【摘要】 近几年来，对建立城市GPS三维形变监测网的有关问题进行了较系统深入的探讨，对GPS监测网的基准和系统性偏差等问题作过论述，在此基础上对有关问题作进一步讨论。研究表明，在GPS的观测和数据处理中采取一些有效措施后，其监测精度可以达到毫米级．因此，建立兼有监测三维形变功能的城市GPS控制网是值得推广的，它对于城市防灾减灾县有重要意义．更多还原

【Abstract】 In recent years, we have investigated deeply some problems about establishment and data processing of three dimensions - GPS monitoring networs for metropolis, such as datum of GPS monitoring networks and systematic deviation. In this paper, the problems concemed and research work in progress are presented. The study results show that the monitoring precision at millimeter level is available if some suitable action are adopted on GPS observing and data processing. Therefore, it is worth recommending for taking precautions against disasters in cities to establish urban GPS control networks in possession of function for monitoring deformation in three dimensions更多还原