Trajectory Shaping Using Line-of-Sight Angle Profile

Due to monotonic variation in line-of-sight angle, proportional navigation based trajectory shaping guidance laws can achieve limited approach angles against a stationary target. Addressing this, a guidance law that governs the line-of-sight angle as a quadratic polynomial of range is proposed. Satisfying boundary conditions on the line-of-sight angle at the launch and the impact point, the two unknown coefficients of the polynomial are obtained. The third coefficient is obtained by imposing an additional line-of-sight angle constraint at a prespecified range separation. Simulation results show the efficacy of the proposed method. With an explicit relation between the range and the line-of-sight angle, the proposed guidance method brings greater spatial control over the trajectory which can be used for imposing additional constraints as terrain/obstacle avoidance.