Small Angle Measurement Technology On Second Order Of Accuracy And Its Application In Space Vehicle

The small angle measurement method with high accuracy plays an important role in the high accuracy measurement field. The traditional methods can't meet the aerospace need. In order to meet the demand for high accuracy and three-dimensional small angle measurement in different environment of the aerospace technology, the angle measurement schemes were explored and studied.1) In order to measure the deformation and attitude of the detector in the satellite, combining moiréfringe principle and self-collimation principle, orthogonal combination grating and digital image processing technology were used to achieve pitch and yaw angle measurement. The roll angle measurement was realized by moiréfringe method based on Talbot self-imaging principle. Validated experimental results show that the accuracy of pitch and yaw angle measurement is 0.3 arc sec, and the accuracy of roll angle is 1 arc sec. The angle measurement range is 30 arc min.2) In order to determine the attitude of detector on the satellite truss, using the angle amplification principle based on the laser multiple reflections between two mirrors, the pitch and yaw angle measurement was achieved by real-time monitoring the position changes of laser spot captured by CCD camera. Verified experiment set was established. The results show that the accuracy and measurement range are, respectively, 0.1 and 340 arc sec. Moreover, the angle measurement based on internal reflection effect was introduced by comparison. In order to achieve three-dimensional small angle measurement, the plane mirror of collimation was replaced by the Fresnel biprism.3) In order to meet the collimation demand in deep space communication, the fabry-perot interference principle was adopted to achieve 2-d small angle measurement. The emulation test results show that the accuracy can reach 2 arc sec. the principle, the device and characteristics of small Angle measurement method based on optical internal reflections were introduced.The digital image processing technology was applied in this field, which greatly improved the measurement accuracy, speed, automation. In the center extraction process of the laser spot, the centroid, weighted centroid, Hough transform and circular fitting methods were studied comparatively. The linear feature extraction method based on the Hough transform algorithm was adopted in the treatment of moiréfringe.The results show that the schemes proposed in this paper have the characters of devices simple, high accuracy, and the measuring error is less than 1 arc sec. This study has a larger reference to the angle measurement system design.