Dynamic measurement of a long-distance moving object using multi-binocular high-speed videogrammetry with adaptive-weighting bundle adjustment

The dynamic measurement of position and attitude information of a long-distance moving object is a common demand in ground testing of aerospace engineering. Due to the movement from far to near and the limitations of camera resolution, it is necessary to use multi-binocular cameras for segmented observation at different distances. However, achieving accurate and continuous position and attitude estimation is a challenging task. Therefore, this paper proposes a dynamic monitoring technique for long-distance movement based on a multi-binocular videogrammetric system. Aiming to solve the problem that the scale in images changes constantly during the moving process, a scale-adaptive tracking method of circular targets is presented. Bundle adjustment (BA) with joint segments using an adaptive-weighting least-squares strategy is developed to enhance the measurement accuracy. The feasibility and reliability of the proposed technique are validated by a ground testing of relative measurement for spacecraft rendezvous and docking. The experimental results indicate that the proposed technique can obtain the actual motion state of the moving object, with a positioning accuracy of 3.2 mm (root mean square error), which can provide a reliable third-party verification for on-orbit measurement systems in ground testing. Compared with the results of BA with individual segments and vision measurement software PhotoModeler, the accuracy is improved by 45% and 30%, respectively.