class_docstr: Class implementing the MTG FCI L1c Filehandler.
  
  This class implements the Meteosat Third Generation (MTG) Flexible
  Combined Imager (FCI) Level-1c NetCDF reader.
  It is designed to be used through the :class:`~satpy.Scene`
  class using the :mod:`~satpy.Scene.load` method with the reader
  ``"fci_l1c_nc"``.
docstr: Compute the orbital parameters for the current segment.
docstr_tok: ["Compute","the","orbital","parameters","for","the","current","segment","."]
code: def orbital_param(self):
      """Compute the orbital parameters for the current segment."""
      actual_subsat_lon = float(
          np.nanmean(
              self._get_aux_data_lut_vector("subsatellite_longitude")
          )
      )
      actual_subsat_lat = float(
          np.nanmean(
              self._get_aux_data_lut_vector("subsatellite_latitude")
          )
      )
      actual_sat_alt = float(
          np.nanmean(self._get_aux_data_lut_vector("platform_altitude"))
      )
      nominal_and_proj_subsat_lon = float(
          self.get_and_cache_npxr(
              "data/mtg_geos_projection/attr/longitude_of_projection_origin"
          )
      )
      nominal_and_proj_subsat_lat = 0
      nominal_and_proj_sat_alt = float(
          self.get_and_cache_npxr(
              "data/mtg_geos_projection/attr/perspective_point_height"
          )
      )
  
      orb_param_dict = {
          "orbital_parameters": {
              "satellite_actual_longitude": actual_subsat_lon,
              "satellite_actual_latitude": actual_subsat_lat,
              "satellite_actual_altitude": actual_sat_alt,
              "satellite_nominal_longitude": nominal_and_proj_subsat_lon,
              "satellite_nominal_latitude": nominal_and_proj_subsat_lat,
              "satellite_nominal_altitude": nominal_and_proj_sat_alt,
              "projection_longitude": nominal_and_proj_subsat_lon,
              "projection_latitude": nominal_and_proj_subsat_lat,
              "projection_altitude": nominal_and_proj_sat_alt,
          }
      }
  
      return orb_param_dict
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  from datetime import timedelta
  from functools import cached_property
  import dask.array
  import numpy
  import xarray
  from netCDF4 import default_fillvals
  from pyresample import geometry
  from satpy.readers._geos_area import get_geos_area_naming
  from satpy.readers.eum_base import get_service_mode
  from .netcdf_utils import NetCDF4FsspecFileHandler
label_desc: Use image node_id 13 for calling the FCIL1cNCFileHandler obj's underlying member method code with example usage: obj.orbital_param() and returns: orb_param_dict