Package org.orekit.models.earth

Class ViennaModelCoefficientsLoader

java.lang.Object

org.orekit.models.earth.ViennaModelCoefficientsLoader

All Implemented Interfaces:

DataLoader

public class ViennaModelCoefficientsLoader
extends Object
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
 

Author:

Bryan Cazabonne

Field Summary

Fields

Modifier and Type	Field	Description
static String	DEFAULT_SUPPORTED_NAMES	Default supported files name pattern.

Constructor Summary

Constructors

Constructor	Description
ViennaModelCoefficientsLoader(double latitude, double longitude, ViennaModelType type)	Constructor with default supported names.
ViennaModelCoefficientsLoader(String supportedNames, double latitude, double longitude, ViennaModelType type)	Constructor with supported names given by user.

Method Summary

Modifier and Type	Method	Description
double[]	getA()	Returns the a coefficients array.
String	getSupportedNames()	Returns the supported names of the loader.
double[]	getZenithDelay()	Returns the zenith delay array.
void	loadData(InputStream input, String name)	Load data from a stream.
void	loadViennaCoefficients()	Load the data using supported names .
void	loadViennaCoefficients(DateTimeComponents dateTimeComponents)	Load the data for a given day.
boolean	stillAcceptsData()	Check if the loader still accepts new data.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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)

Constructor with supported names given by 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)

ViennaModelCoefficientsLoader

public ViennaModelCoefficientsLoader(double latitude,
                                     double longitude,
                                     ViennaModelType type)

Constructor with default supported names.

Parameters:

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)

Method Detail

getA

public double[] getA()

Returns the a coefficients array.

• double[0] = a_h
• double[1] = a_w

Returns:

the a coefficients array

getZenithDelay

public double[] getZenithDelay()

Returns the zenith delay array.

• double[0] = D_hz → zenith hydrostatic delay
• double[1] = D_wz → zenith wet delay

Returns:

the zenith delay array

getSupportedNames

public String getSupportedNames()

Returns the supported names of the loader.

Returns:

the supported names

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.

Throws:

OrekitException - if the coefficients could not be loaded

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

loadData

public void loadData(InputStream input,
                     String name)
              throws IOException,
                     ParseException

Description copied from interface: DataLoader

Load data from a stream.

Specified by:

loadData in interface DataLoader

Parameters:

input - data input stream

name - name of the file (or zip entry)

Throws:

IOException - if data can't be read

ParseException - if data can't be parsed or if some loader specific error occurs