Running and Output

Once a config file has been created, the simulation is initialised by creating a Fast instance with your config file

import fast
sim = fast.Fast(“your_config.py”)

On initialisation, most of the relevant analytical values are automatically computed, including the relevant power spectra and link budget terms. The slow(er) Monte Carlo aspect of the simulation is started by calling run()

sim.run()

This will iterate over random or temporally correlated atmopsheric realisations, computing the coupled flux or relevant metric either at the satellite (uplink) or ground (downlink). A progress bar provides an indication of how long the process will take.

Once completed, the simulation results can be found in sim.result (also returned from sim.run()). This FastResult class allows rapid conversion to useful units. Currently, these are:

  • result.dB_rel - results in dB relative to the diffraction limit (no turbulence).

  • result.dB_abs - results in dB including all link budget terms, i.e. Rx power / Tx power

  • result.dBm - results in dBm including all terms in link budget

  • result.power - results in linear power, units of Watts

Simulation results can be saved to FITS file with most simulation parameters as header information by calling the save() function on the sim class

sim.save(“save_filename.fits”)