为了国土资源调查和防洪防灾，在长江中游建立了 大地形变 GPS监测网，以监测水患区的构造沉降。顾及到对流层延迟的影响，实测了每个测 站处的气象数据。在GPS监测网的数据处理中，采用Saastamoinen 模型来计算对流层延迟的 干分量，而对流层延迟中的湿分量，用分段线性方法进行估计，以提高GPS高程分量的精度 。GPS监测网基线的重复精度优于10-8，GPS监测网的点位水平中误差均优于±2.6 mm，高程均优于±3.3 mm，平差后基线边相对精度优于10-8量级。研究表明， GPS监测网的精度达到并完全满足了大地形变监测的精度要求，可为地质调查和灾害防治提 供准确的垂直变形信息。

In order to investigate land resources and prevent flood and disaster, a GPS geotectonic deformation-monitoring network was established to monitor the tectonic subsidence of the flooded area in the middle reaches of the Changjiang River. Considering the affect of tropospheric delay, the mete orologic data at every site were surveyed. The Saastamoinen model was adopted t o compute the dry component parts of the tropospheric delay in the data processing of GPS monitoring network. The wet components of the tropospheric delay were estimated by using the piece wise linear method for improving the precision of G PS height components. The repeatability of all baselines of GPS monitoring netwo rk was superior to 10-8 level. The horizontal RMS(root mean square) errors of all monitoring points were superior to ±2.6 mm and the height RMS error s of all monitoring points superior to ±3.3 mm. The relative accuracies of all baselines after adjustment were superior to 10-8 level. The research indicates the accuracy of the GPS monitoring network can be achieved and satisfy completely the accuracy requirement of the geotectonic deformation monitoring.It can offer the exact vertical deformation information for the geological inves tigation and preventing disaster.