Meeting the challenges of modern interceptor guidance by non-conventional approaches
The challenge of intercepting threats with non conventional warheads, the major drive for the development of ballistic missile defense systems since the first Gulf War of 1991, became even more serious when the reentry vehicles were assumed to be capable of maneuvering. Successful interception of such targets, requiring very small miss distances, cannot be guaranteed by the classical guidance and estimation methods that have been used against manned aircraft. Future interceptor guidance strategy has to be based on pursuit-evasion game concepts and the estimator design has to be integrated with the guidance law. Following such non conventional approaches has the potential to achieve the requirement of hit-to-kill accuracy against randomly maneuvering threats.
Warhead tracking based on probabilistic data association filter with feature information
This paper presents the novel and efficient warhead tracking filter based on probabilistic data association (PDA) scheme for FMCW radar seeker with anti-ballistic capability. In frequency domain, the warhead tracking problem can be cast into a difficult data-association problem because multiple and closely located frequency measurements are generated by scatterers of a ballistic missile and multi-path clutters. For enhancing the warhead detection and tracking performance, the proposed warhead tracking filter adopts the feature information about scatterers' appearance. The feature information indicates the possibility that the measured frequency measurement is originated from the scatterer in warhead section of ballistic missile. Utilizing the feature information, the proposed tracking filter is able to accurately separate the warhead frequency measurement from others. Moreover, for its simple structure, it is suitable for real-time implementation. Simulation results demonstrate the effectiveness and the reliability of the proposed solution over the conventional PDA based filter.
Botulinum toxin in the management of chronic migraine: clinical evidence and experience
Chronic migraine (CM) is a severely disabling neurological condition characterized by episodes of pulsating unilateral or bilateral headache. The United States Food and Drug Administration (FDA) approved onabotulinumtoxinA (Botox®) for the prophylactic treatment of CM in 2010. It has been shown that onabotulinumtoxinA is effective in the reduction of headache frequency and severity in patients with CM. Treatment is well tolerated by the patients. This review reports on the history of botulinum neurotoxin (BoNT) in CM and presents the current clinical evidence for the use of onabotulinumtoxinA in the treatment of CM.