Analytical Solution of Optimal Line-of-Sight Strategy for Simplified Integrated Guidance and Control System with Stationary Target

In this paper, an explicit formulation of optimal line-of-sight strategy is derived in closed-loop for integrated guidance and control (IGC) system without consideration of fin deflection limit. The airframe dynamics is modeled by a second-order nonminimum phase transfer function, describing short period approximation. In the derivation of our optimal control problem, the actuator is assumed to be perfect and without limitation on fin deflection, whereas fin deflection limit is applied for the performance analysis of the presented optimal IGC solution. The problem geometry is assumed in one dimension and the final position and final time are fixed. The formulation is obtained in four different normalized forms to give more insight into the design and performance analysis of the optimal IGC strategy. In addition, guidance gains are obtained analytically in explicit form for steady-state solution. In overall, the performance of IGC is better than that of IGC with steady-state gains, but have more computational burden; however, it is reasonable for now-a-day microprocessors. Curve fitting or look-up table may be used instead for an implementation of optimal IGC strategy. Moreover, parametric study of nondimensional IGC parameters is carried out, such as weighing factor, dc gain, and short period frequency. Finally, the performance of the both IGC strategies is evaluated with airframe model uncertainties.