SP3 file data.
  Agency | Get the agency identifier. | 
  AvailableIdentifiers | A two-dimensional array of available satellite identifiers and their common names. Each array element contains the satellite identifier and its common name (if one is available). | 
  Filename | Get the file name. | 
  OrbitType | Get the orbit size type. | 
  ReferenceTime | Get the reference time. | 
  StartTime | Get the start time of the ephemeris interval. Uses DateFormat dimension. | 
  StepSize | Get the step size. | 
  StopTime | Get the stop time of the ephemeris interval. Uses DateFormat dimension. | 





