To assess the quality of field observation data and detect gross errors,a generalized algorithm for searching misclosures is proposed.First,based on adjustment theory,the number of independent misclosures in all sorts of triangulations for high-speed railway tunnels is determined,considering the numbers of survey stations,non-station points and observations.The principle for constituting the simplest misclosure is established,based on which the cosine and sine misclosures are proposed.A computation model for the misclosure tolerance is derived,and a method for detecting gross errors in observations using misclosures is established.Next,the mathematical relationship is derived between the misclosure increment and the number of overlapping observation points resulting from a station increment.The bi-directional many-to-many topological relations are established between stations and nodes using a data structure,and based on a divide-and-conquer approach,an increment algorithm with dual loops for queue-station relations is proposed to automatically search for the simplest and independent misclosures.Finally,the algorithm is tested by an example of hybrid triangulation network constructed in a high-speed railway tunnel in southwest China.The results indicate that the incremental algorithm can automatically determine 100％of the simplest independent misclosures and detect 100％of the gross errors existed in observations,which validates the effectiveness in searching for misclosures and detecting gross errors by the proposed algorithm.
关键词
高速铁路长大隧道/闭合差/边角混合网/增量算法/粗差探测
Key words
High-speed railway long tunnels/Misclosures/Hybrid triangulation networks/Incremental algorithm/Gross error detection
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