Research On Uncertainty Analysis Method For Distributed Measurement System Based On Angle Intersection Principle

Distributed measurement systems based on the angle intersection principle have the advantages of wide measurement range and high measurement efficiency in large size measurement scenarios,and their uncertainty analysis results are of great significance for accuracy assessment and instrument layout.Due to the large number of error sources,complex error propagation relations,strong parameter coupling and incomplete accuracy reporting in this type of system,it makes it extremely difficult to carry out uncertainty analysis based on the GUM(Guide to the Expression of Uncertainty in Measurement)method.To address this problem,a full-space uncertainty analysis method that effectively simplifies the error transmission model,solves the parameter coupling relationship and clarifies the correlation coefficients between error sources is proposed,simplifying the GUM calculation process.This paper takes the complex distributed Angle intersection measurement system as the research object,and the vision tracking measurement system and workshop Measurement Positioning System(wMPS)as the verification platform,and the uncertainty analysis method applied to this type of system is studied.The following work is carried out in this paper.1.The external angular motion mechanism is used to obtain the spatial rotation angle directly from the instrument measurement value to replace the mathematical calculation process from the measurement value to the spatial angle,thus effectively simplifying the error source,reducing the complexity of the calculation of the GUM error propagation model and shortening the error transmission chain.It also uses the obtained rotation angles to establish a unified coordinate orientation model by means of quadratic expressions,which simplifies the measurement model and reduces the difficulty of calculating the propagation model.2.By establishing a virtual geometric constraint on the angular feature space,the interaction between the sources of error is effectively decoupled.The spatial mathematical relations based on the angle clarify the coupling between the input error sources and improve the process of determining the covariance matrix.3.The expression of uncertainty in the Cartesian coordinate system is replaced directly by the spatial angle of the angular characteristic space as the coordinate description quantity,and the full spatial uncertainty analysis results are expressed by means of the closure property of the angle.4.The typical complex angle intersection measurement systems: vision tracking measurement system and wMPS are analysed and the combined system design,model establishment and uncertainty analysis are completed.The uncertainty analysis methods of the above two systems are analyzed by simulation and verified by experiment.The experimental results demonstrate the validity of the method studied and improve the uncertainty analysis process using the GUM method.