keplemon.elements

`elements`

`CartesianState`

State represented as x, y, z and vx, vy, vz in a given reference frame.

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	UTC epoch of the state	required
`position`	`CartesianVector`	Cartesian position vector in kilometers	required
`velocity`	`CartesianVector`	Cartesian velocity vector in kilometers per second	required
`frame`	`ReferenceFrame`	reference frame of the state	required

`epoch` `instance-attribute`

UTC epoch of the state

`frame` `instance-attribute`

Current reference frame of the state

`position` `instance-attribute`

Position of the state in kilometers

`velocity` `instance-attribute`

Velocity of the state in kilometers per second

`to_frame(frame)`

Parameters:

Name	Type	Description	Default
`frame`	`ReferenceFrame`	reference frame of the output state	required

Returns:

Name	Type	Description
`CartesianState`	`CartesianState`	Cartesian state in the new frame

`to_keplerian()`

Convert the Cartesian state to osculating Keplerian elements

`CartesianVector`

Parameters:

Name	Type	Description	Default
`x`	`float`	x coordinate	required
`y`	`float`	y coordinate	required
`z`	`float`	z coordinate	required

`magnitude` `instance-attribute`

`angle(other)`

Returns:

Type	Description
`float`	Angle between two Cartesian vectors in *radians*.

`distance(other)`

Note

Take care to use consistent units with this function.

Returns:

Type	Description
`float`	Distance between two Cartesian vectors

`to_spherical()`

Returns:

Type	Description
`SphericalVector`	Spherical representation of the point

`Ephemeris`

`add_state(state)`

Add a state to the ephemeris.

`to_observations()`

Generate angular observations from the ephemeris states.

Steps through the ephemeris epoch range at regular intervals, creating synthetic observations from each interpolated state.

Returns:

Type	Description
`list[Observation]`	List of angular observations derived from the ephemeris

`EquinoctialElements`

Parameters:

Name	Type	Description	Default
`a_f`	`float`	Equinoctial element a_f	required
`a_g`	`float`	Equinoctial element a_g	required
`chi`	`float`	Equinoctial element chi	required
`psi`	`float`	Equinoctial element psi	required
`mean_longitude`	`float`	Mean longitude in *degrees*	required
`mean_motion`	`float`	Mean motion in *revolutions per day*	required

`GeodeticPosition`

Parameters:

Name	Type	Description	Default
`latitude`	`float`	Latitude in *degrees*	required
`longitude`	`float`	Longitude in *degrees*	required
`altitude`	`float`	Altitude in *kilometers*	required

`altitude` `instance-attribute`

Altitude in kilometers

`latitude` `instance-attribute`

Latitude in degrees

`longitude` `instance-attribute`

Longitude in degrees

`HorizonElements`

Parameters:

Name	Description	Default
`range`	Range in *kilometers*	required
`az`	Azimuth in *degrees*	required
`el`	Elevation in *degrees*	required
`range_rate`	Range rate in *kilometers per second*	required
`az_rate`	Azimuth rate in *degrees per second*	required
`el_rate`	Elevation rate in *degrees per second*	required

`HorizonState`

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	UTC epoch of the state	required
`elements`	`HorizonElements`	HorizonElements of the state	required

`azimuth` `instance-attribute`

Azimuth in degrees

`azimuth_rate` `instance-attribute`

Azimuth rate in degrees per second

`elements` `instance-attribute`

Horizon elements of the state

`elevation` `instance-attribute`

Elevation in degrees

`elevation_rate` `instance-attribute`

Elevation rate in degrees per second

`epoch` `instance-attribute`

UTC epoch of the state

`range` `instance-attribute`

Range in kilometers

`range_rate` `instance-attribute`

Range rate in kilometers per second

`KeplerianElements`

Parameters:

Name	Type	Description	Default
`semi_major_axis`	`float`	Average distance from the central body in *kilometers*	required
`eccentricity`	`float`	Eccentricity of the orbit	required
`inclination`	`float`	Inclination of the orbit in *degrees*	required
`raan`	`float`	Right Ascension of Ascending Node in *degrees*	required
`argument_of_perigee`	`float`	Argument of Perigee in *degrees*	required
`mean_anomaly`	`float`	Mean Anomaly in *degrees*	required

`KeplerianState`

Orbit represented as Keplerian elements in a given reference frame.

