利用地面GPS技术绝对测定湿大气含量的可能性

从理论和实测资料处理两方面对单基线模式下利用地面GPS技术绝对测定湿大气含量的可能性进行了探讨。由于短基线模式下测定湿大气含量之间的相关性很强，其测定的湿大气含量值必然有较大的相关误差，当用具有相同测段的不同资料组处理时表现为测定参数的不稳定性。在假设卫星的分布是连续而且均匀的情况下，可以从理论上研究相关系数随基线长度和截止高度角的变化，理论的结果和实际情况一致性较好。

THE POSSIBLITY OF DIRECT ESTIMATION OF THE ABSOLUTE PRECIPITABLE WATER USING TWO GPS RECEIVERS

The possiblity of direct estimation of the absolute value of precipitable water is studiedby using two GPS receivers from two aspects, theory and practice. Using two GPS receiversat each end of a short baseline, high correlation is introduced between the ZND (zenith neutral delay) of ZWD (zenith wet delay) parameters of two stations when ZND or ZWD parameters are estimated, so correlation errors will contaminate the stability of these parameters deteminated by pure GPS technology. If we assume that the GPS satellite observationdistribution in sky is continuous and uniform, we can derive the change of correlation coefficients with the length of baseline and cutoff angle of observation, these result is identicalwith the result from pratice.