长江航道工程测量投影变形修正新方案研究及试验

在长江航道工程测量中，对高斯投影长度变形问题进行修正尤为重要。GPS快速静态定位，能够快速获取较高精度的点位坐标信息以及精准的基线信息。研究利用快速静态测量获取高精度基线信息，在水平距离受地球曲率影响可忽略的范围内，通过在椭球切面上的水平投影计算真实水平距离，实现长度变形的修正。试验数据表明，修正后距离与全站仪精密测距结果偏差在厘米级，最大偏差为1.4 cm，满足航道工程测量精度要求。

New modification program of projection distortion in survey of the Yangtze River engineering

In the engineering survey of Yangtze River waterway,the correction of length deformation in Gauss projection is especially important. The rapid static positioning can quickly acquire the accurate coordinate and baseline information. In case that the influence of the earth curvature on horizontal distance can be ignored,this paper illuminates an original method which employs the exact baseline information acquired by rapid static positioning to calculate the real distance using the baseline horizontal projection on ellipsoid tangent plane,and finally corrects the length deformation. The results indicate that,the deviations between corrected distance and the corresponding distance measured by the total stations are all at cm level,and the maximum deviation is 1.4 cm,which satisfies the requirement of the engineering survey of the Yangtze River waterway.