Capture region for a realistic TPN guidance law

This work obtains the capture region for a realistic true proportional navigation (RTPN) guidance law against a nonmaneuvering target where the assumption of constant closing velocity used in the guidance law is relaxed. This is a realistic departure from earlier treatments of TPN. A capture equation is obtained and a qualitative study carried out for both zero and non-zero miss distances. The results are shown to be significantly different from those of earlier studies, showing a degradation in the performance of the guidance law in the form of reduced capture region. An example problem is computationally solved to obtain the exact capture region for various values of miss distances