The effect of the wet troposphere is sometime mitigated by specifying a minimum elevation angle. This affects orbit determination of satellites using doppler signals as well as positioning receivers on the surface of the Earth. Radar altimeters also encounter the tropospheric delay. Currently this is being done using data sets from water vapor radiometers. Good vertical resolution of data, poor horizontal resolution, and varying temporal resolution.
Vertical resolution is poor.
Vertical resolution is poor. Could potentially provide global information scattered among airports with varying temporal frequency. For more information on Non-GPS techniques, click here . References Bevis, M., S. Businger, T. A. Herring, C. Rocken, R. A. Anthes, and R. H. Ware. Using the Global Positioning System.