Data from: On the Helmert-blocking Technique: its acceleration by Block Choleski decomposition and formulae to insert observations into an adjusted network

The Helmert-blocking (HB) technique is a common approach to adjust large geodetic networks like Europeans and Brazilians. The technique is based upon a division of the network into partial networks called blocks. This way, the global network adjustment can be done by manipulating these blocks. Here we show alternatives to solve the block system that arises from the application of the technique. We show an alternative that optimizes its implementation as the elapsed processing time is decreased by about 33%. We also show that to insert observations into an adjusted network it is not necessary to readjust the whole network. We show the formulae to insert new observations into an adjusted network that are more efficient than simply readjusting the whole new network.

赫尔默特分块（Helmert-blocking，HB）技术是面向欧洲、巴西等地区的大型大地测量网开展平差的常用方法。该技术的核心思路是将整体大地测量网划分为若干被称为“块”的子网络，借此可通过对这些分块进行操作来完成整体网平差。本文针对该技术应用过程中产生的分块方程组，提出了多种求解方案。其中一种优化方案可将处理时长缩短约33%，有效提升了算法执行效率。此外，本文证实，向已完成平差的大地测量网中添加新观测值时，无需对整合后的整体新网络进行重新平差；同时给出了向已平差网络中加入新观测值的计算公式，该方法相较直接对整合后的新网络进行整体平差更为高效。