Influence of seeker measurement errors on precision of the optimal guidance law with impact angle constraint

To study the guidance precision of the optimal guidance law (OGL) with impact angle constraint (IAC) induced by seeker measurement errors, an extended OGL with IAC was introduced into the guidance system. Considering the LOS angle-rate zero-position-error of seeker, zero position error (ZPE) of LOS and seeker angular noise, the guidance precision was performed by using the non-dimensional technique and method of adjoints. Study results show that the miss distance induced by ZPE of LOS angle approaches to zero, and the terminal impact angle error induced by ZPE of LOS approaches to steady values if the missile non-dimensional guidance time is larger than 15; large navigation coefficients are benefit to reduce the effect of LOS angle-rate ZPE on guidance system; the miss distance and terminal impact angle error induced by seeker angular noise increase with the increase of the navigation coefficients. To increase the guidance precision, it is better to increase the response time of missile seekers than to increase the response time of missile autopilots.