Research On Maneuver Estimation Method Of Spiral Maneuvering Target

The development of the modern tactical ballistic missile technology put forward the challenge to the national missile defense system. In order to enhance the penetration ability, the modern TBM target can produce large overload spiral maneuvering in reentry phase, greatly increasing the difficulty of the maneuver estimation. Firstly, the target reentry into the atmosphere is in the near space which has strong electromagnetic interference, and the high speed movement of the target can cause the infrared thermal effect, so that the bearing-only measurement is needed, which makes the observability of the state variable very low. Secondly, the high reentry speed makes the terminal guidance time very short, and the existing estimator has large error and delay, so that it is difficult to meet the requirements of accuracy and real-time performance of the terminal guidance. This paper carries on the researches on the estimation of the spiral maneuvering of the TBM target in reentry phase and related problems, and the modeling of the target motion, the observability influencing factors of the system, estimation algorithm, and the estimator performance is analyzed and studied. The main research content of this article is as follows.Firstly, the motion state of the TBM target in reentry phase is analyzed and the model is established. The target placement inertial coordinate system is established as an inertial reference, and the relative motion equation in the line of sight coordinate system is established. A normal spiral maneuvering description form in three-dimension is given under the target placement inertial coordinate system, and is projected onto the line of sight coordinate system, so that the mechanism model of maneuvering acceleration is established. The simplified description of the mechanism model of maneuvering acceleration is given.Secondly, the observability analysis of the system is given. The intersection angle is introduced to the relative motion equation. With the observability matrix, the factors affecting the observability of relative distance and target maneuvering acceleration is respectively analyzed, as well as the observability degree of the state variables of the system under the condition of different intersection angles. A guidance law to improve the observability of the system is designed.Thirdly, the estimation method of the spiral maneuvering of the target is studied. Since the amplitude of spiral maneuvering is time-varying, and considering both the precision of estimation and the rate of convergence, the process noise adaptive EKF estimator based on switch strategy is designed. Considering that the process noise is equivalent to the model error, and in assuming that the statistical feature of the measurement noise is known, introducing the thought of the predictive control into the filtering method, predicting and correcting the model error(the process noise), and combined with the traditional EKF algorithm, the nonlinear predictive EKF estimator is designed. Simulation and comparison of the two methods is taken, and the condition of covariance constraints is analyzed.Finally, the estimator performance is analyzed using the adjoint method. The adjoint model of the mixed continuous and discrete estimator is established. In the time domain, the dynamic response characteristic of the estimator is analyzed, including the error propagation characteristics, the influence on estimation error and delay with different selection of the system parameters and estimator parameters. In the frequency domain, the transfer function from real target maneuver to maneuver estimation is established, and the bandwidth of the estimator is analyzed, as well as the bandwidth constraint in the design of the estimator and guidance law.