Research On Error Analysis And Calibration Of Airborne Photoelectric Detecting System

Photoelectric detecting system is an important part of the modern detecting and reconnaissance system, and it is mainly used for recognition, orientation, detection and tracing. With the development of optical mechanical and electronic integration system, photoelectric detecting system has been widely used in the field of detecting, orientation, collimation, tracing and navigation. As the decisive evaluation index of the system performance, orientation precision is important to the photoelectric detecting system. Not only influence the observational quality of image, but also concern the precision of tracing and collimation. In order to improve the orientation precision of photoelectric detecting system, the paper analyses the working principle, overall structure, error sources, model theories, evaluations, then calibrates the model, and corrects the pointing error. The following studies are included in this paper:1. Summarize the working principle, overall structure and evaluation index of orientation error. According to the structure feature and the flow of orientation, analyses the error sources and distribution rules of all orientation error in detail.2. Based on the analysis of overall structure and orientation error, the orientation error kinematic model of photoelectric detecting system needs to be established. Firstly, regard the photoelectric detecting system as a complex multi-body system, and divide the continuation coordination system. Establish the Denavit-Hartenberg basic parametric model according to the homogenous coordinate transformation which is obtained by multi-body system theory. Secondly, if the overall structure is unknown, according to the process of orientation, establish the Local POE model by lie group theory and screw theory. Finally, based on the error analysis and basic parametric model, calculate the error sensitivity coefficient by Monte Carlo method and sensitivity analysis, which can tell the proportion of each error source in target orientation error, and the coefficient can direct the correction of orientation error.3. In order to meet the high-precision target of the photoelectric detecting system, pointing error which takes up the chief proportion in orientation error needs to be corrected. Firstly, analyse the correcting principle, process and key problems. Secondly, in consideration of the traditional linear error factors, establish the basic parametric model, and calibrate the parameters by least square calibration algorithm. Then, in consideration of the linear and nonlinear error factors, semi-parametric model is established, and calibrate the parameters by penalized least square calibration algorithm and bicubic spline interpolation. Finally, optimize the traditional algorithm, and calibrate the Local POE model by particle swarm optimization algorithm based on simulated annealing.4. A prototype experimental platform is built. Sample data of pointing error are obtained after pointing error separation, calibration and correction experiments. Calibrate the basic parametric model, semi-parametric model and Local POE model with least square calibration algorithm, penalized least square calibration algorithm and particle swarm optimization algorithm based on simulated annealing, and correct the pointing error of photoelectric detecting system by calibrated model. The experiments and results make it clear that all algorithms can improve the pointing precision and pointing stability of photoelectric detecting system.