فاصله خطا

In the present work, the performance of True Proportional Navigation (TPN) with different profiles for effective navigation ratio in terms of the relative velocity angle with respect to line-of-sight is investigated due to initial heading errors and target maneuvers. Since an appropriate profile of effective navigation ratio for heading error is almost in contrary with the appropriate profile for maneuvering targets, a variable effective navigation ratio in terms of the relative velocity angle and its rate is introduced. In this way, the miss distance (MD) for the first two peaks of the normalized MD graph versus normalized final time, for example under an effective navigation ratio of 4, is reduced together. The analysis is carried out using normalized equations in polar coordinates for perfect and binomial fifth-order control systems without acceleration limit. Due to practical consideration, the effective navigation ratio is tuned and limited between 3 and 5.

In this paper, miss distance analysis of a modified proportional navigation with lateral acceleration feedback is presented using normalized equations of adjoint method in the presence of radome effect and seeker noise. In this analysis, linear model is utilized. Also, radome error slope is assumed to be constant. Approximate formulas of miss distance are presented for second-order control system with two real distinct poles, using obtained nondimensional miss distance curves. These curves and formulas are useful for guidance system analysis and preliminary design. Moreover, using the approximate formulas, the guidance gain and time constant can be designed as variables to enhance the stability and performance of the guidance and control system in low and high altitudes.

In this paper, the effect of non-minimum phase control system on the miss distance of a class of one-dimensional guidance law due to initial heading error and also constant and time-varying target maneuvers (including ramp and sinusoidal) is presented. The guidance and control system dynamics is modeled by a fifth-order transfer function with acceleration limit and radome effect. More precisely, each of the seeker and noise filter is taken as a first-order transfer function. The control system and airframe are modeled by a third-order non-minimum phase one. Miss distance analysis is made by using normalized governing equations and plotting normalized curves, resulting in useful curves for parametric study specially the effect of zero location of airframe dynamics for analysis, modification, and design of a class of linear and nonlinear guidance laws.

In this paper، the linearized 2-D equations of proportional navigation guidance (PNG) are normalized in order to carry out the missdistance analysis considering acceleration saturation and radome effect. The control system dynamics is modeled using the first-order transfer function. To reduce the missdistance due to radome effect، the body rate feedback is added to the commanded acceleration in the analysis. Using this approach، useful normalized curves are obtained for parametric study and modification of PNG. Finally، the normalized equations of a modified PNG، having nonlinear terms consisting of line-of-sight rate with different powers، are derived.