Guidance law with impact angle constraints based on extended disturbance observer

Aimed at the requirement for intercepting maneuvering targets with impact angle constraint, based on the technology of extended disturbance observer (EDO), a novel finite-time convergence guidance law was presented. Considering the relative motion between missile and target, the time-varying uncertainty of missile velocity and the unknown target acceleration were regarded as the disturbance, which is estimated and compensated by EDO. The fast tracking differentiator was introduced to solve the immeasurability problem of the desired line of sight angle rate. Moreover, the domain of sliding mode capturability was introduced to the performance evaluation of guidance law. The simulation experiments of different interception scenarios and different forms of maneuvering target were carried out. The simulation results show that the proposed guidance law has good interception performance and robustness, and it is of less missile acceleration and higher guidance accuracy, which is more helpful for the realization in engineering.