite Link) helper classes.

abstractmethod get_isls(satellites: Satellites, positions: ndarray) → list[tuple[int, int]]

Compute the ISLs between all satellites in the constellation, given their positions.

Parameters:

  • satellites – List of satellites in the constellation.

  • positions – Satellite positions (num_sats, 3).

Returns:

List of ISLs, where each ISL is a tuple of satellite IDs.

class dsns.constellation.MultiISLHelper(isl_helpers: list[ISLHelper])

Helper class allowing the use of multiple ISL helpers at the same time.

__init__(isl_helpers: list[ISLHelper])
get_isls(satellites: Satellites, positions: ndarray) → list[tuple[int, int]]

Compute the ISLs between all satellites in the constellation, given their positions.

Parameters:

  • satellites – List of satellites in the constellation.

  • positions – Satellite positions (num_sats, 3).

Returns:

List of ISLs, where each ISL is a tuple of satellite IDs.

class dsns.constellation.Constellation

Base satellite constellation class.

name: str
satellites: Satellites
isl_helper: ISLHelper
satellite_positions: ndarray
isls: list[tuple[int, int]]
orbital_center: OrbitalCenter
is_relay: bool = False
property num_sats: int
abstractmethod update_positions(time: float)

Update the positions of all satellites in the constellation at a given time.

Parameters:

time – Time in seconds since the epoch.

update_isls()

Update the ISLs for the constellation.

update(time: float)

Update the constellation.

class dsns.constellation.WalkerConstellation(name: str, num_planes: int, sats_per_plane: int, inclination: float, semi_major_axis: float, eccentricity: float, ascending_node_arc: float, phase_offset: float, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, host_mass: float = 5.9722e+24, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>, right_ascending_node: float = 0.0)

Walker constellation class.

__init__(name: str, num_planes: int, sats_per_plane: int, inclination: float, semi_major_axis: float, eccentricity: float, ascending_node_arc: float, phase_offset: float, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, host_mass: float = 5.9722e+24, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>, right_ascending_node: float = 0.0)

Initialize the Walker constellation.

Parameters:

  • name – Name of the constellation.

  • num_planes – Number of orbital planes.

  • sats_per_plane – Number of satellites per orbital plane.

  • inclination – Orbital plane inclination (degrees).

  • semi_major_axis – Semi-major axis of the orbit (m).

  • eccentricity – Orbital eccentricity (0.0 - 1.0).

  • ascending_node_arc – Angle of arc along which to space ascending nodes (degrees). Setting to 360 results in a standard Walker constellation. 180 results in a “Pi” constellation like Iridium.

  • phase_offset – Phase offset between planes (degrees).

  • isl_helper – ISL helper class.

  • id_helper – ID helper class.

  • host_mass – Mass of the central body (kg).

  • orbital_center – Orbital center of the constellation.

  • right_ascending_node – Longitude of the right ascending node in the first plane (degrees).

update_positions(time)

Update the positions of all satellites in the constellation at a given time.

Parameters:

time – Time in seconds since the epoch.

class dsns.constellation.FixedConstellation(name: str, satellite_positions: ~numpy.ndarray, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Constellation class for satellites with fixed positions.

__init__(name: str, satellite_positions: ~numpy.ndarray, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Initialize the fixed constellation.

Parameters:

  • name – Name of the constellation.

  • satellite_positions – Array of satellite positions (x/y/z (m)).

  • isl_helper – ISL helper class.

  • id_helper – ID helper class.

  • orbital_center – Orbital center of the constellation.

update_positions(time)

Update the positions of all satellites in the constellation at a given time.

Parameters:

time – Time in seconds since the epoch.

class dsns.constellation.TLEConstellation(name: str, tles: list[tuple[str, str]], isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, epoch: ~datetime.datetime | None = None, ignore_errors: bool = False, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Constellation composed of satellites described by TLEs. The SGP4 orbital propagator is used to compute satellite positions.

__init__(name: str, tles: list[tuple[str, str]], isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, epoch: ~datetime.datetime | None = None, ignore_errors: bool = False, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Initialize the TLE constellation.

Parameters:

  • name – Name of the constellation.

  • tles – List of TLEs.

  • isl_helper – ISL helper class.

  • id_helper – ID helper class.

  • epoch – Epoch of the TLEs - the real time corresponding to simulation time 0.0.

  • ignore_errors – Ignore errors from the SGP4 propagator.

  • orbital_center – Orbital center of the constellation.

classmethod from_url(name: str, tle_url: str, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, epoch: ~datetime.datetime | None = None, ignore_errors: bool = False, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Initialize the TLE constellation from a URL (e.g. Celestrak).

Parameters:

  • name – Name of the constellation.

  • tle_url – URL of the TLE file.

  • isl_helper – ISL helper class.

  • id_helper – ID helper class.

  • epoch – Epoch of the TLEs - the real time corresponding to simulation time 0.0.

  • ignore_errors – Ignore errors from the SGP4 propagator.

  • orbital_center – Orbital center of the constellation.

classmethod from_file(name: str, tle_file: str, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, epoch: ~datetime.datetime | None = None, ignore_errors: bool = False, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Initialize the TLE constellation from a file.

