Abstract: For guided munitions with strapdown seeker, a suboptimal midcourse guidance law is designed to meet the hand-over requirements from satellite-guided mode to laser-guided mode. In general, the time-varying differential equations can not be analytically solved. Therefore, the design of optimal guidance law with multi-constraints is very difficult for time-varying systems. A new method is presented for the problem. First, the framework of suboptimal midcourse guidance law is determined based on optimal control theory; then, according to the framework, the constant replacement values are derived for time-varying parameters. Using the proposed guidance law, the measured line-of-sight (LOS) deviation angle of seeker is much smaller than the field-of-view angle in the hand-over section, and it considers the constraints of the control energy consumption and the miss distance at landing time. Compared with proportional guidance law, the proposed guidance law has only one term more. Little onboard computational resources are required for the simple form.

Key words: Midcourse Guidance law, Suboptimal, Multi-constraints, Hand-over, Line-of-sight deviation anGle