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Bernese GPS Software Version 5.0 - Bernese GNSS Software

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11. Troposphere Modeling and Estimation<br />

system (see Section 9.3.10). As a result the output troposphere file will contain no troposphere<br />

values or an incomplete set for these stations.<br />

CODE daily troposphere estimates in the form of <strong>Bernese</strong> troposphere files are available<br />

through anonymous ftp (http://www.aiub.unibe.ch/download/BSWUSER50/ATM/) for all<br />

the global sites processed by CODE.<br />

11.5.2 Files Containing Meteorological Data<br />

As already mentioned in Section 11.4.1 the input values for the troposphere a priori model<br />

may stem from meteorological measurements (instead of using a standard atmosphere<br />

model). These values must be introduced into the software in the form of so called meteo<br />

files. You may either prepare these files manually (e.g., by using an ASCII editor) or<br />

they may be converted from RINEX meteo files using program RXMBV3 (see Section 4.10).<br />

One file contains the information for a single station.<br />

There are three different types of meteo files supported by the <strong>Bernese</strong> <strong>GPS</strong> <strong>Software</strong> <strong>Version</strong><br />

<strong>5.0</strong> (see Section 22.9.3, Figures 22.48–22.49). The first type contains pressure, temperature,<br />

and humidity values; the second contains pressure, and dry and wet temperature; the<br />

last type is somewhat different because it contains no surface meteorological measurements<br />

per se but directly the total tropospheric zenith delays (e.g., as obtained from Water Vapor<br />

Radiometers).<br />

Be aware, that if meteo files of type 3 are introduced, no a priori troposphere model is<br />

used and the tropospheric delay in Eqns. (2.34) will be simply the value given in the files<br />

(interpolated for the current epoch) divided by cos z as mapping function.<br />

Note that troposphere result files cannot be re-introduced if the a priori model is based on<br />

introduced meteorological data.<br />

11.5.3 Troposphere SINEX Files<br />

This format is internationally adopted and may be used to exchange station-related total<br />

zenith delay estimates and, optionally, the station coordinates the delay values are based<br />

on. This option is a clear indicator for the high correlation between both parameter types.<br />

The corresponding format specifications are available at ftp://ftp.igs.org/igscb/data/<br />

format/sinex_tropo.txt (see also Section 22.9.2 and [Kouba et al., 1996]). Troposphere<br />

SINEX files may be written by programs <strong>GPS</strong>EST and ADDNEQ2 (do not forget to choose<br />

the correct SINEX header file in the “General Files” panel).<br />

To write a troposphere SINEX file you have to define the offset and time resolution you<br />

want to use for the parameters written to the file (option “EXTRACTION OF PARAMETERS<br />

FOR TROPOSPHERE SINEX FILE” in “<strong>GPS</strong>EST 6.3.1: Site-Specific Troposphere Parameters 1” and in<br />

“ADDNEQ2 9: Options for Atmospheric Parameters”, respectively). The offset and time resolution<br />

specified is independent of the offset and spacing of the parameters. This options simply<br />

define at what epochs the piece-wise function shall be evaluated.<br />

In the <strong>Bernese</strong> <strong>GPS</strong> <strong>Software</strong> <strong>Version</strong> <strong>5.0</strong> the troposphere SINEX format is an output file<br />

format, only. There is no way to directly introduce troposphere SINEX files.<br />

Page 250 AIUB

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