Time-to-go Polynomial Guidance with Trajectory Modulation for Observability Enhancement

A new impact angle control guidance law is introduced for a homing missile system equipped with a passive seeker against a stationary or slowly moving target. The proposed guidance law provides sufficient trajectory modulations, such as oscillatory trajectories, to enhance target observability from angle-only measurements. The derivation of the guidance command is based on the time-to-go polynomial guidance (TPG) law, which is one of the impact angle control laws. Closed-form solutions of the proposed law and their characteristics are investigated. The results inspired the proposed practical time-to-go calculation method and the maximum bounds of guidance gains, which are important for the practical implementation of the guidance law. Linear and nonlinear simulations with a target tracking filter are performed to investigate the performance of the proposed law.