Data-driven observability analysis and enhancement for radome slope estimation with constraints on impact angle and terminal acceleration

The authors address the problem of observability analysis and enhancement for missiles equipped with strapdown seekers, especially considering the line-of-sight angle-only measurements and the constraints on impact angle and terminal acceleration. First, based on the generalised polynomial chaos expansion, a novel data-driven observability analysis method is proposed to quantitatively analyse the observability of the radome aberration estimation system in real time, including the observability condition, the observability degree of each state and the effect of stochastic noises. The results show that under conventional proportional navigation guidance, the radome aberration estimation system is weakly observable with line-of-sight angle-only measurements. To address this problem, a novel manoeuvre algorithm, the observability-enhanced guidance law, is introduced to enhance the system observability within specified constraints, thereby improving the estimation performance. This guidance law incorporates a bias term to meet terminal constraints, and optimises the navigation gain using the proposed observability indices. Simulations are conducted to verify the performance of the proposed guidance law in conjunction with a target state estimator.