Research On Attitude Measurement Theory And Fusion Method Of Infrared Focal Plane Array

In order to meet the needs of military intelligence,the Centennial goal of building the armed forces,the modernization of national defense and the armed forces,with the wars becoming more and more non-contact,precise,information-based and systematic,precisionguided weapons have almost absorbed all the latest science and technology in the information age as the main equipment to achieve battlefield target strike,especially the high-tech development achievements with guidance technology as the core.The accurate measurement of the key parameter of projectile flight attitude is an important prerequisite and necessary guarantee for the realization of precision guidance.To reduce the excessive dependence on satellite navigation and the resulting risks,the research on new methods of autonomous attitude measurement in satellite-denied environment has been widely concerned in recent years.Infrared focal plane array(IRFPA)has the advantages of multi-faceted and rich information.The attitude measurement method of IRFPA and gyroscope fusion has the advantages of high autonomy,strong anti-jamming ability,no cumulative error in pitch angle and roll angle,solid structure and so on.It has important practical significance for the intelligent and diversified development of guided ammunition in China and has a wide application prospect and practical value in military,satellite,aerospace,UAV and so on.In this paper,the infrared radiation theory of IRFPA is studied,the attitude measurement model of IRFPA is established,and the sensors' arrangement and calculation methods of IRFPA are designed.Aiming at the local and full region characteristics caused by infrared radiation interference such as clouds and mountains,the IRFPA interference diagnosis methods are studied,and the adaptive active fault-tolerant extended Kalman filter under infrared interference is proposed.A new attitude measurement method for rotating projectile based on the combination of single-axis IRFPA and three-axis gyroscope is proposed.The hardware-inthe-loop experiments are carried out to verify the effectiveness of the IRFPA and gyroscope fusion attitude measurement method.Main research work can be summed up in the following aspects:(1)Based on the analysis of the generation mechanism of the earth's infrared radiation field and the establishment of the theoretical model of the unit infrared radiation attitude measurement,according to the geometric relationship between the sensitive pixels of the IRFPA,the output law of each pixel of the IRFPA sensor changing with the roll angle is obtained.With Planck's blackbody radiation law and Lambert's cosine law,the theoretical model of IRFPA attitude measurement is constructed,which provides a theoretical basis for the study of the new attitude measurement method of missile based on IRFPA.(2)According to the attitude measurement theoretical model of IRFPA and the motion characteristics of rotating projectile,the different sensors' arrangement and direct solution algorithms are analyzed from three angles: array time-domain signal,infrared image,combination of array time-domain signal and infrared image.In the case of the single-axis IRFPA sensor's arrangement,an extended Kalman filter algorithm is selected to calculate the attitude information.Under the same conditions,the new attitude measurement method of IRFPA is compared with the unit infrared attitude measurement method through simulation.Using IRFPA for attitude measurement has higher accuracy,flexible arrangements and various calculation methods.(3)Aiming at the environmental interference such as clouds and mountains during infrared attitude measurement,according to the abnormal rule of IRFPA when encountering infrared interference,the infrared interference is classified into two categories: local infrared interference and full-region infrared interference.After analyzing the local and the full-region characteristics of infrared interference,the interference diagnosis methods are studied by using image processing algorithms respectively.An adaptive active fault-tolerant extended Kalman filter algorithm is proposed,which provides a solution for the attitude calculation method of IRFPA under infrared interference,and realizes the active elimination of local interference and fault-tolerant isolation of full-region interference.(4)A combined attitude measurement method using data fusion of single-axis IRFPA sensor and three-axis gyroscope is proposed to form an attitude measurement system with high autonomy,strong anti-infrared interference ability and output of full attitude information.Using the structure of federated filter and the interference diagnosis methods of IRFPA,an active fault-tolerant improved federated Extended Kalman filter algorithm is designed.When the IRFPA sensor fails for a short time,the three-axis gyroscope can continue to measure the attitude to enhance the anti-interference ability of the attitude measurement system.(5)According to the practical requirements of the IRFPA and gyroscope fusion attitude measurement system,a combined attitude measurement system based on the IRFPA and gyroscope is designed.And the attitude change of rotating projectile is simulated by a threeaxis turntable.The IRFPA attitude measurement method,the attitude calculation method of IRFPA under infrared interference,and the IRFPA and gyroscope fusion attitude measurement method are verified by hardware-in-the-loop experiments separately.The results show that the above methods are all effective and feasible.