The VMF data server provides a tool for the creation of individual ray-traced delays for observations in the microwave spectrum. By specifying all required information about the desired observation(s), the ray-tracing through numerical weather models (NWM) by the ECMWF is carried out automatically and the resulting .radiate file, containing the ray-traced delays and some more parameters, is sent back to the user by email. Regarding the General Data Protection Regulation it is mentioned that we need to store your email address for this purpose. For all observations from 1980 to 2007 the ERA-Interim NWM is used, whereas starting 2008 the Operational NWM is used.
See below for the syntax and an example of the ray-tracing input. Please mind that the number of observations (lines) is limited to 100.

  1. Enter your email address (the ray-traced delays will be sent to this address):

  2. Specify the space geodetic technique (the specified station(s) must occur in the respective station coordinate file gnss.ell , vlbi.ell or doris.ell):


  3. Input the observation specifications here:

You will receive an email containing the .radiate file within a few minutes. If not, check your spam folder.

Syntax of input

The ray-tracing input must consist of the following columns:
  1. Modified Julian Date: real number; including decimal places in order to specify the exact observation time
  2. Station: maximum 8 characters
  3. Azimuth: real number; in radians
  4. Elevation: real number; in radians


Example for input

53471.70856  KOKEE     4.456821254034057  1.202092193364012
53471.70856  NYALES20  1.218255169340251  0.437707742402452
53471.70856  WETTZELL  1.067042545998244  0.224204632314359
53471.70876  GILCREEK  2.615094914242887  0.295557085448315
53471.70876  WESTFORD  4.092016472325890  0.456109757784886
53471.71149  GILCREEK  5.757777315909077  0.301069010717596

Want to determine ray-traced delays independently on your own machine? Take a look at GitHub where we provide our ray-tracing software for download: