Is capture region of 3D ideal proportional navigation (IPN) also the biggest

It is well known that 2D IPN's capture region is bigger than that of any other existing PN. We now present our research results concerning whether this is also true for 3D IPN. In the full paper, we explain our research results in detail; in this abstract, we just add some pertinent remarks to listing the three topics of explanation: (1) the establishment of missile-target relative motion equations, (2) the unified description of 3D PN laws, (3) the analysis of 3D IPN's capture region; in topic 1, eqs.(6), (7), and (8) in the full paper, taken from the open literature, form the system of missile-target relative motion equations; in topic 2, we utilize Ref. 3, written by Yang and Yang, to describe the command accelerations of a missile under various PN laws; in topic 3, we introduce the well-known transformation of 'capture region' into 'capture length'; also in topic 3, we derive eq.(28) in the full paper needed for calculating the capture length of IPN and give eqs.(29) and (30) in the full paper, taken from the open literature and needed for calculating respectively the capture lengths of RTPN and TPN; still in topic 3, the comparison of eqs.(28), (29) and (30) shows preliminarily that the capture length or capture region of IPN is the biggest among the three capture lengths or capture regions of IPN, RTPN, and TPN. The formulas for calculating capture lengths of other 3D PNs need to be derived before the question of whether the capture region of 3D IPN is the biggest can be finally answered.