Research Of Macro Laser Ranging Sensor For Spacecraft Docking In Orbit

The continuous development of space technology makes human’s activities in space increase. There will be plenty of missions in space, such as equipment maintenance and capturing space satellites and other waste. It has become a hot research in aerospace engineering to replace the astronauts with space manipulator as an important institution to complete such tasks. The premise that space manipulator complete tasks accurately is to detect the position of the target in time and correctly. When the space manipulator is far from the mission, radar, vision and other sensor could be used. But when it comes near, the accuracy of these methods is limited. This paper researched close laser ranging sensor, developed a high-precision, highly integrated short-range distance sensor, and analyzed the performance.Firstly, this paper analyzed and designed the laser ranging sensor from two parts, which are the optical system and the electrical system. For the optics, combined the requirements of the subject, the optical path and the optical element were selected, the optical system was analyzed and the parameters were designed. For the electrical system, a comprehensive analysis of the pros and cons of various controllers were made. In this paper, FPGA was used as the main controller of the sensor. Modules were designed with the VHDL hardware description language, which achieved some software functions into hardware.Secondly, in order to improve the positioning accuracy of the pixel middle, and then to improve the accuracy of the sensor, Labview Real-time work platform used for positioning the middle if CCD pixels was built. With this platform, various pixel subdivision algorithms were analyzed and validated on time. To select the most suitable pixel subdivision algorithm for this sensor, this paper built a model to evaluate the pixel subdivision algorithms by Analytic Hierarchy Process(AHP) and evaluated dichotomy and other there pixels subdivision algorithms with this model.Then, in the case of the sensor has been assembled, in order to reduce the influence of systematic errors, such as processing and installation on the measurement results, this paper made theoretical and experimental studies on sensor calibration methods, and tested the results are within the group and between groups. Refer to the experiment, piecewise polynomial least squares method was selected as the calibration method.Finally, this paper put forward a new algorithm to detect the position and orientation of a plane. Combined with the laser ranging sensor designed in this paper, a position and orientation detection experiment in close range was completed. Experimental result showed that the laser ranging sensor could complete close inspection tasks with high accuracy and in real-time, and it could meet the requirement for measurement of the space manipulator.