Guidance algorithm selection based on line of sight angle in guidance systems

Usually guidance systems based on the Line of sight (LOS) angle are described by an ordinary differential equation. Guidance algorithms attempt to nullify the LOS rate while the closed loop stabilities guaranteed. Using the nonlinear system stability theory, the guidance law is designed such that the LOS angle would be a constant. Hence the guidance commands are applied to the vehicle actuators in term of some lateral accelerations. In practical implementation of the guidance law, the accelerations must be translated into the vehicle angles. Therefore proportional navigation (PN) guidance law firstly investigated in this paper. Then the PN guidance law is corrected such that the vehicle angle would be a constant while the closed loop stability is guaranteed and less computational effort is used. A numerical example is provided to show the efficiency of proposed procedures.