Comments on "True proportional navigation with maneuvering target"

In the paper by D. Ghose (Jan. 1994), the author rightly pointed about the unrealistic target maneuvers considered by C.D. Yang et al. (1989) and by P.J. Yuan (1992) and he carried out the analysis for the target maneuver which is inversely proportional to the relative velocity component normal to the line of sight (LOs). This target maneuver is somewhat near to a realistic one, but still it suffers from one drawback. With this maneuver, the target pulls a high acceleration when the interceptor is on a collision course and a negligible acceleration when the LOS rate is already high. The author discusses realistic true proportional navigation (RTPN) because conventional true proportional navigation (TPN) is not used in actual scenario. The result is a third-order nonlinear equation.