Track algorithm

Abstract: A bearings-only tracking algorithm is described The algorithm is an extended Kalman filter (EKF) which combines the linear-in-state properties of the Cartesian state variable definition with the linear-in-measurement properties of the modified polar (MP) state variable definition This hybrid approach uses the Cartesian system for state and state covariance extrapolation and uses the MP system for state and state covariance updating Accurate state and state covariance extrapolation is achieved without numerical integration The filter equations of this EKF are, furthermore, derived using a line-of-sight algebra which yields equations which are nonlinear algebraic rather than transcendental This approach allows for easier of the filter equations and provides for greater insight into the bearings-only tracking problem Applying recent results from differential geometric system theory, observability is analyzed by applying the Lie bracket criteria to the algebraic filter equations >

Abstract: A critical phase during air-to-air interception is the homing phase. It is characterized by a short time to go and low bearing rates on the homing path. The phase is critical because any misconception with respect to the target maneuver may result in a substantial miss distance. This is essentially due to the lack of time to perform path corrections when the target produces a collision course error by an evasive maneuver. The estimation of the target acceleration is therefore crucial to the design of guidance laws that allow a fast response to target maneuvers. There are, however, severe problems associated with the synthesis of target trackers for air-to-air missiles. These problems include the lack of observability, modeling errors, and the restriction of the computation time due to high sampling rates. In this paper, a new tracking filter is presented that copes with the problems just mentioned. It is based on the time scale separation inherent in the tracking dynamics. In conjunction with a simple adaption scheme, this filter is able to track a large class of target maneuvers in a computationally efficient manner.

Abstract: Within the context of analysis of finite element models, a methodology is developed for the tracking of complex eigenvalues and eigenvectors through changes in aeroelastic eigenvalue problems. The goal is to eliminate difficulties caused by mode switching (i.e., frequency crossing). Two new methods for mode tracking are presented and compared with an existing method. The first new method, the complex higher order eigenpair perturbation algorithm, is based on a perturbation expansion of the eigenproblem. It iteratively computes changes in the eigenpairs due to parameter perturbations with the important feature of maintaining the correspondence between the baseline and perturbed eigenpairs. The second new method is the complex cross-orthogonality check method which uses mass biorthogonality of the left and right eigenvectors to re-establish correspondence after a standard reanalysis. Applications of mode tracking technology are presented in V-g and/?^fc subsonic aeroelastic analyses. Each application procedure is outlined and examples are given. Recommendations are made based on method ease of use and robustness in the example problems.

Abstract: This paper solves the problem of tracking multiple maneuvering ground targets using an unmanned aerial vehicle (UAV). The targets are widespread so that they may not be covered by the UAV’s detecti...