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	UTC epoch of the state	required
`elements`	`KeplerianElements`	Keplerian elements of the state	required
`frame`	`ReferenceFrame`	reference frame of the state	required
`keplerian_type`	`KeplerianType`	type of the Keplerian elements	required

`apoapsis` `instance-attribute`

Furthest point from the central body in kilometers

`argument_of_perigee` `instance-attribute`

Argument of Perigee in degrees

`eccentricity` `instance-attribute`

Eccentricity of the orbit

`inclination` `instance-attribute`

Inclination of the orbit in degrees

`mean_anomaly` `instance-attribute`

Mean Anomaly in degrees

`mean_motion` `instance-attribute`

Mean motion in revolutions per day

`periapsis` `instance-attribute`

Closest point to the central body in kilometers

`raan` `instance-attribute`

Right Ascension of Ascending Node in degrees

`semi_major_axis` `instance-attribute`

Average distance from the central body in kilometers

`to_cartesian()`

Returns:

Type	Description
`CartesianState`	Cartesian state in *kilometers* and *kilometers per second*.

`to_frame(frame)`

Parameters:

Name	Type	Description	Default
`frame`	`ReferenceFrame`	reference frame of the output state	required

Returns:

Type	Description
`KeplerianState`	Keplerian state in the new frame

`SphericalVector`

Note

The range units can be disregarded if this class is not being used for astrodynamic transforms.

Parameters:

Name	Type	Description	Default
`range`	`float`	distance from the origin in *kilometers*	required
`right_ascension`	`float`	right ascension in *degrees*	required
`declination`	`float`	declination in *degrees*	required

`to_cartesian()`

Returns:

Type	Description
`CartesianVector`	Cartesian vector in *kilometers*.

`TLE`

`agom` `instance-attribute`

`apoapsis` `instance-attribute`

Apoapsis radius in kilometers

`argument_of_perigee` `instance-attribute`

Argument of Perigee in degrees

`b_star` `instance-attribute`

`b_term` `instance-attribute`

`cartesian_state` `instance-attribute`

TEME cartesian state of the TLE at epoch

`classification` `instance-attribute`

`designator` `instance-attribute`

8-character identifier of the satellite

`eccentricity` `instance-attribute`

`epoch` `instance-attribute`

UTC epoch of the state

`inclination` `instance-attribute`

Inclination of the orbit in degrees

`lines` `property`

Note

If the TLE was created in the 3LE format, only lines 2 and 3 will be returned. The name must be accessed using the name property.

Returns:

Type	Description
`tuple[str, str]`	Tuple of strings in 2 line format

`mean_anomaly` `instance-attribute`

Mean Anomaly in degrees

`mean_motion` `instance-attribute`

Mean motion in revolutions per day

`mean_motion_dot` `instance-attribute`

`mean_motion_dot_dot` `instance-attribute`

`name` `instance-attribute`

`norad_id` `instance-attribute`

NORAD catalog ID of the satellite

`periapsis` `instance-attribute`

Periapsis radius in kilometers

`raan` `instance-attribute`

Right Ascension of Ascending Node in degrees

`satellite_id` `instance-attribute`

`semi_major_axis` `instance-attribute`

Average distance from the central body in kilometers

Note

This is always calculated using Brouwer mean motion and will differ slightly from Kozai-computed SMA.

`type` `instance-attribute`

`from_ephemeris(ephemeris, tle_type)` `classmethod`

Fit a TLE to an ephemeris using batch least squares.

Generates synthetic observations from the ephemeris and uses batch least squares estimation to produce a TLE of the specified type.

