Laboratory Measurements of L Band Oxygen Opacity Applicable to GNSS Remote Sensing

Accurate models for atmospheric propagation are necessary to derive operational data products from GNSS remote sensing measurements. A laboratory system has been developed to make direct measurements of the refractivity and absorptivity of atmospheric gases at GPS L1 and L2 frequencies. The laboratory system consists of a cylindrical microwave resonator housed within an environmental chamber and is designed for measurements at temperatures and pressures relevant to the Earth's atmosphere. We present measurements of the Debye absorption of oxygen from 1.2-2.3 GHz at pressures of 200-1000 Torr and at temperatures from 290-350 K. These measurements are applicable to the modeling of L band atmospheric opacity in the context of GNSS radio occultation experiments.