Interface for using an external attitude (.a) file.
  AttitudeStartEpoch | If overriding the times contained in the external file, specifies the time of the first attitude point. | 
  Enabled | Opt whether to use an external attitude file. | 
  Filename | External (.a) file name containing attitude data. | 
  FilePath | External (.a) full file name and path containing attitude data. | 
  MessageLevel | Message level used to report messages during file loading. | 
  Override | Opt whether to override times contained in the external file. | 
  StartTime | Get the start time for the external attitude data. Uses DateFormat Dimension. | 
  StopTime | Get the stop time for the external attitude data. Uses DateFormat Dimension. | 





