High resolution Fourier-Transform spectroscopy of atmospheric trace gas has been carried out at DLR since 1990. The primary focus is on supplying well characterized uncertainties. The core instrument is the commercial high-resolution Bruker IFS 125 HR Fourier-transform spectrometer operating from 10 to 40000 cm^-1. The laboratory infrastructure has been continuously improved over the last 30 years, especially the absorption cells. A 22 cm absorption path 200-350 K cell features two windows pairs allowing quasi-simultaneous measurement from FIR to UV. A 200 m absorption path multireflection cell operates in the temperature range 200-350 K with high temperature homogeneity. Line fitting software was steadily improved, resulting in a multispectrum fitting tool with several line shape models including the Hartmann-Tran profile. The instrumental line shape of the Fourier-transform spectrometer is adopted from the LINEFIT software by Frank Hase, IMK, which is also used by the TCCON community.

Recent results are a spectroscopic database of the O₃ fundamentals and temperature dependent UV absorption cross sections for O₃, together solving the 4% discrepancy between UV and MIR atmospheric O₃ columns, a comprehensive H₂O spectroscopic database in the range 1850-4300 cm^-1, a new method to obtain H₂O continua, H₂O foreign- and self-continua in the 3 µm region, and a CO₂ database in the range 6000-7000 cm^-1 with absolute intensity uncertainties <0.15%. Most of these results have become part of the HITRAN20 database.