Computing dispersive atmospheric delay with AATM

Abstract

This is a short and simple illustration of how to use (A)ATM to calculate the dispersive path delay introduced by the atmosphere as well as the non-dispersive parts. The program has only two run-time parameters: the frequency at which to carry out the computation and the relative humidity at ground level.

If you have performed similar calculations and get same or different results, I would very much like to hear from you.

This program is part AATM from version 0.06. The program has been evolving, so the current version has substantially more features.

Example usage

The interaction with the program below is extremely simple and best illustrated by an example:

./dispersive --help

Produces the help message, which for current version is:

Compute dispersive delay in the atmosphere

This program is part of AATM version 0.06
GPL license -- you have the right to the source code. See COPYING

Allowed options:
  --help                Produce this help message
  --freq arg            Frequency at which to compute the dispersion (GHz)
  --ghum arg            Relative humidity at ground level (percent)

The actual computation can look like this:

./dispersive --freq 330 --ghum 25
Freq        Wet Non-Disp            Wet Disp                Dry Non-Disp
330 0.0137844               0.00144976              1.47484

Program source code

Please download AATM (see AATM Download) for the latest version of the dispersive program. It is located in the test/dispersive.cpp file.