基于赫尔默特方差估计的不等精度导线网分析

Analysis of Unequal Precision Wire Network Based on Helmert Variance Estimation

在实际工程中,可能需对不同地形和地貌条件建立不同等级的导线控制网。目前对导线网的平差一般采用在不同阶段或不同精度进行模块化平差计算的方法。该方法将导致不同精度导线模块之间的平差存在一定不足:①增加了平差计算时的工作量,增大了投入,还可能导致模块衔接时出现平面点的错位现象;②利用普通近似方法平差使得导线的平差结果与实际数据差距较大,导线产生旋转或平移。针对这些问题,提出了一种基于赫尔默特方差分量估计的不同精度导线网平差方法,并进行了适当的定权计算,减少了人为定权的主观性。

In practical engineering, the wires for different terrain, landform conditions may need to establish different levels of the control network. At present, the wire network adjustment generally adopts the method of modularized adjustment calculation in different stages or with different precision. This method leads to some deficiencies in the adjustment between different precision wire modules, which increasing the workload of adjustment calculation and input, and may also result in dislocation phenomenon of plane point in module cohesion. The ordinary approximate adjustment method will make the wire adjustment results are far from the actual data, and cause the wire rotation or translation. To solve these problems, we put forward a kind of unequal precision wire network adjustment method based on Helmert variance component estimation, did appropriate weighting calculation, and reduced the subjectivity of factitious weighting.