中国地壳运动观测网络基本网观测精度研究

“中国地壳运动观测网络”于1998～2002年开展过5次基本网GPS联测。利用GIPSY软件处理结果进行的统计分析表明：基线定位水平分量精度为2～5mm，垂直分量为7～15mm；基线变化的水平分量测定精度为0．5mm／a，达到了流动观测的最高水平。分析基线定位误差发现：固定误差是目前相对定位的主要误差；与基线长度有关的比例误差对于水平分量而言，基本可以忽略。对速率的统计分析说明：至少4年观测间隔，才有可能获得比较精确、可靠的测站速率结果。

OBSERVATION PRECISION OF BASIC NETWORK OF CMONOC

Five-epoch GPS campaigns for basic network of CMONOC were carried out in 1998 through 2002. On the basis of data output processed by GIPSY-software, short-term precision of baseline determination is estimated at 2-5 mm for horizontal component and 7-15 mm for the vertical. The long-term precision is similar to the short-term one in magnitude,this suggests that the highest achievable precision can be obtained from these observations. The baseline uncertainty is attributed to site-dependent errors associated with multi-path signal, un-calibrated propagation delays, unstable marker etc.The length-dependent error associated with orbit determination biases is minor if any , can be ignored for the horizontal.We have drawn the conclution that at least four-year interval is required to precisely determine site displacement rate.