Abstract: The effect of inertia of the guidance systems on the closed form solution to guidance problems is investigated and an analytical solution is obtained. It indicates that the solution without considering the inertia is only a special form for long Line-of-Sight, However, this solution is also available to short Line of-Sight. The unstability of angular rate of the Line of-Sight and the reason for miss-distances are also expressed by this solution. The results can be used to analyse the effect of the proportional navigation coefficient and the inertia of guidance system on miss - distances.

Key words: guidance, closed form solution to guidance problem, proportional navigation, miss distance