Field-of-view constrained three-dimensional impact time and angle guidance via dual-step joint approach

A field-of-view constrained three-dimensional impact time and angle guidance law is proposed in this paper. The challenging guidance problem formulated in the three-dimensional scenario while considering multiple constraints is addressed via the proposed dual-step joint approach. The guidance process consists of two steps. In the first step, the equiangular spiral shaping trajectory is conducted to achieve the desired impact time while adhering to the field-of-view constraint. In the second step, the field-of-view constrained impact angle guidance law is derived by employing the error dynamics and auxiliary function. The switching point between the guidance laws in the two steps needs to be determined quickly and accurately. The guidance parameters can be obtained efficiently by employing the three-point secant method, solving a nonlinear implicit equality with 2–3 iterations. Numerical simulation examples are provided to verify the performance of the proposed guidance law on different guidance constraints.