Research On Infrared/Geomagnetic Information Fusion Attitude Measurement Method Under Coning Motion

With the rapid development of science and technology,the intellectualization of conventional weapons is the general trend of modern war.Under this background,a large number of conventional ammunition need to be transformed with the goal of diversification,new type and low cost to obtain the attitude angle information of projectile suitable for different battlefield environments.The infrared/ geomagnetic information fusion attitude measurement technology has the advantages of low cost,small volume,high autonomy and high robustness of infrared and geomagnetic attitude measurement.There is no drift error,cumulative error,initial alignment of inertial attitude measurement,and it is not vulnerable to external interference as GPS.In many applications,it can provide high accuracy for the attitude angle measurement of spinning projectile.Therefore,the research on the theory and practice of infrared/ geomagnetic integrated attitude measurement technology is of great significance to promote the development direction of intellectualization and precision of conventional weapons in China.Taking the coning motion of the spinning projectile caused by Magnus effect as the motion background,the basic theory and generation mechanism of the earth’s infrared radiation field and geomagnetic field are comprehensively studied,and the infrared and geomagnetic attitude measurement model of the spinning projectile under coning motion are established.Based on the analysis and discussion of the multi-source interference of infrared and geomagnetic in the actual movement,the infrared and geomagnetic interference model of spinning projectile are established.By discussing the interference characteristics of infrared and geomagnetic,the interference compensation methods are studied.Infrared sensors and magnetic sensors are used to sense the infrared radiation information and geomagnetic information around the projectile through a reasonable three-axis array.The infrared and geomagnetic attitude solution algorithm of the spinning projectile under coning motion and the infrared / geomagnetic anti-interference adaptive information fusion algorithm are designed to estimate the attitude angles adaptively when some of the sensor outputs of the attitude measurement system are abnormal.In order to verify the effectiveness and reliability of the infrared / geomagnetic information fusion attitude measurement system,a three-axis turntable is used to simulate the coning motion of the spinning projectile.The paper includes the following contents:(1)The common coordinate system and coordinate transformation matrix for navigation and attitude measurement are introduced,and the coning motion model of spinning projectile is constructed.Taking the inherent infrared radiation field in the atmosphere as the background,according to the layered distribution characteristics of physical parameters such as atmospheric temperature and absorption transmittance,the infrared attitude measurement model of spinning projectile under coning motion is established through the atmospheric stratification theory and the measurement characteristics of infrared sensor.According to the three-axis component of the key elements of geomagnetic vector in the carrier coordinate system,the geomagnetic attitude measurement model of spinning projectile under coning motion is established.(2)Aiming at the problem that the equations of tri-orthogonal geomagnetic attitude measurement are not independent of each other,the zero-point derivative ratio algorithm and its correction algorithm of tri-orthogonal geomagnetic sensor are proposed.The roll angles at the certain feature points are obtained by extracting the feature quantities of geomagnetic signal,and the other two attitude angles are solved.The attitude angles under coning motion are further modified by the correction algorithm.According to the characteristics of magnetic sensor and projectile,the static and dynamic interference models of geomagnetic sensor are constructed,and the improved particle swarm optimization algorithm based on Gaussian disturbance and dynamic error parameter identification method are designed to compensate the magnetic interference.Through the geomagnetic measurement error compensation experiment,the feasibility of static compensation and dynamic compensation algorithms are verified.(3)Based on the infrared attitude measurement model of spinning projectile under coning motion,the direct and indirect infrared attitude solution algorithms are designed.The advantages and disadvantages of direct algorithm and indirect algorithm are compared through the error transfer analysis.The effects of eddy current heating,turbulence heating and aerodynamic heating on the infrared radiation field around the projectile are analyzed.The deflection of shock wave and turbulence on the propagation path of infrared radiation and the weakening model of infrared radiation brightness in aerodynamic environment are established,and the attitude angle error compensation method under the background of corresponding infrared interference is studied.(4)In view of the sudden interference and failure that the spinning projectile may suffer in the actual flight process,the Interacting Multiple Model Cubature Kalman Filter algorithm which can adaptively switch the model is designed.The algorithm can switch to other models in time when the sensor signal goes wrong by updating the probability of the filter model,and the convergence speed is fast.The effect of the filtering algorithm on data fusion and model switching is verified by numerical simulation.(5)According to the requirements of the attitude measurement system of spinning projectile,a set of infrared / geomagnetic attitude measurement semi-physical device is designed.The hardware circuit,sensor selection and preprocessing technology of the system are introduced.Through the control of three-axis turntable,the coning motion of spinning projectile is simulated,and various algorithms proposed in this paper are verified by simulation experiments.The experimental results show that the infrared / geomagnetic information fusion attitude measurement and interference compensation method of spinning projectile under coning motion are effective and feasible.