Integrated CLOS and PN Guidance for Increased Effectiveness of Surface to Air Missiles

• Main Authors: Binte Fatima Tuz ZAHRA, Syed Tauqeer ul Islam RIZVI, Syed Irtiza Ali SHAH
• Format: Article
• Language: English
• Published: National Institute for Aerospace Research “Elie Carafoli” - INCAS 2017-06-01
• Series: INCAS Bulletin
• Subjects: guidance; command line-of-sight; proportional navigation; surface-to-air missile
• Online Access: http://bulletin.incas.ro/files/zahra__rizvi__shah__vol_9_iss_2.pdf
• ISSN: 2066-8201; 2247-4528

In this paper, a novel approach has been presented to integrate command to line-of-sight (CLOS) guidance and proportional navigation (PN) guidance in order to reduce miss distance and to increase the effectiveness of surface to air missiles. Initially a comparison of command to line-of-sight guidance and proportional navigation has been presented. Miss distance, variation of angle-of-attack, normal and lateral accelerations and error of missile flight path from direct line-of-sight have been used as noteworthy criteria for comparison of the two guidance laws. Following this comparison a new approach has been proposed for determining the most suitable guidance gains in order to minimize miss distance and improve accuracy of the missile in delivering the warhead, while using CLOS guidance. This proposed technique is based on constrained nonlinear minimization to optimize the guidance gains. CLOS guidance has a further limitation of significant increase in normal and lateral acceleration demands during the terminal phase of missile flight. Furthermore, at large elevation angles, the required angle-of-attack during the terminal phase increases beyond design specifications. Subsequently, a missile with optical sensors only and following just the CLOS guidance has less likelihood to hit high speed targets beyond 45º in elevation plane. A novel approach has thus been proposed to overcome such limitations of CLOS-only guidance for surface to air missiles. In this approach, an integrated guidance algorithm has been proposed whereby the initial guidance law during rocket motor burnout phase remains CLOS, whereas immediately after this phase, the guidance law is automatically switched to PN guidance. This integrated approach has not only resulted in slight increase in range of the missile but also has significantly improved its likelihood to hit targets beyond 30 degrees in elevation plane, thus successfully overcoming various limitations of CLOS-only guidance approach. Hence, proposing an approach to determine most suitable gains for CLOS guidance and integration of CLOS and PN guidance for enhanced effectiveness and accuracy of surface to air missiles are the two significant contributions of this work.