Polynomial Guidance Laws Considering Terminal Impact Angle and Acceleration Constraints

The work presented here investigates proposed impact angle control guidance laws with terminal acceleration constraints for a stationary or slowly moving target. These laws, called time-to-go polynomial guidance (TPG), assume the guidance command as a polynomial function of time-to-go and determine the coefficients of the guidance command to satisfy the specified terminal constraints. The closed-form trajectory solutions of the guidance command and the target look angle for lag-free systems are derived and their characteristics are investigated. Based on the results we propose a systematic method to find the guidance gains that satisfy practical limits, such as the actuator's command limit and the seeker's field-of-view (FOV) limit. A time-to-go estimation method is also discussed for implementing TPG. Nonlinear and adjoint simulations are performed to investigate the performance of TPG.