The generation mechanism and identification of spatially non-continuous error in integral multi-station measurement systems

The integral multi-station measurement system represented by indoor GPS, workshop Measuring and Positioning System or a multi-camera system, realizes high-precision 3D measurement in large-scale space by constructing a global measurement field within a unified temporal-spatial reference. In advanced equipment manufacturing sites such as robot machining, large component (the fuselage or wing of airplanes) assembly and monitoring, the integral multi-station measurement system overcomes the drawbacks of the single-station measurement system such as laser tracker that can hardly balance the measurement range and accuracy. However, with the improvement of automation and intelligence degree in equipment manufacturing, the requirements on accuracy and robustness has become more and more strict, which is a huge challenge to existing measuring technologies. Limited by the measurement principle of multi-observation intersection, the change of geometry constraint in the integral multi-station measurement field will lead to spatially non-continuous error, degrading the performance of the integral multi-station measurement system. In this paper we first analyze the mechanisms and characteristics of spatially non-continuous error at the geometry constraint level. Basing on the error propagation model, a criterion for evaluating the significance of non-continuous error is then proposed for error identification. Finally, simulations and experiments are carried out, and this proposed criterion is verified to be effective.