An Improved Method Of Alignment When Total Station In Middle

In recent years,our country completed numerous high cost world-class engineering project which are difficult in technology independently.High-accuracy measurements have been widely used in these major projects.Combining with the long rail attachment project,this thesis take how to proceed long rail alignment with high-accuracy as the core,the content of the paper mainly includes the following:1.Introducing the background and meaning of the topic selection of this paper,and expounding the current research status about alignment domestic and overseas through making summaries and comparisons about mechanical alignment,laser alignment and auto-optical alignment.2.This paper introduces four traditional alignment methods based on total station such as small angle method,theodolite traverse method and free-stationing method in detail.Makes summaries of the advantages and disadvantages and applicable projects of these methods.3.Combining with the project which makes a straightness inspection to one of the nearly 200m long rail,this paper makes an improvement and innovation to the traditional alignment method based on total station aimed at the particularity of the project.Puts forward an improved method of alignment when total station in middle.And makes an analysis about the principle of the method and the factors affecting alignment precision in detail combining with the NET05 total station.The vertical distance of total station deviates from the baseline has little impact on the alignment accuracy of the area on both ends of the baseline,but has great impact on the accuracy of the area near the total station.When the vertical distance is settled,total station deviating from the baseline midpoint on the longitudinal has little impact on the alignment accuracy.The range of alignment accuracy is between 0.15mm to 0.3mm within the particular scope.When the length of the baseline is 200m,the total station erects on the midperpendicular of the baseline deviating from the baseline 1m on the vertical direction.Alignment accuracy from both ends to the midpoints improves gradually.When the distance between the point to be measured and total station is less than 10m,alignment accuracy reduces rapidly because of the effect of the distance-measuring error.4.Designs an experiment to explore the alignment precision of the small angle method and the improved method of alignment when total station in middle when the distance between reference points is 100m and 180m.And makes a verification of the angle measurement accuracy,the ranging accuracy and the sighting accuracy to the Net05 total station which is used in the experiment.The alignment accuracy of small angle method is lower than the improved method of alignment when total station in middle because of the effect of error of centralization.When the length of the baseline is 100m,the alignment accuracy of small angle method is 0.5mm.When the length of the baseline is 200m,the accuracy is 0.7mm.The accuracy of the improves method of alignment when total station in middle is 0.3mm in both cases.5.Through the analysis of the experimental results,found correlation between the experimental distance values.This paper analyses the cause of the relevance,thus provides a new train of thought to improve the accuracy of alignment.6.Finally,this paper narrates the process of the track checking methods of the parallelism,the straightness and the levelness.The researching object of this paper is an alignment measurement in the optical alignment measurement system.By the studying of this method and applied in the specific project,it lays the foundation of the new direction of the optical alignment measurement and it also provides a new way for the future implementation of these similar projects.