If the AAR data is badly affected by noise or fringes, smoothing may be the best option. The AAR data have already had the fringes taken out by the best RSRF data available (which is present on the CD as the CAL25_x files ). Do not attempt to remove any fringes out of AAR using the CAL25_x files. The CAL25_x files may be used to try and remove the fringes out of SPD .
Note the warning in section 6 concerning confusing the effects of fringes with spectral lines.