Parameters:

Name	Type	Description	Default
`ephemeris`	`Ephemeris`	Ephemeris containing position/velocity states to fit	required
`tle_type`	`KeplerianType`	The type of mean elements for the output TLE	required

Returns:

Type	Description
`TLE`	TLE fitted to the ephemeris

`from_lines(line_1, line_2, line_3=None)` `classmethod`

Create a TLE object using strings in 2 or 3 line format

`get_keplerian_state_at_epoch(epoch)`

Get a Keplerian state at a specific epoch by propagating the TLE.

Returns mean elements appropriate to the TLE type (Kozai for SGP4, Brouwer for XP).

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	The epoch at which to get the state	required

Returns:

Type	Description
`KeplerianState`	KeplerianState in TEME frame at the specified epoch

`get_observation_at_epoch(epoch)`

Get an observation at a specific epoch.

Creates an observation from the TLE's propagated state at the given epoch, useful for batch least squares fitting of multiple TLEs.

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	The epoch at which to generate the observation	required

Returns:

Type	Description
`Observation`	Observation derived from this TLE at the given epoch

`get_state_at_epoch(epoch)`

Get a Cartesian state at a specific epoch by propagating the TLE.

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	The epoch at which to get the state	required

Returns:

Type	Description
`CartesianState`	CartesianState in TEME frame at the specified epoch

`TopocentricElements`

Parameters:

Name	Type	Description	Default
`right_ascension`	`float`	TEME right ascension in *degrees*	required
`declination`	`float`	TEME declination in *degrees*	required

`declination_rate` `instance-attribute`

Declination rate in _degrees per second

`range` `instance-attribute`

Range in kilometers

`range_rate` `instance-attribute`

Range rate in kilometers per second

`right_ascension_rate` `instance-attribute`

Right ascension rate in _degrees per second

`from_j2000(epoch, ra, dec)` `classmethod`

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	UTC epoch of the angles	required
`ra`	`float`	J2000 right ascension in *degrees*	required
`dec`	`float`	J2000 declination in *degrees*	required

`TopocentricState`

Parameters:

Name	Type	Description	Default
`epoch`	`Epoch`	UTC epoch of the state	required
`elements`	`TopocentricElements`	TopocentricElements of the state	required

`declination` `instance-attribute`

TEME declination in degrees

`declination_rate` `instance-attribute`

Declination rate in _degrees per second

`elements` `instance-attribute`

Topocentric elements of the state

`epoch` `instance-attribute`

UTC epoch of the state

`range` `instance-attribute`

Range in kilometers

`range_rate` `instance-attribute`

Range rate in kilometers per second

`right_ascension` `instance-attribute`

TEME right ascension in degrees

`right_ascension_rate` `instance-attribute`

Right ascension rate in _degrees per second

`from_horizon_state(horizon_state, observer)` `classmethod`

Parameters:

Name	Type	Description	Default
`horizon_state`	`HorizonState`	HorizonState of the target	required
`observer`	`Observatory`	Position of the observer	required

keplemon.elements

elements

CartesianState

epoch instance-attribute

frame instance-attribute

position instance-attribute

velocity instance-attribute

to_frame(frame)

to_keplerian()

CartesianVector

magnitude instance-attribute

angle(other)

distance(other)

to_spherical()

Ephemeris

add_state(state)

to_observations()

EquinoctialElements

GeodeticPosition

altitude instance-attribute

latitude instance-attribute

longitude instance-attribute

HorizonElements

HorizonState

azimuth instance-attribute

azimuth_rate instance-attribute

elements instance-attribute

elevation instance-attribute

elevation_rate instance-attribute

epoch instance-attribute

range instance-attribute

range_rate instance-attribute

KeplerianElements

KeplerianState

apoapsis instance-attribute

argument_of_perigee instance-attribute

eccentricity instance-attribute

inclination instance-attribute

mean_anomaly instance-attribute

mean_motion instance-attribute

periapsis instance-attribute

raan instance-attribute

semi_major_axis instance-attribute

to_cartesian()

to_frame(frame)

