Synopsis of VTD control file language ( 2009.02.21 )
                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
    LEAP_SECOND: leap_second_file_name
    DE403_EPHEMERIDES: planetary_ephemerides_file_name
    STATION_DESCRIPTION: station_description_file_name
    STATION_COORDINATES: station_coordinates_file_name
    STATION_VELOCITIES: station_velocities_file_name
    STATION_ECCENTRICITIES: station_eccentricities_file_name
    SOURCE_COORDINATES: source_coordinates_file_name
    SOURCE_COORDINATES: [source_coordinates_file_name_2 or NONE]
    SOURCE_COORDINATES: [source_coordinates_file_name_3 or NONE]
    SOURCE_COORDINATES: [source_coordinates_file_name_4 or NONE]
    AEM_FILE: aem_file_name or NONE
    ERM_FILE: erm_file_name or NONE
    HARMONIC_EOP_FILE: [NONE or file_name]
    EOP_SERIES: [NONE or earth_orientation_parameters_file_name]
    EOP_TIME_SCALE: time_scale_of_eop_table
    UZT_MODEL: UT1_zonal_tides_model_name
    UZT_USE: [NONE or ADD or INTERPOLATE or SUBTRACT]
    EROT_COMPAT: [NONE or CALC10]
    PRECESSION_EXPRESSION: precession_model_name
    NUTATION_EXPANSION: nutation_expansion_name
    GEODESIC_NUTATION usage_flag
    SOLID_EARTH_TIDES_ZERO_FREQ: Love_model_name
    SOLID_EARTH_TIDES_2ND_DEGREE: Love_model_name
    SOLID_EARTH_TIDES_3RD_DEGREE: Love_model_name
    POLE_TIDE_MODEL: Love_model_name
    MPL_FILE: file_name
    POSVAR_FIL: model_index  model_file_name
    POSVAR_MOD: model_index  model_type
    POSVAR_INT: model_index  interpolation_type
    POSVAR_USE: model_index  usage_flag
    AXIS_OFFSET_MODEL: usage_flag
    ANTENNA_DEFORMATIONS_FILE: [NONE or agd_file]
    ANTENNA_THERMAL_EXPANSION NONE or [MODEL antenna_information_file
                                       INSITU [NONE or insitu_file]]
    METEO_DEF model
    HYDROSTATIC_ZENITH_DELAY: [NONE or  zenith_delay_path_model_name or
                                    MMF mmd_model_file ]
    WET_ZENITH_DELAY: [NONE or zenith_delay_path_model_name]
    HYDROSTATIC_MAPPING_FUNCTION: [NONE or mapping_function_name
                                        or [MMF mmf_mode file] ]
    WET_MAPPING_FUNCTION: [NONE or mapping_function_name
                                or [MMF mmf_mode file]
                                or external_delay_dir ]
    ATMOSPHERE_TILT_PARTIALS: tilt_partials
    SLANTED_PATH_DELAY [SPD_3D or NONE]
    EXTERNAL_DELAY_DIR [NONE or directory_name]
    EXTERNAL_DELAY_DIR_2ND [NONE or directory_name]
    EXTERNAL_DELAY_DIR_3RD [NONE or directory_name]
    EXTERNAL_DELAY_DIR_4TG [NONE or directory_name]
    IONOSPHERE_MODEL: [NONE or directory_name]
    IONOSPHERE_DATA_DIR: [NONE or directory_name]
    IONOSPHERE_DATA_DIR_2ND: [NONE or directory_name]
    IONOSPHERE_DATA_DIR_3RD: [NONE or directory_name]
    IONOSPHERE_DATA_DIR_4TH: [NONE or directory_name]
    GRS_METRIC: metric_identifier
    TROP_AXOF_COUPLING: usage_flag
    TROP_GEOMETRIC_COUPLING: usage_flag
    PARALLACTIC_ANGLE: usage_flag
    GALACTIC_ABERRATION: usage_flag
    GEOM_EXPR_FAR_ZONE: model_name
    GEOM_EXPR_NEAR_ZONE: model_name
    SOURCE_STRUCTURE: control_file_name
    DOPPLER_EXPR: model_name
    DELAY_RATE: YES or NONE
 
Notation:
~~~~~~~~~
 
   The symbols used to describe the control file's syntax have the following
meanings:
 
     {}  - contents of braces are optional
     []  - contents of brackets are mandatory
 
 
Contact:
~~~~~~~~
 
Questions and comments about this guide should be directed to:
 
Leonid Petrov ( http://astrogeo.org/petrov )