Satellite State Representation

class satkit.satstate(time: satstate.__init__.time, pos: numpy.typing.NDArray[numpy.float64], vel: numpy.typing.NDArray[numpy.float64], cov: numpy.typing.NDArray[numpy.float64] | None = None)

A convenience class representing a satellite position and velocity, and optionally 6x6 position/velocity covariance at a particular instant in time

This class can be used to propagate the position, velocity, and optional covariance to different points in time.

property cov: numpy.typing.NDArray[numpy.float64] | None

6x6 state covariance matrix in GCRF frame

Returns:

6x6 numpy array representing state covariance in GCRF frame or None if not set

Return type:

npt.ArrayLike[np.float64] | None

property pos: numpy.typing.NDArray[numpy.float64]

state position in meters in GCRF frame

Returns:

3-element numpy array representing position in meters in GCRF frame

Return type:

npt.ArrayLike[np.float64]

propagate(time: satstate.propagate.time | duration, propsettings=None) satstate

Propagate this state to a new time, specified by the “time” input, updating the position, the velocity, and the covariance if set

Parameters:
  • time (satkit.time|satkit.duration) – Time or duration from current time to which to propagate the state

  • propsettings (satkit.propsettings, optional) – object describing settings to use in the propagation. If omitted, default is used

Returns:

New satellite state object representing the state at the new time

Return type:

satstate

property qgcrf2lvlh: quaternion

Quaternion that rotates from the GCRF to the LVLH frame for the current state

Returns:

Quaternion that rotates from the GCRF to the LVLH frame for the current state

Return type:

satkit.quaternion

property time: time

Return time of this satellite state

Returns:

Time instant of this state

Return type:

satkit.time

property vel: numpy.typing.NDArray[numpy.float64]

Return this state velocity in meters / second in GCRF

Returns:

3-element numpy array representing velocity in meters / second in GCRF frame

Return type:

npt.ArrayLike[np.float64]