In the past few decades, designing homing guidance laws for tactical guided missiles has been an area of intense research owing to the stringent perfor- mance requirement. Although the classical (constant gain) pure proportional navigation (PPN) guidance law provides satisfactory performance, there exist situations such as the maneuvering target scenario where the simple PPN may not o er satisfactory performance. To this end, a 3-dimensional state depen- dent Riccati equation 3-dimensional nonlinear PPN guidance law for missiles to against maneuvering targets is proposed in this work. To have a simple equations of motion used for describing the relative dynamics between missile and target, a 3-dimensional line-of-sight xed coordinate system is adopted. This makes possible the real-time computation of the state dependent Riccati equation nonlinear guidance law for missiles to against maneuvering targets, then a nite time Lyapunov exponent is used to de ne the timescale gap for evaluating the performance of the guidance law. For completeness, both non- maneuvering and maneuvering target will be considered.