Package org.orekit.models.earth.troposphere

Class ViennaModelCoefficientsLoader

  • All Implemented Interfaces:
    DataLoader
    public class ViennaModelCoefficientsLoader
extends AbstractSelfFeedingLoader
implements DataLoader
    Loads Vienna tropospheric coefficients a given input stream. A stream contains, for a given day and a given hour, the hydrostatic and wet zenith delays and the ah and aw coefficients used for the computation of the mapping function. The coefficients are given with a time interval of 6 hours.

    A bilinear interpolation is performed the case of the user initialize the latitude and the longitude with values that are not contained in the stream.

    The coefficients are obtained from Vienna Mapping Functions Open Access Data. Find more on the files at the VMF Model Documentation.

    The files have to be extracted to UTF-8 text files before being read by this loader.

    After extraction, it is assumed they are named VMFG_YYYYMMDD.Hhh for ViennaOneModel and VMF3_YYYYMMDD.Hhh ViennaThreeModel. Where YYYY is the 4-digits year, MM the month, DD the day and hh the 2-digits hour.

    The format is always the same, with and example shown below for VMF1 model.

    Example: 

     ! Version:            1.0
 ! Source:             J. Boehm, TU Vienna (created: 2018-11-20)
 ! Data_types:         VMF1 (lat lon ah aw zhd zwd)
 ! Epoch:              2018 11 19 18 00  0.0
 ! Scale_factor:       1.e+00
 ! Range/resolution:   -90 90 0 360 2 2.5
 ! Comment:            http://vmf.geo.tuwien.ac.at/trop_products/GRID/2.5x2/VMF1/VMF1_OP/
  90.0   0.0 0.00116059  0.00055318  2.3043  0.0096
  90.0   2.5 0.00116059  0.00055318  2.3043  0.0096
  90.0   5.0 0.00116059  0.00055318  2.3043  0.0096
  90.0   7.5 0.00116059  0.00055318  2.3043  0.0096
  90.0  10.0 0.00116059  0.00055318  2.3043  0.0096
  90.0  12.5 0.00116059  0.00055318  2.3043  0.0096
  90.0  15.0 0.00116059  0.00055318  2.3043  0.0096
  90.0  17.5 0.00116059  0.00055318  2.3043  0.0096
  90.0  20.0 0.00116059  0.00055318  2.3043  0.0096
  90.0  22.5 0.00116059  0.00055318  2.3043  0.0096
  90.0  25.0 0.00116059  0.00055318  2.3043  0.0096
  90.0  27.5 0.00116059  0.00055318  2.3043  0.0096

    It is not safe for multiple threads to share a single instance of this class.

    Author:
    Bryan Cazabonne

    • Field Detail

      • DEFAULT_SUPPORTED_NAMES

        public static final String DEFAULT_SUPPORTED_NAMES
        Default supported files name pattern.
        See Also:
        Constant Field Values

    • Constructor Detail

      • ViennaModelCoefficientsLoader

        public ViennaModelCoefficientsLoader​(String supportedNames,
                                     double latitude,
                                     double longitude,
                                     ViennaModelType type,
                                     DataProvidersManager dataProvidersManager)
        Constructor with supported names and source of mapping function files given by the user.
        Parameters:
        supportedNames - Supported names
        latitude - geodetic latitude of the station, in radians
        longitude - geodetic latitude of the station, in radians
        type - the type of Vienna tropospheric model (one or three)
        dataProvidersManager - provides access to auxiliary files.
        Since:
        10.1

    • Method Detail

      • getA

        public double[] getA()
        Returns the a coefficients array.
        • double[0] = ah
        • double[1] = aw
        Returns:
        the a coefficients array

      • getZenithDelay

        public double[] getZenithDelay()
        Returns the zenith delay array.
        • double[0] = Dhz → zenith hydrostatic delay
        • double[1] = Dwz → zenith wet delay
        Returns:
        the zenith delay array

      • loadViennaCoefficients

        public void loadViennaCoefficients()
        Load the data using supported names .

      • loadViennaCoefficients

        public void loadViennaCoefficients​(DateTimeComponents dateTimeComponents)
        Load the data for a given day.
        Parameters:
        dateTimeComponents - date and time component.

      • stillAcceptsData

        public boolean stillAcceptsData()
        Description copied from interface: DataLoader
        Check if the loader still accepts new data.

        This method is used to speed up data loading by interrupting crawling the data sets as soon as a loader has found the data it was waiting for. For loaders that can merge data from any number of sources (for example JPL ephemerides or Earth Orientation Parameters that are split among several files), this method should always return true to make sure no data is left over.

        Specified by:
        stillAcceptsData in interface DataLoader
        Returns:
        true while the loader still accepts new data