Parameters:

  • name – Name of the constellation.

  • tle_file – Path to the TLE file.

  • isl_helper – ISL helper class.

  • id_helper – ID helper class.

  • epoch – Epoch of the TLEs - the real time corresponding to simulation time 0.0.

  • ignore_errors – Ignore errors from the SGP4 propagator.

  • orbital_center – Orbital center of the constellation.

update_positions(time)

Update the positions of all satellites in the constellation at a given time.

Parameters:

time – Time in seconds since the epoch.

class dsns.constellation.GroundConstellation(name: str, ground_station_positions: ~numpy.ndarray, host_radius: float, rotation_period: float | None, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Constellation class for ground stations. These are simulated as satellites with a fixed position.

__init__(name: str, ground_station_positions: ~numpy.ndarray, host_radius: float, rotation_period: float | None, isl_helper: ~dsns.constellation.ISLHelper, id_helper: ~dsns.helpers.IDHelper, orbital_center: ~dsns.constellation.OrbitalCenter = <dsns.constellation.OrbitalCenter object>)

Initialize the ground constellation.

Parameters:

  • name – Name of the constellation.

  • ground_station_positions – Array of ground station positions (lat/lon/alt (deg, deg, m)).

  • host_radius – Radius of the central body (m).

  • rotation_period – Rotation period of the body on which the ground stations are orbiting (s).

  • isl_helper – ISL helper class.

  • id_helper – ID helper class.

  • orbital_center – Orbital center of the constellation.

update_positions(time)

Update the positions of all satellites in the constellation at a given time.

Parameters:

time – Time in seconds since the epoch.

class dsns.constellation.WalkerISLHelper(num_planes: int, sats_per_plane: int, intra_layer_links: bool, inter_layer_links: int | None, disable_cross_seam_links: bool = False)

Walker ISL helper class.

__init__(num_planes: int, sats_per_plane: int, intra_layer_links: bool, inter_layer_links: int | None, disable_cross_seam_links: bool = False)

Initialize the Walker ISL helper class.

Parameters:

  • num_planes – Number of orbital planes.

  • sats_per_plane – Number of satellites per orbital plane.

  • intra_layer_links – Include intra-layer links (links between adjacent satellites on the same layer).

  • inter_layer_links – Include inter-layer links (links between adjacent satellites on adjacent layers). If None, no inter-layer links are included. Otherwise, specify the offset between layers.

  • disable_cross_seam_links – Disable inter-layer links between satellites on opposite sides of the seam. Only relevant for polar constellations.

get_isls(satellites: Satellites, positions: ndarray) → list[tuple[int, int]]

Compute the ISLs between all satellites in the constellation, given their positions.

Parameters:

  • satellites – List of satellites in the constellation.

  • positions – Satellite positions (num_sats, 3).

Returns:

List of ISLs, where each ISL is a tuple of satellite IDs.

class dsns.constellation.FixedISLHelper(isls: list[tuple[int, int]])

ISL helper class with fixed ISLs.

__init__(isls: list[tuple[int, int]])

Initialize the fixed ISL helper class.

Parameters:

isls – List of ISLs.

classmethod from_names(isls: list[tuple[str, str]], id_helper: IDHelper)

Initialize the fixed ISL helper class from a list of ISL names.

Parameters:

isls – List of ISL names.

get_isls(satellites: Satellites, positions: ndarray) → list[tuple[int, int]]

Compute the ISLs between all satellites in the constellation, given their positions.

Parameters:

  • satellites – List of satellites in the constellation.

  • positions – Satellite positions (num_sats, 3).

Returns:

List of ISLs, where each ISL is a tuple of satellite IDs.

class dsns.constellation.NullISLHelper

Null ISL helper class - no ISLs are returned.

__init__()

Initialize the Null ISL helper class.

get_isls(satellites: Satellites, positions: ndarray) → list[tuple[int, int]]

Compute the ISLs between all satellites in the constellation, given their positions.

Parameters:

  • satellites – List of satellites in the constellation.

  • positions – Satellite positions (num_sats, 3).

Returns:

List of ISLs, where each ISL is a tuple of satellite IDs.

class dsns.constellation.AdHocISLHelper(max_range: float, max_links: int | None, min_altitude: float | None)

Ad-Hoc ISL helper class. Satellites are connected to the nearest satellite(s) within a specified range.

__init__(max_range: float, max_links: int | None, min_altitude: float | None)

Initialize the Ad-Hoc ISL helper class.

Parameters:

  • max_range – Maximum range for ISLs (m).

  • max_links – Maximum number of links per satellite. If None, no maximum is enforced.

  • min_altitude – Minimum altitude for line-of-sight between satellites (m). If None, no line-of-sight checks are performed.

get_isls(satellites: Satellites, positions: ndarray) → list[tuple[int, int]]

Compute the ISLs between all satellites in the constellation, given their positions.

Parameters:

  • satellites – List of satellites in the constellation.

  • positions – Satellite positions (num_sats, 3).

Returns:

List of ISLs, where each ISL is a tuple of satellite IDs.