Three-Dimensional Validation of an Integrated Estimation/Guidance Algorithm Against Randomly Maneuvering Targets

S UCCESSFUL interception of maneuvering tactical ballistic missiles (TBM), requiring very small miss distances or even a direct hit, has been a challenging problem since their reintroduction as a terror weapon in the 1991GulfWar. At the Faculty of Aerospace Engineering of the Technion—Israel Institute of Technology, a multiyear research has been conducted investigating the difficulties of effective ballistic missile defense (BMD). It has been aimed to identify and correct the deficiencies of the conservative common practice in the estimation/guidance law design. In the last years, several papers dealing with this yet unsolved problem were published [1–9]. In a recently published work [9], an integrated estimation/guidance design paradigm against randomly maneuvering targets was introduced, based on several innovative concepts that provide robust satisfactory homing performance. The main ideas involved in this revolutionary design concept were developed and tested by using a simplified linearized planar (horizontal) constantspeed model of the interception scenario. A set of Monte Carlo simulations demonstrated that in such scenarios this new approach yields a substantial improvement in homing accuracy, compared with earlier results. The simplified mathematical model of the interception scenario raised two critical questions. The main concern has been whether an algorithm that was developed for a time-invariant planar model will perform well in a realistic endoatmospheric BMD scenario, which is inherently three-dimensional with variable speeds and maneuverability constraints. The other question related to target maneuver types. Because the study in [9] was focused on a single maneuver structure (a bang–bang type with random switching time), can the algorithm deal with other types of feasible target maneuvers? The objective of the present Note is to provide answers to these questions by reporting the results of an extensive simulation study evaluating the validity of the integrated estimation/guidance algorithm of [9] in a set of three-dimensional nonlinear endoatmospheric BMD interception scenarios. The test was performed against two types of the most stressing random target maneuvers: namely, the bang–bang-type with random switching time (used in [9]) and a periodical random-phase maneuver discussed in some recent work [10]. Although an eventual threat can generate other maneuver structures, they will be less effective and therefore less likely. Early distinction between the two types of evasive maneuvering is one of the new elements of this study,modifying the originally planar algorithm of [9] to suit a realistic three-dimensional environment. The limited length of a Technical Note did not allow elaborating on the theory and the underlying mathematics. More details can be found in the references and, in particular, in [9]. The structure of this Note is the following. In the next section, the three-dimensional BMD problem is formulated. In Sec. III, the main elements of the integrated estimation/guidance algorithm used in [9] are summarized and the modifications needed for its application in a realistic three-dimensional BMD are outlined. This is followed by the scenario data, including the generic target and interceptor models used in this validation study. The three-dimensional simulation philosophy and the results of extensive Monte Carlo simulations are presented in Sec.V. Summary and conclusions are offered in Sec.VI.