GPS隧道控制网横向贯通精度估算

以GPS测量的基线向量为观测量，推导出适合GPS隧道控制网横向贯通精度的计算式．经实例验证，忽略观测量协方差的计算结果与严密计算结果非常接近；采用GPS接收机标称精度进行估算，其结果也满足隧道控制网的要求．这种估算横向贯通精度的方法完全适合GPS隧道控制网的测前设计．算例结果表明，影响隧道横向贯通精度的主要因素是两端洞口进洞基线方位角测量的相对精度．

Accuracy Estimation of Lateral Piercing for GPS Tunnel Control Network

Based on the observations of the baseline vector measured by GPS technology, a formula of accuracy estimation of lateral piercing for GPS tunnel control networks was deduced. A practical example verifies that the estimated results obtained by ignoring the covariance of the observations are very close to those by strict calculation taking the covariance into account. When estimated by inherent standard deviations of GPS receivers, the accuracy of lateral piercing can also meet the needs of a horizontal tunnel control network. This method of accuracy estimation of lateral piercing can adapt to the design of a GPS control network before tunnel construction surveying. The research result shows that the key factor to affect the lateral piercing accuracy for a tunnel is the relative accuracy of baseline azimuth surveying at the two entrances of the tunnel.