useful_functions

Useful functions

Eclipses

• compute_shadow_vector Compute the shadow vector of the spacecraft at each epoch.
  Parameters:

  • satellite_position : ndarray
    Array of satellite positions in ECI frame
  • sun_position : ndarray
    Array of sun positions in ECI frame
  • sun_radius : float
    Sun radius in meters
  • earth_radius : float
    Earth radius in meters

  Returns:

  • visibility_vector: np.ndarray
    Returns a vector with the value of the shadow function at each epoch:
    • 0 if the satellite is in umbra
    • 1 if the satellite is fully sunlit
    • a value between 0 and 1 if the satellite is in penumbra

• compute_ecplipses Compute the eclipses of the spacecraft from a given ground station and organise it into a data frame, following the steps found at link.
  Parameters:

  • satellite_position : ndarray
    Array of satellite positions in ECI frame
  • sun_position : ndarray
    Array of sun positions in ECI frame
  • sun_radius : float
    Sun radius in meters
  • earth_radius : float
    Earth radius in meters
  • epochs : np.ndarray
    Array of epochs in seconds since J2000
  • eclipse_type : string
    Type of eclipse to compute. Can be 'Umbra' or 'Penumbra'. optional, default is 'Umbra'.

  Returns:

  • shadow_df: pd.DataFrame
    Returns a data frame containing the following information about the eclipses
    • 'start' : start date of the eclipse
    • 'end' : end date of the eclipse
    • 'start_epoch' : start epoch of the eclipse in seconds since J2000
    • 'end_epoch' : end epoch of the eclipse in seconds since J2000
    • 'duration' : duration of the eclipse in seconds
    • 'partial' : True if it is a partial eclipse, False if not

Communication windows

• compute_communication_vector Compute the visibility vector of the spacecraft from a given ground station.
  Parameters:

  • pos_ecf : np.ndarray
    Array of satellite positions in ECEF frame
  • groundstation_name : string
    Name of a csv file containing the longitude, latitude, altitude, and minimum elevation of the groundstation.

  Returns:

  • visibility_vector: np.ndarray
    Returns an array of booleans indicating whether the spacecraft is visible or not at each epoch.

• compute_communication_windows Compute the communication windows of the spacecraft from a given ground station and organise it into a data frame, following the steps found at this link.
  Parameters:

  • pos_ecf : np.ndarray
    Array of satellite positions in ECEF frame
  • groundstation_name : string
    Name of a csv file containing the longitude, latitude, altitude, and minimum elevation of the groundstation.
  • epochs : np.ndarray
    Array of epochs in seconds since J2000

  Returns:

  • visibility_df: pd.DataFrame
    Returns a data frame containing the following information about the communication windows:
    • 'start' : start date of the communication window
    • 'end' : end date of the communication window
    • 'start_epoch' : start epoch of the communication window in seconds since J2000
    • 'end_epoch' : end epoch of the communication window in seconds since J2000
    • 'duration' : duration of the communication window in seconds
    • 'partial' : True if it is a partial communication window, False if not