High-precision attitude measurement of free-drop testing of aircraft in wind tunnel with self-correcting camera extrinsic

The attitude of a free-flight drop model refers to the changes in its spatial orientation, typically captured in wind tunnel tests through target-based videogrammetric measurements. Existing measurement methods are often constrained by limited fields of view and significant vibration, leading to reduced accuracy in large-scale wind tunnel environments. To address these challenges, this paper proposes a high-precision attitude measurement approach for drop models in large wind tunnels, based on camera extrinsic parameter self-calibration. This technique ensures accurate attitude measurement under strong vibration and enhances the stability and reliability of motion correction. Additionally, a global point cloud matching method is introduced for 3D coordinate reconstruction, enabling robust attitude tracking even when markers are occluded due to rapid rotation or airflow disturbances. Experimental validation shows that the proposed method achieves an attitude measurement accuracy within 0.01° in high-precision dual-axis turntable tests. In free jet wind tunnel tests, the overall attitude error remains below 0.1°. These results demonstrate accuracy comparable to systems such as the Langley Research Center in the United States and the ETW-SPT System in Europe. The proposed framework offers a robust and high-precision videogrammetric solution for attitude determination of drop models in wind tunnel applications.