7Businger S, S Chiswell et al. The promise of GPS in atmospheric monitoring[J]. Bull Amer Meteor Soc, 1996, 77: 5-18.
8Duan J, M Bevis, Peng Fang et al. GPS Meteorology: Direct estimation of the absolute value of precipitable water[J]. J Appl Meteor, 1996, 35(6) : 830-838.
9Elgered G. Tropospheric Radio-Path Delay from Ground-based Microwave Radiometry[M]. Atmospheric Remote Sensing by Microwave Radiometry. New York: John Wiley & Sons Inc., 1993. 215-258.
10Bevis M, S Businger, Steven chiswell et al. GPS Meteorology: Mapping Zenith wet delays onto precipitable water[J]. J Appl Meteor, 1994, 33(3) : 379-386.