SphericalVector

to_cartesian()

TLE

agom instance-attribute

apoapsis instance-attribute

argument_of_perigee instance-attribute

b_star instance-attribute

b_term instance-attribute

cartesian_state instance-attribute

classification instance-attribute

designator instance-attribute

eccentricity instance-attribute

epoch instance-attribute

inclination instance-attribute

lines property

mean_anomaly instance-attribute

mean_motion instance-attribute

mean_motion_dot instance-attribute

mean_motion_dot_dot instance-attribute

name instance-attribute

norad_id instance-attribute

periapsis instance-attribute

raan instance-attribute

satellite_id instance-attribute

semi_major_axis instance-attribute

type instance-attribute

from_ephemeris(ephemeris, tle_type) classmethod

from_lines(line_1, line_2, line_3=None) classmethod

get_keplerian_state_at_epoch(epoch)

get_observation_at_epoch(epoch)

get_state_at_epoch(epoch)

TopocentricElements

declination_rate instance-attribute

range instance-attribute

range_rate instance-attribute

`elements`

`CartesianState`

`epoch` `instance-attribute`

`frame` `instance-attribute`

`position` `instance-attribute`

`velocity` `instance-attribute`

`to_frame(frame)`

`to_keplerian()`

`CartesianVector`

`magnitude` `instance-attribute`

`angle(other)`

`distance(other)`

`to_spherical()`

`Ephemeris`

`add_state(state)`

`to_observations()`

`EquinoctialElements`

`GeodeticPosition`

`altitude` `instance-attribute`

`latitude` `instance-attribute`

`longitude` `instance-attribute`

`HorizonElements`

`HorizonState`

`azimuth` `instance-attribute`

`azimuth_rate` `instance-attribute`

`elements` `instance-attribute`

`elevation` `instance-attribute`

`elevation_rate` `instance-attribute`

`epoch` `instance-attribute`

`range` `instance-attribute`

`range_rate` `instance-attribute`

`KeplerianElements`

`KeplerianState`

`apoapsis` `instance-attribute`

`argument_of_perigee` `instance-attribute`

`eccentricity` `instance-attribute`

`inclination` `instance-attribute`

`mean_anomaly` `instance-attribute`

`mean_motion` `instance-attribute`

`periapsis` `instance-attribute`

`raan` `instance-attribute`

`semi_major_axis` `instance-attribute`

`to_cartesian()`

`to_frame(frame)`

`SphericalVector`

`to_cartesian()`

`TLE`

`agom` `instance-attribute`

`apoapsis` `instance-attribute`

`argument_of_perigee` `instance-attribute`

`b_star` `instance-attribute`

`b_term` `instance-attribute`

`cartesian_state` `instance-attribute`

`classification` `instance-attribute`

`designator` `instance-attribute`

`eccentricity` `instance-attribute`

`epoch` `instance-attribute`

`inclination` `instance-attribute`

`lines` `property`

`mean_anomaly` `instance-attribute`

`mean_motion` `instance-attribute`

`mean_motion_dot` `instance-attribute`

`mean_motion_dot_dot` `instance-attribute`

`name` `instance-attribute`

`norad_id` `instance-attribute`

`periapsis` `instance-attribute`

`raan` `instance-attribute`

`satellite_id` `instance-attribute`

`semi_major_axis` `instance-attribute`

`type` `instance-attribute`

`from_ephemeris(ephemeris, tle_type)` `classmethod`

`from_lines(line_1, line_2, line_3=None)` `classmethod`

`get_keplerian_state_at_epoch(epoch)`

`get_observation_at_epoch(epoch)`

`get_state_at_epoch(epoch)`

`TopocentricElements`

`declination_rate` `instance-attribute`

`range` `instance-attribute`

`range_rate` `instance-attribute`

`right_ascension_rate` `instance-attribute`